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Patient-Specific Imaging and Missed Tumors: A Catastrophic Outcome
Accuracy and Safety of the Placement of Thoracic and Lumbar Pedicle Screws Using the O-arm Intraoperative Computed Tomography System and Stealth Stereotactic Guidance
Navigation in Total Knee Arthroplasty: Truth, Myths, and Controversies
The overall success of total knee arthroplasty (TKA) depends on proper implant choice, meticulous surgical technique, appropriate patient selection, and
effective postoperative rehabilitation. Inappropriate technique leads to suboptimal placement of implants in coronal, sagittal, or axial planes.1-3 This results in eccentric prosthetic loading, which may contribute to accelerated polyethylene wear, early component loosening, higher rates of revision surgery, and unsatisfactory clinical outcomes. The need to optimize component positioning during TKA stimulated the development of computer-assisted navigation in TKA in the late 1990’s. Proponents of this technology believe that it helps to reduce outliers, improves coronal, sagittal, and rotational alignment, and optimizes flexion and extension gap-balancing. This is believed to result in improved implant survival and better functional outcomes. However, despite these postulated advantages, less than 5% of surgeons in the United States currently use navigation during TKA perhaps due to concerns of costs, increased operating time, learn- ing curve issues, and lack of improvement in functional outcomes at mid-term follow-up.
Navigated TKA, due to its accuracy and low margins of error, has the potential to reduce component malalignment to within 1o to 2o of neutral mechanical axis.4 However, others have reported that alignment of the femoral and tibial components achieved with computer navigation is not different than TKA using conventional techniques.5-12 This lack of improvement reported in these studies may be due to a number of potential sources of errors, which can be either surgeon- or device-related. These errors may pre-dispose to discrepancies between alignments calculated by the computer and the actual position of the implants. Apart from software- and hardware-related calibration issues, the majority of inaccuracies, which are often surgeon-related, result from registration of anatomical landmarks, pin array movements after registration, incorrect bone cuts despite accurate jig placement, and incorrect placement of final components during cementation. Of these surgeon-related factors, variability in the identification of the anatomical landmarks appears to be critical and occurs due to anatomical variations or from inaccurate recognition of intraoperative bony landmarks. A recent study found that registration of the distal femoral epicondyles was more likely to be inaccurate than other anatomical landmarks, as it was found that a small change of 2 mm in the sagittal plane can lead to a 1o change in the femoral component rotation.13
Nevertheless, the general consensus from recent high- level evidence (Level I and II) suggests that navigated TKA leads to improved coronal-alignment outcomes and reduced numbers of outliers.14-18 In a recent systematic review of 27 randomized controlled trials of 2541 patients, Hetaimish and colleagues19 compared the alignment outcomes of navigated with conventional TKA. The authors found that the navigated cohort had a significantly lower risk of producing a mechanical axis deviation of greater than 3o, compared with conventional TKA (relative risk [RR] = 0.37; P<.001). The femoral and tibial, coronal and sagittal malalignment (>3o) were also found to be significantly lower with navigated TKA, compared with conventional techniques. However, no substantial differences were found in the rotation alignment of the femoral component between the 2 comparison cohorts (navigated group, 18.8%; conventional group, 14.5%).
Advocates of navigation believe that improved component alignment would lead to better functional outcomes and lower revision rates.20,21 However, at short- to mid-term follow-up, most studies have failed to show any substantial benefits in terms of functional outcomes, revision rates, patient satisfaction, or patient-perceived quality-of-life, when comparing computer-assisted navigation to conventional techniques.11,22-25 Recent systematic reviews by Zamora et al24 and Burnett et al25 found no significant differences in the functional outcomes between navigated and conventional TKA (P>.05). This lack of the expected improvement in functional outcomes reported in various studies with navigation could be due to variability in registration of anatomical landmarks leading to errors in the rotational axis, or a lack of complete understanding of the interplay of alignment, ligament balance, in vivo joint loading and kinematics. In a report from the Mayo Clinic,26 the authors believed that there may be little practical value in relying on a mechanical alignment of ±3o from neutral as an isolated variable in predicting the longevity of modern TKA. In addition, they suggested that factors apart from mechanical alignment may have a more profound impact on implant durability.
Several studies27-31 that compared the joint line changes or ligament balance between navigated and conventional TKA, report no substantial differences in the maintenance of the joint line, quality of life, and functional outcomes. Despite claims of decreased blood loss, length-of stay, cardiac complications, and lower risks of fat embolism with computer-assisted navigation by some authors, other reports have failed to demonstrate any substantial advantages, therefore, it is controversial if any clear benefit exists.6,32-34 It is postulated that the high initial institutional costs of navigation can even out in the long run if the goals of improved survivorship and functional outcomes are achieved.35 However, as mid-term follow-up studies have failed to show a survival or functional benefit, the purported costs savings from computer navigation may not be accurate. Navigated TKA has been reported to increase operative time by about 15 to 20 minutes, compared with conventional TKA. Although, this increases operative time, it has not been reported to increase the risk of deep prosthetic joint infections.
