Orthopedics

Men who continuously participate in high-impact activities, such as jogging and tennis, during adolescence and young adulthood have greater hip and lumbar spine bone mineral density than those who do not take part in such activities, according to a study published in American Journal of Men’s Health.

In a cross-sectional study, researchers analyzed the physical histories of 203 healthy, physically active males ages 30 to 65. Participants’ sports and exercise histories varied in the type and level of activity and the length of time spent doing various physical activities.

Exercise-associated bone loading scores were calculated based on the biomechanical ground-reaction forces of the patients’ past and current physical activities. Current bone mineral density (BMD) was measured using dual-energy x-ray absorptiometry. In addition, participants were grouped based on current participation in a high-impact activity, resistance training, both, or neither.

Bone loading during adolescence and young adulthood were significant, positive predictors of BMD of the whole body, total hip, and lumbar spine, adjusting for lean body mass and/or age Individuals who currently participate in a high-impact activity had greater lumbar spine BMD than nonparticipants. Men who continuously participated in a high-impact activity had greater hip and lumbar spine BMD than those who did not.

Men who continuously participate in high-impact activities, such as jogging and tennis, during adolescence and young adulthood have greater hip and lumbar spine bone mineral density than those who do not take part in such activities, according to a study published in American Journal of Men’s Health.

In a cross-sectional study, researchers analyzed the physical histories of 203 healthy, physically active males ages 30 to 65. Participants’ sports and exercise histories varied in the type and level of activity and the length of time spent doing various physical activities.

Exercise-associated bone loading scores were calculated based on the biomechanical ground-reaction forces of the patients’ past and current physical activities. Current bone mineral density (BMD) was measured using dual-energy x-ray absorptiometry. In addition, participants were grouped based on current participation in a high-impact activity, resistance training, both, or neither.

Bone loading during adolescence and young adulthood were significant, positive predictors of BMD of the whole body, total hip, and lumbar spine, adjusting for lean body mass and/or age Individuals who currently participate in a high-impact activity had greater lumbar spine BMD than nonparticipants. Men who continuously participated in a high-impact activity had greater hip and lumbar spine BMD than those who did not.

Men who continuously participate in high-impact activities, such as jogging and tennis, during adolescence and young adulthood have greater hip and lumbar spine bone mineral density than those who do not take part in such activities, according to a study published in American Journal of Men’s Health.

In a cross-sectional study, researchers analyzed the physical histories of 203 healthy, physically active males ages 30 to 65. Participants’ sports and exercise histories varied in the type and level of activity and the length of time spent doing various physical activities.

Exercise-associated bone loading scores were calculated based on the biomechanical ground-reaction forces of the patients’ past and current physical activities. Current bone mineral density (BMD) was measured using dual-energy x-ray absorptiometry. In addition, participants were grouped based on current participation in a high-impact activity, resistance training, both, or neither.

Bone loading during adolescence and young adulthood were significant, positive predictors of BMD of the whole body, total hip, and lumbar spine, adjusting for lean body mass and/or age Individuals who currently participate in a high-impact activity had greater lumbar spine BMD than nonparticipants. Men who continuously participated in a high-impact activity had greater hip and lumbar spine BMD than those who did not.

On July 9, 2015, the Centers for Medicare and Medicaid Services announced the Comprehensive Care for Joint Replacement model, which aims to improve coordination of the whole episode of care for total hip and knee replacement.¹ At stake is the fact that hip and knee replacements are the most common inpatient procedures among Medicare beneficiaries, costing over $7 billion in 2014¹ and projected to grow to $50 billion by 2030.² Under Medicare’s new initiative, hospitals and physicians are held accountable for the quality and cost of care delivered from the time of surgery through 90 days after discharge. For the first time in the history of our profession, large-scale reimbursement is based on outcomes and value rather than fee-for-service. As a result, a hospital can either earn a reward or be held liable for added expenses related to events such as prolonged hospitalization, readmissions, and complications.

How can we optimize outcomes for total joint arthroplasty (TJA) patients in this era of Medicare (r)evolution? A good outcome starts with good patient selection. Numerous studies have been published on patient-related risk factors for postoperative TJA complications including obesity, congestive heart failure, lung disease, and depression.^3,4 The risks and benefits of TJA should be carefully weighed in high-risk patients and surgery delayed until appropriate medical optimization has been achieved. Following the famous saying, “Good surgeons know how to operate, better surgeons know when to operate, and the best surgeons know when not to operate,” one cannot overemphasize the need for an objective assessment of the likelihood of patient outcome weighed against patient risk factors.

Moderating patient expectation is another crucial component given the changing demographics of our country. Patients seeking TJA today are younger, more obese, and better educated; live longer; and have higher expectations.⁵ Unrealistic expectations can have a profound impact on surgical outcomes, leading to frustration, dissatisfaction, and unnecessary resource utilization. For example, despite alleviating pain and restoring function in a severely degenerative joint, TJA does not necessarily translate to weight loss. There is currently conflicting evidence on this topic,^6-8 and the expectation of weight loss after TJA cannot be supported. There is also a paucity of data regarding return to athletic activity after TJA and the effect of athletic activity on TJA survivorship.⁹ Communication and transparency are needed to moderate unrealistic expectations before surgery, outlining clear and achievable goals.

Clinical pathways for TJA have seen tremendous improvements in the past decade with the advent of multimodal analgesia, rapid recovery programs, use of spinal and regional anesthesia, and evidence-based guidelines for prevention of venous thromboembolic disease. Adequate pain control is critical to recovery. In a prospective, randomized controlled trial, Lamplot and colleagues¹⁰ showed that the use of multimodal analgesia correlated with improved pain scores, decreased narcotic usage, faster functional recovery, and higher patient satisfaction after total knee arthroplasty (TKA). In another study, Quack and colleagues¹¹ performed a systematic review of the literature on fast-track rehabilitation and found that it reduced both inpatient length of stay and costs after TKA. With respect to anesthetic choice, Pugely and colleagues¹² reviewed a national database of 14,052 cases of primary TKA and found that patients with multiple comorbidities were at higher risk of complications after general anesthesia when compared with spinal anesthesia. We should continue to invest in safer and more effective modalities for pain control and functional recovery.

Last but not least, in today’s era of Medicare’s Comprehensive Care for Joint Replacement, the role of low-volume orthopedic surgeons performing TJA deserves special mention. Over the next few years, we could likely see a decline in the role of low-volume surgeons in favor of high-volume surgeons. While most orthopedic surgeons are comfortable doing primary TJA, failed cases and complications are frequently referred to larger centers, which may create frustration among patients owing to fragmentation of care. The economic pressures related to bundled payments could further influence this transition. Given the lack of a widespread, long-standing national joint registry, the incidence of failed TJA performed by low-volume orthopedic surgeons compared with high-volume orthopedic surgeons is unknown. However, multiple studies have shown surgeon volume to be associated with lower rates of complication, mortality, readmission, reoperation, and discharge to postacute facilities.^13-16 As hospitals assume further financial risk, considerable data on physician performance will undoubtedly be gathered and leveraged. Time and data will determine the value of this transition of care.

Today, more than ever, we are challenged to provide efficient, high-quality, patient-centered care. As our nation grapples with reforming a broken health care system, initiatives like the Comprehensive Care for Joint Replacement will continue to emerge in the future. Orthopedic surgeons are the gatekeepers of the system and therefore hold significant responsibility to patients and society. Ensuring good outcomes should be a top priority not just from a financial standpoint, but as a moral obligation. We shall continue to be leaders in the face of challenges, using innovation and integrity to produce the best results and advance our profession.

On July 9, 2015, the Centers for Medicare and Medicaid Services announced the Comprehensive Care for Joint Replacement model, which aims to improve coordination of the whole episode of care for total hip and knee replacement.¹ At stake is the fact that hip and knee replacements are the most common inpatient procedures among Medicare beneficiaries, costing over $7 billion in 2014¹ and projected to grow to $50 billion by 2030.² Under Medicare’s new initiative, hospitals and physicians are held accountable for the quality and cost of care delivered from the time of surgery through 90 days after discharge. For the first time in the history of our profession, large-scale reimbursement is based on outcomes and value rather than fee-for-service. As a result, a hospital can either earn a reward or be held liable for added expenses related to events such as prolonged hospitalization, readmissions, and complications.

How can we optimize outcomes for total joint arthroplasty (TJA) patients in this era of Medicare (r)evolution? A good outcome starts with good patient selection. Numerous studies have been published on patient-related risk factors for postoperative TJA complications including obesity, congestive heart failure, lung disease, and depression.^3,4 The risks and benefits of TJA should be carefully weighed in high-risk patients and surgery delayed until appropriate medical optimization has been achieved. Following the famous saying, “Good surgeons know how to operate, better surgeons know when to operate, and the best surgeons know when not to operate,” one cannot overemphasize the need for an objective assessment of the likelihood of patient outcome weighed against patient risk factors.

Moderating patient expectation is another crucial component given the changing demographics of our country. Patients seeking TJA today are younger, more obese, and better educated; live longer; and have higher expectations.⁵ Unrealistic expectations can have a profound impact on surgical outcomes, leading to frustration, dissatisfaction, and unnecessary resource utilization. For example, despite alleviating pain and restoring function in a severely degenerative joint, TJA does not necessarily translate to weight loss. There is currently conflicting evidence on this topic,^6-8 and the expectation of weight loss after TJA cannot be supported. There is also a paucity of data regarding return to athletic activity after TJA and the effect of athletic activity on TJA survivorship.⁹ Communication and transparency are needed to moderate unrealistic expectations before surgery, outlining clear and achievable goals.

Clinical pathways for TJA have seen tremendous improvements in the past decade with the advent of multimodal analgesia, rapid recovery programs, use of spinal and regional anesthesia, and evidence-based guidelines for prevention of venous thromboembolic disease. Adequate pain control is critical to recovery. In a prospective, randomized controlled trial, Lamplot and colleagues¹⁰ showed that the use of multimodal analgesia correlated with improved pain scores, decreased narcotic usage, faster functional recovery, and higher patient satisfaction after total knee arthroplasty (TKA). In another study, Quack and colleagues¹¹ performed a systematic review of the literature on fast-track rehabilitation and found that it reduced both inpatient length of stay and costs after TKA. With respect to anesthetic choice, Pugely and colleagues¹² reviewed a national database of 14,052 cases of primary TKA and found that patients with multiple comorbidities were at higher risk of complications after general anesthesia when compared with spinal anesthesia. We should continue to invest in safer and more effective modalities for pain control and functional recovery.

Last but not least, in today’s era of Medicare’s Comprehensive Care for Joint Replacement, the role of low-volume orthopedic surgeons performing TJA deserves special mention. Over the next few years, we could likely see a decline in the role of low-volume surgeons in favor of high-volume surgeons. While most orthopedic surgeons are comfortable doing primary TJA, failed cases and complications are frequently referred to larger centers, which may create frustration among patients owing to fragmentation of care. The economic pressures related to bundled payments could further influence this transition. Given the lack of a widespread, long-standing national joint registry, the incidence of failed TJA performed by low-volume orthopedic surgeons compared with high-volume orthopedic surgeons is unknown. However, multiple studies have shown surgeon volume to be associated with lower rates of complication, mortality, readmission, reoperation, and discharge to postacute facilities.^13-16 As hospitals assume further financial risk, considerable data on physician performance will undoubtedly be gathered and leveraged. Time and data will determine the value of this transition of care.

Today, more than ever, we are challenged to provide efficient, high-quality, patient-centered care. As our nation grapples with reforming a broken health care system, initiatives like the Comprehensive Care for Joint Replacement will continue to emerge in the future. Orthopedic surgeons are the gatekeepers of the system and therefore hold significant responsibility to patients and society. Ensuring good outcomes should be a top priority not just from a financial standpoint, but as a moral obligation. We shall continue to be leaders in the face of challenges, using innovation and integrity to produce the best results and advance our profession.

On July 9, 2015, the Centers for Medicare and Medicaid Services announced the Comprehensive Care for Joint Replacement model, which aims to improve coordination of the whole episode of care for total hip and knee replacement.¹ At stake is the fact that hip and knee replacements are the most common inpatient procedures among Medicare beneficiaries, costing over $7 billion in 2014¹ and projected to grow to $50 billion by 2030.² Under Medicare’s new initiative, hospitals and physicians are held accountable for the quality and cost of care delivered from the time of surgery through 90 days after discharge. For the first time in the history of our profession, large-scale reimbursement is based on outcomes and value rather than fee-for-service. As a result, a hospital can either earn a reward or be held liable for added expenses related to events such as prolonged hospitalization, readmissions, and complications.

How can we optimize outcomes for total joint arthroplasty (TJA) patients in this era of Medicare (r)evolution? A good outcome starts with good patient selection. Numerous studies have been published on patient-related risk factors for postoperative TJA complications including obesity, congestive heart failure, lung disease, and depression.^3,4 The risks and benefits of TJA should be carefully weighed in high-risk patients and surgery delayed until appropriate medical optimization has been achieved. Following the famous saying, “Good surgeons know how to operate, better surgeons know when to operate, and the best surgeons know when not to operate,” one cannot overemphasize the need for an objective assessment of the likelihood of patient outcome weighed against patient risk factors.

Moderating patient expectation is another crucial component given the changing demographics of our country. Patients seeking TJA today are younger, more obese, and better educated; live longer; and have higher expectations.⁵ Unrealistic expectations can have a profound impact on surgical outcomes, leading to frustration, dissatisfaction, and unnecessary resource utilization. For example, despite alleviating pain and restoring function in a severely degenerative joint, TJA does not necessarily translate to weight loss. There is currently conflicting evidence on this topic,^6-8 and the expectation of weight loss after TJA cannot be supported. There is also a paucity of data regarding return to athletic activity after TJA and the effect of athletic activity on TJA survivorship.⁹ Communication and transparency are needed to moderate unrealistic expectations before surgery, outlining clear and achievable goals.

Clinical pathways for TJA have seen tremendous improvements in the past decade with the advent of multimodal analgesia, rapid recovery programs, use of spinal and regional anesthesia, and evidence-based guidelines for prevention of venous thromboembolic disease. Adequate pain control is critical to recovery. In a prospective, randomized controlled trial, Lamplot and colleagues¹⁰ showed that the use of multimodal analgesia correlated with improved pain scores, decreased narcotic usage, faster functional recovery, and higher patient satisfaction after total knee arthroplasty (TKA). In another study, Quack and colleagues¹¹ performed a systematic review of the literature on fast-track rehabilitation and found that it reduced both inpatient length of stay and costs after TKA. With respect to anesthetic choice, Pugely and colleagues¹² reviewed a national database of 14,052 cases of primary TKA and found that patients with multiple comorbidities were at higher risk of complications after general anesthesia when compared with spinal anesthesia. We should continue to invest in safer and more effective modalities for pain control and functional recovery.

Last but not least, in today’s era of Medicare’s Comprehensive Care for Joint Replacement, the role of low-volume orthopedic surgeons performing TJA deserves special mention. Over the next few years, we could likely see a decline in the role of low-volume surgeons in favor of high-volume surgeons. While most orthopedic surgeons are comfortable doing primary TJA, failed cases and complications are frequently referred to larger centers, which may create frustration among patients owing to fragmentation of care. The economic pressures related to bundled payments could further influence this transition. Given the lack of a widespread, long-standing national joint registry, the incidence of failed TJA performed by low-volume orthopedic surgeons compared with high-volume orthopedic surgeons is unknown. However, multiple studies have shown surgeon volume to be associated with lower rates of complication, mortality, readmission, reoperation, and discharge to postacute facilities.^13-16 As hospitals assume further financial risk, considerable data on physician performance will undoubtedly be gathered and leveraged. Time and data will determine the value of this transition of care.

Today, more than ever, we are challenged to provide efficient, high-quality, patient-centered care. As our nation grapples with reforming a broken health care system, initiatives like the Comprehensive Care for Joint Replacement will continue to emerge in the future. Orthopedic surgeons are the gatekeepers of the system and therefore hold significant responsibility to patients and society. Ensuring good outcomes should be a top priority not just from a financial standpoint, but as a moral obligation. We shall continue to be leaders in the face of challenges, using innovation and integrity to produce the best results and advance our profession.

Irreducible ankle fracture-dislocation secondary to tibialis posterior tendon interposition is a rare but documented complication most commonly associated with Lauge-Hansen classification pronation–external rotation ankle fractures.^1-4 Entrapment of the tibialis posterior tendon has been documented in the syndesmosis (tibiotalar joint)^1,2,4 and within a medial malleolus fracture.5 To our knowledge, however, there are no case reports of entrapment of the tibialis posterior tendon in a posterior malleolus fracture.

Ankle arthroscopy performed at time of fracture fixation is gaining in popularity because of its enhanced ability to document and treat intra-articular pathology associated with the initial injury.^6,7 In addition, percutaneous fixation of a posterior malleolar fragment with arthroscopic assessment of the articular surface reduction may be valuable, as evaluation of tibial plafond fracture reduction by plain radiographs and fluoroscopy has proved to have limitations.^8,9

In this article, we present the case of a patient who underwent attempted arthroscopy-assisted reduction of the posterior malleolus with entrapment of the tibialis posterior tendon within the posterior malleolar fracture fragment. The tendon was irreducible with arthroscopic techniques, necessitating posteromedial incision and subsequent open reduction of the incarcerated structure. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 67-year-old man slipped and fell on ice while jogging and subsequently presented to the emergency department with a closed bimalleolar ankle fracture-dislocation. Plain radiography (Figure 1) and computed tomography (CT) showed an oblique lateral malleolar fracture and a large posterior malleolar fracture. Further examination of the CT scan revealed entrapment of the tibialis posterior tendon within the posterior malleolar fracture (Figure 2).

Two days after injury, the patient was taken to the operating room for ankle arthroscopy with planned extrication of the entrapped tibialis posterior tendon and possible arthroscopy-assisted percutaneous fixation of the posterior malleolar fracture and open fixation of the distal fibula fracture. Diagnostic arthroscopy revealed a deltoid ligament injury (Figure 3) and a loose piece of articular cartilage (~1 cm in diameter), which was excised. No donor site for this cartilage fragment was identified with further arthroscopic evaluation. During arthroscopic examination, the tibialis posterior tendon was visualized within the joint, incarcerated within the posterior malleolar fracture (Figure 4). Attempts to release the tibialis posterior tendon from the fracture site using arthroscopic instruments and closed reduction techniques were unsuccessful, both with and without noninvasive skeletal traction applied to the ankle.

After multiple unsuccessful attempts to extract the tibialis posterior tendon arthroscopically, traction was removed, and a separate incision was made over the posteromedial aspect of the ankle. The tibialis posterior tendon was identified within the fracture site and was removed using an angled clamp (Figure 5). The fracture was reduced and held provisionally with a large tenaculum clamp. Two anterior-to-posterior, partially threaded cannulated screws were placed for fixation after adequate fracture reduction was confirmed on fluoroscopy. As a medial incision was made to extract the tibialis posterior tendon, the joint could not retain arthroscopic fluid, and visualization of the posterior fracture fragment after tendon removal was difficult. Therefore, arthroscopy-assisted reduction could not be completed.

Next, the lateral malleolus was open-reduced, and fixation was achieved using a standard interfragmentary lag screw and a lateral neutralization plate technique (Figure 6). After surgery, the patient was immobilized in a posterior splint with side gussets. Two weeks later, the incisions were healing well, and the tibialis posterior tendon was functioning normally. The sutures were removed, the patient was transitioned to a controlled ankle movement (CAM) boot, and ankle and subtalar range-of-motion exercises were initiated. The patient remained non-weight-bearing for 6 weeks. Radiographs 6 weeks after surgery showed healing fractures with stable hardware (Figure 7). The patient demonstrated 5/5 strength of the tibialis posterior tendon without subluxation or dislocation. There was no tenderness to palpation over the fracture sites or tibialis posterior tendon. The patient began progressive weight-bearing in a CAM boot and physical therapy for range of motion and strengthening.

Discussion

Tibialis posterior tendon injuries—including rupture, dislocation, and entrapment—are well-described complications of ankle injuries.^1,2,5,10 Most commonly, the tibialis posterior tendon has been reported to cause a mechanical block to reduction in lateral subtalar dislocations.^11-13 In addition, there are case reports of isolated traumatic dislocations of the tibialis posterior tendon without rupture, requiring operative stabilization and retinaculum repair with or without deepening of the posterior groove.^14,15

Posterior malleolar ankle fractures remain controversial, with respect to both need for fixation and fixation methods. Although multiple investigators have advocated operative treatment for such fractures that exceed 25% to 33% of the anteroposterior dimension of the tibial plafond, there are no conclusive studies or evidence-based guidelines for treating these fractures.^16,17 Anatomical reduction and plating are important to restore articular congruity and increase syndesmotic stability; recent studies have demonstrated that fixation of posterior malleolar fractures provides more syndesmotic stability than trans-syndesmotic screws do.^18,19 Indirect reduction of the posterior malleolar fragment after fibula fixation is often accepted as adequate. Whether indirect or direct reduction is attempted, close attention should be given to plain radiographs after attempted reduction, and consideration should be given to possible soft-tissue or bony interposition if malreduction is identified.^16,17 Plain radiographs are unreliable in assessing posterior malleolar fragment size as well as amount of comminution and impaction.^8,9 Therefore, an arthroscopy-assisted approach coupled with percutaneous fixation may provide more reliable fracture reduction over indirect fracture reduction with fibular fixation, with less dissection than a formal posterolateral approach with posterior plating.

Not all ankle fractures require CT. However, for posterior malleolus fractures thought to require fixation, preoperative CT may help in determining if percutaneous fixation with or without arthroscopic guidance is a feasible treatment option. Ideally, percutaneous reduction can obviate the need for a larger posterolateral incision and buttress plate and, with arthroscopic assistance, may be superior to indirect reduction with fluoroscopy.

In our patient’s case, arthroscopic assistance facilitated diagnosis of an entrapped structure that would have been difficult to identify, particularly without preoperative CT. It may be difficult to identify imperfect reduction of the posterior malleolus on plain radiographs alone, and arthroscopy-assisted fixation enhances the surgeon’s ability to consider reduction, view incarcerated structures within the joint, and treat articular injuries. We do not routinely use ankle arthroscopy as an adjunct to ankle fracture fixation, but judicious use in select cases can facilitate treatment of intra-articular injuries and facilitate visualization and reduction of posterior malleolar fracture fragments before percutaneous anterior-to-posterior cannulated screw fixation. If an open incision is required, as in the present case, visualization becomes difficult secondary to fluid extravasation. However, we think avoiding the morbidity associated with an open incision is worthwhile for fixation of posterior malleolus fractures.

Conclusion

Close inspection of both preoperative and intraoperative radiographs is required to ensure adequate reduction of a posterior malleolar fragment without soft-tissue or bony interposition in the reduction of ankle fractures. Although not previously reported, posterior tendon entrapment within the posterior malleolus fracture may occur and may require arthroscopic or open techniques to ensure adequate extrication of the tendon to allow for posterior malleolar fracture reduction and fixation. This case report highlights one indication for arthroscopy in the treatment of ankle fractures despite the fact that the tibialis posterior tendon was openly removed. Arthroscopic assistance in acute ankle injuries allows the surgeon to evaluate articular cartilage injuries and ensure there are no interposed structures while checking reduction of the posterior malleolar fracture fragment when present.

Irreducible ankle fracture-dislocation secondary to tibialis posterior tendon interposition is a rare but documented complication most commonly associated with Lauge-Hansen classification pronation–external rotation ankle fractures.^1-4 Entrapment of the tibialis posterior tendon has been documented in the syndesmosis (tibiotalar joint)^1,2,4 and within a medial malleolus fracture.5 To our knowledge, however, there are no case reports of entrapment of the tibialis posterior tendon in a posterior malleolus fracture.

Ankle arthroscopy performed at time of fracture fixation is gaining in popularity because of its enhanced ability to document and treat intra-articular pathology associated with the initial injury.^6,7 In addition, percutaneous fixation of a posterior malleolar fragment with arthroscopic assessment of the articular surface reduction may be valuable, as evaluation of tibial plafond fracture reduction by plain radiographs and fluoroscopy has proved to have limitations.^8,9

In this article, we present the case of a patient who underwent attempted arthroscopy-assisted reduction of the posterior malleolus with entrapment of the tibialis posterior tendon within the posterior malleolar fracture fragment. The tendon was irreducible with arthroscopic techniques, necessitating posteromedial incision and subsequent open reduction of the incarcerated structure. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 67-year-old man slipped and fell on ice while jogging and subsequently presented to the emergency department with a closed bimalleolar ankle fracture-dislocation. Plain radiography (Figure 1) and computed tomography (CT) showed an oblique lateral malleolar fracture and a large posterior malleolar fracture. Further examination of the CT scan revealed entrapment of the tibialis posterior tendon within the posterior malleolar fracture (Figure 2).

Two days after injury, the patient was taken to the operating room for ankle arthroscopy with planned extrication of the entrapped tibialis posterior tendon and possible arthroscopy-assisted percutaneous fixation of the posterior malleolar fracture and open fixation of the distal fibula fracture. Diagnostic arthroscopy revealed a deltoid ligament injury (Figure 3) and a loose piece of articular cartilage (~1 cm in diameter), which was excised. No donor site for this cartilage fragment was identified with further arthroscopic evaluation. During arthroscopic examination, the tibialis posterior tendon was visualized within the joint, incarcerated within the posterior malleolar fracture (Figure 4). Attempts to release the tibialis posterior tendon from the fracture site using arthroscopic instruments and closed reduction techniques were unsuccessful, both with and without noninvasive skeletal traction applied to the ankle.

After multiple unsuccessful attempts to extract the tibialis posterior tendon arthroscopically, traction was removed, and a separate incision was made over the posteromedial aspect of the ankle. The tibialis posterior tendon was identified within the fracture site and was removed using an angled clamp (Figure 5). The fracture was reduced and held provisionally with a large tenaculum clamp. Two anterior-to-posterior, partially threaded cannulated screws were placed for fixation after adequate fracture reduction was confirmed on fluoroscopy. As a medial incision was made to extract the tibialis posterior tendon, the joint could not retain arthroscopic fluid, and visualization of the posterior fracture fragment after tendon removal was difficult. Therefore, arthroscopy-assisted reduction could not be completed.

Next, the lateral malleolus was open-reduced, and fixation was achieved using a standard interfragmentary lag screw and a lateral neutralization plate technique (Figure 6). After surgery, the patient was immobilized in a posterior splint with side gussets. Two weeks later, the incisions were healing well, and the tibialis posterior tendon was functioning normally. The sutures were removed, the patient was transitioned to a controlled ankle movement (CAM) boot, and ankle and subtalar range-of-motion exercises were initiated. The patient remained non-weight-bearing for 6 weeks. Radiographs 6 weeks after surgery showed healing fractures with stable hardware (Figure 7). The patient demonstrated 5/5 strength of the tibialis posterior tendon without subluxation or dislocation. There was no tenderness to palpation over the fracture sites or tibialis posterior tendon. The patient began progressive weight-bearing in a CAM boot and physical therapy for range of motion and strengthening.

Discussion

Tibialis posterior tendon injuries—including rupture, dislocation, and entrapment—are well-described complications of ankle injuries.^1,2,5,10 Most commonly, the tibialis posterior tendon has been reported to cause a mechanical block to reduction in lateral subtalar dislocations.^11-13 In addition, there are case reports of isolated traumatic dislocations of the tibialis posterior tendon without rupture, requiring operative stabilization and retinaculum repair with or without deepening of the posterior groove.^14,15

Posterior malleolar ankle fractures remain controversial, with respect to both need for fixation and fixation methods. Although multiple investigators have advocated operative treatment for such fractures that exceed 25% to 33% of the anteroposterior dimension of the tibial plafond, there are no conclusive studies or evidence-based guidelines for treating these fractures.^16,17 Anatomical reduction and plating are important to restore articular congruity and increase syndesmotic stability; recent studies have demonstrated that fixation of posterior malleolar fractures provides more syndesmotic stability than trans-syndesmotic screws do.^18,19 Indirect reduction of the posterior malleolar fragment after fibula fixation is often accepted as adequate. Whether indirect or direct reduction is attempted, close attention should be given to plain radiographs after attempted reduction, and consideration should be given to possible soft-tissue or bony interposition if malreduction is identified.^16,17 Plain radiographs are unreliable in assessing posterior malleolar fragment size as well as amount of comminution and impaction.^8,9 Therefore, an arthroscopy-assisted approach coupled with percutaneous fixation may provide more reliable fracture reduction over indirect fracture reduction with fibular fixation, with less dissection than a formal posterolateral approach with posterior plating.

Not all ankle fractures require CT. However, for posterior malleolus fractures thought to require fixation, preoperative CT may help in determining if percutaneous fixation with or without arthroscopic guidance is a feasible treatment option. Ideally, percutaneous reduction can obviate the need for a larger posterolateral incision and buttress plate and, with arthroscopic assistance, may be superior to indirect reduction with fluoroscopy.

In our patient’s case, arthroscopic assistance facilitated diagnosis of an entrapped structure that would have been difficult to identify, particularly without preoperative CT. It may be difficult to identify imperfect reduction of the posterior malleolus on plain radiographs alone, and arthroscopy-assisted fixation enhances the surgeon’s ability to consider reduction, view incarcerated structures within the joint, and treat articular injuries. We do not routinely use ankle arthroscopy as an adjunct to ankle fracture fixation, but judicious use in select cases can facilitate treatment of intra-articular injuries and facilitate visualization and reduction of posterior malleolar fracture fragments before percutaneous anterior-to-posterior cannulated screw fixation. If an open incision is required, as in the present case, visualization becomes difficult secondary to fluid extravasation. However, we think avoiding the morbidity associated with an open incision is worthwhile for fixation of posterior malleolus fractures.

Conclusion

Close inspection of both preoperative and intraoperative radiographs is required to ensure adequate reduction of a posterior malleolar fragment without soft-tissue or bony interposition in the reduction of ankle fractures. Although not previously reported, posterior tendon entrapment within the posterior malleolus fracture may occur and may require arthroscopic or open techniques to ensure adequate extrication of the tendon to allow for posterior malleolar fracture reduction and fixation. This case report highlights one indication for arthroscopy in the treatment of ankle fractures despite the fact that the tibialis posterior tendon was openly removed. Arthroscopic assistance in acute ankle injuries allows the surgeon to evaluate articular cartilage injuries and ensure there are no interposed structures while checking reduction of the posterior malleolar fracture fragment when present.