Navigation provides some benefits in terms of radiological alignment. However, the clinical advantages are yet to be defined. Currently, there are many unanswered ques- tions concerning alignment in TKA, such as having a more individual approach based on the patients’ own anatomic variations including considerations about the presence of constitutional varus in patients. Navigation may have a role when TKA is performed for complex deformities, fractures, or in the presence of retained implants that prevent the use of conventional guides. Nevertheless, one should always keep in mind cost considerations. This has been true with any technological advancement we have had in the past and will be of concern in the future as well, especially with rising healthcare costs. When analyzing costs with naviga- tion, one must take in to account not only the overall costs of technology, but also the added costs of training, increased operating room times, and disposables when performing these procedures. Although we are advocates of change and are excited about this technology, the cost-benefit ratio for computer navigated TKA needs to be reconciled.
The overall success of total knee arthroplasty (TKA) depends on proper implant choice, meticulous surgical technique, appropriate patient selection, and
effective postoperative rehabilitation. Inappropriate technique leads to suboptimal placement of implants in coronal, sagittal, or axial planes.1-3 This results in eccentric prosthetic loading, which may contribute to accelerated polyethylene wear, early component loosening, higher rates of revision surgery, and unsatisfactory clinical outcomes. The need to optimize component positioning during TKA stimulated the development of computer-assisted navigation in TKA in the late 1990’s. Proponents of this technology believe that it helps to reduce outliers, improves coronal, sagittal, and rotational alignment, and optimizes flexion and extension gap-balancing. This is believed to result in improved implant survival and better functional outcomes. However, despite these postulated advantages, less than 5% of surgeons in the United States currently use navigation during TKA perhaps due to concerns of costs, increased operating time, learn- ing curve issues, and lack of improvement in functional outcomes at mid-term follow-up.
Navigated TKA, due to its accuracy and low margins of error, has the potential to reduce component malalignment to within 1o to 2o of neutral mechanical axis.4 However, others have reported that alignment of the femoral and tibial components achieved with computer navigation is not different than TKA using conventional techniques.5-12 This lack of improvement reported in these studies may be due to a number of potential sources of errors, which can be either surgeon- or device-related. These errors may pre-dispose to discrepancies between alignments calculated by the computer and the actual position of the implants. Apart from software- and hardware-related calibration issues, the majority of inaccuracies, which are often surgeon-related, result from registration of anatomical landmarks, pin array movements after registration, incorrect bone cuts despite accurate jig placement, and incorrect placement of final components during cementation. Of these surgeon-related factors, variability in the identification of the anatomical landmarks appears to be critical and occurs due to anatomical variations or from inaccurate recognition of intraoperative bony landmarks. A recent study found that registration of the distal femoral epicondyles was more likely to be inaccurate than other anatomical landmarks, as it was found that a small change of 2 mm in the sagittal plane can lead to a 1o change in the femoral component rotation.13
Nevertheless, the general consensus from recent high- level evidence (Level I and II) suggests that navigated TKA leads to improved coronal-alignment outcomes and reduced numbers of outliers.14-18 In a recent systematic review of 27 randomized controlled trials of 2541 patients, Hetaimish and colleagues19 compared the alignment outcomes of navigated with conventional TKA. The authors found that the navigated cohort had a significantly lower risk of producing a mechanical axis deviation of greater than 3o, compared with conventional TKA (relative risk [RR] = 0.37; P<.001). The femoral and tibial, coronal and sagittal malalignment (>3o) were also found to be significantly lower with navigated TKA, compared with conventional techniques. However, no substantial differences were found in the rotation alignment of the femoral component between the 2 comparison cohorts (navigated group, 18.8%; conventional group, 14.5%).
Advocates of navigation believe that improved component alignment would lead to better functional outcomes and lower revision rates.20,21 However, at short- to mid-term follow-up, most studies have failed to show any substantial benefits in terms of functional outcomes, revision rates, patient satisfaction, or patient-perceived quality-of-life, when comparing computer-assisted navigation to conventional techniques.11,22-25 Recent systematic reviews by Zamora et al24 and Burnett et al25 found no significant differences in the functional outcomes between navigated and conventional TKA (P>.05). This lack of the expected improvement in functional outcomes reported in various studies with navigation could be due to variability in registration of anatomical landmarks leading to errors in the rotational axis, or a lack of complete understanding of the interplay of alignment, ligament balance, in vivo joint loading and kinematics. In a report from the Mayo Clinic,26 the authors believed that there may be little practical value in relying on a mechanical alignment of ±3o from neutral as an isolated variable in predicting the longevity of modern TKA. In addition, they suggested that factors apart from mechanical alignment may have a more profound impact on implant durability.