Irreducible ankle fracture-dislocation secondary to tibialis posterior tendon interposition is a rare but documented complication most commonly associated with Lauge-Hansen classification pronation–external rotation ankle fractures.^1-4 Entrapment of the tibialis posterior tendon has been documented in the syndesmosis (tibiotalar joint)^1,2,4 and within a medial malleolus fracture.5 To our knowledge, however, there are no case reports of entrapment of the tibialis posterior tendon in a posterior malleolus fracture.

Ankle arthroscopy performed at time of fracture fixation is gaining in popularity because of its enhanced ability to document and treat intra-articular pathology associated with the initial injury.^6,7 In addition, percutaneous fixation of a posterior malleolar fragment with arthroscopic assessment of the articular surface reduction may be valuable, as evaluation of tibial plafond fracture reduction by plain radiographs and fluoroscopy has proved to have limitations.^8,9

In this article, we present the case of a patient who underwent attempted arthroscopy-assisted reduction of the posterior malleolus with entrapment of the tibialis posterior tendon within the posterior malleolar fracture fragment. The tendon was irreducible with arthroscopic techniques, necessitating posteromedial incision and subsequent open reduction of the incarcerated structure. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 67-year-old man slipped and fell on ice while jogging and subsequently presented to the emergency department with a closed bimalleolar ankle fracture-dislocation. Plain radiography (Figure 1) and computed tomography (CT) showed an oblique lateral malleolar fracture and a large posterior malleolar fracture. Further examination of the CT scan revealed entrapment of the tibialis posterior tendon within the posterior malleolar fracture (Figure 2).

Two days after injury, the patient was taken to the operating room for ankle arthroscopy with planned extrication of the entrapped tibialis posterior tendon and possible arthroscopy-assisted percutaneous fixation of the posterior malleolar fracture and open fixation of the distal fibula fracture. Diagnostic arthroscopy revealed a deltoid ligament injury (Figure 3) and a loose piece of articular cartilage (~1 cm in diameter), which was excised. No donor site for this cartilage fragment was identified with further arthroscopic evaluation. During arthroscopic examination, the tibialis posterior tendon was visualized within the joint, incarcerated within the posterior malleolar fracture (Figure 4). Attempts to release the tibialis posterior tendon from the fracture site using arthroscopic instruments and closed reduction techniques were unsuccessful, both with and without noninvasive skeletal traction applied to the ankle.

After multiple unsuccessful attempts to extract the tibialis posterior tendon arthroscopically, traction was removed, and a separate incision was made over the posteromedial aspect of the ankle. The tibialis posterior tendon was identified within the fracture site and was removed using an angled clamp (Figure 5). The fracture was reduced and held provisionally with a large tenaculum clamp. Two anterior-to-posterior, partially threaded cannulated screws were placed for fixation after adequate fracture reduction was confirmed on fluoroscopy. As a medial incision was made to extract the tibialis posterior tendon, the joint could not retain arthroscopic fluid, and visualization of the posterior fracture fragment after tendon removal was difficult. Therefore, arthroscopy-assisted reduction could not be completed.

Next, the lateral malleolus was open-reduced, and fixation was achieved using a standard interfragmentary lag screw and a lateral neutralization plate technique (Figure 6). After surgery, the patient was immobilized in a posterior splint with side gussets. Two weeks later, the incisions were healing well, and the tibialis posterior tendon was functioning normally. The sutures were removed, the patient was transitioned to a controlled ankle movement (CAM) boot, and ankle and subtalar range-of-motion exercises were initiated. The patient remained non-weight-bearing for 6 weeks. Radiographs 6 weeks after surgery showed healing fractures with stable hardware (Figure 7). The patient demonstrated 5/5 strength of the tibialis posterior tendon without subluxation or dislocation. There was no tenderness to palpation over the fracture sites or tibialis posterior tendon. The patient began progressive weight-bearing in a CAM boot and physical therapy for range of motion and strengthening.

Discussion

Tibialis posterior tendon injuries—including rupture, dislocation, and entrapment—are well-described complications of ankle injuries.^1,2,5,10 Most commonly, the tibialis posterior tendon has been reported to cause a mechanical block to reduction in lateral subtalar dislocations.^11-13 In addition, there are case reports of isolated traumatic dislocations of the tibialis posterior tendon without rupture, requiring operative stabilization and retinaculum repair with or without deepening of the posterior groove.^14,15

Posterior malleolar ankle fractures remain controversial, with respect to both need for fixation and fixation methods. Although multiple investigators have advocated operative treatment for such fractures that exceed 25% to 33% of the anteroposterior dimension of the tibial plafond, there are no conclusive studies or evidence-based guidelines for treating these fractures.^16,17 Anatomical reduction and plating are important to restore articular congruity and increase syndesmotic stability; recent studies have demonstrated that fixation of posterior malleolar fractures provides more syndesmotic stability than trans-syndesmotic screws do.^18,19 Indirect reduction of the posterior malleolar fragment after fibula fixation is often accepted as adequate. Whether indirect or direct reduction is attempted, close attention should be given to plain radiographs after attempted reduction, and consideration should be given to possible soft-tissue or bony interposition if malreduction is identified.^16,17 Plain radiographs are unreliable in assessing posterior malleolar fragment size as well as amount of comminution and impaction.^8,9 Therefore, an arthroscopy-assisted approach coupled with percutaneous fixation may provide more reliable fracture reduction over indirect fracture reduction with fibular fixation, with less dissection than a formal posterolateral approach with posterior plating.

Not all ankle fractures require CT. However, for posterior malleolus fractures thought to require fixation, preoperative CT may help in determining if percutaneous fixation with or without arthroscopic guidance is a feasible treatment option. Ideally, percutaneous reduction can obviate the need for a larger posterolateral incision and buttress plate and, with arthroscopic assistance, may be superior to indirect reduction with fluoroscopy.

In our patient’s case, arthroscopic assistance facilitated diagnosis of an entrapped structure that would have been difficult to identify, particularly without preoperative CT. It may be difficult to identify imperfect reduction of the posterior malleolus on plain radiographs alone, and arthroscopy-assisted fixation enhances the surgeon’s ability to consider reduction, view incarcerated structures within the joint, and treat articular injuries. We do not routinely use ankle arthroscopy as an adjunct to ankle fracture fixation, but judicious use in select cases can facilitate treatment of intra-articular injuries and facilitate visualization and reduction of posterior malleolar fracture fragments before percutaneous anterior-to-posterior cannulated screw fixation. If an open incision is required, as in the present case, visualization becomes difficult secondary to fluid extravasation. However, we think avoiding the morbidity associated with an open incision is worthwhile for fixation of posterior malleolus fractures.

Conclusion

Close inspection of both preoperative and intraoperative radiographs is required to ensure adequate reduction of a posterior malleolar fragment without soft-tissue or bony interposition in the reduction of ankle fractures. Although not previously reported, posterior tendon entrapment within the posterior malleolus fracture may occur and may require arthroscopic or open techniques to ensure adequate extrication of the tendon to allow for posterior malleolar fracture reduction and fixation. This case report highlights one indication for arthroscopy in the treatment of ankle fractures despite the fact that the tibialis posterior tendon was openly removed. Arthroscopic assistance in acute ankle injuries allows the surgeon to evaluate articular cartilage injuries and ensure there are no interposed structures while checking reduction of the posterior malleolar fracture fragment when present.

Supination-adduction (SAD)-type fractures of the ankle comprise approximately 5% to 20% of ankle fractures.^1-3 As the name describes, this fracture is caused by forceful adduction of the supinated foot. There are 2 stages of the fracture pattern: the injury usually occurs first on the lateral side of the ankle with injury to the soft tissues or a low transverse fracture of the distal fibula. With continued force, in the second stage, the talus causes a shearing of the medial malleolus, creating the vertical shear fracture pattern.^4-7 The vertical shear medial malleolus fracture pattern is the subject of this investigation.

Several techniques have been traditionally recommended for fixation of SAD-type ankle fracture, including: a 2-screw construct without plate fixation, oriented perpendicular to the fracture; and an AG plate construct with variable positioning and numbers of screws for fixation. There have been, however, only 2 published articles about the biomechanical properties of fixation of vertical shear medial malleolar fractures, which reported conflicting results.^8,9 The most recent of these studies argued that one-third tubular plate fixation offers significant mechanical advantage over screw-only fixation, supporting the use of AG plates for fixation of SAD ankle fractures.⁸

An additional design for fixation of medial malleolus fractures has been introduced, consisting of a hook plate (HP) contoured for the medial malleolus. To our knowledge, no studies have investigated HP’s biomechanical properties. Thus, the objective of this study was to investigate and compare the biomechanical properties of 3 constructs for fixation of SAD-ankle fractures: an antiglide (AG) plate, an AG plate with an additional lag-screw across the fracture, and a precontoured HP.

Materials and Methods

Thirty 4th-generation–composite polyurethane models of the left tibia were obtained (Sawbones, Pacific Research Laboratories, Inc.). Largely, our methods accorded with the precedent set by other studies on these fracture types.^8,9

Prior to creation of the fractures, each model was individually evaluated for pretest stiffness by using the slope of the linear portion of the load-displacement curve during offset-axial loading. This demonstrated the baseline elasticity of the models during loading. Assessing pretest stiffness was performed to reduce potential variables in the stiffness of individual models in the analysis of the testing data.

The models were numbered 1 through 30 on the shaft and on the medial malleolus. A custom jig was constructed with a table saw to create identical vertical shear medial malleolar fracture patterns in each model. The jig created the vertical shear SAD fracture described by Lauge-Hansen.⁷ All models were randomly assigned to 1 of 3 groups; each group consisted of 10 models (Figures 1A, 1B).

The 10 specimens in group 1 were fixed with a 5-hole, 3.5-mm, one-third tubular plate (Smith & Nephew) in a traditional AG fashion. The plates were placed at the same location on all tibiae. The proximal hole and the hole closest to the fracture line were filled with 3.5-mm cortical screws, which were long enough to achieve bicortical fixation. No lag screws were placed in this specimen group. In group 2, specimens were fixed with the same plate used in group 1 (Smith & Nephew). In this modified AG (MAG) construct, specimens were fixed identically to group 1 for plate placement and fixation of the 2 proximal screws. In this group, an additional screw was placed perpendicular to the fracture and parallel to the distal tibial articular surface. In both groups (AG and MAG), the plates were not bent before application.

Group 3 consisted of specimens fixed with a 5-hole, precontoured medial malleolar HP (Arthrex). This HP construct was fixed with two 3.5-mm cortical screws long enough to achieve bicortical fixation. The plate also engaged the bone at the tip of the medial malleolus by using 2 sharp prongs. The screws were placed in the most proximal hole and the hole just proximal to the fracture line. No lag screws were placed in the HP construct.

All models were tested in offset-axial loading to replicate a SAD moment similar to previous studies. To test offset-axial loading, a vice held each model identically with a 17º angle from the longitudinal axis (Figure 2). Loading was performed with a material testing system; a material testing system plunger was directed at the inferior articulating cartilage surface of the medial malleolus. The specimens were loaded at a rate of 1 mm/sec until 2 mm of displacement was reached (Figure 3) or catastrophic failure occurred. The raw data analyzed consisted of the initial stiffness of the construct and the overall load-to-failure. The slope of the linear portion of the load-displacement curve of stiffness determined stiffness of the construct.

One-way analysis of variance with post hoc Tukey HSD data analysis was performed to determine if there were statistical differences among the different fixation constructs during load-to-failure. To prevent skewing of results by different values of model elasticity, pretest stiffness was accounted for by calculating a ratio of construct stiffness as a function of pretest model stiffness. Total force-to-failure was the recorded maximum force (in N) to cause failure. A P value of < .05 was set for significance. All data were analyzed using SPSS software (SPSS Version 15.0; SPSS Inc.).

Results

Analysis of pretest stiffness showed no significant difference among models (P = .490). All models failed by a gap of 2 mm at the distal fracture site except for 3 models in the MAG group. These 3 models failed at a much higher load than the remainder of the models and failed by fracture of the models.

The MAG group demonstrated significantly superior stiffness to the 2 other models tested (Figure 4). On average, this group required 753.5 N of force before failure. This was 530 N higher than the HP (P < .05) and 638 N higher than the AG constructs, respectively (P < .05). The HP and AG groups required forces of 223.2 N and 115.5 N for failure, respectively. These numbers were not significant (P= .063).

The absolute construct stiffness and construct stiffness as a function of pretest stiffness of the MAG group was the highest of all groups, 271.7 N/mm and 57.2%, respectively (Figure 5). These numbers showed significance when compared with the values of the HP group (P < .05 for both) and the AG group (P < .05 for both). The average stiffness of the HP group was 159.7 N/mm, which was 36.8% of pretest stiffness.

The AG group had the lowest construct stiffness and percent of pretest stiffness (128.1 N/mm and 29.6%). The HP and AG groups were not statistically different in these comparisons, P = .350 for construct stiffness and P = .395 for percent of pretest stiffness.

Discussion

These results support the use of a one-third tubular plate and lag-screw construct for fixation of vertical shear medial malleolus fractures. This is clinically important because one-third tubular plates with 3.5-mm screws are readily available and cost significantly less than a precountoured anatomic-specific type of fixation. These results are based on the biomechanical properties of the constructs tested in this study.

The previous 2 studies^8,9showed conflicting results about the most biomechanically sound fixation for SAD medial malleolar fractures. The study by Toolan and colleagues⁹ reported that 2 screws placed perpendicular to the fracture demonstrated the strongest overall construct. This study compared 3 separate types of 2-screw–only fixations and 2 plate-and-screw fixations. One construct was similar to the AG group in our study, and the other construct had a lag screw at the apex of the fracture. This previous study,⁹ however, did not investigate a similar construct to the MAG group that was tested in our study.

According to Dumigan and associates,⁸ a construct that consisted of a 4-hole plate with 2 screws proximal to the fracture and 2 lag screws showed the strongest fixation. This study, however, did not include a group like our study’s AG group, which is the traditional AG form of fixation.

In our study, we examined the biomechanic properties of a traditional fixation (AG construct), a commonly used fixation (MAG construct), and a newer construct (HP construct). The HP group is unique to this study and, to our knowledge, there is no literature on its use as fixation for this fracture. We did not include a 2-screw–only group, which is a limitation, because this fixation type is not common for the SAD fracture. This study also did not include an HP construct with an additional lag screw, which is an available option as well.

The current investigation used synthetic bone models constructed for biomechanical testing. The models were thought to provide a consistent model for fixation as opposed to using potentially osteopenic cadaveric bone. Each model was the same size and laterality. The stiffness as determined by pretest stiffness was not significantly different among models. Because all models were similar in composition and size, this allowed for more consistent osteotomies and similarly sized malleolar fragments. Theoretically, this allowed a more uniform comparison of all specimens and constructs.

Using models, however, is a limit of this study. While the models were of similar biomechanical quality, it is possible that a model may not reproduce the biology of a cavaderic specimen or the physiology of a construct in vivo. Of the 2 studies that investigated SAD fractures, the Dumigan study8 used cadaveric specimens. The fact that these models were all mildly osteoporotic and were embalmed specimens were study limits. The Toolan study⁹ used synthetic models. Although these models were consistent, they were models of bones and not intended for biomechanical studies, thereby increasing the potential for skewed results.

Our study investigated loading only in the offset-axial direction, a difference when compared to the Dumigan and colleagues8 and Toolan and colleagues⁹ studies. The offest transverse loading previously investigated would most likely represent an external rotation moment. While fixation in vivo could experience an external rotation moment, the specific fracture pattern of interest fails in offset-axial loading. In the original discription of the SAD fracture, Lauge-Hanson7 stated that the talus causes the vertically oriented medial malleolar fracture in the extreme of ankle supination with an adduction moment. Considering this, we investigated failure with a force in the direction that causes this type of fracture.

There are some additional limitations. This study demonstrated superiority of a one-third tubular plate with 2 screws proximally and 1 lag screw. While this was shown in the laboratory under pure offset-axial loading conditions, this may not reproduce daily forces experienced by the constructs. Additionally, this study examined load-to-failure of the constructs and did not investigate cyclic loading that a construct would experience in vivo. Because the testing is not recognizably consistent with day-to-day stresses of these constructs in vivo, this confounds the clinical application of our study.

The stiffness required for clinical healing is undetermined and, therefore, all 3 types of fixation could be adequate clinically. Patients are typically instructed to adhere to weight-bearing limitations on the affected extremity, and casts or splints are applied postoperatively for extended periods of time. Clinical studies would have significant benefit in the evaluation of fixation of vertical shear medial malleolar fractures.

Conclusion

AG plating technique with lag-screw placement is biomechanically superior to the other 2 constructs investigated. The clinical applications of these results are not known, and clinical trials are suggested to determine the best type of fixation for SAD-type medial malleolar fractures.

Supination-adduction (SAD)-type fractures of the ankle comprise approximately 5% to 20% of ankle fractures.^1-3 As the name describes, this fracture is caused by forceful adduction of the supinated foot. There are 2 stages of the fracture pattern: the injury usually occurs first on the lateral side of the ankle with injury to the soft tissues or a low transverse fracture of the distal fibula. With continued force, in the second stage, the talus causes a shearing of the medial malleolus, creating the vertical shear fracture pattern.^4-7 The vertical shear medial malleolus fracture pattern is the subject of this investigation.

Several techniques have been traditionally recommended for fixation of SAD-type ankle fracture, including: a 2-screw construct without plate fixation, oriented perpendicular to the fracture; and an AG plate construct with variable positioning and numbers of screws for fixation. There have been, however, only 2 published articles about the biomechanical properties of fixation of vertical shear medial malleolar fractures, which reported conflicting results.^8,9 The most recent of these studies argued that one-third tubular plate fixation offers significant mechanical advantage over screw-only fixation, supporting the use of AG plates for fixation of SAD ankle fractures.⁸

An additional design for fixation of medial malleolus fractures has been introduced, consisting of a hook plate (HP) contoured for the medial malleolus. To our knowledge, no studies have investigated HP’s biomechanical properties. Thus, the objective of this study was to investigate and compare the biomechanical properties of 3 constructs for fixation of SAD-ankle fractures: an antiglide (AG) plate, an AG plate with an additional lag-screw across the fracture, and a precontoured HP.

Materials and Methods

Thirty 4th-generation–composite polyurethane models of the left tibia were obtained (Sawbones, Pacific Research Laboratories, Inc.). Largely, our methods accorded with the precedent set by other studies on these fracture types.^8,9

Prior to creation of the fractures, each model was individually evaluated for pretest stiffness by using the slope of the linear portion of the load-displacement curve during offset-axial loading. This demonstrated the baseline elasticity of the models during loading. Assessing pretest stiffness was performed to reduce potential variables in the stiffness of individual models in the analysis of the testing data.

The models were numbered 1 through 30 on the shaft and on the medial malleolus. A custom jig was constructed with a table saw to create identical vertical shear medial malleolar fracture patterns in each model. The jig created the vertical shear SAD fracture described by Lauge-Hansen.⁷ All models were randomly assigned to 1 of 3 groups; each group consisted of 10 models (Figures 1A, 1B).

The 10 specimens in group 1 were fixed with a 5-hole, 3.5-mm, one-third tubular plate (Smith & Nephew) in a traditional AG fashion. The plates were placed at the same location on all tibiae. The proximal hole and the hole closest to the fracture line were filled with 3.5-mm cortical screws, which were long enough to achieve bicortical fixation. No lag screws were placed in this specimen group. In group 2, specimens were fixed with the same plate used in group 1 (Smith & Nephew). In this modified AG (MAG) construct, specimens were fixed identically to group 1 for plate placement and fixation of the 2 proximal screws. In this group, an additional screw was placed perpendicular to the fracture and parallel to the distal tibial articular surface. In both groups (AG and MAG), the plates were not bent before application.

Group 3 consisted of specimens fixed with a 5-hole, precontoured medial malleolar HP (Arthrex). This HP construct was fixed with two 3.5-mm cortical screws long enough to achieve bicortical fixation. The plate also engaged the bone at the tip of the medial malleolus by using 2 sharp prongs. The screws were placed in the most proximal hole and the hole just proximal to the fracture line. No lag screws were placed in the HP construct.

All models were tested in offset-axial loading to replicate a SAD moment similar to previous studies. To test offset-axial loading, a vice held each model identically with a 17º angle from the longitudinal axis (Figure 2). Loading was performed with a material testing system; a material testing system plunger was directed at the inferior articulating cartilage surface of the medial malleolus. The specimens were loaded at a rate of 1 mm/sec until 2 mm of displacement was reached (Figure 3) or catastrophic failure occurred. The raw data analyzed consisted of the initial stiffness of the construct and the overall load-to-failure. The slope of the linear portion of the load-displacement curve of stiffness determined stiffness of the construct.

One-way analysis of variance with post hoc Tukey HSD data analysis was performed to determine if there were statistical differences among the different fixation constructs during load-to-failure. To prevent skewing of results by different values of model elasticity, pretest stiffness was accounted for by calculating a ratio of construct stiffness as a function of pretest model stiffness. Total force-to-failure was the recorded maximum force (in N) to cause failure. A P value of < .05 was set for significance. All data were analyzed using SPSS software (SPSS Version 15.0; SPSS Inc.).

Results

Analysis of pretest stiffness showed no significant difference among models (P = .490). All models failed by a gap of 2 mm at the distal fracture site except for 3 models in the MAG group. These 3 models failed at a much higher load than the remainder of the models and failed by fracture of the models.

The MAG group demonstrated significantly superior stiffness to the 2 other models tested (Figure 4). On average, this group required 753.5 N of force before failure. This was 530 N higher than the HP (P < .05) and 638 N higher than the AG constructs, respectively (P < .05). The HP and AG groups required forces of 223.2 N and 115.5 N for failure, respectively. These numbers were not significant (P= .063).

The absolute construct stiffness and construct stiffness as a function of pretest stiffness of the MAG group was the highest of all groups, 271.7 N/mm and 57.2%, respectively (Figure 5). These numbers showed significance when compared with the values of the HP group (P < .05 for both) and the AG group (P < .05 for both). The average stiffness of the HP group was 159.7 N/mm, which was 36.8% of pretest stiffness.

The AG group had the lowest construct stiffness and percent of pretest stiffness (128.1 N/mm and 29.6%). The HP and AG groups were not statistically different in these comparisons, P = .350 for construct stiffness and P = .395 for percent of pretest stiffness.

Discussion

These results support the use of a one-third tubular plate and lag-screw construct for fixation of vertical shear medial malleolus fractures. This is clinically important because one-third tubular plates with 3.5-mm screws are readily available and cost significantly less than a precountoured anatomic-specific type of fixation. These results are based on the biomechanical properties of the constructs tested in this study.

The previous 2 studies^8,9showed conflicting results about the most biomechanically sound fixation for SAD medial malleolar fractures. The study by Toolan and colleagues⁹ reported that 2 screws placed perpendicular to the fracture demonstrated the strongest overall construct. This study compared 3 separate types of 2-screw–only fixations and 2 plate-and-screw fixations. One construct was similar to the AG group in our study, and the other construct had a lag screw at the apex of the fracture. This previous study,⁹ however, did not investigate a similar construct to the MAG group that was tested in our study.

According to Dumigan and associates,⁸ a construct that consisted of a 4-hole plate with 2 screws proximal to the fracture and 2 lag screws showed the strongest fixation. This study, however, did not include a group like our study’s AG group, which is the traditional AG form of fixation.

In our study, we examined the biomechanic properties of a traditional fixation (AG construct), a commonly used fixation (MAG construct), and a newer construct (HP construct). The HP group is unique to this study and, to our knowledge, there is no literature on its use as fixation for this fracture. We did not include a 2-screw–only group, which is a limitation, because this fixation type is not common for the SAD fracture. This study also did not include an HP construct with an additional lag screw, which is an available option as well.

The current investigation used synthetic bone models constructed for biomechanical testing. The models were thought to provide a consistent model for fixation as opposed to using potentially osteopenic cadaveric bone. Each model was the same size and laterality. The stiffness as determined by pretest stiffness was not significantly different among models. Because all models were similar in composition and size, this allowed for more consistent osteotomies and similarly sized malleolar fragments. Theoretically, this allowed a more uniform comparison of all specimens and constructs.

Using models, however, is a limit of this study. While the models were of similar biomechanical quality, it is possible that a model may not reproduce the biology of a cavaderic specimen or the physiology of a construct in vivo. Of the 2 studies that investigated SAD fractures, the Dumigan study8 used cadaveric specimens. The fact that these models were all mildly osteoporotic and were embalmed specimens were study limits. The Toolan study⁹ used synthetic models. Although these models were consistent, they were models of bones and not intended for biomechanical studies, thereby increasing the potential for skewed results.

Our study investigated loading only in the offset-axial direction, a difference when compared to the Dumigan and colleagues8 and Toolan and colleagues⁹ studies. The offest transverse loading previously investigated would most likely represent an external rotation moment. While fixation in vivo could experience an external rotation moment, the specific fracture pattern of interest fails in offset-axial loading. In the original discription of the SAD fracture, Lauge-Hanson7 stated that the talus causes the vertically oriented medial malleolar fracture in the extreme of ankle supination with an adduction moment. Considering this, we investigated failure with a force in the direction that causes this type of fracture.

There are some additional limitations. This study demonstrated superiority of a one-third tubular plate with 2 screws proximally and 1 lag screw. While this was shown in the laboratory under pure offset-axial loading conditions, this may not reproduce daily forces experienced by the constructs. Additionally, this study examined load-to-failure of the constructs and did not investigate cyclic loading that a construct would experience in vivo. Because the testing is not recognizably consistent with day-to-day stresses of these constructs in vivo, this confounds the clinical application of our study.

The stiffness required for clinical healing is undetermined and, therefore, all 3 types of fixation could be adequate clinically. Patients are typically instructed to adhere to weight-bearing limitations on the affected extremity, and casts or splints are applied postoperatively for extended periods of time. Clinical studies would have significant benefit in the evaluation of fixation of vertical shear medial malleolar fractures.

Conclusion

AG plating technique with lag-screw placement is biomechanically superior to the other 2 constructs investigated. The clinical applications of these results are not known, and clinical trials are suggested to determine the best type of fixation for SAD-type medial malleolar fractures.

Supination-adduction (SAD)-type fractures of the ankle comprise approximately 5% to 20% of ankle fractures.^1-3 As the name describes, this fracture is caused by forceful adduction of the supinated foot. There are 2 stages of the fracture pattern: the injury usually occurs first on the lateral side of the ankle with injury to the soft tissues or a low transverse fracture of the distal fibula. With continued force, in the second stage, the talus causes a shearing of the medial malleolus, creating the vertical shear fracture pattern.^4-7 The vertical shear medial malleolus fracture pattern is the subject of this investigation.

Several techniques have been traditionally recommended for fixation of SAD-type ankle fracture, including: a 2-screw construct without plate fixation, oriented perpendicular to the fracture; and an AG plate construct with variable positioning and numbers of screws for fixation. There have been, however, only 2 published articles about the biomechanical properties of fixation of vertical shear medial malleolar fractures, which reported conflicting results.^8,9 The most recent of these studies argued that one-third tubular plate fixation offers significant mechanical advantage over screw-only fixation, supporting the use of AG plates for fixation of SAD ankle fractures.⁸

An additional design for fixation of medial malleolus fractures has been introduced, consisting of a hook plate (HP) contoured for the medial malleolus. To our knowledge, no studies have investigated HP’s biomechanical properties. Thus, the objective of this study was to investigate and compare the biomechanical properties of 3 constructs for fixation of SAD-ankle fractures: an antiglide (AG) plate, an AG plate with an additional lag-screw across the fracture, and a precontoured HP.

Materials and Methods

Thirty 4th-generation–composite polyurethane models of the left tibia were obtained (Sawbones, Pacific Research Laboratories, Inc.). Largely, our methods accorded with the precedent set by other studies on these fracture types.^8,9

Prior to creation of the fractures, each model was individually evaluated for pretest stiffness by using the slope of the linear portion of the load-displacement curve during offset-axial loading. This demonstrated the baseline elasticity of the models during loading. Assessing pretest stiffness was performed to reduce potential variables in the stiffness of individual models in the analysis of the testing data.

The models were numbered 1 through 30 on the shaft and on the medial malleolus. A custom jig was constructed with a table saw to create identical vertical shear medial malleolar fracture patterns in each model. The jig created the vertical shear SAD fracture described by Lauge-Hansen.⁷ All models were randomly assigned to 1 of 3 groups; each group consisted of 10 models (Figures 1A, 1B).

The 10 specimens in group 1 were fixed with a 5-hole, 3.5-mm, one-third tubular plate (Smith & Nephew) in a traditional AG fashion. The plates were placed at the same location on all tibiae. The proximal hole and the hole closest to the fracture line were filled with 3.5-mm cortical screws, which were long enough to achieve bicortical fixation. No lag screws were placed in this specimen group. In group 2, specimens were fixed with the same plate used in group 1 (Smith & Nephew). In this modified AG (MAG) construct, specimens were fixed identically to group 1 for plate placement and fixation of the 2 proximal screws. In this group, an additional screw was placed perpendicular to the fracture and parallel to the distal tibial articular surface. In both groups (AG and MAG), the plates were not bent before application.

Group 3 consisted of specimens fixed with a 5-hole, precontoured medial malleolar HP (Arthrex). This HP construct was fixed with two 3.5-mm cortical screws long enough to achieve bicortical fixation. The plate also engaged the bone at the tip of the medial malleolus by using 2 sharp prongs. The screws were placed in the most proximal hole and the hole just proximal to the fracture line. No lag screws were placed in the HP construct.

All models were tested in offset-axial loading to replicate a SAD moment similar to previous studies. To test offset-axial loading, a vice held each model identically with a 17º angle from the longitudinal axis (Figure 2). Loading was performed with a material testing system; a material testing system plunger was directed at the inferior articulating cartilage surface of the medial malleolus. The specimens were loaded at a rate of 1 mm/sec until 2 mm of displacement was reached (Figure 3) or catastrophic failure occurred. The raw data analyzed consisted of the initial stiffness of the construct and the overall load-to-failure. The slope of the linear portion of the load-displacement curve of stiffness determined stiffness of the construct.

One-way analysis of variance with post hoc Tukey HSD data analysis was performed to determine if there were statistical differences among the different fixation constructs during load-to-failure. To prevent skewing of results by different values of model elasticity, pretest stiffness was accounted for by calculating a ratio of construct stiffness as a function of pretest model stiffness. Total force-to-failure was the recorded maximum force (in N) to cause failure. A P value of < .05 was set for significance. All data were analyzed using SPSS software (SPSS Version 15.0; SPSS Inc.).

Results

Analysis of pretest stiffness showed no significant difference among models (P = .490). All models failed by a gap of 2 mm at the distal fracture site except for 3 models in the MAG group. These 3 models failed at a much higher load than the remainder of the models and failed by fracture of the models.

The MAG group demonstrated significantly superior stiffness to the 2 other models tested (Figure 4). On average, this group required 753.5 N of force before failure. This was 530 N higher than the HP (P < .05) and 638 N higher than the AG constructs, respectively (P < .05). The HP and AG groups required forces of 223.2 N and 115.5 N for failure, respectively. These numbers were not significant (P= .063).

The absolute construct stiffness and construct stiffness as a function of pretest stiffness of the MAG group was the highest of all groups, 271.7 N/mm and 57.2%, respectively (Figure 5). These numbers showed significance when compared with the values of the HP group (P < .05 for both) and the AG group (P < .05 for both). The average stiffness of the HP group was 159.7 N/mm, which was 36.8% of pretest stiffness.

The AG group had the lowest construct stiffness and percent of pretest stiffness (128.1 N/mm and 29.6%). The HP and AG groups were not statistically different in these comparisons, P = .350 for construct stiffness and P = .395 for percent of pretest stiffness.

Discussion

These results support the use of a one-third tubular plate and lag-screw construct for fixation of vertical shear medial malleolus fractures. This is clinically important because one-third tubular plates with 3.5-mm screws are readily available and cost significantly less than a precountoured anatomic-specific type of fixation. These results are based on the biomechanical properties of the constructs tested in this study.

The previous 2 studies^8,9showed conflicting results about the most biomechanically sound fixation for SAD medial malleolar fractures. The study by Toolan and colleagues⁹ reported that 2 screws placed perpendicular to the fracture demonstrated the strongest overall construct. This study compared 3 separate types of 2-screw–only fixations and 2 plate-and-screw fixations. One construct was similar to the AG group in our study, and the other construct had a lag screw at the apex of the fracture. This previous study,⁹ however, did not investigate a similar construct to the MAG group that was tested in our study.

According to Dumigan and associates,⁸ a construct that consisted of a 4-hole plate with 2 screws proximal to the fracture and 2 lag screws showed the strongest fixation. This study, however, did not include a group like our study’s AG group, which is the traditional AG form of fixation.

In our study, we examined the biomechanic properties of a traditional fixation (AG construct), a commonly used fixation (MAG construct), and a newer construct (HP construct). The HP group is unique to this study and, to our knowledge, there is no literature on its use as fixation for this fracture. We did not include a 2-screw–only group, which is a limitation, because this fixation type is not common for the SAD fracture. This study also did not include an HP construct with an additional lag screw, which is an available option as well.

The current investigation used synthetic bone models constructed for biomechanical testing. The models were thought to provide a consistent model for fixation as opposed to using potentially osteopenic cadaveric bone. Each model was the same size and laterality. The stiffness as determined by pretest stiffness was not significantly different among models. Because all models were similar in composition and size, this allowed for more consistent osteotomies and similarly sized malleolar fragments. Theoretically, this allowed a more uniform comparison of all specimens and constructs.

Using models, however, is a limit of this study. While the models were of similar biomechanical quality, it is possible that a model may not reproduce the biology of a cavaderic specimen or the physiology of a construct in vivo. Of the 2 studies that investigated SAD fractures, the Dumigan study8 used cadaveric specimens. The fact that these models were all mildly osteoporotic and were embalmed specimens were study limits. The Toolan study⁹ used synthetic models. Although these models were consistent, they were models of bones and not intended for biomechanical studies, thereby increasing the potential for skewed results.

Our study investigated loading only in the offset-axial direction, a difference when compared to the Dumigan and colleagues8 and Toolan and colleagues⁹ studies. The offest transverse loading previously investigated would most likely represent an external rotation moment. While fixation in vivo could experience an external rotation moment, the specific fracture pattern of interest fails in offset-axial loading. In the original discription of the SAD fracture, Lauge-Hanson7 stated that the talus causes the vertically oriented medial malleolar fracture in the extreme of ankle supination with an adduction moment. Considering this, we investigated failure with a force in the direction that causes this type of fracture.

There are some additional limitations. This study demonstrated superiority of a one-third tubular plate with 2 screws proximally and 1 lag screw. While this was shown in the laboratory under pure offset-axial loading conditions, this may not reproduce daily forces experienced by the constructs. Additionally, this study examined load-to-failure of the constructs and did not investigate cyclic loading that a construct would experience in vivo. Because the testing is not recognizably consistent with day-to-day stresses of these constructs in vivo, this confounds the clinical application of our study.

The stiffness required for clinical healing is undetermined and, therefore, all 3 types of fixation could be adequate clinically. Patients are typically instructed to adhere to weight-bearing limitations on the affected extremity, and casts or splints are applied postoperatively for extended periods of time. Clinical studies would have significant benefit in the evaluation of fixation of vertical shear medial malleolar fractures.

Conclusion

AG plating technique with lag-screw placement is biomechanically superior to the other 2 constructs investigated. The clinical applications of these results are not known, and clinical trials are suggested to determine the best type of fixation for SAD-type medial malleolar fractures.

Despite an abundance of peer-reviewed resources, there is wide variation in the surgical management of shoulder instability.^1,2 Current American Academy of Orthopaedic Surgeons (AAOS) clinical practice guidelines regarding the shoulder address only generalized shoulder pain, glenohumeral osteoarthritis, and rotator cuff injuries,^3,4 and treatment algorithms focus on conservative treatment, rather than surgical recommendations.^4-7

Shoulder instability most commonly results from 1 or more of 4 common lesions (capsular laxity, glenoid bone loss, humeral bone loss, and capsulolabral insufficiency).⁸ While it is a relatively common condition that represents 1% to 2% of all athletic injuries,^9,10 little consensus exists about surgical indications, ideal treatment algorithms, or optimal operative technique. This is a critical issue because more than 50% of patients with glenohumeral instability will undergo surgical intervention.¹¹ Chahal and associates⁶ surveyed 44 shoulder experts and reported strong consensus about diagnosis, but little agreement regarding surgical management. Owens and colleagues¹ have also evaluated current trends for surgical treatment of this pathology. Randelli and associates⁵ attempted to categorize operative management based upon case-specific shoulder scenarios through online surveys. Their survey, however, covered a broad range of shoulder injuries rather than instability in particular. In this study, we assess trends for surgical management of glenohumeral instability in a case-based survey of shoulder experts.

Materials and Methods

Survey Information

An online survey (Survey Monkey) of 417 active members of the American Shoulder and Elbow Surgeons (ASES) was administered on May 1, 2014. Respondents were blinded to the institution and co-investigators conducting the survey. The survey link was distributed via email because it has been shown to be a more efficacious conduit than standard postal mail.¹² The case-based, 25-question survey (Appendix) was designed to assess respondents’ selection of surgical intervention. Section 1 determined member demographics, including fellowship training, arthroscopy experience, and years of practice. Section 2 involved the presentation of 5 case scenarios. For each case, respondents were asked to identify the optimal surgical procedure in both primary and revision settings. Section 3 posed several general questions regarding shoulder-instability management.

Statistical Analysis

Data were stored using Microsoft Excel (Microsoft) and analyzed using SAS Software version 9.3 (SAS Institute, Inc.). Demographic survey responses were reported using descriptive statistics. Responses to clinical survey questions were reported using frequencies and percentages. To identify when a majority consensus was achieved for a given question, responses were flagged as reaching consensus when more than 50% of participants gave the same response.¹³In the event that only 2 response options were available, reaching consensus required 67% of respondents to choose a single answer (since, by default, a consensus would be reached with only 2 response options). Because this was an analysis of all respondents, an a priori power calculation was not performed. Associations between training and practice demographics and responses to clinical questions were investigated using chi-square analyses. All comparative analyses were two-tailed and used P = .05 as the threshold for statistical significance.

Results

Demographics

One hundred and twenty-five (29.9%) ASES members responded to the survey. Of the respondents, 71.2% reported at least 15 years of experience, and 71% performed more than 150 shoulder cases annually. Surgeons came from academic institutions (41.6%), private practice (24.8%), or mixed (33.6%). The majority of respondents were fellowship-trained in shoulder/elbow surgery (52.8%), while fewer had completed a sports-medicine fellowship (24.0%). For arthroscopic procedures, responses were nearly divided between those who preferred beach-chair positioning (47.2%) and those who preferred the lateral decubitus position (46.4%). The majority (70.4%) of respondents practiced in the United States and with a relatively even distribution among states and region. The remaining 29.6% of those surveyed practiced abroad.

Degree of Consensus Responses and Cases

Of the 25 survey questions, 6 questions were omitted from consensus calculations because these were designed for demographic categorization rather than professional opinion (questions 1-5, 8). Thirteen of the remaining 19 questions (68%) reached consensus response. All clinical case scenarios (5 of 5) reached consensus for selection of technique for the primary procedure; however, only 40% (2 of 5) of cases had a consensus in the revision setting.

In case 1, a young soccer player (noncontact athlete) with negligible bone loss, arthroscopic Bankart repair was recommended by 81.6% of respondents. In the event of revision surgery, only 22.4% recommended arthroscopic Bankart repair, and the remainder split between open Bankart repair with possible capsular shift (36%) or Latarjet procedure (32.8%).

In case 2, a college American football player (contact athlete) with negligible bone loss, arthroscopic Bankart repair was recommended by 56.8%. In the event of revision surgery, a majority of members (51.2%) suggested a Latarjet procedure.

In case 3, the weekend warrior with significant bone loss, most respondents recommended a Latarjet procedure for both primary (72.8%) and revision surgery (79.0%).

In case 4, a weekend warrior with multidirectional instability, 60% of respondents suggested arthroscopic Bankart repair, 21.6% recommended rotator interval closure, and 10.4% chose a capsular shift. As a revision procedure, there was less agreement, with a split between open Bankart repair (39.2%) and capsular shift only (39.2%).

In case 5, the weekend warrior with large engaging Hill-Sachs lesions, 60% of respondent selected a remplissage procedure. If revision was required, a Latarjet procedure was the choice of 48.8% of respondents (Table).

General Questions

For contact athletes, most respondents (87.2%) would allow return to play in the same season and recommended surgery after the end of the season. After surgical intervention, 56.8% prescribed 4 weeks of immobilization. When counseling a return to contact sports, 51.2% recommended waiting for 4 to 6 months.

The ASES members were divided on conservative management of instability injuries. Responses included immobilization in internal rotation (39.2%), no immobilization (39.2%), and external-rotation bracing (21.6%).

Finally, members thought the most important factor in choosing surgical technique was the patient’s pathology, then age; the least influential criteria was the patient’s sports participation.

Analysis of Training Demographics and Surgical Technique Preferences

Chi-square analyses demonstrated that respondents who completed a sports fellowship were more likely to do at least 50% of cases arthroscopically (odds ratio [OR], 15.3; P < .001) and were more likely to use the lateral decubitus position (OR, 2.8; P < .021). Furthermore, American respondents had a higher likelihood of having completed either a sports fellowship (OR, 12.8; P < .001) or a shoulder/elbow fellowship (OR, 4.6; P = .002) when compared with foreign respondents.

Discussion

In the absence of formal clinical practice guidelines, most surgeons formulate treatment strategy based upon a combination of experience and peer-reviewed evidence. The cohort analyzed in the current study was highly experienced, with more than 70% performing 150 shoulder cases annually and having more than 15 years of experience. We found a consensus response in 68% of questions and all primary surgical techniques for our shoulder instability scenarios. While expert consensus reported here is not equivalent to evidence-based clinical practice guidelines, it does provide important information to consider when treating anterior shoulder instability.

Specific responses to our case scenarios invite further reflection. Considering young (both noncontact and contact) athletes without bony pathology (cases 1 and 2, respectively), the ASES surgeons recommended arthroscopic Bankart repair for both. Randelli and associates5 found 71% of survey respondents recommended arthroscopic Bankart repair in a similar setting. It is interesting to note that consensus persisted regardless of the sport in which they engaged. Contact athletes have the highest rates of dislocation (up to 7 times higher incidence) compared with the general population.¹⁴ In addition, they have a higher recurrence rate after surgery.¹⁵ It should be noted, however, that although both cases reached consensus, the percentage of experts who recommended an arthroscopic procedure fell from 82% in the noncontact athlete to 57% in the contact athlete. This concurs with a recent review by Harris and Romeo,¹⁶ who recommended similar treatments for athletes without bony defects. In an older patient population with recurrent instability (case 3), responses varied more widely but still reached a consensus on primary surgical techniques. Respondents agreed that, even for patients with multidirectional instability, initial management should consist of arthroscopic capsulolabral repair. Overall, the agreement for arthroscopy for cases 1 through 3 mimics recent US practice patterns, showing 90% of stabilizations are being performed arthroscopically.¹⁷ Additionally, a recent meta-analysis by Harris and associates18 favored arthroscopic Bankart repair, showing no significant difference vs open stabilization even on long-term follow-up.

Glenoid bone loss is a difficult clinical scenario and that is reflected in this study’s findings. The literature suggests that arthroscopic Bankart repair, in this setting, is usually not sufficient and may result in a recurrence rate up to 75%, if bone loss greater than 20% is unaddressed.¹⁹ Our study supports this trend because ASES members recommended a Latarjet procedure when there is substantial bone loss.

While open Latarjet procedure was the consensus for dealing with glenoid bone loss, arthroscopic techniques were strongly favored for humeral head defects. This change in practice patterns results from the introduction of the arthroscopic remplissage technique.²⁰ Two recent systemic reviews have supported this technique, reporting good functional outcomes for engaging Hill-Sachs lesions.^21,22 Our study had similar agreement, with most respondents recommending remplissage for these patients.

This study found the lowest rates of expert consensus in the setting of revision surgery, likely caused, in part, by the paucity of available large cohort studies. This is a major void in the literature, and more studies are needed to help guide surgeons on the best techniques to deal with this difficult patient population.

Conservative bracing technique was 1 of the survey questions lacking a consensus response. Interestingly, 39% of members recommended no immobilization after an instability event. This contrasts with recent literature concerning the best position for bracing. We also found twice as many surgeons recommended internal rotation immobilization over external rotation. This is a subject of debate, with some studies stating improvement with external rotation immobilization,²³ while other studies reported no difference.²⁴ Overall, recommendations regarding type of immobilization are unclear, which will likely continue until larger studies can be performed.

The literature describing surgical trends in the treatment of shoulder instability is sparse and variable. With regard to other shoulder etiologies, only rotator cuff pathology has used expert consensus. Acevedo and colleagues¹³ reported agreement of ASES members surveyed regarding rotator cuff management. There was no consensus among surgeons in more than 50% of questions, despite AAOS published guidelines for rotator cuff treatment.²⁵ Despite the lack of guidelines for our topic, we found a consensus among respondents with 68% of survey questions.

To date, only 2 studies of shoulder instability management have elicited the opinion of experts in shoulder surgery. Chahal and associates⁶ surveyed 42 members of ASES and JOINTS (Joined Orthopaedic Initiatives for National Trials of the Shoulder) Canada on shoulder instability cases and found substantial agreement on diagnosis but little consensus regarding surgical technique. This lack of agreement on procedures differs from our findings and may be related to their complicated case scenarios that generated a wide array of treatment recommendations. Randelli and colleagues⁵ surveyed more than 1000 European Society of Sports Traumatology, Knee Surgery, and Arthroscopy members and reported similar agreement on arthroscopic Bankart repair in young male shoulder-dislocation patients, although no other instability scenarios were investigated. Our study is the first to report responses from expert shoulder surgeons on surgical-treatment strategies for an array of common shoulder instability pathologies.

This study had several limitations. First, while our study suffered from a low response rate (29.9%), it was similar to other published studies.^5,13 Second, because the case series included in the survey attempted to capture the most common instability scenarios, they were limited in their scope and failed to address additional etiologies or pathologic permutations. We believe, however, that a more comprehensive survey would have resulted in respondent fatigue and lowered the response rate. It is unlikely that any survey could capture all variables that come into play during clinical decision-making, and we sought to evaluate the most common shoulder instability scenarios. Third, 30% of respondents were from outside the United States, where the Latarjet procedure is much more popular. While this was not a majority, Latarjet’s regional preference may have decreased the consensus response in some scenarios if only the United States was included. Finally, there is inherent bias in a respondent pool that is heavily weighted to shoulder-surgery experts (ASES members) and does not consider the responses of the general orthopedic surgery community as have other studies.⁷

Conclusion

This study demonstrates that expert shoulder surgeons often agreed on shoulder-treatment principles for anterior shoulder instability. In the setting of primary repair, arthroscopic Bankart repair was favored in the absence of bony pathology, regardless of age (20 to 35 years) or nature of sport (contact versus noncontact). Latarjet procedures were favored in the setting of glenoid bone loss, and remplissage for an engaging Hill-Sachs lesion. Less agreement was observed for revision stabilization. It should be noted that, while consensus was often reached for our cases, there was a wide distribution of technical considerations and surgical preferences even among those who are fellowship-trained and high-volume surgeons, and who can be considered experts in the field of shoulder surgery.

Despite an abundance of peer-reviewed resources, there is wide variation in the surgical management of shoulder instability.^1,2 Current American Academy of Orthopaedic Surgeons (AAOS) clinical practice guidelines regarding the shoulder address only generalized shoulder pain, glenohumeral osteoarthritis, and rotator cuff injuries,^3,4 and treatment algorithms focus on conservative treatment, rather than surgical recommendations.^4-7

Shoulder instability most commonly results from 1 or more of 4 common lesions (capsular laxity, glenoid bone loss, humeral bone loss, and capsulolabral insufficiency).⁸ While it is a relatively common condition that represents 1% to 2% of all athletic injuries,^9,10 little consensus exists about surgical indications, ideal treatment algorithms, or optimal operative technique. This is a critical issue because more than 50% of patients with glenohumeral instability will undergo surgical intervention.¹¹ Chahal and associates⁶ surveyed 44 shoulder experts and reported strong consensus about diagnosis, but little agreement regarding surgical management. Owens and colleagues¹ have also evaluated current trends for surgical treatment of this pathology. Randelli and associates⁵ attempted to categorize operative management based upon case-specific shoulder scenarios through online surveys. Their survey, however, covered a broad range of shoulder injuries rather than instability in particular. In this study, we assess trends for surgical management of glenohumeral instability in a case-based survey of shoulder experts.

Materials and Methods

Survey Information

An online survey (Survey Monkey) of 417 active members of the American Shoulder and Elbow Surgeons (ASES) was administered on May 1, 2014. Respondents were blinded to the institution and co-investigators conducting the survey. The survey link was distributed via email because it has been shown to be a more efficacious conduit than standard postal mail.¹² The case-based, 25-question survey (Appendix) was designed to assess respondents’ selection of surgical intervention. Section 1 determined member demographics, including fellowship training, arthroscopy experience, and years of practice. Section 2 involved the presentation of 5 case scenarios. For each case, respondents were asked to identify the optimal surgical procedure in both primary and revision settings. Section 3 posed several general questions regarding shoulder-instability management.

Statistical Analysis

Data were stored using Microsoft Excel (Microsoft) and analyzed using SAS Software version 9.3 (SAS Institute, Inc.). Demographic survey responses were reported using descriptive statistics. Responses to clinical survey questions were reported using frequencies and percentages. To identify when a majority consensus was achieved for a given question, responses were flagged as reaching consensus when more than 50% of participants gave the same response.¹³In the event that only 2 response options were available, reaching consensus required 67% of respondents to choose a single answer (since, by default, a consensus would be reached with only 2 response options). Because this was an analysis of all respondents, an a priori power calculation was not performed. Associations between training and practice demographics and responses to clinical questions were investigated using chi-square analyses. All comparative analyses were two-tailed and used P = .05 as the threshold for statistical significance.

Results

Demographics

One hundred and twenty-five (29.9%) ASES members responded to the survey. Of the respondents, 71.2% reported at least 15 years of experience, and 71% performed more than 150 shoulder cases annually. Surgeons came from academic institutions (41.6%), private practice (24.8%), or mixed (33.6%). The majority of respondents were fellowship-trained in shoulder/elbow surgery (52.8%), while fewer had completed a sports-medicine fellowship (24.0%). For arthroscopic procedures, responses were nearly divided between those who preferred beach-chair positioning (47.2%) and those who preferred the lateral decubitus position (46.4%). The majority (70.4%) of respondents practiced in the United States and with a relatively even distribution among states and region. The remaining 29.6% of those surveyed practiced abroad.

Degree of Consensus Responses and Cases

Of the 25 survey questions, 6 questions were omitted from consensus calculations because these were designed for demographic categorization rather than professional opinion (questions 1-5, 8). Thirteen of the remaining 19 questions (68%) reached consensus response. All clinical case scenarios (5 of 5) reached consensus for selection of technique for the primary procedure; however, only 40% (2 of 5) of cases had a consensus in the revision setting.

In case 1, a young soccer player (noncontact athlete) with negligible bone loss, arthroscopic Bankart repair was recommended by 81.6% of respondents. In the event of revision surgery, only 22.4% recommended arthroscopic Bankart repair, and the remainder split between open Bankart repair with possible capsular shift (36%) or Latarjet procedure (32.8%).

In case 2, a college American football player (contact athlete) with negligible bone loss, arthroscopic Bankart repair was recommended by 56.8%. In the event of revision surgery, a majority of members (51.2%) suggested a Latarjet procedure.

In case 3, the weekend warrior with significant bone loss, most respondents recommended a Latarjet procedure for both primary (72.8%) and revision surgery (79.0%).

In case 4, a weekend warrior with multidirectional instability, 60% of respondents suggested arthroscopic Bankart repair, 21.6% recommended rotator interval closure, and 10.4% chose a capsular shift. As a revision procedure, there was less agreement, with a split between open Bankart repair (39.2%) and capsular shift only (39.2%).

In case 5, the weekend warrior with large engaging Hill-Sachs lesions, 60% of respondent selected a remplissage procedure. If revision was required, a Latarjet procedure was the choice of 48.8% of respondents (Table).

General Questions

For contact athletes, most respondents (87.2%) would allow return to play in the same season and recommended surgery after the end of the season. After surgical intervention, 56.8% prescribed 4 weeks of immobilization. When counseling a return to contact sports, 51.2% recommended waiting for 4 to 6 months.

The ASES members were divided on conservative management of instability injuries. Responses included immobilization in internal rotation (39.2%), no immobilization (39.2%), and external-rotation bracing (21.6%).

Finally, members thought the most important factor in choosing surgical technique was the patient’s pathology, then age; the least influential criteria was the patient’s sports participation.

Analysis of Training Demographics and Surgical Technique Preferences

Chi-square analyses demonstrated that respondents who completed a sports fellowship were more likely to do at least 50% of cases arthroscopically (odds ratio [OR], 15.3; P < .001) and were more likely to use the lateral decubitus position (OR, 2.8; P < .021). Furthermore, American respondents had a higher likelihood of having completed either a sports fellowship (OR, 12.8; P < .001) or a shoulder/elbow fellowship (OR, 4.6; P = .002) when compared with foreign respondents.

Discussion

In the absence of formal clinical practice guidelines, most surgeons formulate treatment strategy based upon a combination of experience and peer-reviewed evidence. The cohort analyzed in the current study was highly experienced, with more than 70% performing 150 shoulder cases annually and having more than 15 years of experience. We found a consensus response in 68% of questions and all primary surgical techniques for our shoulder instability scenarios. While expert consensus reported here is not equivalent to evidence-based clinical practice guidelines, it does provide important information to consider when treating anterior shoulder instability.

Specific responses to our case scenarios invite further reflection. Considering young (both noncontact and contact) athletes without bony pathology (cases 1 and 2, respectively), the ASES surgeons recommended arthroscopic Bankart repair for both. Randelli and associates5 found 71% of survey respondents recommended arthroscopic Bankart repair in a similar setting. It is interesting to note that consensus persisted regardless of the sport in which they engaged. Contact athletes have the highest rates of dislocation (up to 7 times higher incidence) compared with the general population.¹⁴ In addition, they have a higher recurrence rate after surgery.¹⁵ It should be noted, however, that although both cases reached consensus, the percentage of experts who recommended an arthroscopic procedure fell from 82% in the noncontact athlete to 57% in the contact athlete. This concurs with a recent review by Harris and Romeo,¹⁶ who recommended similar treatments for athletes without bony defects. In an older patient population with recurrent instability (case 3), responses varied more widely but still reached a consensus on primary surgical techniques. Respondents agreed that, even for patients with multidirectional instability, initial management should consist of arthroscopic capsulolabral repair. Overall, the agreement for arthroscopy for cases 1 through 3 mimics recent US practice patterns, showing 90% of stabilizations are being performed arthroscopically.¹⁷ Additionally, a recent meta-analysis by Harris and associates18 favored arthroscopic Bankart repair, showing no significant difference vs open stabilization even on long-term follow-up.

Glenoid bone loss is a difficult clinical scenario and that is reflected in this study’s findings. The literature suggests that arthroscopic Bankart repair, in this setting, is usually not sufficient and may result in a recurrence rate up to 75%, if bone loss greater than 20% is unaddressed.¹⁹ Our study supports this trend because ASES members recommended a Latarjet procedure when there is substantial bone loss.

While open Latarjet procedure was the consensus for dealing with glenoid bone loss, arthroscopic techniques were strongly favored for humeral head defects. This change in practice patterns results from the introduction of the arthroscopic remplissage technique.²⁰ Two recent systemic reviews have supported this technique, reporting good functional outcomes for engaging Hill-Sachs lesions.^21,22 Our study had similar agreement, with most respondents recommending remplissage for these patients.

This study found the lowest rates of expert consensus in the setting of revision surgery, likely caused, in part, by the paucity of available large cohort studies. This is a major void in the literature, and more studies are needed to help guide surgeons on the best techniques to deal with this difficult patient population.

Conservative bracing technique was 1 of the survey questions lacking a consensus response. Interestingly, 39% of members recommended no immobilization after an instability event. This contrasts with recent literature concerning the best position for bracing. We also found twice as many surgeons recommended internal rotation immobilization over external rotation. This is a subject of debate, with some studies stating improvement with external rotation immobilization,²³ while other studies reported no difference.²⁴ Overall, recommendations regarding type of immobilization are unclear, which will likely continue until larger studies can be performed.

The literature describing surgical trends in the treatment of shoulder instability is sparse and variable. With regard to other shoulder etiologies, only rotator cuff pathology has used expert consensus. Acevedo and colleagues¹³ reported agreement of ASES members surveyed regarding rotator cuff management. There was no consensus among surgeons in more than 50% of questions, despite AAOS published guidelines for rotator cuff treatment.²⁵ Despite the lack of guidelines for our topic, we found a consensus among respondents with 68% of survey questions.

To date, only 2 studies of shoulder instability management have elicited the opinion of experts in shoulder surgery. Chahal and associates⁶ surveyed 42 members of ASES and JOINTS (Joined Orthopaedic Initiatives for National Trials of the Shoulder) Canada on shoulder instability cases and found substantial agreement on diagnosis but little consensus regarding surgical technique. This lack of agreement on procedures differs from our findings and may be related to their complicated case scenarios that generated a wide array of treatment recommendations. Randelli and colleagues⁵ surveyed more than 1000 European Society of Sports Traumatology, Knee Surgery, and Arthroscopy members and reported similar agreement on arthroscopic Bankart repair in young male shoulder-dislocation patients, although no other instability scenarios were investigated. Our study is the first to report responses from expert shoulder surgeons on surgical-treatment strategies for an array of common shoulder instability pathologies.

This study had several limitations. First, while our study suffered from a low response rate (29.9%), it was similar to other published studies.^5,13 Second, because the case series included in the survey attempted to capture the most common instability scenarios, they were limited in their scope and failed to address additional etiologies or pathologic permutations. We believe, however, that a more comprehensive survey would have resulted in respondent fatigue and lowered the response rate. It is unlikely that any survey could capture all variables that come into play during clinical decision-making, and we sought to evaluate the most common shoulder instability scenarios. Third, 30% of respondents were from outside the United States, where the Latarjet procedure is much more popular. While this was not a majority, Latarjet’s regional preference may have decreased the consensus response in some scenarios if only the United States was included. Finally, there is inherent bias in a respondent pool that is heavily weighted to shoulder-surgery experts (ASES members) and does not consider the responses of the general orthopedic surgery community as have other studies.⁷

Conclusion

This study demonstrates that expert shoulder surgeons often agreed on shoulder-treatment principles for anterior shoulder instability. In the setting of primary repair, arthroscopic Bankart repair was favored in the absence of bony pathology, regardless of age (20 to 35 years) or nature of sport (contact versus noncontact). Latarjet procedures were favored in the setting of glenoid bone loss, and remplissage for an engaging Hill-Sachs lesion. Less agreement was observed for revision stabilization. It should be noted that, while consensus was often reached for our cases, there was a wide distribution of technical considerations and surgical preferences even among those who are fellowship-trained and high-volume surgeons, and who can be considered experts in the field of shoulder surgery.

Despite an abundance of peer-reviewed resources, there is wide variation in the surgical management of shoulder instability.^1,2 Current American Academy of Orthopaedic Surgeons (AAOS) clinical practice guidelines regarding the shoulder address only generalized shoulder pain, glenohumeral osteoarthritis, and rotator cuff injuries,^3,4 and treatment algorithms focus on conservative treatment, rather than surgical recommendations.^4-7

Shoulder instability most commonly results from 1 or more of 4 common lesions (capsular laxity, glenoid bone loss, humeral bone loss, and capsulolabral insufficiency).⁸ While it is a relatively common condition that represents 1% to 2% of all athletic injuries,^9,10 little consensus exists about surgical indications, ideal treatment algorithms, or optimal operative technique. This is a critical issue because more than 50% of patients with glenohumeral instability will undergo surgical intervention.¹¹ Chahal and associates⁶ surveyed 44 shoulder experts and reported strong consensus about diagnosis, but little agreement regarding surgical management. Owens and colleagues¹ have also evaluated current trends for surgical treatment of this pathology. Randelli and associates⁵ attempted to categorize operative management based upon case-specific shoulder scenarios through online surveys. Their survey, however, covered a broad range of shoulder injuries rather than instability in particular. In this study, we assess trends for surgical management of glenohumeral instability in a case-based survey of shoulder experts.

Materials and Methods

Survey Information

An online survey (Survey Monkey) of 417 active members of the American Shoulder and Elbow Surgeons (ASES) was administered on May 1, 2014. Respondents were blinded to the institution and co-investigators conducting the survey. The survey link was distributed via email because it has been shown to be a more efficacious conduit than standard postal mail.¹² The case-based, 25-question survey (Appendix) was designed to assess respondents’ selection of surgical intervention. Section 1 determined member demographics, including fellowship training, arthroscopy experience, and years of practice. Section 2 involved the presentation of 5 case scenarios. For each case, respondents were asked to identify the optimal surgical procedure in both primary and revision settings. Section 3 posed several general questions regarding shoulder-instability management.

Statistical Analysis

Data were stored using Microsoft Excel (Microsoft) and analyzed using SAS Software version 9.3 (SAS Institute, Inc.). Demographic survey responses were reported using descriptive statistics. Responses to clinical survey questions were reported using frequencies and percentages. To identify when a majority consensus was achieved for a given question, responses were flagged as reaching consensus when more than 50% of participants gave the same response.¹³In the event that only 2 response options were available, reaching consensus required 67% of respondents to choose a single answer (since, by default, a consensus would be reached with only 2 response options). Because this was an analysis of all respondents, an a priori power calculation was not performed. Associations between training and practice demographics and responses to clinical questions were investigated using chi-square analyses. All comparative analyses were two-tailed and used P = .05 as the threshold for statistical significance.

Results

Demographics

One hundred and twenty-five (29.9%) ASES members responded to the survey. Of the respondents, 71.2% reported at least 15 years of experience, and 71% performed more than 150 shoulder cases annually. Surgeons came from academic institutions (41.6%), private practice (24.8%), or mixed (33.6%). The majority of respondents were fellowship-trained in shoulder/elbow surgery (52.8%), while fewer had completed a sports-medicine fellowship (24.0%). For arthroscopic procedures, responses were nearly divided between those who preferred beach-chair positioning (47.2%) and those who preferred the lateral decubitus position (46.4%). The majority (70.4%) of respondents practiced in the United States and with a relatively even distribution among states and region. The remaining 29.6% of those surveyed practiced abroad.

Degree of Consensus Responses and Cases

Of the 25 survey questions, 6 questions were omitted from consensus calculations because these were designed for demographic categorization rather than professional opinion (questions 1-5, 8). Thirteen of the remaining 19 questions (68%) reached consensus response. All clinical case scenarios (5 of 5) reached consensus for selection of technique for the primary procedure; however, only 40% (2 of 5) of cases had a consensus in the revision setting.

In case 1, a young soccer player (noncontact athlete) with negligible bone loss, arthroscopic Bankart repair was recommended by 81.6% of respondents. In the event of revision surgery, only 22.4% recommended arthroscopic Bankart repair, and the remainder split between open Bankart repair with possible capsular shift (36%) or Latarjet procedure (32.8%).

In case 2, a college American football player (contact athlete) with negligible bone loss, arthroscopic Bankart repair was recommended by 56.8%. In the event of revision surgery, a majority of members (51.2%) suggested a Latarjet procedure.

In case 3, the weekend warrior with significant bone loss, most respondents recommended a Latarjet procedure for both primary (72.8%) and revision surgery (79.0%).

In case 4, a weekend warrior with multidirectional instability, 60% of respondents suggested arthroscopic Bankart repair, 21.6% recommended rotator interval closure, and 10.4% chose a capsular shift. As a revision procedure, there was less agreement, with a split between open Bankart repair (39.2%) and capsular shift only (39.2%).

In case 5, the weekend warrior with large engaging Hill-Sachs lesions, 60% of respondent selected a remplissage procedure. If revision was required, a Latarjet procedure was the choice of 48.8% of respondents (Table).

General Questions

For contact athletes, most respondents (87.2%) would allow return to play in the same season and recommended surgery after the end of the season. After surgical intervention, 56.8% prescribed 4 weeks of immobilization. When counseling a return to contact sports, 51.2% recommended waiting for 4 to 6 months.

The ASES members were divided on conservative management of instability injuries. Responses included immobilization in internal rotation (39.2%), no immobilization (39.2%), and external-rotation bracing (21.6%).

Finally, members thought the most important factor in choosing surgical technique was the patient’s pathology, then age; the least influential criteria was the patient’s sports participation.

Analysis of Training Demographics and Surgical Technique Preferences

Chi-square analyses demonstrated that respondents who completed a sports fellowship were more likely to do at least 50% of cases arthroscopically (odds ratio [OR], 15.3; P < .001) and were more likely to use the lateral decubitus position (OR, 2.8; P < .021). Furthermore, American respondents had a higher likelihood of having completed either a sports fellowship (OR, 12.8; P < .001) or a shoulder/elbow fellowship (OR, 4.6; P = .002) when compared with foreign respondents.

Discussion

In the absence of formal clinical practice guidelines, most surgeons formulate treatment strategy based upon a combination of experience and peer-reviewed evidence. The cohort analyzed in the current study was highly experienced, with more than 70% performing 150 shoulder cases annually and having more than 15 years of experience. We found a consensus response in 68% of questions and all primary surgical techniques for our shoulder instability scenarios. While expert consensus reported here is not equivalent to evidence-based clinical practice guidelines, it does provide important information to consider when treating anterior shoulder instability.

Specific responses to our case scenarios invite further reflection. Considering young (both noncontact and contact) athletes without bony pathology (cases 1 and 2, respectively), the ASES surgeons recommended arthroscopic Bankart repair for both. Randelli and associates5 found 71% of survey respondents recommended arthroscopic Bankart repair in a similar setting. It is interesting to note that consensus persisted regardless of the sport in which they engaged. Contact athletes have the highest rates of dislocation (up to 7 times higher incidence) compared with the general population.¹⁴ In addition, they have a higher recurrence rate after surgery.¹⁵ It should be noted, however, that although both cases reached consensus, the percentage of experts who recommended an arthroscopic procedure fell from 82% in the noncontact athlete to 57% in the contact athlete. This concurs with a recent review by Harris and Romeo,¹⁶ who recommended similar treatments for athletes without bony defects. In an older patient population with recurrent instability (case 3), responses varied more widely but still reached a consensus on primary surgical techniques. Respondents agreed that, even for patients with multidirectional instability, initial management should consist of arthroscopic capsulolabral repair. Overall, the agreement for arthroscopy for cases 1 through 3 mimics recent US practice patterns, showing 90% of stabilizations are being performed arthroscopically.¹⁷ Additionally, a recent meta-analysis by Harris and associates18 favored arthroscopic Bankart repair, showing no significant difference vs open stabilization even on long-term follow-up.

Glenoid bone loss is a difficult clinical scenario and that is reflected in this study’s findings. The literature suggests that arthroscopic Bankart repair, in this setting, is usually not sufficient and may result in a recurrence rate up to 75%, if bone loss greater than 20% is unaddressed.¹⁹ Our study supports this trend because ASES members recommended a Latarjet procedure when there is substantial bone loss.

While open Latarjet procedure was the consensus for dealing with glenoid bone loss, arthroscopic techniques were strongly favored for humeral head defects. This change in practice patterns results from the introduction of the arthroscopic remplissage technique.²⁰ Two recent systemic reviews have supported this technique, reporting good functional outcomes for engaging Hill-Sachs lesions.^21,22 Our study had similar agreement, with most respondents recommending remplissage for these patients.

This study found the lowest rates of expert consensus in the setting of revision surgery, likely caused, in part, by the paucity of available large cohort studies. This is a major void in the literature, and more studies are needed to help guide surgeons on the best techniques to deal with this difficult patient population.

Conservative bracing technique was 1 of the survey questions lacking a consensus response. Interestingly, 39% of members recommended no immobilization after an instability event. This contrasts with recent literature concerning the best position for bracing. We also found twice as many surgeons recommended internal rotation immobilization over external rotation. This is a subject of debate, with some studies stating improvement with external rotation immobilization,²³ while other studies reported no difference.²⁴ Overall, recommendations regarding type of immobilization are unclear, which will likely continue until larger studies can be performed.

The literature describing surgical trends in the treatment of shoulder instability is sparse and variable. With regard to other shoulder etiologies, only rotator cuff pathology has used expert consensus. Acevedo and colleagues¹³ reported agreement of ASES members surveyed regarding rotator cuff management. There was no consensus among surgeons in more than 50% of questions, despite AAOS published guidelines for rotator cuff treatment.²⁵ Despite the lack of guidelines for our topic, we found a consensus among respondents with 68% of survey questions.

To date, only 2 studies of shoulder instability management have elicited the opinion of experts in shoulder surgery. Chahal and associates⁶ surveyed 42 members of ASES and JOINTS (Joined Orthopaedic Initiatives for National Trials of the Shoulder) Canada on shoulder instability cases and found substantial agreement on diagnosis but little consensus regarding surgical technique. This lack of agreement on procedures differs from our findings and may be related to their complicated case scenarios that generated a wide array of treatment recommendations. Randelli and colleagues⁵ surveyed more than 1000 European Society of Sports Traumatology, Knee Surgery, and Arthroscopy members and reported similar agreement on arthroscopic Bankart repair in young male shoulder-dislocation patients, although no other instability scenarios were investigated. Our study is the first to report responses from expert shoulder surgeons on surgical-treatment strategies for an array of common shoulder instability pathologies.

This study had several limitations. First, while our study suffered from a low response rate (29.9%), it was similar to other published studies.^5,13 Second, because the case series included in the survey attempted to capture the most common instability scenarios, they were limited in their scope and failed to address additional etiologies or pathologic permutations. We believe, however, that a more comprehensive survey would have resulted in respondent fatigue and lowered the response rate. It is unlikely that any survey could capture all variables that come into play during clinical decision-making, and we sought to evaluate the most common shoulder instability scenarios. Third, 30% of respondents were from outside the United States, where the Latarjet procedure is much more popular. While this was not a majority, Latarjet’s regional preference may have decreased the consensus response in some scenarios if only the United States was included. Finally, there is inherent bias in a respondent pool that is heavily weighted to shoulder-surgery experts (ASES members) and does not consider the responses of the general orthopedic surgery community as have other studies.⁷

Conclusion

This study demonstrates that expert shoulder surgeons often agreed on shoulder-treatment principles for anterior shoulder instability. In the setting of primary repair, arthroscopic Bankart repair was favored in the absence of bony pathology, regardless of age (20 to 35 years) or nature of sport (contact versus noncontact). Latarjet procedures were favored in the setting of glenoid bone loss, and remplissage for an engaging Hill-Sachs lesion. Less agreement was observed for revision stabilization. It should be noted that, while consensus was often reached for our cases, there was a wide distribution of technical considerations and surgical preferences even among those who are fellowship-trained and high-volume surgeons, and who can be considered experts in the field of shoulder surgery.

Although recent clinical results of arthroscopic rotator cuff repair (RCR) have been encouraging, achieving anatomical healing of full-thickness rotator cuff tears remains a challenge.^1-4 Several factors influence rotator cuff healing after repair.^1,3-8 Patient-related factors include advanced patient age, tear size, tear chronicity, and amount of fatty infiltration.^1,3,5,6,8-10 Tension applied to the repair construct is a significant factor as well.^11,12

In the literature, limited consideration has been given to repair tension.¹³ The majority of studies have focused on other factors, mainly repair technique. Some surgeons advocate use of a double-row repair construct in which the rotator cuff tendon is pulled to the lateral margin of the footprint.^14-19 Double-row techniques, which include the transosseous-equivalent (TOE) construct, are biomechanically superior to other repairs.^20-26 Another purported benefit of double-row repair is more complete restoration and pressurization of the rotator cuff footprint.^21,24,27,28

Rotator cuff tears typically occur near the dysvascular region of the diseased musculotendinous unit, often leaving a stump of tissue attached to the tuberosity and ultimately a shortened tendon.²⁹ In addition, full-thickness tears often retract over time. Meyer and colleagues²⁹ recently demonstrated that this shortening is irreversible. Snyder³⁰ and Sostak and colleagues³¹ suggested that pulling a shortened, degenerative rotator cuff tendon to the lateral margin of the footprint results in increased tissue tension compared with that produced with a more medially based repair just off the articular margin. In our opinion, the possible increase in tension during a laterally based repair, whether single- or double-row, may place excessive strain on the diseased tissue as well as the surgical construct, potentially contributing to repair failure.

We conducted a study to evaluate the difference, if any, in tension applied to the rotator cuff tendon positioned at the medial versus lateral margin of the footprint during arthroscopic RCR. We hypothesized significantly more tension would be placed on the rotator cuff tendon when positioned at the lateral versus medial footprint.

Methods

After obtaining Institutional Review Board approval for this study, we collected data on a consecutive series of patients who underwent arthroscopic RCR performed by Dr. Getelman at a single institution. Only patients with primary full-thickness tears of the supraspinatus and/or infraspinatus were included. Exclusion criteria included revision rotator cuff surgeries, partial-thickness tears, concurrent subscapularis tears requiring anchor fixation, and any tears that could not be mobilized to the lateral footprint without interval slides or margin convergence. The 20 identified patients constituted the study group.

Demographic factors, including age and preoperative length of symptoms, were recorded after chart review. Magnetic resonance imaging (MRI) was performed for all patients before surgery and was retrospectively reviewed. Dr. Getelman assigned each patient a modified Goutallier score, based on MRI, to assess for fatty infiltration/atrophy.³² Each patient was placed in the lateral decubitus position with the operative arm in balanced suspension at 70° of abduction. Standard glenohumeral and subacromial diagnostic arthroscopy was performed. The rotator cuff tear was gently debrided back to a healthy-appearing margin in preparation for repair. The tear was then measured in the anterior-posterior (A-P) and medial-lateral (M-L) planes using a premeasured, marked suture, as previously described.33 Complete bursal and articular-sided releases were performed to allow for appropriate mobilization of the tendon. The tear was classified as crescent-shaped, U-shaped, or L-shaped.

Viewing from the posterior portal, the surgeon inserted a tissue grasper through the lateral portal. The tendon was grasped at multiple points along its edge, anterior to posterior, and was translated laterally to assess its reducibility; the apex of the tear correlated with the point of maximal excursion and coverage of the footprint. Once confirmed, the rotator cuff tear apex was clamped with a tissue grasper. After placement in a sterile arthroscopic camera sleeve (DeRoyal camera drape with perforated tip), a calibrated digital weigh scale (American Weigh Scales model H22 portable electronic hanging scale, with accuracy of 0.01 lb) was attached to the tissue grasper with an S-hook (Figure 1). The tendon edge was first translated about 3 mm lateral to the articular margin (the medial footprint position), and tension was recorded (Figures 2A, 2B). After a 1-minute relaxation period, the tendon edge was translated to the lateral edge of the rotator cuff footprint (the lateral footprint position), and tension was recorded again (Figures 2C, 2D). A medially based single-row RCR with triple-loaded sutures and bone marrow vents placed in the lateral tuberosity was then completed, regardless of tension, tear size, or tear morphology.³¹ Typically, 1 anchor was used for every 10 to 15 mm of A-P tear length.

SAS software was used for statistical analysis, the Wilcoxon signed rank test for continuous or ordinal data comparisons between paired groups, and the Mann-Whitney test for continuous or ordinal data comparisons between independent, unmatched groups. One-way analysis of variance (ANOVA) was used to compare means among the 3 groups of morphology subtypes. Linear regression was performed to assess the simultaneous relationship between potential predictors (age, sex, length of symptoms, Goutallier score, tear size) and medial or lateral tension, where medial tension was included as an additional potential predictor for lateral tension. Restricted cubic splines were fit to assess linearity. Predictors were retained in multivariate regression using backward variable retention. Because of inadequate sample size, additivity was assumed except for sex. Statistical significance was set at P < .05.

Results

Of the 20 rotator cuff tears evaluated (Table 1), 13 were crescent-shaped, 5 were U-shaped, and 2 were L-shaped. Mean (SD) A-P tear size was 17.7 (5.8) mm, and mean (SD) M-L tear size was 19.1 (8.6) mm. Mean age of the 20 patients (15 men, 5 women) was 57.9 years (range, 44-72 years). Mean (SD) length of symptoms was 12.9 (12.4) months (range, 3-48 months). Mean (SD) modified Goutallier score was 1.4 (0.7; range, 0-3).

Mean (SD) rotator cuff tension for all tears approximated to the medial footprint was 0.41 (0.33) pound, and mean (SD) cuff tension for all tears approximated to the lateral footprint was 2.21 (1.20) pounds—representing a 5.4-fold difference (P < .0001).

No statistically significant differences were detected in the ANOVA comparing tensions at medial and lateral positions among tear morphologic subtypes (all Ps >.05).

Subgroup analysis (Table 2) was performed for smaller (≤20 mm A-P) and larger (>20 mm A-P) tears. For smaller tears, mean (SD) tension was 0.27 (0.24) pound applied with the cuff tendon pulled to the medial footprint and 2.06 (1.06) pounds applied with the tendon pulled to the lateral footprint—a 7.6-fold difference (P < .0018). For larger tears, mean (SD) tension was 0.58 (0.37) pound applied with the tendon pulled to the medial footprint and 2.38 (1.4) pounds applied with the tendon pulled to the lateral footprint—a 4.1-fold difference (P < .005).

A statistically significant difference in tensions was found between small and large cuff tears positioned at the medial footprint (0.27 vs 0.58 lb; P = .0367); no difference was found between groups with the tendon at the lateral footprint (2.06 vs 2.38 lb; P = .284).

Univariate and multivariate analyses were performed using linear regression analysis (Table 3). During univariate analysis for medial footprint position, A-P tear size and Goutallier score both positively correlated with increasing tension; for lateral footprint position, no factors statistically correlated with lateral tension, though there was a positive trend for medial tension and female sex. During multivariate analysis for medial footprint position, only A-P tear size positively correlated with increasing tension; for lateral footprint position, both age (in nonlinear fashion as function of age + age²) and medial tension positively correlated with increasing tension.

Discussion

Our results indicated that significantly more tension is placed on the torn rotator cuff tendon when it is reduced across the footprint from a medial to a more lateral position in vivo. More tension was required for all tears to be reduced to the lateral footprint compared with the medial footprint. As expected, compared with smaller tears, larger tears required significantly more tension in order to be reduced to the medial footprint. Interestingly, no statistical difference was found between tensions required to reduce either small or large tears to the lateral footprint, which suggests that, regardless of tear size, more force must be applied to reduce the torn tendon to the lateral footprint compared with the medial footprint.

Hersche and Gerber³⁴ were the first to report rotator cuff tension measurements in vivo. Although their study did not specifically compare cuff tensions reducing the tear to the medial versus lateral footprint, it did examine tension at displacement of 10 and 20 mm. Tension increased from 27 N to 60 N, correlating with a 2.2-fold difference between the 2 distances. Domb and colleagues35 also compared in vivo rotator cuff tension differences between the medial footprint and the lateral footprint in 4 patients. Mean tension applied to the cuff during reduction to the articular margin was 27 N, or 6 pounds. Mean tension needed to reduce the cuff to the lateral tuberosity was 76 N, or 17 pounds, for a 2.8-fold difference. Tears were not measured but were described as massive and retracted.

Although repair tension has long been recognized as a crucial factor in RCR healing, little clinical research has focused on the effects of excess tension. Davidson and Rivenburgh11 prospectively followed the clinical outcomes of 67 consecutive cuff repairs after intraoperative tension measurement and found that high-tension repairs (>8 lb) had significantly lower clinical outcome measures. However, the authors did not report on correlations with radiologic healing and stated, “Functional outcome is inversely proportional to rotator cuff repair tension.” Further study of the in vivo effects of increased tension on clinical and radiologic outcomes is needed.

Several animal studies have been conducted on the effects of tension on RCRs. Gerber and colleagues36 reported that the force needed to produce 1 cm of sheep supraspinatus tendon excursion increased 7-fold, from 6.8 N to 47.8 N, after 40 weeks of tendon tear. Coleman and colleagues³⁷ compared the modulus of elasticity in sheep supraspinatus tendon after 6 weeks and 18 weeks of detachment and reported increases of 60% and 70%, respectively. Gimbel and colleagues³⁸ showed that, in a rat model, “repair tension rapidly increased initially after injury followed by a progressive, but less dramatic, increase with additional time.” Of note, we did not identify any correlation between chronicity of symptoms and the tension needed to reduce the tendon medially or to a more lateral position on the footprint.

In acute tears, the cuff tissue is more compliant and mobile and can be pulled laterally across its anatomical footprint with minimal tension.³⁹ In contrast, cuff tissue in the more commonly encountered chronic tear is less compliant and is not mobile enough to be pulled to the lateral margin of the footprint without added stress.^30,34,35 In large, acute tears in which there are minimal tissue degeneration and retraction, a laterally based footprint-restoring technique may be performed with minimal tension. This technique may have advantages over a medially based repair. In the literature, more attention needs to be directed toward the biomechanics and biology of chronic rotator cuff tears, as these are more commonly encountered.

Almost all of the prospective studies that have compared single- and double-row RCR have found no significant differences in MRI healing rates or clinical results at follow-up up to 2 years.^14,16,40-45 Detailed analysis of the surgical techniques used in all these studies revealed that the rotator cuff tendons were repaired back to the lateral footprint in both the single- and double-row constructs.^14,16,40-45 Although no clinical studies have compared medially and laterally based single-row repairs, our data suggest that medially based repairs have lower tensions and therefore should not be considered equivalent. Sostak and colleagues³¹ and Murray and colleagues⁴⁶ have shown that a medially based single-row RCR can achieve excellent clinical and anatomical results, likely partly because of the lower tension applied to the torn cuff tissue.^31,46 Studies are needed to compare medially and laterally based repairs, including single- and double-row repairs.

The vast majority of recent research has aimed to counteract construct tension with stronger biomechanical constructs.^20-26 Surgeons have also aimed to improve biological healing by pulling the tendon laterally across the footprint to achieve complete footprint coverage, ultimately increasing the surface area for tendon–bone healing. This has led to the development of various double-row repair techniques, in which the cuff tendon is pulled to the lateral margin of its footprint. One row of anchors is placed in the medial aspect of the footprint, while a second is placed in the lateral aspect; the cuff is reduced and compressed to the tuberosity with various suture configurations. The TOE technique was developed to improve pressurization of the cuff tendon across the footprint by linking the 2 rows with bridging sutures. In doing so, however, the potentially deleterious effects of increased tension introduced by pulling the tendon laterally may have been overlooked. Nevertheless, the biomechanics and stress distribution likely differ between single-row repair and TOE repairs, and direct comparisons cannot be made at this time. The medial row of a double-row or TOE construct may stress-shield or “unload” the more lateral tissue. Studies are needed in order to better understand the tension differential and stress distribution of various double-row constructs.

Recognizing tear morphology is crucial in maximizing chances of healing after cuff repair. For example, a crescent-shaped tear is reduced to the tuberosity with direct lateral translation of the apex of the tear, which is also the deepest or most displaced part of the tear. On the other hand, reducing an L- or reverse L-shaped tear to the tuberosity is not as direct; reducing the deepest or most displaced part of the tear would lead to overreduction and overtensioning of the tendon. However, often the exact “elbow” of the tear is not obvious and appears more rounded; therefore, it is crucial for the surgeon to examine the mobility of the torn tendon along its entire length to minimize tension. Study is needed to assess tension along the entire length of the tear for different tear morphologies and sizes.

Although our results showed that increased tension was needed to reduce a torn tendon to its lateral footprint, no study has indicated exactly how much is “too much” tension. As stated earlier, use of stronger biomechanical constructs, including TOE constructs, may overcome the increased tension associated with laterally based repairs. In addition, laterally based repairs, either single- or double-row, may be best suited for tears with lower tension, whereas medially based repairs may be best suited for higher tension tears. It is also possible that the difference in tensions noted in this study is not significant enough to have a clinical impact on choice of construct or on anatomical healing. We need studies that correlate anatomical healing rates with repair tension in order to better guide surgeons on when to use a medially or laterally based repair.

Other possible effects of increased tension associated with laterally based repairs, including beneficial effects, must be considered as well. Viscoelastic properties of human rotator cuff tendon may dissipate increased tension over time through a variety of mechanisms. Stress relaxation, gap formation, creep, and the hysteresis effect, all associated with cyclical loading in the early healing period, may lead to dissipation of force over time.^47,48 These more complex biomechanical properties of RCR constructs are yet to be clearly defined.

This study had several weaknesses. Its data represent a static measurement of time-zero rotator cuff tension, which greatly simplifies the biomechanics of the torn rotator cuff and repair construct as well as changes that occur with healing. During cuff repair, forces typically are distributed through several fixation points in stepwise process and are not focused on a single point of tissue with a grasper. Therefore, the findings of this study may not directly correlate with medially versus laterally based repairs in vivo. Furthermore, as this is a time-zero measurement, we could not determine whether the tension differential between the 2 repair positions remained static over time. Current literature suggests that muscle atrophy, fatty infiltration, and loss of elasticity of the musculotendinous unit are relatively irreversible.^35,37,49 In addition, determining the precise apex of a cuff tear can be difficult, so error may have been introduced during this process. Last, although placement of the cuff tissue at the medial or lateral footprint position was based on visual estimation by an experienced and skilled arthroscopist, error may have been introduced based on this imprecise technique.

Conclusion

This study demonstrated a significant, 5.4-fold increase in in vivo time-zero rotator cuff tension with the tendon edge reduced to the lateral footprint rather than the medial footprint.

Although recent clinical results of arthroscopic rotator cuff repair (RCR) have been encouraging, achieving anatomical healing of full-thickness rotator cuff tears remains a challenge.^1-4 Several factors influence rotator cuff healing after repair.^1,3-8 Patient-related factors include advanced patient age, tear size, tear chronicity, and amount of fatty infiltration.^1,3,5,6,8-10 Tension applied to the repair construct is a significant factor as well.^11,12

In the literature, limited consideration has been given to repair tension.¹³ The majority of studies have focused on other factors, mainly repair technique. Some surgeons advocate use of a double-row repair construct in which the rotator cuff tendon is pulled to the lateral margin of the footprint.^14-19 Double-row techniques, which include the transosseous-equivalent (TOE) construct, are biomechanically superior to other repairs.^20-26 Another purported benefit of double-row repair is more complete restoration and pressurization of the rotator cuff footprint.^21,24,27,28

Rotator cuff tears typically occur near the dysvascular region of the diseased musculotendinous unit, often leaving a stump of tissue attached to the tuberosity and ultimately a shortened tendon.²⁹ In addition, full-thickness tears often retract over time. Meyer and colleagues²⁹ recently demonstrated that this shortening is irreversible. Snyder³⁰ and Sostak and colleagues³¹ suggested that pulling a shortened, degenerative rotator cuff tendon to the lateral margin of the footprint results in increased tissue tension compared with that produced with a more medially based repair just off the articular margin. In our opinion, the possible increase in tension during a laterally based repair, whether single- or double-row, may place excessive strain on the diseased tissue as well as the surgical construct, potentially contributing to repair failure.

We conducted a study to evaluate the difference, if any, in tension applied to the rotator cuff tendon positioned at the medial versus lateral margin of the footprint during arthroscopic RCR. We hypothesized significantly more tension would be placed on the rotator cuff tendon when positioned at the lateral versus medial footprint.

Methods

After obtaining Institutional Review Board approval for this study, we collected data on a consecutive series of patients who underwent arthroscopic RCR performed by Dr. Getelman at a single institution. Only patients with primary full-thickness tears of the supraspinatus and/or infraspinatus were included. Exclusion criteria included revision rotator cuff surgeries, partial-thickness tears, concurrent subscapularis tears requiring anchor fixation, and any tears that could not be mobilized to the lateral footprint without interval slides or margin convergence. The 20 identified patients constituted the study group.

Demographic factors, including age and preoperative length of symptoms, were recorded after chart review. Magnetic resonance imaging (MRI) was performed for all patients before surgery and was retrospectively reviewed. Dr. Getelman assigned each patient a modified Goutallier score, based on MRI, to assess for fatty infiltration/atrophy.³² Each patient was placed in the lateral decubitus position with the operative arm in balanced suspension at 70° of abduction. Standard glenohumeral and subacromial diagnostic arthroscopy was performed. The rotator cuff tear was gently debrided back to a healthy-appearing margin in preparation for repair. The tear was then measured in the anterior-posterior (A-P) and medial-lateral (M-L) planes using a premeasured, marked suture, as previously described.33 Complete bursal and articular-sided releases were performed to allow for appropriate mobilization of the tendon. The tear was classified as crescent-shaped, U-shaped, or L-shaped.

Viewing from the posterior portal, the surgeon inserted a tissue grasper through the lateral portal. The tendon was grasped at multiple points along its edge, anterior to posterior, and was translated laterally to assess its reducibility; the apex of the tear correlated with the point of maximal excursion and coverage of the footprint. Once confirmed, the rotator cuff tear apex was clamped with a tissue grasper. After placement in a sterile arthroscopic camera sleeve (DeRoyal camera drape with perforated tip), a calibrated digital weigh scale (American Weigh Scales model H22 portable electronic hanging scale, with accuracy of 0.01 lb) was attached to the tissue grasper with an S-hook (Figure 1). The tendon edge was first translated about 3 mm lateral to the articular margin (the medial footprint position), and tension was recorded (Figures 2A, 2B). After a 1-minute relaxation period, the tendon edge was translated to the lateral edge of the rotator cuff footprint (the lateral footprint position), and tension was recorded again (Figures 2C, 2D). A medially based single-row RCR with triple-loaded sutures and bone marrow vents placed in the lateral tuberosity was then completed, regardless of tension, tear size, or tear morphology.³¹ Typically, 1 anchor was used for every 10 to 15 mm of A-P tear length.

SAS software was used for statistical analysis, the Wilcoxon signed rank test for continuous or ordinal data comparisons between paired groups, and the Mann-Whitney test for continuous or ordinal data comparisons between independent, unmatched groups. One-way analysis of variance (ANOVA) was used to compare means among the 3 groups of morphology subtypes. Linear regression was performed to assess the simultaneous relationship between potential predictors (age, sex, length of symptoms, Goutallier score, tear size) and medial or lateral tension, where medial tension was included as an additional potential predictor for lateral tension. Restricted cubic splines were fit to assess linearity. Predictors were retained in multivariate regression using backward variable retention. Because of inadequate sample size, additivity was assumed except for sex. Statistical significance was set at P < .05.

Results

Of the 20 rotator cuff tears evaluated (Table 1), 13 were crescent-shaped, 5 were U-shaped, and 2 were L-shaped. Mean (SD) A-P tear size was 17.7 (5.8) mm, and mean (SD) M-L tear size was 19.1 (8.6) mm. Mean age of the 20 patients (15 men, 5 women) was 57.9 years (range, 44-72 years). Mean (SD) length of symptoms was 12.9 (12.4) months (range, 3-48 months). Mean (SD) modified Goutallier score was 1.4 (0.7; range, 0-3).

Mean (SD) rotator cuff tension for all tears approximated to the medial footprint was 0.41 (0.33) pound, and mean (SD) cuff tension for all tears approximated to the lateral footprint was 2.21 (1.20) pounds—representing a 5.4-fold difference (P < .0001).

No statistically significant differences were detected in the ANOVA comparing tensions at medial and lateral positions among tear morphologic subtypes (all Ps >.05).

Subgroup analysis (Table 2) was performed for smaller (≤20 mm A-P) and larger (>20 mm A-P) tears. For smaller tears, mean (SD) tension was 0.27 (0.24) pound applied with the cuff tendon pulled to the medial footprint and 2.06 (1.06) pounds applied with the tendon pulled to the lateral footprint—a 7.6-fold difference (P < .0018). For larger tears, mean (SD) tension was 0.58 (0.37) pound applied with the tendon pulled to the medial footprint and 2.38 (1.4) pounds applied with the tendon pulled to the lateral footprint—a 4.1-fold difference (P < .005).

A statistically significant difference in tensions was found between small and large cuff tears positioned at the medial footprint (0.27 vs 0.58 lb; P = .0367); no difference was found between groups with the tendon at the lateral footprint (2.06 vs 2.38 lb; P = .284).

Univariate and multivariate analyses were performed using linear regression analysis (Table 3). During univariate analysis for medial footprint position, A-P tear size and Goutallier score both positively correlated with increasing tension; for lateral footprint position, no factors statistically correlated with lateral tension, though there was a positive trend for medial tension and female sex. During multivariate analysis for medial footprint position, only A-P tear size positively correlated with increasing tension; for lateral footprint position, both age (in nonlinear fashion as function of age + age²) and medial tension positively correlated with increasing tension.

Discussion

Our results indicated that significantly more tension is placed on the torn rotator cuff tendon when it is reduced across the footprint from a medial to a more lateral position in vivo. More tension was required for all tears to be reduced to the lateral footprint compared with the medial footprint. As expected, compared with smaller tears, larger tears required significantly more tension in order to be reduced to the medial footprint. Interestingly, no statistical difference was found between tensions required to reduce either small or large tears to the lateral footprint, which suggests that, regardless of tear size, more force must be applied to reduce the torn tendon to the lateral footprint compared with the medial footprint.

Hersche and Gerber³⁴ were the first to report rotator cuff tension measurements in vivo. Although their study did not specifically compare cuff tensions reducing the tear to the medial versus lateral footprint, it did examine tension at displacement of 10 and 20 mm. Tension increased from 27 N to 60 N, correlating with a 2.2-fold difference between the 2 distances. Domb and colleagues35 also compared in vivo rotator cuff tension differences between the medial footprint and the lateral footprint in 4 patients. Mean tension applied to the cuff during reduction to the articular margin was 27 N, or 6 pounds. Mean tension needed to reduce the cuff to the lateral tuberosity was 76 N, or 17 pounds, for a 2.8-fold difference. Tears were not measured but were described as massive and retracted.

Although repair tension has long been recognized as a crucial factor in RCR healing, little clinical research has focused on the effects of excess tension. Davidson and Rivenburgh11 prospectively followed the clinical outcomes of 67 consecutive cuff repairs after intraoperative tension measurement and found that high-tension repairs (>8 lb) had significantly lower clinical outcome measures. However, the authors did not report on correlations with radiologic healing and stated, “Functional outcome is inversely proportional to rotator cuff repair tension.” Further study of the in vivo effects of increased tension on clinical and radiologic outcomes is needed.

Several animal studies have been conducted on the effects of tension on RCRs. Gerber and colleagues36 reported that the force needed to produce 1 cm of sheep supraspinatus tendon excursion increased 7-fold, from 6.8 N to 47.8 N, after 40 weeks of tendon tear. Coleman and colleagues³⁷ compared the modulus of elasticity in sheep supraspinatus tendon after 6 weeks and 18 weeks of detachment and reported increases of 60% and 70%, respectively. Gimbel and colleagues³⁸ showed that, in a rat model, “repair tension rapidly increased initially after injury followed by a progressive, but less dramatic, increase with additional time.” Of note, we did not identify any correlation between chronicity of symptoms and the tension needed to reduce the tendon medially or to a more lateral position on the footprint.

In acute tears, the cuff tissue is more compliant and mobile and can be pulled laterally across its anatomical footprint with minimal tension.³⁹ In contrast, cuff tissue in the more commonly encountered chronic tear is less compliant and is not mobile enough to be pulled to the lateral margin of the footprint without added stress.^30,34,35 In large, acute tears in which there are minimal tissue degeneration and retraction, a laterally based footprint-restoring technique may be performed with minimal tension. This technique may have advantages over a medially based repair. In the literature, more attention needs to be directed toward the biomechanics and biology of chronic rotator cuff tears, as these are more commonly encountered.

Almost all of the prospective studies that have compared single- and double-row RCR have found no significant differences in MRI healing rates or clinical results at follow-up up to 2 years.^14,16,40-45 Detailed analysis of the surgical techniques used in all these studies revealed that the rotator cuff tendons were repaired back to the lateral footprint in both the single- and double-row constructs.^14,16,40-45 Although no clinical studies have compared medially and laterally based single-row repairs, our data suggest that medially based repairs have lower tensions and therefore should not be considered equivalent. Sostak and colleagues³¹ and Murray and colleagues⁴⁶ have shown that a medially based single-row RCR can achieve excellent clinical and anatomical results, likely partly because of the lower tension applied to the torn cuff tissue.^31,46 Studies are needed to compare medially and laterally based repairs, including single- and double-row repairs.

The vast majority of recent research has aimed to counteract construct tension with stronger biomechanical constructs.^20-26 Surgeons have also aimed to improve biological healing by pulling the tendon laterally across the footprint to achieve complete footprint coverage, ultimately increasing the surface area for tendon–bone healing. This has led to the development of various double-row repair techniques, in which the cuff tendon is pulled to the lateral margin of its footprint. One row of anchors is placed in the medial aspect of the footprint, while a second is placed in the lateral aspect; the cuff is reduced and compressed to the tuberosity with various suture configurations. The TOE technique was developed to improve pressurization of the cuff tendon across the footprint by linking the 2 rows with bridging sutures. In doing so, however, the potentially deleterious effects of increased tension introduced by pulling the tendon laterally may have been overlooked. Nevertheless, the biomechanics and stress distribution likely differ between single-row repair and TOE repairs, and direct comparisons cannot be made at this time. The medial row of a double-row or TOE construct may stress-shield or “unload” the more lateral tissue. Studies are needed in order to better understand the tension differential and stress distribution of various double-row constructs.

Recognizing tear morphology is crucial in maximizing chances of healing after cuff repair. For example, a crescent-shaped tear is reduced to the tuberosity with direct lateral translation of the apex of the tear, which is also the deepest or most displaced part of the tear. On the other hand, reducing an L- or reverse L-shaped tear to the tuberosity is not as direct; reducing the deepest or most displaced part of the tear would lead to overreduction and overtensioning of the tendon. However, often the exact “elbow” of the tear is not obvious and appears more rounded; therefore, it is crucial for the surgeon to examine the mobility of the torn tendon along its entire length to minimize tension. Study is needed to assess tension along the entire length of the tear for different tear morphologies and sizes.

Although our results showed that increased tension was needed to reduce a torn tendon to its lateral footprint, no study has indicated exactly how much is “too much” tension. As stated earlier, use of stronger biomechanical constructs, including TOE constructs, may overcome the increased tension associated with laterally based repairs. In addition, laterally based repairs, either single- or double-row, may be best suited for tears with lower tension, whereas medially based repairs may be best suited for higher tension tears. It is also possible that the difference in tensions noted in this study is not significant enough to have a clinical impact on choice of construct or on anatomical healing. We need studies that correlate anatomical healing rates with repair tension in order to better guide surgeons on when to use a medially or laterally based repair.

Other possible effects of increased tension associated with laterally based repairs, including beneficial effects, must be considered as well. Viscoelastic properties of human rotator cuff tendon may dissipate increased tension over time through a variety of mechanisms. Stress relaxation, gap formation, creep, and the hysteresis effect, all associated with cyclical loading in the early healing period, may lead to dissipation of force over time.^47,48 These more complex biomechanical properties of RCR constructs are yet to be clearly defined.

This study had several weaknesses. Its data represent a static measurement of time-zero rotator cuff tension, which greatly simplifies the biomechanics of the torn rotator cuff and repair construct as well as changes that occur with healing. During cuff repair, forces typically are distributed through several fixation points in stepwise process and are not focused on a single point of tissue with a grasper. Therefore, the findings of this study may not directly correlate with medially versus laterally based repairs in vivo. Furthermore, as this is a time-zero measurement, we could not determine whether the tension differential between the 2 repair positions remained static over time. Current literature suggests that muscle atrophy, fatty infiltration, and loss of elasticity of the musculotendinous unit are relatively irreversible.^35,37,49 In addition, determining the precise apex of a cuff tear can be difficult, so error may have been introduced during this process. Last, although placement of the cuff tissue at the medial or lateral footprint position was based on visual estimation by an experienced and skilled arthroscopist, error may have been introduced based on this imprecise technique.

Conclusion

This study demonstrated a significant, 5.4-fold increase in in vivo time-zero rotator cuff tension with the tendon edge reduced to the lateral footprint rather than the medial footprint.

Although recent clinical results of arthroscopic rotator cuff repair (RCR) have been encouraging, achieving anatomical healing of full-thickness rotator cuff tears remains a challenge.^1-4 Several factors influence rotator cuff healing after repair.^1,3-8 Patient-related factors include advanced patient age, tear size, tear chronicity, and amount of fatty infiltration.^1,3,5,6,8-10 Tension applied to the repair construct is a significant factor as well.^11,12

In the literature, limited consideration has been given to repair tension.¹³ The majority of studies have focused on other factors, mainly repair technique. Some surgeons advocate use of a double-row repair construct in which the rotator cuff tendon is pulled to the lateral margin of the footprint.^14-19 Double-row techniques, which include the transosseous-equivalent (TOE) construct, are biomechanically superior to other repairs.^20-26 Another purported benefit of double-row repair is more complete restoration and pressurization of the rotator cuff footprint.^21,24,27,28

Rotator cuff tears typically occur near the dysvascular region of the diseased musculotendinous unit, often leaving a stump of tissue attached to the tuberosity and ultimately a shortened tendon.²⁹ In addition, full-thickness tears often retract over time. Meyer and colleagues²⁹ recently demonstrated that this shortening is irreversible. Snyder³⁰ and Sostak and colleagues³¹ suggested that pulling a shortened, degenerative rotator cuff tendon to the lateral margin of the footprint results in increased tissue tension compared with that produced with a more medially based repair just off the articular margin. In our opinion, the possible increase in tension during a laterally based repair, whether single- or double-row, may place excessive strain on the diseased tissue as well as the surgical construct, potentially contributing to repair failure.

We conducted a study to evaluate the difference, if any, in tension applied to the rotator cuff tendon positioned at the medial versus lateral margin of the footprint during arthroscopic RCR. We hypothesized significantly more tension would be placed on the rotator cuff tendon when positioned at the lateral versus medial footprint.

Methods

After obtaining Institutional Review Board approval for this study, we collected data on a consecutive series of patients who underwent arthroscopic RCR performed by Dr. Getelman at a single institution. Only patients with primary full-thickness tears of the supraspinatus and/or infraspinatus were included. Exclusion criteria included revision rotator cuff surgeries, partial-thickness tears, concurrent subscapularis tears requiring anchor fixation, and any tears that could not be mobilized to the lateral footprint without interval slides or margin convergence. The 20 identified patients constituted the study group.

Demographic factors, including age and preoperative length of symptoms, were recorded after chart review. Magnetic resonance imaging (MRI) was performed for all patients before surgery and was retrospectively reviewed. Dr. Getelman assigned each patient a modified Goutallier score, based on MRI, to assess for fatty infiltration/atrophy.³² Each patient was placed in the lateral decubitus position with the operative arm in balanced suspension at 70° of abduction. Standard glenohumeral and subacromial diagnostic arthroscopy was performed. The rotator cuff tear was gently debrided back to a healthy-appearing margin in preparation for repair. The tear was then measured in the anterior-posterior (A-P) and medial-lateral (M-L) planes using a premeasured, marked suture, as previously described.33 Complete bursal and articular-sided releases were performed to allow for appropriate mobilization of the tendon. The tear was classified as crescent-shaped, U-shaped, or L-shaped.

Viewing from the posterior portal, the surgeon inserted a tissue grasper through the lateral portal. The tendon was grasped at multiple points along its edge, anterior to posterior, and was translated laterally to assess its reducibility; the apex of the tear correlated with the point of maximal excursion and coverage of the footprint. Once confirmed, the rotator cuff tear apex was clamped with a tissue grasper. After placement in a sterile arthroscopic camera sleeve (DeRoyal camera drape with perforated tip), a calibrated digital weigh scale (American Weigh Scales model H22 portable electronic hanging scale, with accuracy of 0.01 lb) was attached to the tissue grasper with an S-hook (Figure 1). The tendon edge was first translated about 3 mm lateral to the articular margin (the medial footprint position), and tension was recorded (Figures 2A, 2B). After a 1-minute relaxation period, the tendon edge was translated to the lateral edge of the rotator cuff footprint (the lateral footprint position), and tension was recorded again (Figures 2C, 2D). A medially based single-row RCR with triple-loaded sutures and bone marrow vents placed in the lateral tuberosity was then completed, regardless of tension, tear size, or tear morphology.³¹ Typically, 1 anchor was used for every 10 to 15 mm of A-P tear length.

SAS software was used for statistical analysis, the Wilcoxon signed rank test for continuous or ordinal data comparisons between paired groups, and the Mann-Whitney test for continuous or ordinal data comparisons between independent, unmatched groups. One-way analysis of variance (ANOVA) was used to compare means among the 3 groups of morphology subtypes. Linear regression was performed to assess the simultaneous relationship between potential predictors (age, sex, length of symptoms, Goutallier score, tear size) and medial or lateral tension, where medial tension was included as an additional potential predictor for lateral tension. Restricted cubic splines were fit to assess linearity. Predictors were retained in multivariate regression using backward variable retention. Because of inadequate sample size, additivity was assumed except for sex. Statistical significance was set at P < .05.

Results

Of the 20 rotator cuff tears evaluated (Table 1), 13 were crescent-shaped, 5 were U-shaped, and 2 were L-shaped. Mean (SD) A-P tear size was 17.7 (5.8) mm, and mean (SD) M-L tear size was 19.1 (8.6) mm. Mean age of the 20 patients (15 men, 5 women) was 57.9 years (range, 44-72 years). Mean (SD) length of symptoms was 12.9 (12.4) months (range, 3-48 months). Mean (SD) modified Goutallier score was 1.4 (0.7; range, 0-3).

Mean (SD) rotator cuff tension for all tears approximated to the medial footprint was 0.41 (0.33) pound, and mean (SD) cuff tension for all tears approximated to the lateral footprint was 2.21 (1.20) pounds—representing a 5.4-fold difference (P < .0001).

No statistically significant differences were detected in the ANOVA comparing tensions at medial and lateral positions among tear morphologic subtypes (all Ps >.05).

Subgroup analysis (Table 2) was performed for smaller (≤20 mm A-P) and larger (>20 mm A-P) tears. For smaller tears, mean (SD) tension was 0.27 (0.24) pound applied with the cuff tendon pulled to the medial footprint and 2.06 (1.06) pounds applied with the tendon pulled to the lateral footprint—a 7.6-fold difference (P < .0018). For larger tears, mean (SD) tension was 0.58 (0.37) pound applied with the tendon pulled to the medial footprint and 2.38 (1.4) pounds applied with the tendon pulled to the lateral footprint—a 4.1-fold difference (P < .005).

A statistically significant difference in tensions was found between small and large cuff tears positioned at the medial footprint (0.27 vs 0.58 lb; P = .0367); no difference was found between groups with the tendon at the lateral footprint (2.06 vs 2.38 lb; P = .284).

Univariate and multivariate analyses were performed using linear regression analysis (Table 3). During univariate analysis for medial footprint position, A-P tear size and Goutallier score both positively correlated with increasing tension; for lateral footprint position, no factors statistically correlated with lateral tension, though there was a positive trend for medial tension and female sex. During multivariate analysis for medial footprint position, only A-P tear size positively correlated with increasing tension; for lateral footprint position, both age (in nonlinear fashion as function of age + age²) and medial tension positively correlated with increasing tension.

Discussion

Our results indicated that significantly more tension is placed on the torn rotator cuff tendon when it is reduced across the footprint from a medial to a more lateral position in vivo. More tension was required for all tears to be reduced to the lateral footprint compared with the medial footprint. As expected, compared with smaller tears, larger tears required significantly more tension in order to be reduced to the medial footprint. Interestingly, no statistical difference was found between tensions required to reduce either small or large tears to the lateral footprint, which suggests that, regardless of tear size, more force must be applied to reduce the torn tendon to the lateral footprint compared with the medial footprint.

Hersche and Gerber³⁴ were the first to report rotator cuff tension measurements in vivo. Although their study did not specifically compare cuff tensions reducing the tear to the medial versus lateral footprint, it did examine tension at displacement of 10 and 20 mm. Tension increased from 27 N to 60 N, correlating with a 2.2-fold difference between the 2 distances. Domb and colleagues35 also compared in vivo rotator cuff tension differences between the medial footprint and the lateral footprint in 4 patients. Mean tension applied to the cuff during reduction to the articular margin was 27 N, or 6 pounds. Mean tension needed to reduce the cuff to the lateral tuberosity was 76 N, or 17 pounds, for a 2.8-fold difference. Tears were not measured but were described as massive and retracted.

Although repair tension has long been recognized as a crucial factor in RCR healing, little clinical research has focused on the effects of excess tension. Davidson and Rivenburgh11 prospectively followed the clinical outcomes of 67 consecutive cuff repairs after intraoperative tension measurement and found that high-tension repairs (>8 lb) had significantly lower clinical outcome measures. However, the authors did not report on correlations with radiologic healing and stated, “Functional outcome is inversely proportional to rotator cuff repair tension.” Further study of the in vivo effects of increased tension on clinical and radiologic outcomes is needed.

Several animal studies have been conducted on the effects of tension on RCRs. Gerber and colleagues36 reported that the force needed to produce 1 cm of sheep supraspinatus tendon excursion increased 7-fold, from 6.8 N to 47.8 N, after 40 weeks of tendon tear. Coleman and colleagues³⁷ compared the modulus of elasticity in sheep supraspinatus tendon after 6 weeks and 18 weeks of detachment and reported increases of 60% and 70%, respectively. Gimbel and colleagues³⁸ showed that, in a rat model, “repair tension rapidly increased initially after injury followed by a progressive, but less dramatic, increase with additional time.” Of note, we did not identify any correlation between chronicity of symptoms and the tension needed to reduce the tendon medially or to a more lateral position on the footprint.

In acute tears, the cuff tissue is more compliant and mobile and can be pulled laterally across its anatomical footprint with minimal tension.³⁹ In contrast, cuff tissue in the more commonly encountered chronic tear is less compliant and is not mobile enough to be pulled to the lateral margin of the footprint without added stress.^30,34,35 In large, acute tears in which there are minimal tissue degeneration and retraction, a laterally based footprint-restoring technique may be performed with minimal tension. This technique may have advantages over a medially based repair. In the literature, more attention needs to be directed toward the biomechanics and biology of chronic rotator cuff tears, as these are more commonly encountered.

Almost all of the prospective studies that have compared single- and double-row RCR have found no significant differences in MRI healing rates or clinical results at follow-up up to 2 years.^14,16,40-45 Detailed analysis of the surgical techniques used in all these studies revealed that the rotator cuff tendons were repaired back to the lateral footprint in both the single- and double-row constructs.^14,16,40-45 Although no clinical studies have compared medially and laterally based single-row repairs, our data suggest that medially based repairs have lower tensions and therefore should not be considered equivalent. Sostak and colleagues³¹ and Murray and colleagues⁴⁶ have shown that a medially based single-row RCR can achieve excellent clinical and anatomical results, likely partly because of the lower tension applied to the torn cuff tissue.^31,46 Studies are needed to compare medially and laterally based repairs, including single- and double-row repairs.

The vast majority of recent research has aimed to counteract construct tension with stronger biomechanical constructs.^20-26 Surgeons have also aimed to improve biological healing by pulling the tendon laterally across the footprint to achieve complete footprint coverage, ultimately increasing the surface area for tendon–bone healing. This has led to the development of various double-row repair techniques, in which the cuff tendon is pulled to the lateral margin of its footprint. One row of anchors is placed in the medial aspect of the footprint, while a second is placed in the lateral aspect; the cuff is reduced and compressed to the tuberosity with various suture configurations. The TOE technique was developed to improve pressurization of the cuff tendon across the footprint by linking the 2 rows with bridging sutures. In doing so, however, the potentially deleterious effects of increased tension introduced by pulling the tendon laterally may have been overlooked. Nevertheless, the biomechanics and stress distribution likely differ between single-row repair and TOE repairs, and direct comparisons cannot be made at this time. The medial row of a double-row or TOE construct may stress-shield or “unload” the more lateral tissue. Studies are needed in order to better understand the tension differential and stress distribution of various double-row constructs.

Recognizing tear morphology is crucial in maximizing chances of healing after cuff repair. For example, a crescent-shaped tear is reduced to the tuberosity with direct lateral translation of the apex of the tear, which is also the deepest or most displaced part of the tear. On the other hand, reducing an L- or reverse L-shaped tear to the tuberosity is not as direct; reducing the deepest or most displaced part of the tear would lead to overreduction and overtensioning of the tendon. However, often the exact “elbow” of the tear is not obvious and appears more rounded; therefore, it is crucial for the surgeon to examine the mobility of the torn tendon along its entire length to minimize tension. Study is needed to assess tension along the entire length of the tear for different tear morphologies and sizes.

Although our results showed that increased tension was needed to reduce a torn tendon to its lateral footprint, no study has indicated exactly how much is “too much” tension. As stated earlier, use of stronger biomechanical constructs, including TOE constructs, may overcome the increased tension associated with laterally based repairs. In addition, laterally based repairs, either single- or double-row, may be best suited for tears with lower tension, whereas medially based repairs may be best suited for higher tension tears. It is also possible that the difference in tensions noted in this study is not significant enough to have a clinical impact on choice of construct or on anatomical healing. We need studies that correlate anatomical healing rates with repair tension in order to better guide surgeons on when to use a medially or laterally based repair.

Other possible effects of increased tension associated with laterally based repairs, including beneficial effects, must be considered as well. Viscoelastic properties of human rotator cuff tendon may dissipate increased tension over time through a variety of mechanisms. Stress relaxation, gap formation, creep, and the hysteresis effect, all associated with cyclical loading in the early healing period, may lead to dissipation of force over time.^47,48 These more complex biomechanical properties of RCR constructs are yet to be clearly defined.

This study had several weaknesses. Its data represent a static measurement of time-zero rotator cuff tension, which greatly simplifies the biomechanics of the torn rotator cuff and repair construct as well as changes that occur with healing. During cuff repair, forces typically are distributed through several fixation points in stepwise process and are not focused on a single point of tissue with a grasper. Therefore, the findings of this study may not directly correlate with medially versus laterally based repairs in vivo. Furthermore, as this is a time-zero measurement, we could not determine whether the tension differential between the 2 repair positions remained static over time. Current literature suggests that muscle atrophy, fatty infiltration, and loss of elasticity of the musculotendinous unit are relatively irreversible.^35,37,49 In addition, determining the precise apex of a cuff tear can be difficult, so error may have been introduced during this process. Last, although placement of the cuff tissue at the medial or lateral footprint position was based on visual estimation by an experienced and skilled arthroscopist, error may have been introduced based on this imprecise technique.

Conclusion

This study demonstrated a significant, 5.4-fold increase in in vivo time-zero rotator cuff tension with the tendon edge reduced to the lateral footprint rather than the medial footprint.

Transforaminal lumbar interbody fusion (TLIF) has become an increasingly popular method of lumbar fusion, since its introduction by Harms and Rolinger in 1982.¹ The procedure allows for a circumferential fusion through a posterior-only approach, with improved sagittal alignment² and minimal risk for iatrogenic nerve injury. In the past decade, a minimally invasive surgical method of TLIF (MIS TLIF) has been introduced^3-5 and involves neural decompression and interbody fusion through a tubular retractor, and percutaneous placement of pedicle-screw instrumentation. This technique uses muscle dilation rather than large-scale detachment of muscle. Proponents of the MIS technique have postulated that decreased muscle damage would lead to better short-term, and possibly long-term, clinical outcomes, because of less iatrogenic soft-tissue damage.

Studies that have compared results of MIS TLIF with open TLIF have shown improved perioperative outcomes, but most have shown similar intermediate-term clinical outcomes.6 In the short term, multiple studies demonstrate that MIS TLIF is associated with decreased blood loss, less postoperative pain and narcotic requirements, and shorter hospital length of stay.^7-13 However, changes in pain score and disease-specific and generic health-related quality of life measures have been similar for the 2 procedures, beyond 6 months postoperatively.^10,13-15 These studies have generally involved retrospective reviews of unmatched patient groups, with small sample sizes and significant heterogeneity in surgical indications and case complexity. In our study, we compared intermediate-term clinical outcomes of MIS TLIF with open TLIF, using propensity matching to optimize baseline similarity of the groups.

Methods

This retrospective study was conducted after receiving approval from the Institutional Review Board. Surgical and clinical databases of 2 centers from 2008 to 2012 were reviewed for eligible subjects. Cases in 2007 were excluded because this was the year that MIS was introduced as a new technique in the practice. Inclusion criteria consisted of patients who underwent 1- to 2-level MIS TLIF and had complete baseline, 1- and 2-year postoperative outcome measures. Patients who had surgery for trauma, tumor, or osteomyelitis were excluded. Outcome measures collected and reviewed in this study included the Oswestry Disability Index (ODI),^16,17 the Medical Outcomes Study Short-Form 36 (SF-36),¹⁸ and numeric rating scales for back and leg pain (0-100 scale).¹⁹ The Physical Composite Summary (PCS) and Mental Composite Summary of the SF-36 were reviewed separately. We recorded the following patient demographic data: age, gender, American Society of Anesthesiologists (ASA) grade, body mass index, indication for surgery, workers’ compensation, and smoking status. Surgical data included number of levels fused, operative time, estimated blood loss, and length of hospital stay.

Propensity-scoring technique^20,21 was used to match the MIS TLIF patients to a control group of patients who underwent TLIF using an open approach (open TLIF), matching for multiple characteristics to produce 2 similar comparison groups. Propensity matching was performed to control for bias. In controlling for known confounders or biases, propensity matching, in theory, should also control for unknown confounders. Gender, age, body mass index, smoking status, indication for fusion, as well as preoperative ODI, SF-36 PCS, SF-36 Mental Composite Summary, and pain scores were used to generate a control open TLIF group.

MIS TLIF Surgical Technique

Patients in the MIS TLIF group underwent neural decompression and interbody fusion through a tubular retractor system (METRx, Medtronic Inc.), followed by percutaneous pedicle-screw fixation under fluoroscopic guidance (Sextant, Medtronic Inc.). After successful induction of general endotracheal anesthesia, patients were positioned prone on a radiolucent table. Posteroanterior (PA) and lateral fluoroscopic images were used to localize 2 paramedian incisions, approximately 3-cm to 5-cm lateral to midline, over the pedicles of interest. Modified Jamshidi needles (Medtronic Inc.) were used to cannulate the pedicles under PA, posterior-oblique, PA, and lateral fluoroscopic guidance. The pedicles were tapped with a cannulated tap. Pedicle screws and rods were introduced on the side contralateral to the TLIF and were used as needed to maintain intradiscal distraction during the TLIF portion of the procedure.

Decompression and TLIF were carried out on the side of the patient’s radicular pain or bilaterally, according to the surgeon’s discretion. A K-wire was advanced to the facet joint complex, after which sequential dilators were used to dilate through the muscles to establish an intramuscular corridor to the facet. A 26-mm fixed tubular retractor was docked over the facet and locked in place, using a post attached to the operating room table. Neural decompression was obtained by removal of the entire facet-joint complex and lamina to the base of the spinous process, using a combination of high-speed drills and Kerrison rongeurs. The ligamentum flavum was completely resected. The superior articular process of the caudal vertebra was removed all the way to the pedicle below. Ball-tipped probes were used to confirm that traversing and exiting nerve roots were completely free. An annulotomy was performed, and all disc material was removed from the disc through a combination of rotating shavers, serrated curettes, endplate scrapers, and rasps. Bone graft was placed anterior and contralateral to the interbody cage. (Bone grafts included autogenous iliac crest, local bone obtained from the decompression, recombinant human bone morphogenetic protein 2, or allograft demineralized bone matrix at the surgeon’s discretion.) After placement of the interbody cage, the ipsilateral pedicle-screw instrumentation was put over the remaining guide wires and compression applied across the construct to lock the interbody cage and restore lordosis. Wounds were closed without drains.

Open TLIF Surgical Technique

In patients undergoing open TLIF, a midline incision was made over the vertebrae of interest, and paraspinal muscles were subperiosteally dissected to the tips of the transverse processes. The appropriate level was confirmed with intraoperative radiograph. Pedicle screws were placed free-hand using anatomic landmarks, and appropriate placement was confirmed with intraoperative radiograph and evoked electromyography stimulation. Laminectomy and facetectomy were performed, and the disc was entered on the side of the facetectomy. After thorough disc-space preparation, bone graft and an interbody cage were placed, rods inserted, and compression carried out. A supplemental posterolateral fusion was also performed after decortication of the transverse processes and cartilaginous surface of the contralateral facet. Layered wound closure was performed over drains.

Analysis

Statistical analysis was carried out using SPSS Statistics version 17.0 (IBM) with significance set at the P < .01 level. A small, conservative P-value threshold was used to minimize type II error that resulted from the multiple comparisons performed. Student t test was used to determine any significant differences between continuous demographic variables, and to compare preoperative and postoperative outcome measure scores within and between study groups. Fisher’s exact test was used to compare categorical variables between the 2 groups.

Results

The MIS TLIF group consisted of 64 patients (average age, 52 years), and included 22 patients with degenerative spondylolisthesis, 33 with disc pathology, 8 with postdecompression, and 1 non-union patient. The open TLIF group consisted of 64 patients (average age, 54 years), and included 39 degenerative spondylolisthesis, 15 disc pathology, 7 postdecompression, and 3 nonunion patients (Table 1). All 64 open and 19 MIS cases were from a spine practice with 6 surgeons, and 45 MIS cases came from a spine practice with 2 surgeons. There was also an unequal distribution of the specific levels fused between the open and MIS groups.

Although the operative time was similar in both groups, the MIS TLIF group had a statistically significantly lower blood loss compared with the open TLIF group (Table 2). Both MIS TLIF and open TLIF lead to significant improvements in pain, ODI, and SF-36 PCS (P < .01) (Table 3). At 1 year, both groups had similar improvements in pain (36.9 vs 30.8, P = .178) and SF-36 PCS (9.9 vs 7.5, P = .231), but the MIS TLIF group had a statistically significantly greater improvement in ODI compared with the open TLIF group (30.4 vs 15.1, P < .000). At 2 years, both groups had similar improvements in SF-36 PCS (12.1 vs 7.5, P = .033), but the MIS TLIF group had a statistically significantly greater improvement in pain (40.2 vs 27.0, P = .005) and ODI (33.1 vs 15.4, P < .000) compared with the open TLIF group (Table 4).

Discussion

The current study compared intermediate-term clinical outcomes of MIS TLIF to open TLIF. We used propensity matching to identify a control group of open TLIFs that were comparable to the MIS TLIF group across a variety of covariates that are known to influence the results of lumbar fusion. This created comparison groups that were as closely matched at baseline as possible. We found that, at 2-year follow-up, MIS TLIF patients had less pain and less low-back pain–related disability as measured by ODI. There was also a trend toward better generic health-related quality of life in the MIS TLIF group.

These data suggest that the decreased soft-tissue trauma of the minimally invasive surgical technique, which leads to improved perioperative parameters in the short term, may also lead to some advantages that translate to improved intermediate-term clinical outcomes. Traditional lumbar fusion procedures have shown excellent clinical results when used for accepted clinical indications.²² However, the procedure requires extensive dissection of the paraspinal muscles, which causes significant muscle damage as evidenced by muscle breakdown products that can be detected in the bloodstream postoperatively.^23,24 The lateral dissection also transects the dorsal ramus of the segmental nerves, which innervate the paraspinal muscles, leading to significant scarring and atrophy on postoperative imaging studies.²³ Some authors have used the term “fusion disease” to describe the constellation of soft-tissue degradation seen after open lumbar fusion.⁵

An MIS version of the TLIF procedure that was described in 2003³ avoids much of this iatrogenic soft-tissue trauma. It involves intramuscular dilation to approach the spine and to carry out neural decompression and interbody fusion, in conjunction with percutaneous pedicle-screw instrumentation. Proponents of this technique point to diminished iatrogenic soft-tissue and muscle damage as an advantage. Multiple studies have, in fact, confirmed improved short-term perioperative parameters, such as less blood loss, lower narcotic requirements, and decreased length-of-hospital stay.²⁵ Economic analyses have also shown lower direct and indirect costs with the MIS technique.²⁶

Several studies have compared patient-reported outcome measures of MIS and open TLIF, and the results have been mixed. Most of these studies have shown similar improvement in clinical outcomes between the 2 procedures, but the MIS technique demonstrated short-term perioperative advantages, such as lower blood loss, less narcotic requirements, and shorter length of stay.^7-15 The authors of these studies conclude that the MIS technique can provide similar long-term results with lower short-term morbidity when compared with open TLIF. In contrast, some studies have shown better short- and intermediate-term clinical outcomes with the MIS technique.^23,27-29 As a whole, the literature comparing the 2 procedures consists of mostly small retrospective studies with nonrandomized patient samples, heterogeneous surgical indications, and differing surgical techniques, making it difficult to draw conclusions.

The current study suggests that MIS TLIF may lead to improved clinical results at 2-year follow-up, compared with open TLIF. Our study used propensity-score matching to minimize the effects of nonrandom assignment of subjects to MIS TLIF or open TLIF. A limitation of observational studies is that bias in assignment of subjects to treatment groups can lead to overestimation or underestimation of the effect of the treatment itself. Propensity-score matching attempts to reduce this bias by accounting for several covariates that predict whether a subject will receive a certain treatment. These covariates are used in a logistic regression to produce a propensity score, which can be used to match subjects to controls across multiple dimensions, thus ensuring groups are as comparable as possible at baseline.

Our study still has several limitations. Sample size is relatively small, and follow-up is still only intermediate, at 2 years. There was unequal distribution of specific levels of surgery. Because patients were not blinded to the treatment they received, it is possible that patient perception of receiving a newer, less-invasive treatment method may influence their subjective improvement. The study sample was drawn from 2 different centers, with one center providing mostly MIS cases and the other providing mostly open cases. Because of this, undetected differences in how patients were selected for surgery could also affect outcomes. Any latent confounding variables, which are not identified a priori, will not be accounted for in the matching process. Only a prospective, randomized study with large numbers can control for observed and unobserved confounding patient characteristics.

In summary, our study shows that MIS TLIF is associated with improved low back pain and low back–related disability at 2 years compared with open TLIF. Other studies comparing the 2 techniques have come to different conclusions regarding whether the short-term benefits of MIS TLIF translate into long-term differences in clinical outcome. This study adds to this evidence and suggests there may be longer term advantages to the MIS approach, but prospective randomized trials are needed to confirm this finding and determine the true magnitude of these differences.

Transforaminal lumbar interbody fusion (TLIF) has become an increasingly popular method of lumbar fusion, since its introduction by Harms and Rolinger in 1982.¹ The procedure allows for a circumferential fusion through a posterior-only approach, with improved sagittal alignment² and minimal risk for iatrogenic nerve injury. In the past decade, a minimally invasive surgical method of TLIF (MIS TLIF) has been introduced^3-5 and involves neural decompression and interbody fusion through a tubular retractor, and percutaneous placement of pedicle-screw instrumentation. This technique uses muscle dilation rather than large-scale detachment of muscle. Proponents of the MIS technique have postulated that decreased muscle damage would lead to better short-term, and possibly long-term, clinical outcomes, because of less iatrogenic soft-tissue damage.

Studies that have compared results of MIS TLIF with open TLIF have shown improved perioperative outcomes, but most have shown similar intermediate-term clinical outcomes.6 In the short term, multiple studies demonstrate that MIS TLIF is associated with decreased blood loss, less postoperative pain and narcotic requirements, and shorter hospital length of stay.^7-13 However, changes in pain score and disease-specific and generic health-related quality of life measures have been similar for the 2 procedures, beyond 6 months postoperatively.^10,13-15 These studies have generally involved retrospective reviews of unmatched patient groups, with small sample sizes and significant heterogeneity in surgical indications and case complexity. In our study, we compared intermediate-term clinical outcomes of MIS TLIF with open TLIF, using propensity matching to optimize baseline similarity of the groups.

Methods

This retrospective study was conducted after receiving approval from the Institutional Review Board. Surgical and clinical databases of 2 centers from 2008 to 2012 were reviewed for eligible subjects. Cases in 2007 were excluded because this was the year that MIS was introduced as a new technique in the practice. Inclusion criteria consisted of patients who underwent 1- to 2-level MIS TLIF and had complete baseline, 1- and 2-year postoperative outcome measures. Patients who had surgery for trauma, tumor, or osteomyelitis were excluded. Outcome measures collected and reviewed in this study included the Oswestry Disability Index (ODI),^16,17 the Medical Outcomes Study Short-Form 36 (SF-36),¹⁸ and numeric rating scales for back and leg pain (0-100 scale).¹⁹ The Physical Composite Summary (PCS) and Mental Composite Summary of the SF-36 were reviewed separately. We recorded the following patient demographic data: age, gender, American Society of Anesthesiologists (ASA) grade, body mass index, indication for surgery, workers’ compensation, and smoking status. Surgical data included number of levels fused, operative time, estimated blood loss, and length of hospital stay.

Propensity-scoring technique^20,21 was used to match the MIS TLIF patients to a control group of patients who underwent TLIF using an open approach (open TLIF), matching for multiple characteristics to produce 2 similar comparison groups. Propensity matching was performed to control for bias. In controlling for known confounders or biases, propensity matching, in theory, should also control for unknown confounders. Gender, age, body mass index, smoking status, indication for fusion, as well as preoperative ODI, SF-36 PCS, SF-36 Mental Composite Summary, and pain scores were used to generate a control open TLIF group.

MIS TLIF Surgical Technique

Patients in the MIS TLIF group underwent neural decompression and interbody fusion through a tubular retractor system (METRx, Medtronic Inc.), followed by percutaneous pedicle-screw fixation under fluoroscopic guidance (Sextant, Medtronic Inc.). After successful induction of general endotracheal anesthesia, patients were positioned prone on a radiolucent table. Posteroanterior (PA) and lateral fluoroscopic images were used to localize 2 paramedian incisions, approximately 3-cm to 5-cm lateral to midline, over the pedicles of interest. Modified Jamshidi needles (Medtronic Inc.) were used to cannulate the pedicles under PA, posterior-oblique, PA, and lateral fluoroscopic guidance. The pedicles were tapped with a cannulated tap. Pedicle screws and rods were introduced on the side contralateral to the TLIF and were used as needed to maintain intradiscal distraction during the TLIF portion of the procedure.

Decompression and TLIF were carried out on the side of the patient’s radicular pain or bilaterally, according to the surgeon’s discretion. A K-wire was advanced to the facet joint complex, after which sequential dilators were used to dilate through the muscles to establish an intramuscular corridor to the facet. A 26-mm fixed tubular retractor was docked over the facet and locked in place, using a post attached to the operating room table. Neural decompression was obtained by removal of the entire facet-joint complex and lamina to the base of the spinous process, using a combination of high-speed drills and Kerrison rongeurs. The ligamentum flavum was completely resected. The superior articular process of the caudal vertebra was removed all the way to the pedicle below. Ball-tipped probes were used to confirm that traversing and exiting nerve roots were completely free. An annulotomy was performed, and all disc material was removed from the disc through a combination of rotating shavers, serrated curettes, endplate scrapers, and rasps. Bone graft was placed anterior and contralateral to the interbody cage. (Bone grafts included autogenous iliac crest, local bone obtained from the decompression, recombinant human bone morphogenetic protein 2, or allograft demineralized bone matrix at the surgeon’s discretion.) After placement of the interbody cage, the ipsilateral pedicle-screw instrumentation was put over the remaining guide wires and compression applied across the construct to lock the interbody cage and restore lordosis. Wounds were closed without drains.

Open TLIF Surgical Technique

In patients undergoing open TLIF, a midline incision was made over the vertebrae of interest, and paraspinal muscles were subperiosteally dissected to the tips of the transverse processes. The appropriate level was confirmed with intraoperative radiograph. Pedicle screws were placed free-hand using anatomic landmarks, and appropriate placement was confirmed with intraoperative radiograph and evoked electromyography stimulation. Laminectomy and facetectomy were performed, and the disc was entered on the side of the facetectomy. After thorough disc-space preparation, bone graft and an interbody cage were placed, rods inserted, and compression carried out. A supplemental posterolateral fusion was also performed after decortication of the transverse processes and cartilaginous surface of the contralateral facet. Layered wound closure was performed over drains.

Analysis

Statistical analysis was carried out using SPSS Statistics version 17.0 (IBM) with significance set at the P < .01 level. A small, conservative P-value threshold was used to minimize type II error that resulted from the multiple comparisons performed. Student t test was used to determine any significant differences between continuous demographic variables, and to compare preoperative and postoperative outcome measure scores within and between study groups. Fisher’s exact test was used to compare categorical variables between the 2 groups.

Results

The MIS TLIF group consisted of 64 patients (average age, 52 years), and included 22 patients with degenerative spondylolisthesis, 33 with disc pathology, 8 with postdecompression, and 1 non-union patient. The open TLIF group consisted of 64 patients (average age, 54 years), and included 39 degenerative spondylolisthesis, 15 disc pathology, 7 postdecompression, and 3 nonunion patients (Table 1). All 64 open and 19 MIS cases were from a spine practice with 6 surgeons, and 45 MIS cases came from a spine practice with 2 surgeons. There was also an unequal distribution of the specific levels fused between the open and MIS groups.

Although the operative time was similar in both groups, the MIS TLIF group had a statistically significantly lower blood loss compared with the open TLIF group (Table 2). Both MIS TLIF and open TLIF lead to significant improvements in pain, ODI, and SF-36 PCS (P < .01) (Table 3). At 1 year, both groups had similar improvements in pain (36.9 vs 30.8, P = .178) and SF-36 PCS (9.9 vs 7.5, P = .231), but the MIS TLIF group had a statistically significantly greater improvement in ODI compared with the open TLIF group (30.4 vs 15.1, P < .000). At 2 years, both groups had similar improvements in SF-36 PCS (12.1 vs 7.5, P = .033), but the MIS TLIF group had a statistically significantly greater improvement in pain (40.2 vs 27.0, P = .005) and ODI (33.1 vs 15.4, P < .000) compared with the open TLIF group (Table 4).

Discussion

The current study compared intermediate-term clinical outcomes of MIS TLIF to open TLIF. We used propensity matching to identify a control group of open TLIFs that were comparable to the MIS TLIF group across a variety of covariates that are known to influence the results of lumbar fusion. This created comparison groups that were as closely matched at baseline as possible. We found that, at 2-year follow-up, MIS TLIF patients had less pain and less low-back pain–related disability as measured by ODI. There was also a trend toward better generic health-related quality of life in the MIS TLIF group.

These data suggest that the decreased soft-tissue trauma of the minimally invasive surgical technique, which leads to improved perioperative parameters in the short term, may also lead to some advantages that translate to improved intermediate-term clinical outcomes. Traditional lumbar fusion procedures have shown excellent clinical results when used for accepted clinical indications.²² However, the procedure requires extensive dissection of the paraspinal muscles, which causes significant muscle damage as evidenced by muscle breakdown products that can be detected in the bloodstream postoperatively.^23,24 The lateral dissection also transects the dorsal ramus of the segmental nerves, which innervate the paraspinal muscles, leading to significant scarring and atrophy on postoperative imaging studies.²³ Some authors have used the term “fusion disease” to describe the constellation of soft-tissue degradation seen after open lumbar fusion.⁵

An MIS version of the TLIF procedure that was described in 2003³ avoids much of this iatrogenic soft-tissue trauma. It involves intramuscular dilation to approach the spine and to carry out neural decompression and interbody fusion, in conjunction with percutaneous pedicle-screw instrumentation. Proponents of this technique point to diminished iatrogenic soft-tissue and muscle damage as an advantage. Multiple studies have, in fact, confirmed improved short-term perioperative parameters, such as less blood loss, lower narcotic requirements, and decreased length-of-hospital stay.²⁵ Economic analyses have also shown lower direct and indirect costs with the MIS technique.²⁶

Several studies have compared patient-reported outcome measures of MIS and open TLIF, and the results have been mixed. Most of these studies have shown similar improvement in clinical outcomes between the 2 procedures, but the MIS technique demonstrated short-term perioperative advantages, such as lower blood loss, less narcotic requirements, and shorter length of stay.^7-15 The authors of these studies conclude that the MIS technique can provide similar long-term results with lower short-term morbidity when compared with open TLIF. In contrast, some studies have shown better short- and intermediate-term clinical outcomes with the MIS technique.^23,27-29 As a whole, the literature comparing the 2 procedures consists of mostly small retrospective studies with nonrandomized patient samples, heterogeneous surgical indications, and differing surgical techniques, making it difficult to draw conclusions.

The current study suggests that MIS TLIF may lead to improved clinical results at 2-year follow-up, compared with open TLIF. Our study used propensity-score matching to minimize the effects of nonrandom assignment of subjects to MIS TLIF or open TLIF. A limitation of observational studies is that bias in assignment of subjects to treatment groups can lead to overestimation or underestimation of the effect of the treatment itself. Propensity-score matching attempts to reduce this bias by accounting for several covariates that predict whether a subject will receive a certain treatment. These covariates are used in a logistic regression to produce a propensity score, which can be used to match subjects to controls across multiple dimensions, thus ensuring groups are as comparable as possible at baseline.

Our study still has several limitations. Sample size is relatively small, and follow-up is still only intermediate, at 2 years. There was unequal distribution of specific levels of surgery. Because patients were not blinded to the treatment they received, it is possible that patient perception of receiving a newer, less-invasive treatment method may influence their subjective improvement. The study sample was drawn from 2 different centers, with one center providing mostly MIS cases and the other providing mostly open cases. Because of this, undetected differences in how patients were selected for surgery could also affect outcomes. Any latent confounding variables, which are not identified a priori, will not be accounted for in the matching process. Only a prospective, randomized study with large numbers can control for observed and unobserved confounding patient characteristics.

In summary, our study shows that MIS TLIF is associated with improved low back pain and low back–related disability at 2 years compared with open TLIF. Other studies comparing the 2 techniques have come to different conclusions regarding whether the short-term benefits of MIS TLIF translate into long-term differences in clinical outcome. This study adds to this evidence and suggests there may be longer term advantages to the MIS approach, but prospective randomized trials are needed to confirm this finding and determine the true magnitude of these differences.

Transforaminal lumbar interbody fusion (TLIF) has become an increasingly popular method of lumbar fusion, since its introduction by Harms and Rolinger in 1982.¹ The procedure allows for a circumferential fusion through a posterior-only approach, with improved sagittal alignment² and minimal risk for iatrogenic nerve injury. In the past decade, a minimally invasive surgical method of TLIF (MIS TLIF) has been introduced^3-5 and involves neural decompression and interbody fusion through a tubular retractor, and percutaneous placement of pedicle-screw instrumentation. This technique uses muscle dilation rather than large-scale detachment of muscle. Proponents of the MIS technique have postulated that decreased muscle damage would lead to better short-term, and possibly long-term, clinical outcomes, because of less iatrogenic soft-tissue damage.

Studies that have compared results of MIS TLIF with open TLIF have shown improved perioperative outcomes, but most have shown similar intermediate-term clinical outcomes.6 In the short term, multiple studies demonstrate that MIS TLIF is associated with decreased blood loss, less postoperative pain and narcotic requirements, and shorter hospital length of stay.^7-13 However, changes in pain score and disease-specific and generic health-related quality of life measures have been similar for the 2 procedures, beyond 6 months postoperatively.^10,13-15 These studies have generally involved retrospective reviews of unmatched patient groups, with small sample sizes and significant heterogeneity in surgical indications and case complexity. In our study, we compared intermediate-term clinical outcomes of MIS TLIF with open TLIF, using propensity matching to optimize baseline similarity of the groups.

Methods

This retrospective study was conducted after receiving approval from the Institutional Review Board. Surgical and clinical databases of 2 centers from 2008 to 2012 were reviewed for eligible subjects. Cases in 2007 were excluded because this was the year that MIS was introduced as a new technique in the practice. Inclusion criteria consisted of patients who underwent 1- to 2-level MIS TLIF and had complete baseline, 1- and 2-year postoperative outcome measures. Patients who had surgery for trauma, tumor, or osteomyelitis were excluded. Outcome measures collected and reviewed in this study included the Oswestry Disability Index (ODI),^16,17 the Medical Outcomes Study Short-Form 36 (SF-36),¹⁸ and numeric rating scales for back and leg pain (0-100 scale).¹⁹ The Physical Composite Summary (PCS) and Mental Composite Summary of the SF-36 were reviewed separately. We recorded the following patient demographic data: age, gender, American Society of Anesthesiologists (ASA) grade, body mass index, indication for surgery, workers’ compensation, and smoking status. Surgical data included number of levels fused, operative time, estimated blood loss, and length of hospital stay.

Propensity-scoring technique^20,21 was used to match the MIS TLIF patients to a control group of patients who underwent TLIF using an open approach (open TLIF), matching for multiple characteristics to produce 2 similar comparison groups. Propensity matching was performed to control for bias. In controlling for known confounders or biases, propensity matching, in theory, should also control for unknown confounders. Gender, age, body mass index, smoking status, indication for fusion, as well as preoperative ODI, SF-36 PCS, SF-36 Mental Composite Summary, and pain scores were used to generate a control open TLIF group.

MIS TLIF Surgical Technique

Patients in the MIS TLIF group underwent neural decompression and interbody fusion through a tubular retractor system (METRx, Medtronic Inc.), followed by percutaneous pedicle-screw fixation under fluoroscopic guidance (Sextant, Medtronic Inc.). After successful induction of general endotracheal anesthesia, patients were positioned prone on a radiolucent table. Posteroanterior (PA) and lateral fluoroscopic images were used to localize 2 paramedian incisions, approximately 3-cm to 5-cm lateral to midline, over the pedicles of interest. Modified Jamshidi needles (Medtronic Inc.) were used to cannulate the pedicles under PA, posterior-oblique, PA, and lateral fluoroscopic guidance. The pedicles were tapped with a cannulated tap. Pedicle screws and rods were introduced on the side contralateral to the TLIF and were used as needed to maintain intradiscal distraction during the TLIF portion of the procedure.

Decompression and TLIF were carried out on the side of the patient’s radicular pain or bilaterally, according to the surgeon’s discretion. A K-wire was advanced to the facet joint complex, after which sequential dilators were used to dilate through the muscles to establish an intramuscular corridor to the facet. A 26-mm fixed tubular retractor was docked over the facet and locked in place, using a post attached to the operating room table. Neural decompression was obtained by removal of the entire facet-joint complex and lamina to the base of the spinous process, using a combination of high-speed drills and Kerrison rongeurs. The ligamentum flavum was completely resected. The superior articular process of the caudal vertebra was removed all the way to the pedicle below. Ball-tipped probes were used to confirm that traversing and exiting nerve roots were completely free. An annulotomy was performed, and all disc material was removed from the disc through a combination of rotating shavers, serrated curettes, endplate scrapers, and rasps. Bone graft was placed anterior and contralateral to the interbody cage. (Bone grafts included autogenous iliac crest, local bone obtained from the decompression, recombinant human bone morphogenetic protein 2, or allograft demineralized bone matrix at the surgeon’s discretion.) After placement of the interbody cage, the ipsilateral pedicle-screw instrumentation was put over the remaining guide wires and compression applied across the construct to lock the interbody cage and restore lordosis. Wounds were closed without drains.

Open TLIF Surgical Technique

In patients undergoing open TLIF, a midline incision was made over the vertebrae of interest, and paraspinal muscles were subperiosteally dissected to the tips of the transverse processes. The appropriate level was confirmed with intraoperative radiograph. Pedicle screws were placed free-hand using anatomic landmarks, and appropriate placement was confirmed with intraoperative radiograph and evoked electromyography stimulation. Laminectomy and facetectomy were performed, and the disc was entered on the side of the facetectomy. After thorough disc-space preparation, bone graft and an interbody cage were placed, rods inserted, and compression carried out. A supplemental posterolateral fusion was also performed after decortication of the transverse processes and cartilaginous surface of the contralateral facet. Layered wound closure was performed over drains.

Analysis

Statistical analysis was carried out using SPSS Statistics version 17.0 (IBM) with significance set at the P < .01 level. A small, conservative P-value threshold was used to minimize type II error that resulted from the multiple comparisons performed. Student t test was used to determine any significant differences between continuous demographic variables, and to compare preoperative and postoperative outcome measure scores within and between study groups. Fisher’s exact test was used to compare categorical variables between the 2 groups.

Results

The MIS TLIF group consisted of 64 patients (average age, 52 years), and included 22 patients with degenerative spondylolisthesis, 33 with disc pathology, 8 with postdecompression, and 1 non-union patient. The open TLIF group consisted of 64 patients (average age, 54 years), and included 39 degenerative spondylolisthesis, 15 disc pathology, 7 postdecompression, and 3 nonunion patients (Table 1). All 64 open and 19 MIS cases were from a spine practice with 6 surgeons, and 45 MIS cases came from a spine practice with 2 surgeons. There was also an unequal distribution of the specific levels fused between the open and MIS groups.

Although the operative time was similar in both groups, the MIS TLIF group had a statistically significantly lower blood loss compared with the open TLIF group (Table 2). Both MIS TLIF and open TLIF lead to significant improvements in pain, ODI, and SF-36 PCS (P < .01) (Table 3). At 1 year, both groups had similar improvements in pain (36.9 vs 30.8, P = .178) and SF-36 PCS (9.9 vs 7.5, P = .231), but the MIS TLIF group had a statistically significantly greater improvement in ODI compared with the open TLIF group (30.4 vs 15.1, P < .000). At 2 years, both groups had similar improvements in SF-36 PCS (12.1 vs 7.5, P = .033), but the MIS TLIF group had a statistically significantly greater improvement in pain (40.2 vs 27.0, P = .005) and ODI (33.1 vs 15.4, P < .000) compared with the open TLIF group (Table 4).

Discussion

The current study compared intermediate-term clinical outcomes of MIS TLIF to open TLIF. We used propensity matching to identify a control group of open TLIFs that were comparable to the MIS TLIF group across a variety of covariates that are known to influence the results of lumbar fusion. This created comparison groups that were as closely matched at baseline as possible. We found that, at 2-year follow-up, MIS TLIF patients had less pain and less low-back pain–related disability as measured by ODI. There was also a trend toward better generic health-related quality of life in the MIS TLIF group.

These data suggest that the decreased soft-tissue trauma of the minimally invasive surgical technique, which leads to improved perioperative parameters in the short term, may also lead to some advantages that translate to improved intermediate-term clinical outcomes. Traditional lumbar fusion procedures have shown excellent clinical results when used for accepted clinical indications.²² However, the procedure requires extensive dissection of the paraspinal muscles, which causes significant muscle damage as evidenced by muscle breakdown products that can be detected in the bloodstream postoperatively.^23,24 The lateral dissection also transects the dorsal ramus of the segmental nerves, which innervate the paraspinal muscles, leading to significant scarring and atrophy on postoperative imaging studies.²³ Some authors have used the term “fusion disease” to describe the constellation of soft-tissue degradation seen after open lumbar fusion.⁵

An MIS version of the TLIF procedure that was described in 2003³ avoids much of this iatrogenic soft-tissue trauma. It involves intramuscular dilation to approach the spine and to carry out neural decompression and interbody fusion, in conjunction with percutaneous pedicle-screw instrumentation. Proponents of this technique point to diminished iatrogenic soft-tissue and muscle damage as an advantage. Multiple studies have, in fact, confirmed improved short-term perioperative parameters, such as less blood loss, lower narcotic requirements, and decreased length-of-hospital stay.²⁵ Economic analyses have also shown lower direct and indirect costs with the MIS technique.²⁶

Several studies have compared patient-reported outcome measures of MIS and open TLIF, and the results have been mixed. Most of these studies have shown similar improvement in clinical outcomes between the 2 procedures, but the MIS technique demonstrated short-term perioperative advantages, such as lower blood loss, less narcotic requirements, and shorter length of stay.^7-15 The authors of these studies conclude that the MIS technique can provide similar long-term results with lower short-term morbidity when compared with open TLIF. In contrast, some studies have shown better short- and intermediate-term clinical outcomes with the MIS technique.^23,27-29 As a whole, the literature comparing the 2 procedures consists of mostly small retrospective studies with nonrandomized patient samples, heterogeneous surgical indications, and differing surgical techniques, making it difficult to draw conclusions.

The current study suggests that MIS TLIF may lead to improved clinical results at 2-year follow-up, compared with open TLIF. Our study used propensity-score matching to minimize the effects of nonrandom assignment of subjects to MIS TLIF or open TLIF. A limitation of observational studies is that bias in assignment of subjects to treatment groups can lead to overestimation or underestimation of the effect of the treatment itself. Propensity-score matching attempts to reduce this bias by accounting for several covariates that predict whether a subject will receive a certain treatment. These covariates are used in a logistic regression to produce a propensity score, which can be used to match subjects to controls across multiple dimensions, thus ensuring groups are as comparable as possible at baseline.

Our study still has several limitations. Sample size is relatively small, and follow-up is still only intermediate, at 2 years. There was unequal distribution of specific levels of surgery. Because patients were not blinded to the treatment they received, it is possible that patient perception of receiving a newer, less-invasive treatment method may influence their subjective improvement. The study sample was drawn from 2 different centers, with one center providing mostly MIS cases and the other providing mostly open cases. Because of this, undetected differences in how patients were selected for surgery could also affect outcomes. Any latent confounding variables, which are not identified a priori, will not be accounted for in the matching process. Only a prospective, randomized study with large numbers can control for observed and unobserved confounding patient characteristics.

In summary, our study shows that MIS TLIF is associated with improved low back pain and low back–related disability at 2 years compared with open TLIF. Other studies comparing the 2 techniques have come to different conclusions regarding whether the short-term benefits of MIS TLIF translate into long-term differences in clinical outcome. This study adds to this evidence and suggests there may be longer term advantages to the MIS approach, but prospective randomized trials are needed to confirm this finding and determine the true magnitude of these differences.

The optimal management strategy for acute fractures of the metadiaphyseal fifth metatarsal (Jones fractures) is controversial. Patients can be successfully treated nonoperatively with non-weight-bearing and immobilization in a short leg cast^1-7 or operatively with placement of an intramedullary screw.^8-10 The primary advantage of nonoperative treatment is avoiding the risks and discomfort of surgery; disadvantages include the need for prolonged immobilization and protected weight-bearing as well as a decreased union rate.^8,9 Advantages of operative treatment include accelerated functional recovery and an improved union rate; disadvantages include exposure to the risks, inconvenience, and discomfort of surgery. Clear, definitive evidence for guiding treatment is not available in the orthopedic literature, and treatment strategies vary substantially according to surgeon and patient preference.

Expected-value decision analysis, a research tool that helps guide decision-making in situations of uncertainty, has been effectively applied to other areas of uncertainty in the orthopedic literature.^11-14 Borrowed from gaming theory, the technique involves creating a decision tree to define the clinical problem, determining outcome probabilities and utilities, performing a fold-back analysis to determine the optimal decision-making strategy, and performing a sensitivity analysis to model the effect of varying outcome probabilities and utilities on decision-making. Decision analysis may therefore allow the clinician and the patient to optimize decision-making based on best available evidence and patient preferences. It also helps determine the most important factors affecting management strategies and the decision-making process, which may not always be intuitive.

In the present study, we used expected-value decision analysis to determine the optimal management strategy, operative or nonoperative, for acute Jones fracture. We also explored factors with the most influence on the model and identified important questions for future research.

Materials and Methods

Institutional review board approval was obtained for this study. Analysis was performed with Treeage Pro statistical software (Treeage Software).

Outcome Probabilities

Outcome probabilities were determined by reviewing the literature for articles on Jones fractures. This body of literature was summarized in a comprehensive review by Dean and colleagues¹⁵, who extracted data from 19 studies: 1 randomized controlled trial, 1 prospective case series, and 17 retrospective case series.¹⁵ We used data from these studies to determine outcome probabilities (Table).

Outcome Utilities

Utilities represent patient preferences for various disease states. Outcome utility values were obtained from 32 adults (25 women, 7 men) with no history of foot injury. Mean age was 32.4 years (range, 20-69 years). The questionnaire presented scenarios for the different outcomes and asked patients to rate these outcomes on a scale ranging from 0 (worst possible outcome) to 10 (best possible outcome). The Sports subscale of the Foot and Ankle Ability Measure (FAAM) 16 was used to quantify patient activity level.

Decision Tree and Fold-Back Analysis

A decision tree was constructed with 1 decision node, 4 chance nodes, and 7 terminal nodes (Figure 1). The decision tree demonstrates 2 different strategies for managing a Jones fracture. The decision node divides the tree into 2 branches: initial operative or nonoperative treatment. Both branches are followed by various chance nodes, each terminating in a discrete clinical outcome. Per convention, utility data were placed to the right of the terminal nodes, and probability data were placed under the terminal nodes.

Fold-back analysis was performed to identify the optimal strategy. Fold-back analysis involves multiplying each outcome utility by its associated probability, thereby providing an “expected value” for each clinical endpoint. Then, the expected values for each endpoint can be summed for a given management strategy, and the ultimate expected values of the different strategies can be compared. The management strategy associated with the highest expected value is optimal for the given outcome utilities and probabilities.

Sensitivity Analysis

One-way sensitivity analysis was performed to model the effect on decision-making of changing the values for utility for uncomplicated surgery, utility for healing with nonoperative treatment, utility for uncomplicated treatment of nonunion, likelihood of healing with nonoperative treatment, likelihood of healing with surgery, and likelihood of minor complication with surgery. These were the variables found to affect the decision-making strategy within their clinically plausible ranges.

Results

Outcome Probabilities and Utilities

Outcome probabilities and utilities are illustrated in Figure 1. By convention, probabilities appear below the corresponding branches of the decision tree, and utilities appear at the end of each branch. Mean (SD) FAAM Sports subscale score was 84.6 (27.4). This subscale is scored as a percentage from 0% to 100%, with higher scores indicating a higher level of physical function.

Decision Analysis

The expected value for nonoperative treatment was 7.74, and the expected value for intramedullary screw fixation was 7.88 (Figure 1). Therefore, operative treatment was identified as the optimal treatment strategy.

Sensitivity analyses revealed that the optimal decision making strategy was very sensitive to small changes in several variables. Nonoperative treatment becomes the preferred strategy when the utility value for uncomplicated surgery falls below 8.04 (Figure 2), when the utility for healing with nonoperative treatment rises above 8.49 (Figure 3), when the likelihood of healing with nonoperative treatment rises above 82% (Figure 4), or when the probability of healing after surgery falls below 92% (Figure 5). Nonoperative treatment is also favored when the probability of minor complication with surgery is above 17% (Figure 6) and when utility for a successfully treated nonunion is higher than 6.9 (Figure 7).

Discussion

Optimal management of a metadiaphyseal fracture of the fifth metatarsal (Jones fracture) remains controversial. The decision between initial operative or nonoperative treatment lends itself to expected-value decision analysis because of well-defined treatment options and relatively discrete outcomes. The principal advantages of nonoperative treatment are that it allows the patient to avoid the risks and discomfort of surgery, and the principal advantages of operative treatment are that it maximizes the chance of fracture union and may accelerate functional recovery.

Our decision analysis determined that operative fixation is the optimal decision path, given the outcome probabilities derived from the literature and the utilities obtained from surveys. This finding is in accordance with several expert opinions in foot and ankle fracture surgery.^17,18 However, the expected values of the operative and nonoperative treatment strategies differed by only 0.3 on a 10-point scale. Such similar expected values in our model are not surprising given the controversy surrounding clinical decision making in the treatment of these fractures.¹⁹

In addition, our analysis identified the important variables in the decision-making process. Patients averse to surgery, patients not averse to successful nonoperative treatment, and patients who view successful nonunion surgery after initial nonoperative treatment as a relatively positive outcome may be best treated nonoperatively. These findings emphasize the importance of patient preferences and shared decision-making. Higher rates of healing with nonoperative treatment, lower rates of healing with surgery, and higher complication rates with surgery also favor nonoperative management. It would therefore be valuable to identify risk factors for nonunion with nonoperative treatment and to identify the technical details of surgery that maximize rates of healing and minimize the risk of complications.

The limitations of decision analysis involve the methods by which probabilities and utilities are obtained. In general, the most accurate, stable, and robust estimates of outcome probabilities are derived from a meta-analytic synthesis of randomized clinical trials, the highest level of clinical evidence. In our model, data were extracted primarily from level IV studies; only 1 level III study²⁰ and 1 level II study²¹ were available for analysis. Thus, as is the case with many foot and ankle disorders²², the information on treatment of Jones fractures is very limited in its level of clinical evidence.

Determination of outcome utility also has limitations. Utility is a subjective value that an individual places on a specific outcome. This can be very difficult to quantify. In general, the most robust estimates of patient-derived utilities are derived from complex qualitative methods, such as the standard reference gamble or time trade-offs, in which patients are asked to gamble or choose between health states usually referenced to death. In this study, we determined patient-derived utility values from a direct scaling method using a Likert scale because of the complexity of the standard reference gamble and the difficulty of referencing to death for metatarsal fracture. Although use of a direct scale to determine utility values is less rigorous than the standard reference gamble, this technique has been corroborated methodologically,²³ is advantageous in terms of feasibility and reliability,²⁴ and has been successfully used in other orthopedic decision analysis models.^12,25,26 In our estimation, generally active patients without a history of foot pathology constituted a sample of convenience but also were representative of individuals at risk for Jones fracture. Although specific scenarios were presented, the patients who completed the questionnaire may not have had deep insights into the subtleties and implications of the various disease states and treatments. Regardless of how outcome probabilities and utilities are determined, they are considered point estimates in decision analysis, and sensitivity analyses are therefore performed to assess how decision making changes over a range of values.

Conclusion

The results of this study may help optimize the process of deciding between operative and nonoperative treatment for Jones fracture. For a given patient, the optimal strategy depends not only on the probabilities of the various outcomes but also on personal preference. Thus, there may not be one right answer for all patients. Patients who value a higher chance of fracture healing with initial treatment or an earlier return to sports are best treated operatively, whereas patients who are risk-averse and place a high value on fracture healing without surgery should be managed nonoperatively. We therefore advocate a model of shared medical decision-making in which the physician and the patient are jointly involved, considering both outcome probabilities and patient preferences. Ongoing research efforts should focus on predictors of nonunion with nonoperative treatment.

The optimal management strategy for acute fractures of the metadiaphyseal fifth metatarsal (Jones fractures) is controversial. Patients can be successfully treated nonoperatively with non-weight-bearing and immobilization in a short leg cast^1-7 or operatively with placement of an intramedullary screw.^8-10 The primary advantage of nonoperative treatment is avoiding the risks and discomfort of surgery; disadvantages include the need for prolonged immobilization and protected weight-bearing as well as a decreased union rate.^8,9 Advantages of operative treatment include accelerated functional recovery and an improved union rate; disadvantages include exposure to the risks, inconvenience, and discomfort of surgery. Clear, definitive evidence for guiding treatment is not available in the orthopedic literature, and treatment strategies vary substantially according to surgeon and patient preference.

Expected-value decision analysis, a research tool that helps guide decision-making in situations of uncertainty, has been effectively applied to other areas of uncertainty in the orthopedic literature.^11-14 Borrowed from gaming theory, the technique involves creating a decision tree to define the clinical problem, determining outcome probabilities and utilities, performing a fold-back analysis to determine the optimal decision-making strategy, and performing a sensitivity analysis to model the effect of varying outcome probabilities and utilities on decision-making. Decision analysis may therefore allow the clinician and the patient to optimize decision-making based on best available evidence and patient preferences. It also helps determine the most important factors affecting management strategies and the decision-making process, which may not always be intuitive.

In the present study, we used expected-value decision analysis to determine the optimal management strategy, operative or nonoperative, for acute Jones fracture. We also explored factors with the most influence on the model and identified important questions for future research.

Materials and Methods

Institutional review board approval was obtained for this study. Analysis was performed with Treeage Pro statistical software (Treeage Software).

Outcome Probabilities

Outcome probabilities were determined by reviewing the literature for articles on Jones fractures. This body of literature was summarized in a comprehensive review by Dean and colleagues¹⁵, who extracted data from 19 studies: 1 randomized controlled trial, 1 prospective case series, and 17 retrospective case series.¹⁵ We used data from these studies to determine outcome probabilities (Table).

Outcome Utilities

Utilities represent patient preferences for various disease states. Outcome utility values were obtained from 32 adults (25 women, 7 men) with no history of foot injury. Mean age was 32.4 years (range, 20-69 years). The questionnaire presented scenarios for the different outcomes and asked patients to rate these outcomes on a scale ranging from 0 (worst possible outcome) to 10 (best possible outcome). The Sports subscale of the Foot and Ankle Ability Measure (FAAM) 16 was used to quantify patient activity level.

Decision Tree and Fold-Back Analysis

A decision tree was constructed with 1 decision node, 4 chance nodes, and 7 terminal nodes (Figure 1). The decision tree demonstrates 2 different strategies for managing a Jones fracture. The decision node divides the tree into 2 branches: initial operative or nonoperative treatment. Both branches are followed by various chance nodes, each terminating in a discrete clinical outcome. Per convention, utility data were placed to the right of the terminal nodes, and probability data were placed under the terminal nodes.

Fold-back analysis was performed to identify the optimal strategy. Fold-back analysis involves multiplying each outcome utility by its associated probability, thereby providing an “expected value” for each clinical endpoint. Then, the expected values for each endpoint can be summed for a given management strategy, and the ultimate expected values of the different strategies can be compared. The management strategy associated with the highest expected value is optimal for the given outcome utilities and probabilities.

Sensitivity Analysis

One-way sensitivity analysis was performed to model the effect on decision-making of changing the values for utility for uncomplicated surgery, utility for healing with nonoperative treatment, utility for uncomplicated treatment of nonunion, likelihood of healing with nonoperative treatment, likelihood of healing with surgery, and likelihood of minor complication with surgery. These were the variables found to affect the decision-making strategy within their clinically plausible ranges.

Results

Outcome Probabilities and Utilities

Outcome probabilities and utilities are illustrated in Figure 1. By convention, probabilities appear below the corresponding branches of the decision tree, and utilities appear at the end of each branch. Mean (SD) FAAM Sports subscale score was 84.6 (27.4). This subscale is scored as a percentage from 0% to 100%, with higher scores indicating a higher level of physical function.

Decision Analysis

The expected value for nonoperative treatment was 7.74, and the expected value for intramedullary screw fixation was 7.88 (Figure 1). Therefore, operative treatment was identified as the optimal treatment strategy.

Sensitivity analyses revealed that the optimal decision making strategy was very sensitive to small changes in several variables. Nonoperative treatment becomes the preferred strategy when the utility value for uncomplicated surgery falls below 8.04 (Figure 2), when the utility for healing with nonoperative treatment rises above 8.49 (Figure 3), when the likelihood of healing with nonoperative treatment rises above 82% (Figure 4), or when the probability of healing after surgery falls below 92% (Figure 5). Nonoperative treatment is also favored when the probability of minor complication with surgery is above 17% (Figure 6) and when utility for a successfully treated nonunion is higher than 6.9 (Figure 7).

Discussion

Optimal management of a metadiaphyseal fracture of the fifth metatarsal (Jones fracture) remains controversial. The decision between initial operative or nonoperative treatment lends itself to expected-value decision analysis because of well-defined treatment options and relatively discrete outcomes. The principal advantages of nonoperative treatment are that it allows the patient to avoid the risks and discomfort of surgery, and the principal advantages of operative treatment are that it maximizes the chance of fracture union and may accelerate functional recovery.

Our decision analysis determined that operative fixation is the optimal decision path, given the outcome probabilities derived from the literature and the utilities obtained from surveys. This finding is in accordance with several expert opinions in foot and ankle fracture surgery.^17,18 However, the expected values of the operative and nonoperative treatment strategies differed by only 0.3 on a 10-point scale. Such similar expected values in our model are not surprising given the controversy surrounding clinical decision making in the treatment of these fractures.¹⁹

In addition, our analysis identified the important variables in the decision-making process. Patients averse to surgery, patients not averse to successful nonoperative treatment, and patients who view successful nonunion surgery after initial nonoperative treatment as a relatively positive outcome may be best treated nonoperatively. These findings emphasize the importance of patient preferences and shared decision-making. Higher rates of healing with nonoperative treatment, lower rates of healing with surgery, and higher complication rates with surgery also favor nonoperative management. It would therefore be valuable to identify risk factors for nonunion with nonoperative treatment and to identify the technical details of surgery that maximize rates of healing and minimize the risk of complications.

The limitations of decision analysis involve the methods by which probabilities and utilities are obtained. In general, the most accurate, stable, and robust estimates of outcome probabilities are derived from a meta-analytic synthesis of randomized clinical trials, the highest level of clinical evidence. In our model, data were extracted primarily from level IV studies; only 1 level III study²⁰ and 1 level II study²¹ were available for analysis. Thus, as is the case with many foot and ankle disorders²², the information on treatment of Jones fractures is very limited in its level of clinical evidence.

Determination of outcome utility also has limitations. Utility is a subjective value that an individual places on a specific outcome. This can be very difficult to quantify. In general, the most robust estimates of patient-derived utilities are derived from complex qualitative methods, such as the standard reference gamble or time trade-offs, in which patients are asked to gamble or choose between health states usually referenced to death. In this study, we determined patient-derived utility values from a direct scaling method using a Likert scale because of the complexity of the standard reference gamble and the difficulty of referencing to death for metatarsal fracture. Although use of a direct scale to determine utility values is less rigorous than the standard reference gamble, this technique has been corroborated methodologically,²³ is advantageous in terms of feasibility and reliability,²⁴ and has been successfully used in other orthopedic decision analysis models.^12,25,26 In our estimation, generally active patients without a history of foot pathology constituted a sample of convenience but also were representative of individuals at risk for Jones fracture. Although specific scenarios were presented, the patients who completed the questionnaire may not have had deep insights into the subtleties and implications of the various disease states and treatments. Regardless of how outcome probabilities and utilities are determined, they are considered point estimates in decision analysis, and sensitivity analyses are therefore performed to assess how decision making changes over a range of values.

Conclusion

The results of this study may help optimize the process of deciding between operative and nonoperative treatment for Jones fracture. For a given patient, the optimal strategy depends not only on the probabilities of the various outcomes but also on personal preference. Thus, there may not be one right answer for all patients. Patients who value a higher chance of fracture healing with initial treatment or an earlier return to sports are best treated operatively, whereas patients who are risk-averse and place a high value on fracture healing without surgery should be managed nonoperatively. We therefore advocate a model of shared medical decision-making in which the physician and the patient are jointly involved, considering both outcome probabilities and patient preferences. Ongoing research efforts should focus on predictors of nonunion with nonoperative treatment.

The optimal management strategy for acute fractures of the metadiaphyseal fifth metatarsal (Jones fractures) is controversial. Patients can be successfully treated nonoperatively with non-weight-bearing and immobilization in a short leg cast^1-7 or operatively with placement of an intramedullary screw.^8-10 The primary advantage of nonoperative treatment is avoiding the risks and discomfort of surgery; disadvantages include the need for prolonged immobilization and protected weight-bearing as well as a decreased union rate.^8,9 Advantages of operative treatment include accelerated functional recovery and an improved union rate; disadvantages include exposure to the risks, inconvenience, and discomfort of surgery. Clear, definitive evidence for guiding treatment is not available in the orthopedic literature, and treatment strategies vary substantially according to surgeon and patient preference.

Expected-value decision analysis, a research tool that helps guide decision-making in situations of uncertainty, has been effectively applied to other areas of uncertainty in the orthopedic literature.^11-14 Borrowed from gaming theory, the technique involves creating a decision tree to define the clinical problem, determining outcome probabilities and utilities, performing a fold-back analysis to determine the optimal decision-making strategy, and performing a sensitivity analysis to model the effect of varying outcome probabilities and utilities on decision-making. Decision analysis may therefore allow the clinician and the patient to optimize decision-making based on best available evidence and patient preferences. It also helps determine the most important factors affecting management strategies and the decision-making process, which may not always be intuitive.

In the present study, we used expected-value decision analysis to determine the optimal management strategy, operative or nonoperative, for acute Jones fracture. We also explored factors with the most influence on the model and identified important questions for future research.

Materials and Methods

Institutional review board approval was obtained for this study. Analysis was performed with Treeage Pro statistical software (Treeage Software).

Outcome Probabilities

Outcome probabilities were determined by reviewing the literature for articles on Jones fractures. This body of literature was summarized in a comprehensive review by Dean and colleagues¹⁵, who extracted data from 19 studies: 1 randomized controlled trial, 1 prospective case series, and 17 retrospective case series.¹⁵ We used data from these studies to determine outcome probabilities (Table).

Outcome Utilities

Utilities represent patient preferences for various disease states. Outcome utility values were obtained from 32 adults (25 women, 7 men) with no history of foot injury. Mean age was 32.4 years (range, 20-69 years). The questionnaire presented scenarios for the different outcomes and asked patients to rate these outcomes on a scale ranging from 0 (worst possible outcome) to 10 (best possible outcome). The Sports subscale of the Foot and Ankle Ability Measure (FAAM) 16 was used to quantify patient activity level.

Decision Tree and Fold-Back Analysis

A decision tree was constructed with 1 decision node, 4 chance nodes, and 7 terminal nodes (Figure 1). The decision tree demonstrates 2 different strategies for managing a Jones fracture. The decision node divides the tree into 2 branches: initial operative or nonoperative treatment. Both branches are followed by various chance nodes, each terminating in a discrete clinical outcome. Per convention, utility data were placed to the right of the terminal nodes, and probability data were placed under the terminal nodes.

Fold-back analysis was performed to identify the optimal strategy. Fold-back analysis involves multiplying each outcome utility by its associated probability, thereby providing an “expected value” for each clinical endpoint. Then, the expected values for each endpoint can be summed for a given management strategy, and the ultimate expected values of the different strategies can be compared. The management strategy associated with the highest expected value is optimal for the given outcome utilities and probabilities.

Sensitivity Analysis

One-way sensitivity analysis was performed to model the effect on decision-making of changing the values for utility for uncomplicated surgery, utility for healing with nonoperative treatment, utility for uncomplicated treatment of nonunion, likelihood of healing with nonoperative treatment, likelihood of healing with surgery, and likelihood of minor complication with surgery. These were the variables found to affect the decision-making strategy within their clinically plausible ranges.

Results

Outcome Probabilities and Utilities

Outcome probabilities and utilities are illustrated in Figure 1. By convention, probabilities appear below the corresponding branches of the decision tree, and utilities appear at the end of each branch. Mean (SD) FAAM Sports subscale score was 84.6 (27.4). This subscale is scored as a percentage from 0% to 100%, with higher scores indicating a higher level of physical function.

Decision Analysis

The expected value for nonoperative treatment was 7.74, and the expected value for intramedullary screw fixation was 7.88 (Figure 1). Therefore, operative treatment was identified as the optimal treatment strategy.

Sensitivity analyses revealed that the optimal decision making strategy was very sensitive to small changes in several variables. Nonoperative treatment becomes the preferred strategy when the utility value for uncomplicated surgery falls below 8.04 (Figure 2), when the utility for healing with nonoperative treatment rises above 8.49 (Figure 3), when the likelihood of healing with nonoperative treatment rises above 82% (Figure 4), or when the probability of healing after surgery falls below 92% (Figure 5). Nonoperative treatment is also favored when the probability of minor complication with surgery is above 17% (Figure 6) and when utility for a successfully treated nonunion is higher than 6.9 (Figure 7).

Discussion

Optimal management of a metadiaphyseal fracture of the fifth metatarsal (Jones fracture) remains controversial. The decision between initial operative or nonoperative treatment lends itself to expected-value decision analysis because of well-defined treatment options and relatively discrete outcomes. The principal advantages of nonoperative treatment are that it allows the patient to avoid the risks and discomfort of surgery, and the principal advantages of operative treatment are that it maximizes the chance of fracture union and may accelerate functional recovery.

Our decision analysis determined that operative fixation is the optimal decision path, given the outcome probabilities derived from the literature and the utilities obtained from surveys. This finding is in accordance with several expert opinions in foot and ankle fracture surgery.^17,18 However, the expected values of the operative and nonoperative treatment strategies differed by only 0.3 on a 10-point scale. Such similar expected values in our model are not surprising given the controversy surrounding clinical decision making in the treatment of these fractures.¹⁹

In addition, our analysis identified the important variables in the decision-making process. Patients averse to surgery, patients not averse to successful nonoperative treatment, and patients who view successful nonunion surgery after initial nonoperative treatment as a relatively positive outcome may be best treated nonoperatively. These findings emphasize the importance of patient preferences and shared decision-making. Higher rates of healing with nonoperative treatment, lower rates of healing with surgery, and higher complication rates with surgery also favor nonoperative management. It would therefore be valuable to identify risk factors for nonunion with nonoperative treatment and to identify the technical details of surgery that maximize rates of healing and minimize the risk of complications.

The limitations of decision analysis involve the methods by which probabilities and utilities are obtained. In general, the most accurate, stable, and robust estimates of outcome probabilities are derived from a meta-analytic synthesis of randomized clinical trials, the highest level of clinical evidence. In our model, data were extracted primarily from level IV studies; only 1 level III study²⁰ and 1 level II study²¹ were available for analysis. Thus, as is the case with many foot and ankle disorders²², the information on treatment of Jones fractures is very limited in its level of clinical evidence.

Determination of outcome utility also has limitations. Utility is a subjective value that an individual places on a specific outcome. This can be very difficult to quantify. In general, the most robust estimates of patient-derived utilities are derived from complex qualitative methods, such as the standard reference gamble or time trade-offs, in which patients are asked to gamble or choose between health states usually referenced to death. In this study, we determined patient-derived utility values from a direct scaling method using a Likert scale because of the complexity of the standard reference gamble and the difficulty of referencing to death for metatarsal fracture. Although use of a direct scale to determine utility values is less rigorous than the standard reference gamble, this technique has been corroborated methodologically,²³ is advantageous in terms of feasibility and reliability,²⁴ and has been successfully used in other orthopedic decision analysis models.^12,25,26 In our estimation, generally active patients without a history of foot pathology constituted a sample of convenience but also were representative of individuals at risk for Jones fracture. Although specific scenarios were presented, the patients who completed the questionnaire may not have had deep insights into the subtleties and implications of the various disease states and treatments. Regardless of how outcome probabilities and utilities are determined, they are considered point estimates in decision analysis, and sensitivity analyses are therefore performed to assess how decision making changes over a range of values.

Conclusion

The results of this study may help optimize the process of deciding between operative and nonoperative treatment for Jones fracture. For a given patient, the optimal strategy depends not only on the probabilities of the various outcomes but also on personal preference. Thus, there may not be one right answer for all patients. Patients who value a higher chance of fracture healing with initial treatment or an earlier return to sports are best treated operatively, whereas patients who are risk-averse and place a high value on fracture healing without surgery should be managed nonoperatively. We therefore advocate a model of shared medical decision-making in which the physician and the patient are jointly involved, considering both outcome probabilities and patient preferences. Ongoing research efforts should focus on predictors of nonunion with nonoperative treatment.

The beach-chair position (BCP) is commonly used for both arthroscopic and open shoulder surgery. This technique positions the shoulder in an anatomical upright position, facilitating shoulder access and visualization.¹ Compared with the lateral decubitus position, the BCP also improves airway access, reduces bleeding, and lessens the risk for brachial plexus injury.²

Despite the advantages of using the BCP, there have been multiple reports of catastrophic neurologic complications, including severe brain damage and death, in relatively healthy patients without any known risk factors.^3-6 The definitive etiology of these complications remains unclear, but it has been hypothesized that BCP use may be an independent risk factor for cerebrovascular ischemia,^1,5-16 as the upright position can cause hypotension leading to increased risk for cerebral hypoperfusion.^7-11,17 Reducing cerebral perfusion pressure below critical thresholds may result in permanent neurologic injury.^4-6,14 Therefore, monitoring of cerebral perfusion and optimization of intraoperative cerebral oxygenation have been recommended to help avoid potential neurologic complications. However, a direct relationship between intraoperative cerebral desaturation events (CDEs) and postoperative neurocognitive deficits has not been definitively established.^1,9-12

To put into perspective the importance of detecting and preventing CDEs and neurologic complications, we can consider the incidence of fatal pulmonary embolism associated with total joint arthroplasty. Although the incidence is very low, about 0.1% to 2.0%, some form of venous thromboembolism prophylaxis is the standard of care for helping prevent this serious complication. Similarly, catastrophic neurologic complications of upright shoulder arthroscopy are very rare, but it is still important to consider measures that help minimize them.

We reviewed the literature for the incidence of postoperative neurocognitive deficits, number of reported neurocognitive complications, and incidence of intraoperative CDEs in patients who underwent arthroscopic shoulder surgery in the BCP.

Methods

Dr. Salazar and Dr. Hazel independently searched the Medline, Cochrane, and Embase databases for case series, prospective studies, and cohort studies that reported neurocognitive complications associated with the BCP and the incidence of intraoperative CDEs. The authors used beach chair, desaturation, near infrared spectroscopy, and shoulder as medical subject headings (MeSH). In addition, bibliographies of retrieved articles were checked for studies that the search terms may have missed. Eighty-one publications were identified and reviewed for possible inclusion.

Next, the same 2 authors reviewed the titles and abstracts for relevance and determined which articles had potential to contribute to the study. Only English-language publications were considered for inclusion. To review the incidence of postoperative neurocognitive deficits, we included only those studies with more than 25 patients, documentation of postoperative complications, and arthroscopic shoulder surgery performed with the patient in the seated, semi-upright, or BCP. Only studies with at least 25 patients were used in order to increase the power and improve the level of evidence. To review reported cases of neurocognitive complications, we included all relevant case reports and case series. To review the incidence of intraoperative CDEs and investigate their relationship with postoperative neurocognitive deficits, we included studies that reported on use of intraoperative cerebral perfusion monitoring. Modalities used in these studies included near infrared spectroscopy, electroencephalography, and invasive blood pressure monitoring calculated at the brain level. Studies were excluded if they did not involve arthroscopic shoulder surgery or were not conducted with human subjects.

Information recorded for each study included general information such as author and publication year, type of study, number of patients enrolled, type of intraoperative monitoring, anesthesia protocol, number of patients with CDEs, and number of patients with neurocognitive complications after surgery.

Results

Our search identified 81 publications for potential inclusion. Our first aim was to identify the overall incidence of reported neurocognitive deficits after arthroscopic shoulder surgery with the patient in the BCP. We identified 10 studies (Table 1) that met the inclusion criteria. Among the 24,701 patients in these 10 studies, there was only 1 reported case of neurocognitive deficit after surgery, in a mixed prospective-retrospective study of 15,014 cases by Rohrbaugh and colleagues.18 The deficit they reported was an ischemic cerebral vascular accident. The 0.0067% incidence in their study demonstrates how rare the complication is. Two large retrospective studies (Ns = 4169 and 5177 patients) found no postoperative neurocognitive complications.^19,20 Only 3 studies performed formal postoperative cognitive testing. Salazar and colleagues²¹ used the Repeatable Battery for the Assessment of Neuropsychological Status before and after surgery, and Gillespie and colleagues⁸ and Lee and colleagues¹⁰ used the Mini–Mental State Examination before and after surgery. Total incidence of reported neurocognitive deficits from our review was 0.004% (1/24,701).

Our second aim was to review all reported cases of neurocognitive complications after arthroscopic shoulder surgery with the patient in the BCP. We identified 4 publications that fit our inclusion criteria (Table 2). Pohl and Cullen6 described 4 cases of ischemic brain injury after arthroscopic shoulder surgery with the patient in the BCP. Age range was 47 to 57 years. Specific intraoperative cerebral monitoring was not used. However, these patients had several episodes of intraoperative hypotension (systolic blood pressures, 80-90 mm Hg), measured with a traditional blood pressure cuff on the arm. In general, these patients had minimal cerebrovascular risk factors and no known preexisting cerebrovascular disease. Drummond and colleagues²² described an ischemic stroke in a 50-year-old man after arthroscopic subacromial decompression and open rotator cuff repair that resulted in unresolved right hemiplegia. Subsequent diagnostic investigation revealed an asymmetry of the circle of Willis resulting in limited flow to the left anterior and middle cerebral artery distributions. Bhatti and Enneking³ reported the case of a 64-year-old man who lost vision in the right eye immediately after arthroscopic rotator cuff repair. His vision improved spontaneously the next morning and continued to improve over the next 6 months—he regained 20/20 vision with some residual optic neuropathy.

Our third aim was to determine the incidence of intraoperative CDEs during arthroscopic shoulder surgery with the patient in the BCP. Incidence of CDEs varied widely among the 7 studies reviewed (Table 3). Minimum incidence of intraoperative CDE was 0% in a cohort of 30 patients,¹ and maximum incidence was 80% in a study of 61 patients,¹² all of whom underwent elective arthroscopic shoulder surgery in the BCP. Although there was wide variability in CDE incidence, the studies were consistent with respect to their definition of a CDE. Most authors used a decrease in regional cerebral tissue oxygen saturation of 20% or more from baseline, or an absolute value up to 55%, to define a CDE. None of the 7 studies reviewed reported a clinically significant adverse neurocognitive event.

Discussion

Of concern, there have been several surveys, case reports, and small case series of previously healthy patients who had no known risk factors, underwent arthroscopic shoulder surgery in the BCP, and developed unanticipated postoperative neurologic complications.^4-6,14 Beach-chair positioning during surgical procedures has been implicated as a contributing factor leading to cerebral hypoperfusion with potential for cerebral ischemia.^1,12,23 These changes in cerebral perfusion pressure are thought to be the major determinant of poor neurologic outcomes. Such reports have exposed the potential need for heightened vigilance, alternative anesthesia techniques, and improved monitoring, though the exact etiology of the central nervous system injuries in this patient population is incompletely understood and is likely multifactorial. Therefore, in this study we wanted to determine the incidence of postoperative neurocognitive deficits and review all reported cases of neurocognitive complications in patients who have undergone arthroscopic shoulder surgery in the BCP. In addition, we wanted to define the incidence of intraoperative CDEs and investigate their relationship with postoperative neurocognitive complications.

According to our review, the incidence of postoperative neurocognitive complications after surgery in the BCP is 0.004% (1/24,701). However, this finding is based only on what has been reported; the true incidence is not known. It is also important to note that the incidence of neurocognitive deficits after many other types of surgery is not known and that surgery itself may be a risk factor for postoperative neurocognitive deficits.²⁴ In their retrospective review of 15,014 patients who underwent arthroscopic shoulder surgery in the BCP at a single institution over an 11-year period, Rohrbaugh and colleagues18 found an overall postoperative complication rate of 0.37% and a 0.0067% incidence of neurocognitive deficits. One patient in the series was given a diagnosis of ischemic stroke on the basis of neurologic deficits that occurred 24 hours after surgery. Yadeau and colleagues²⁰ found no postoperative neurocognitive complications in a mixed prospective-retrospective study of 4169 patients—3000 identified retrospectively, 1169 prospectively—who underwent arthroscopic shoulder surgery in the BCP at an ambulatory surgery center. Pin-on and colleagues¹⁹ reported on a series of 5177 orthopedic and neurosurgical patients who underwent surgery in the BCP. In those who had arthroscopic shoulder surgery, intraoperative systolic blood pressures obtained from an arterial line referenced to heart level decreased a mean (SD) of 14.4% (12.7%), whereas in those whose pressures were obtained from a noninvasive blood pressure cuff referenced to heart level decreased 19.3% (12.6%). However, the authors reported no incidence of postoperative stroke or neurologic deficits.

Although uncommon, perioperative cerebral ischemic accidents are potentially devastating for patients, their families, and the health care professionals involved. These events have tremendous economic, social, professional, and medicolegal implications, with perioperative stroke being particularly morbid. Perioperative stroke has a mortality rate of 60%, versus 15% to 46% for stroke in general.^25,26 In 2005, Pohl and Cullen⁶ published a landmark article on a series of 4 relatively healthy middle-aged patients who were at low risk for stroke but had catastrophic neurocognitive complications (including 1 death) after arthroscopic shoulder surgery in the BCP. Bhatti and Enneking³ described a case of acute postoperative vision loss and ophthalmoplegia attributed to intraoperative hypotension leading to ischemia in a patient who underwent an elective shoulder arthroscopic procedure in the BCP. These reports prompted multiple investigations into the physiologic hemodynamic changes associated with surgery in the BCP and the treatment strategies used to improve patient safety.

In the normal physiologic state, the sympathetic nervous system is activated when a person assumes the seated position. The result is increased systemic vascular resistance and heart rate alterations to maintain cardiac output and mean arterial pressure. In anesthetized patients, this response is blunted by the vasodilatory effects of intravenous and volatile anesthetics. Multiple studies have demonstrated substantial hemodynamic changes in both awake and anesthetized patients during the maneuver from the supine position to the seated position^1,27,28; these changes include diminished cardiac index, stroke volume, and arterial pressure.¹⁷ The data underscore the need for attentiveness and accurate monitoring of cerebral perfusion when the transition is made from the supine position to the BCP, particularly in the early phase of surgery and in high-risk patients.

Knowledge of these hemodynamic changes has led several authors to recommend additional intraoperative monitoring of cerebral perfusion. Monitoring techniques have included use of invasive blood pressure monitoring adjusted to brain level, cerebral oximetry using near infrared spectroscopy, and electroencephalography. However, the clinical relevance of intraoperative CDEs in isolation is not well understood.^1,6,7,23 In addition, cost and availability of additional advanced monitoring likely factor into why it is not more commonly used. For this patient population, the severity, frequency, and duration of desaturation that causes cerebral ischemia and the relationship with postoperative neurocognitive deficits remain undefined.

The incidence of CDEs in patients being monitored with near infrared spectroscopy while undergoing elective arthroscopic shoulder surgery in the BCP varies widely, from 0% to 80% (mean, 41%).^{1,4,7,10,12,21} Magnitude and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remain unidentified as well. In conscious patients, a 20% reduction in frontal lobe oxygenation is associated with clinical manifestations of cerebral hypoperfusion, such as syncope.^15,29 As none of the patients in the studies we reviewed experienced any sort of deficit, we cannot definitively state there is a correlation between CDE occurrence and neurocognitive deficit.

One limitation of our investigation is that it was a systemic review, and thus there was substantial heterogeneity in the methods and designs of the studies included in the analysis. Among the different series, there was variability in multiple aspects of the study design, including type of anesthetic, patient inclusion criteria, type of surgery, type of intraoperative cerebral perfusion monitoring, and type of neurocognitive testing. As a result, comparing the groups was difficult, and the generalizability of our findings may be limited. In addition, it is difficult to accurately establish incidence and comprehensively review these events because of the paucity of literature.

Conclusion

Neurocognitive complications after shoulder arthroscopy with the patient in the BCP are extremely rare but potentially devastating events that can affect healthy patients with no preexisting cerebrovascular risk factors. Our review indicated the incidence of permanent neurologic deficit after arthroscopy in the BCP may be as low as 0.004%. The exact etiology of such complications is not clear. Basic science research and large prospective studies are needed to identify the clinically relevant thresholds of magnitude, duration, and frequency of intraoperative CDEs in order to establish their relationship with postoperative neurocognitive complications. Such large studies may also elucidate modifiable patient-specific risk factors and establish the most sensitive, safe, and cost-effective intraoperative monitoring tools. Current literature suggests that accurate intraoperative monitoring of cerebral perfusion, alternatives to general anesthesia, and prudent use of intraoperative blood pressure control may improve patient safety.

The beach-chair position (BCP) is commonly used for both arthroscopic and open shoulder surgery. This technique positions the shoulder in an anatomical upright position, facilitating shoulder access and visualization.¹ Compared with the lateral decubitus position, the BCP also improves airway access, reduces bleeding, and lessens the risk for brachial plexus injury.²

Despite the advantages of using the BCP, there have been multiple reports of catastrophic neurologic complications, including severe brain damage and death, in relatively healthy patients without any known risk factors.^3-6 The definitive etiology of these complications remains unclear, but it has been hypothesized that BCP use may be an independent risk factor for cerebrovascular ischemia,^1,5-16 as the upright position can cause hypotension leading to increased risk for cerebral hypoperfusion.^7-11,17 Reducing cerebral perfusion pressure below critical thresholds may result in permanent neurologic injury.^4-6,14 Therefore, monitoring of cerebral perfusion and optimization of intraoperative cerebral oxygenation have been recommended to help avoid potential neurologic complications. However, a direct relationship between intraoperative cerebral desaturation events (CDEs) and postoperative neurocognitive deficits has not been definitively established.^1,9-12

To put into perspective the importance of detecting and preventing CDEs and neurologic complications, we can consider the incidence of fatal pulmonary embolism associated with total joint arthroplasty. Although the incidence is very low, about 0.1% to 2.0%, some form of venous thromboembolism prophylaxis is the standard of care for helping prevent this serious complication. Similarly, catastrophic neurologic complications of upright shoulder arthroscopy are very rare, but it is still important to consider measures that help minimize them.

We reviewed the literature for the incidence of postoperative neurocognitive deficits, number of reported neurocognitive complications, and incidence of intraoperative CDEs in patients who underwent arthroscopic shoulder surgery in the BCP.

Methods

Dr. Salazar and Dr. Hazel independently searched the Medline, Cochrane, and Embase databases for case series, prospective studies, and cohort studies that reported neurocognitive complications associated with the BCP and the incidence of intraoperative CDEs. The authors used beach chair, desaturation, near infrared spectroscopy, and shoulder as medical subject headings (MeSH). In addition, bibliographies of retrieved articles were checked for studies that the search terms may have missed. Eighty-one publications were identified and reviewed for possible inclusion.

Next, the same 2 authors reviewed the titles and abstracts for relevance and determined which articles had potential to contribute to the study. Only English-language publications were considered for inclusion. To review the incidence of postoperative neurocognitive deficits, we included only those studies with more than 25 patients, documentation of postoperative complications, and arthroscopic shoulder surgery performed with the patient in the seated, semi-upright, or BCP. Only studies with at least 25 patients were used in order to increase the power and improve the level of evidence. To review reported cases of neurocognitive complications, we included all relevant case reports and case series. To review the incidence of intraoperative CDEs and investigate their relationship with postoperative neurocognitive deficits, we included studies that reported on use of intraoperative cerebral perfusion monitoring. Modalities used in these studies included near infrared spectroscopy, electroencephalography, and invasive blood pressure monitoring calculated at the brain level. Studies were excluded if they did not involve arthroscopic shoulder surgery or were not conducted with human subjects.

Information recorded for each study included general information such as author and publication year, type of study, number of patients enrolled, type of intraoperative monitoring, anesthesia protocol, number of patients with CDEs, and number of patients with neurocognitive complications after surgery.

Results

Our search identified 81 publications for potential inclusion. Our first aim was to identify the overall incidence of reported neurocognitive deficits after arthroscopic shoulder surgery with the patient in the BCP. We identified 10 studies (Table 1) that met the inclusion criteria. Among the 24,701 patients in these 10 studies, there was only 1 reported case of neurocognitive deficit after surgery, in a mixed prospective-retrospective study of 15,014 cases by Rohrbaugh and colleagues.18 The deficit they reported was an ischemic cerebral vascular accident. The 0.0067% incidence in their study demonstrates how rare the complication is. Two large retrospective studies (Ns = 4169 and 5177 patients) found no postoperative neurocognitive complications.^19,20 Only 3 studies performed formal postoperative cognitive testing. Salazar and colleagues²¹ used the Repeatable Battery for the Assessment of Neuropsychological Status before and after surgery, and Gillespie and colleagues⁸ and Lee and colleagues¹⁰ used the Mini–Mental State Examination before and after surgery. Total incidence of reported neurocognitive deficits from our review was 0.004% (1/24,701).

Our second aim was to review all reported cases of neurocognitive complications after arthroscopic shoulder surgery with the patient in the BCP. We identified 4 publications that fit our inclusion criteria (Table 2). Pohl and Cullen6 described 4 cases of ischemic brain injury after arthroscopic shoulder surgery with the patient in the BCP. Age range was 47 to 57 years. Specific intraoperative cerebral monitoring was not used. However, these patients had several episodes of intraoperative hypotension (systolic blood pressures, 80-90 mm Hg), measured with a traditional blood pressure cuff on the arm. In general, these patients had minimal cerebrovascular risk factors and no known preexisting cerebrovascular disease. Drummond and colleagues²² described an ischemic stroke in a 50-year-old man after arthroscopic subacromial decompression and open rotator cuff repair that resulted in unresolved right hemiplegia. Subsequent diagnostic investigation revealed an asymmetry of the circle of Willis resulting in limited flow to the left anterior and middle cerebral artery distributions. Bhatti and Enneking³ reported the case of a 64-year-old man who lost vision in the right eye immediately after arthroscopic rotator cuff repair. His vision improved spontaneously the next morning and continued to improve over the next 6 months—he regained 20/20 vision with some residual optic neuropathy.

Our third aim was to determine the incidence of intraoperative CDEs during arthroscopic shoulder surgery with the patient in the BCP. Incidence of CDEs varied widely among the 7 studies reviewed (Table 3). Minimum incidence of intraoperative CDE was 0% in a cohort of 30 patients,¹ and maximum incidence was 80% in a study of 61 patients,¹² all of whom underwent elective arthroscopic shoulder surgery in the BCP. Although there was wide variability in CDE incidence, the studies were consistent with respect to their definition of a CDE. Most authors used a decrease in regional cerebral tissue oxygen saturation of 20% or more from baseline, or an absolute value up to 55%, to define a CDE. None of the 7 studies reviewed reported a clinically significant adverse neurocognitive event.

Discussion

Of concern, there have been several surveys, case reports, and small case series of previously healthy patients who had no known risk factors, underwent arthroscopic shoulder surgery in the BCP, and developed unanticipated postoperative neurologic complications.^4-6,14 Beach-chair positioning during surgical procedures has been implicated as a contributing factor leading to cerebral hypoperfusion with potential for cerebral ischemia.^1,12,23 These changes in cerebral perfusion pressure are thought to be the major determinant of poor neurologic outcomes. Such reports have exposed the potential need for heightened vigilance, alternative anesthesia techniques, and improved monitoring, though the exact etiology of the central nervous system injuries in this patient population is incompletely understood and is likely multifactorial. Therefore, in this study we wanted to determine the incidence of postoperative neurocognitive deficits and review all reported cases of neurocognitive complications in patients who have undergone arthroscopic shoulder surgery in the BCP. In addition, we wanted to define the incidence of intraoperative CDEs and investigate their relationship with postoperative neurocognitive complications.

According to our review, the incidence of postoperative neurocognitive complications after surgery in the BCP is 0.004% (1/24,701). However, this finding is based only on what has been reported; the true incidence is not known. It is also important to note that the incidence of neurocognitive deficits after many other types of surgery is not known and that surgery itself may be a risk factor for postoperative neurocognitive deficits.²⁴ In their retrospective review of 15,014 patients who underwent arthroscopic shoulder surgery in the BCP at a single institution over an 11-year period, Rohrbaugh and colleagues18 found an overall postoperative complication rate of 0.37% and a 0.0067% incidence of neurocognitive deficits. One patient in the series was given a diagnosis of ischemic stroke on the basis of neurologic deficits that occurred 24 hours after surgery. Yadeau and colleagues²⁰ found no postoperative neurocognitive complications in a mixed prospective-retrospective study of 4169 patients—3000 identified retrospectively, 1169 prospectively—who underwent arthroscopic shoulder surgery in the BCP at an ambulatory surgery center. Pin-on and colleagues¹⁹ reported on a series of 5177 orthopedic and neurosurgical patients who underwent surgery in the BCP. In those who had arthroscopic shoulder surgery, intraoperative systolic blood pressures obtained from an arterial line referenced to heart level decreased a mean (SD) of 14.4% (12.7%), whereas in those whose pressures were obtained from a noninvasive blood pressure cuff referenced to heart level decreased 19.3% (12.6%). However, the authors reported no incidence of postoperative stroke or neurologic deficits.

Although uncommon, perioperative cerebral ischemic accidents are potentially devastating for patients, their families, and the health care professionals involved. These events have tremendous economic, social, professional, and medicolegal implications, with perioperative stroke being particularly morbid. Perioperative stroke has a mortality rate of 60%, versus 15% to 46% for stroke in general.^25,26 In 2005, Pohl and Cullen⁶ published a landmark article on a series of 4 relatively healthy middle-aged patients who were at low risk for stroke but had catastrophic neurocognitive complications (including 1 death) after arthroscopic shoulder surgery in the BCP. Bhatti and Enneking³ described a case of acute postoperative vision loss and ophthalmoplegia attributed to intraoperative hypotension leading to ischemia in a patient who underwent an elective shoulder arthroscopic procedure in the BCP. These reports prompted multiple investigations into the physiologic hemodynamic changes associated with surgery in the BCP and the treatment strategies used to improve patient safety.

In the normal physiologic state, the sympathetic nervous system is activated when a person assumes the seated position. The result is increased systemic vascular resistance and heart rate alterations to maintain cardiac output and mean arterial pressure. In anesthetized patients, this response is blunted by the vasodilatory effects of intravenous and volatile anesthetics. Multiple studies have demonstrated substantial hemodynamic changes in both awake and anesthetized patients during the maneuver from the supine position to the seated position^1,27,28; these changes include diminished cardiac index, stroke volume, and arterial pressure.¹⁷ The data underscore the need for attentiveness and accurate monitoring of cerebral perfusion when the transition is made from the supine position to the BCP, particularly in the early phase of surgery and in high-risk patients.

Knowledge of these hemodynamic changes has led several authors to recommend additional intraoperative monitoring of cerebral perfusion. Monitoring techniques have included use of invasive blood pressure monitoring adjusted to brain level, cerebral oximetry using near infrared spectroscopy, and electroencephalography. However, the clinical relevance of intraoperative CDEs in isolation is not well understood.^1,6,7,23 In addition, cost and availability of additional advanced monitoring likely factor into why it is not more commonly used. For this patient population, the severity, frequency, and duration of desaturation that causes cerebral ischemia and the relationship with postoperative neurocognitive deficits remain undefined.

The incidence of CDEs in patients being monitored with near infrared spectroscopy while undergoing elective arthroscopic shoulder surgery in the BCP varies widely, from 0% to 80% (mean, 41%).^{1,4,7,10,12,21} Magnitude and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remain unidentified as well. In conscious patients, a 20% reduction in frontal lobe oxygenation is associated with clinical manifestations of cerebral hypoperfusion, such as syncope.^15,29 As none of the patients in the studies we reviewed experienced any sort of deficit, we cannot definitively state there is a correlation between CDE occurrence and neurocognitive deficit.

One limitation of our investigation is that it was a systemic review, and thus there was substantial heterogeneity in the methods and designs of the studies included in the analysis. Among the different series, there was variability in multiple aspects of the study design, including type of anesthetic, patient inclusion criteria, type of surgery, type of intraoperative cerebral perfusion monitoring, and type of neurocognitive testing. As a result, comparing the groups was difficult, and the generalizability of our findings may be limited. In addition, it is difficult to accurately establish incidence and comprehensively review these events because of the paucity of literature.

Conclusion

Neurocognitive complications after shoulder arthroscopy with the patient in the BCP are extremely rare but potentially devastating events that can affect healthy patients with no preexisting cerebrovascular risk factors. Our review indicated the incidence of permanent neurologic deficit after arthroscopy in the BCP may be as low as 0.004%. The exact etiology of such complications is not clear. Basic science research and large prospective studies are needed to identify the clinically relevant thresholds of magnitude, duration, and frequency of intraoperative CDEs in order to establish their relationship with postoperative neurocognitive complications. Such large studies may also elucidate modifiable patient-specific risk factors and establish the most sensitive, safe, and cost-effective intraoperative monitoring tools. Current literature suggests that accurate intraoperative monitoring of cerebral perfusion, alternatives to general anesthesia, and prudent use of intraoperative blood pressure control may improve patient safety.

The beach-chair position (BCP) is commonly used for both arthroscopic and open shoulder surgery. This technique positions the shoulder in an anatomical upright position, facilitating shoulder access and visualization.¹ Compared with the lateral decubitus position, the BCP also improves airway access, reduces bleeding, and lessens the risk for brachial plexus injury.²

Despite the advantages of using the BCP, there have been multiple reports of catastrophic neurologic complications, including severe brain damage and death, in relatively healthy patients without any known risk factors.^3-6 The definitive etiology of these complications remains unclear, but it has been hypothesized that BCP use may be an independent risk factor for cerebrovascular ischemia,^1,5-16 as the upright position can cause hypotension leading to increased risk for cerebral hypoperfusion.^7-11,17 Reducing cerebral perfusion pressure below critical thresholds may result in permanent neurologic injury.^4-6,14 Therefore, monitoring of cerebral perfusion and optimization of intraoperative cerebral oxygenation have been recommended to help avoid potential neurologic complications. However, a direct relationship between intraoperative cerebral desaturation events (CDEs) and postoperative neurocognitive deficits has not been definitively established.^1,9-12

To put into perspective the importance of detecting and preventing CDEs and neurologic complications, we can consider the incidence of fatal pulmonary embolism associated with total joint arthroplasty. Although the incidence is very low, about 0.1% to 2.0%, some form of venous thromboembolism prophylaxis is the standard of care for helping prevent this serious complication. Similarly, catastrophic neurologic complications of upright shoulder arthroscopy are very rare, but it is still important to consider measures that help minimize them.

We reviewed the literature for the incidence of postoperative neurocognitive deficits, number of reported neurocognitive complications, and incidence of intraoperative CDEs in patients who underwent arthroscopic shoulder surgery in the BCP.

Methods

Dr. Salazar and Dr. Hazel independently searched the Medline, Cochrane, and Embase databases for case series, prospective studies, and cohort studies that reported neurocognitive complications associated with the BCP and the incidence of intraoperative CDEs. The authors used beach chair, desaturation, near infrared spectroscopy, and shoulder as medical subject headings (MeSH). In addition, bibliographies of retrieved articles were checked for studies that the search terms may have missed. Eighty-one publications were identified and reviewed for possible inclusion.

Next, the same 2 authors reviewed the titles and abstracts for relevance and determined which articles had potential to contribute to the study. Only English-language publications were considered for inclusion. To review the incidence of postoperative neurocognitive deficits, we included only those studies with more than 25 patients, documentation of postoperative complications, and arthroscopic shoulder surgery performed with the patient in the seated, semi-upright, or BCP. Only studies with at least 25 patients were used in order to increase the power and improve the level of evidence. To review reported cases of neurocognitive complications, we included all relevant case reports and case series. To review the incidence of intraoperative CDEs and investigate their relationship with postoperative neurocognitive deficits, we included studies that reported on use of intraoperative cerebral perfusion monitoring. Modalities used in these studies included near infrared spectroscopy, electroencephalography, and invasive blood pressure monitoring calculated at the brain level. Studies were excluded if they did not involve arthroscopic shoulder surgery or were not conducted with human subjects.

Information recorded for each study included general information such as author and publication year, type of study, number of patients enrolled, type of intraoperative monitoring, anesthesia protocol, number of patients with CDEs, and number of patients with neurocognitive complications after surgery.

Results

Our search identified 81 publications for potential inclusion. Our first aim was to identify the overall incidence of reported neurocognitive deficits after arthroscopic shoulder surgery with the patient in the BCP. We identified 10 studies (Table 1) that met the inclusion criteria. Among the 24,701 patients in these 10 studies, there was only 1 reported case of neurocognitive deficit after surgery, in a mixed prospective-retrospective study of 15,014 cases by Rohrbaugh and colleagues.18 The deficit they reported was an ischemic cerebral vascular accident. The 0.0067% incidence in their study demonstrates how rare the complication is. Two large retrospective studies (Ns = 4169 and 5177 patients) found no postoperative neurocognitive complications.^19,20 Only 3 studies performed formal postoperative cognitive testing. Salazar and colleagues²¹ used the Repeatable Battery for the Assessment of Neuropsychological Status before and after surgery, and Gillespie and colleagues⁸ and Lee and colleagues¹⁰ used the Mini–Mental State Examination before and after surgery. Total incidence of reported neurocognitive deficits from our review was 0.004% (1/24,701).

Our second aim was to review all reported cases of neurocognitive complications after arthroscopic shoulder surgery with the patient in the BCP. We identified 4 publications that fit our inclusion criteria (Table 2). Pohl and Cullen6 described 4 cases of ischemic brain injury after arthroscopic shoulder surgery with the patient in the BCP. Age range was 47 to 57 years. Specific intraoperative cerebral monitoring was not used. However, these patients had several episodes of intraoperative hypotension (systolic blood pressures, 80-90 mm Hg), measured with a traditional blood pressure cuff on the arm. In general, these patients had minimal cerebrovascular risk factors and no known preexisting cerebrovascular disease. Drummond and colleagues²² described an ischemic stroke in a 50-year-old man after arthroscopic subacromial decompression and open rotator cuff repair that resulted in unresolved right hemiplegia. Subsequent diagnostic investigation revealed an asymmetry of the circle of Willis resulting in limited flow to the left anterior and middle cerebral artery distributions. Bhatti and Enneking³ reported the case of a 64-year-old man who lost vision in the right eye immediately after arthroscopic rotator cuff repair. His vision improved spontaneously the next morning and continued to improve over the next 6 months—he regained 20/20 vision with some residual optic neuropathy.

Our third aim was to determine the incidence of intraoperative CDEs during arthroscopic shoulder surgery with the patient in the BCP. Incidence of CDEs varied widely among the 7 studies reviewed (Table 3). Minimum incidence of intraoperative CDE was 0% in a cohort of 30 patients,¹ and maximum incidence was 80% in a study of 61 patients,¹² all of whom underwent elective arthroscopic shoulder surgery in the BCP. Although there was wide variability in CDE incidence, the studies were consistent with respect to their definition of a CDE. Most authors used a decrease in regional cerebral tissue oxygen saturation of 20% or more from baseline, or an absolute value up to 55%, to define a CDE. None of the 7 studies reviewed reported a clinically significant adverse neurocognitive event.

Discussion

Of concern, there have been several surveys, case reports, and small case series of previously healthy patients who had no known risk factors, underwent arthroscopic shoulder surgery in the BCP, and developed unanticipated postoperative neurologic complications.^4-6,14 Beach-chair positioning during surgical procedures has been implicated as a contributing factor leading to cerebral hypoperfusion with potential for cerebral ischemia.^1,12,23 These changes in cerebral perfusion pressure are thought to be the major determinant of poor neurologic outcomes. Such reports have exposed the potential need for heightened vigilance, alternative anesthesia techniques, and improved monitoring, though the exact etiology of the central nervous system injuries in this patient population is incompletely understood and is likely multifactorial. Therefore, in this study we wanted to determine the incidence of postoperative neurocognitive deficits and review all reported cases of neurocognitive complications in patients who have undergone arthroscopic shoulder surgery in the BCP. In addition, we wanted to define the incidence of intraoperative CDEs and investigate their relationship with postoperative neurocognitive complications.

According to our review, the incidence of postoperative neurocognitive complications after surgery in the BCP is 0.004% (1/24,701). However, this finding is based only on what has been reported; the true incidence is not known. It is also important to note that the incidence of neurocognitive deficits after many other types of surgery is not known and that surgery itself may be a risk factor for postoperative neurocognitive deficits.²⁴ In their retrospective review of 15,014 patients who underwent arthroscopic shoulder surgery in the BCP at a single institution over an 11-year period, Rohrbaugh and colleagues18 found an overall postoperative complication rate of 0.37% and a 0.0067% incidence of neurocognitive deficits. One patient in the series was given a diagnosis of ischemic stroke on the basis of neurologic deficits that occurred 24 hours after surgery. Yadeau and colleagues²⁰ found no postoperative neurocognitive complications in a mixed prospective-retrospective study of 4169 patients—3000 identified retrospectively, 1169 prospectively—who underwent arthroscopic shoulder surgery in the BCP at an ambulatory surgery center. Pin-on and colleagues¹⁹ reported on a series of 5177 orthopedic and neurosurgical patients who underwent surgery in the BCP. In those who had arthroscopic shoulder surgery, intraoperative systolic blood pressures obtained from an arterial line referenced to heart level decreased a mean (SD) of 14.4% (12.7%), whereas in those whose pressures were obtained from a noninvasive blood pressure cuff referenced to heart level decreased 19.3% (12.6%). However, the authors reported no incidence of postoperative stroke or neurologic deficits.

Although uncommon, perioperative cerebral ischemic accidents are potentially devastating for patients, their families, and the health care professionals involved. These events have tremendous economic, social, professional, and medicolegal implications, with perioperative stroke being particularly morbid. Perioperative stroke has a mortality rate of 60%, versus 15% to 46% for stroke in general.^25,26 In 2005, Pohl and Cullen⁶ published a landmark article on a series of 4 relatively healthy middle-aged patients who were at low risk for stroke but had catastrophic neurocognitive complications (including 1 death) after arthroscopic shoulder surgery in the BCP. Bhatti and Enneking³ described a case of acute postoperative vision loss and ophthalmoplegia attributed to intraoperative hypotension leading to ischemia in a patient who underwent an elective shoulder arthroscopic procedure in the BCP. These reports prompted multiple investigations into the physiologic hemodynamic changes associated with surgery in the BCP and the treatment strategies used to improve patient safety.

In the normal physiologic state, the sympathetic nervous system is activated when a person assumes the seated position. The result is increased systemic vascular resistance and heart rate alterations to maintain cardiac output and mean arterial pressure. In anesthetized patients, this response is blunted by the vasodilatory effects of intravenous and volatile anesthetics. Multiple studies have demonstrated substantial hemodynamic changes in both awake and anesthetized patients during the maneuver from the supine position to the seated position^1,27,28; these changes include diminished cardiac index, stroke volume, and arterial pressure.¹⁷ The data underscore the need for attentiveness and accurate monitoring of cerebral perfusion when the transition is made from the supine position to the BCP, particularly in the early phase of surgery and in high-risk patients.

Knowledge of these hemodynamic changes has led several authors to recommend additional intraoperative monitoring of cerebral perfusion. Monitoring techniques have included use of invasive blood pressure monitoring adjusted to brain level, cerebral oximetry using near infrared spectroscopy, and electroencephalography. However, the clinical relevance of intraoperative CDEs in isolation is not well understood.^1,6,7,23 In addition, cost and availability of additional advanced monitoring likely factor into why it is not more commonly used. For this patient population, the severity, frequency, and duration of desaturation that causes cerebral ischemia and the relationship with postoperative neurocognitive deficits remain undefined.

The incidence of CDEs in patients being monitored with near infrared spectroscopy while undergoing elective arthroscopic shoulder surgery in the BCP varies widely, from 0% to 80% (mean, 41%).^{1,4,7,10,12,21} Magnitude and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remain unidentified as well. In conscious patients, a 20% reduction in frontal lobe oxygenation is associated with clinical manifestations of cerebral hypoperfusion, such as syncope.^15,29 As none of the patients in the studies we reviewed experienced any sort of deficit, we cannot definitively state there is a correlation between CDE occurrence and neurocognitive deficit.

One limitation of our investigation is that it was a systemic review, and thus there was substantial heterogeneity in the methods and designs of the studies included in the analysis. Among the different series, there was variability in multiple aspects of the study design, including type of anesthetic, patient inclusion criteria, type of surgery, type of intraoperative cerebral perfusion monitoring, and type of neurocognitive testing. As a result, comparing the groups was difficult, and the generalizability of our findings may be limited. In addition, it is difficult to accurately establish incidence and comprehensively review these events because of the paucity of literature.

Conclusion

Neurocognitive complications after shoulder arthroscopy with the patient in the BCP are extremely rare but potentially devastating events that can affect healthy patients with no preexisting cerebrovascular risk factors. Our review indicated the incidence of permanent neurologic deficit after arthroscopy in the BCP may be as low as 0.004%. The exact etiology of such complications is not clear. Basic science research and large prospective studies are needed to identify the clinically relevant thresholds of magnitude, duration, and frequency of intraoperative CDEs in order to establish their relationship with postoperative neurocognitive complications. Such large studies may also elucidate modifiable patient-specific risk factors and establish the most sensitive, safe, and cost-effective intraoperative monitoring tools. Current literature suggests that accurate intraoperative monitoring of cerebral perfusion, alternatives to general anesthesia, and prudent use of intraoperative blood pressure control may improve patient safety.