Several studies27-31 that compared the joint line changes or ligament balance between navigated and conventional TKA, report no substantial differences in the maintenance of the joint line, quality of life, and functional outcomes. Despite claims of decreased blood loss, length-of stay, cardiac complications, and lower risks of fat embolism with computer-assisted navigation by some authors, other reports have failed to demonstrate any substantial advantages, therefore, it is controversial if any clear benefit exists.6,32-34 It is postulated that the high initial institutional costs of navigation can even out in the long run if the goals of improved survivorship and functional outcomes are achieved.35 However, as mid-term follow-up studies have failed to show a survival or functional benefit, the purported costs savings from computer navigation may not be accurate. Navigated TKA has been reported to increase operative time by about 15 to 20 minutes, compared with conventional TKA. Although, this increases operative time, it has not been reported to increase the risk of deep prosthetic joint infections.
Navigation provides some benefits in terms of radiological alignment. However, the clinical advantages are yet to be defined. Currently, there are many unanswered ques- tions concerning alignment in TKA, such as having a more individual approach based on the patients’ own anatomic variations including considerations about the presence of constitutional varus in patients. Navigation may have a role when TKA is performed for complex deformities, fractures, or in the presence of retained implants that prevent the use of conventional guides. Nevertheless, one should always keep in mind cost considerations. This has been true with any technological advancement we have had in the past and will be of concern in the future as well, especially with rising healthcare costs. When analyzing costs with naviga- tion, one must take in to account not only the overall costs of technology, but also the added costs of training, increased operating room times, and disposables when performing these procedures. Although we are advocates of change and are excited about this technology, the cost-benefit ratio for computer navigated TKA needs to be reconciled.
The overall success of total knee arthroplasty (TKA) depends on proper implant choice, meticulous surgical technique, appropriate patient selection, and
effective postoperative rehabilitation. Inappropriate technique leads to suboptimal placement of implants in coronal, sagittal, or axial planes.1-3 This results in eccentric prosthetic loading, which may contribute to accelerated polyethylene wear, early component loosening, higher rates of revision surgery, and unsatisfactory clinical outcomes. The need to optimize component positioning during TKA stimulated the development of computer-assisted navigation in TKA in the late 1990’s. Proponents of this technology believe that it helps to reduce outliers, improves coronal, sagittal, and rotational alignment, and optimizes flexion and extension gap-balancing. This is believed to result in improved implant survival and better functional outcomes. However, despite these postulated advantages, less than 5% of surgeons in the United States currently use navigation during TKA perhaps due to concerns of costs, increased operating time, learn- ing curve issues, and lack of improvement in functional outcomes at mid-term follow-up.
Navigated TKA, due to its accuracy and low margins of error, has the potential to reduce component malalignment to within 1o to 2o of neutral mechanical axis.4 However, others have reported that alignment of the femoral and tibial components achieved with computer navigation is not different than TKA using conventional techniques.5-12 This lack of improvement reported in these studies may be due to a number of potential sources of errors, which can be either surgeon- or device-related. These errors may pre-dispose to discrepancies between alignments calculated by the computer and the actual position of the implants. Apart from software- and hardware-related calibration issues, the majority of inaccuracies, which are often surgeon-related, result from registration of anatomical landmarks, pin array movements after registration, incorrect bone cuts despite accurate jig placement, and incorrect placement of final components during cementation. Of these surgeon-related factors, variability in the identification of the anatomical landmarks appears to be critical and occurs due to anatomical variations or from inaccurate recognition of intraoperative bony landmarks. A recent study found that registration of the distal femoral epicondyles was more likely to be inaccurate than other anatomical landmarks, as it was found that a small change of 2 mm in the sagittal plane can lead to a 1o change in the femoral component rotation.13
Nevertheless, the general consensus from recent high- level evidence (Level I and II) suggests that navigated TKA leads to improved coronal-alignment outcomes and reduced numbers of outliers.14-18 In a recent systematic review of 27 randomized controlled trials of 2541 patients, Hetaimish and colleagues19 compared the alignment outcomes of navigated with conventional TKA. The authors found that the navigated cohort had a significantly lower risk of producing a mechanical axis deviation of greater than 3o, compared with conventional TKA (relative risk [RR] = 0.37; P<.001). The femoral and tibial, coronal and sagittal malalignment (>3o) were also found to be significantly lower with navigated TKA, compared with conventional techniques. However, no substantial differences were found in the rotation alignment of the femoral component between the 2 comparison cohorts (navigated group, 18.8%; conventional group, 14.5%).
Advocates of navigation believe that improved component alignment would lead to better functional outcomes and lower revision rates.20,21 However, at short- to mid-term follow-up, most studies have failed to show any substantial benefits in terms of functional outcomes, revision rates, patient satisfaction, or patient-perceived quality-of-life, when comparing computer-assisted navigation to conventional techniques.11,22-25 Recent systematic reviews by Zamora et al24 and Burnett et al25 found no significant differences in the functional outcomes between navigated and conventional TKA (P>.05). This lack of the expected improvement in functional outcomes reported in various studies with navigation could be due to variability in registration of anatomical landmarks leading to errors in the rotational axis, or a lack of complete understanding of the interplay of alignment, ligament balance, in vivo joint loading and kinematics. In a report from the Mayo Clinic,26 the authors believed that there may be little practical value in relying on a mechanical alignment of ±3o from neutral as an isolated variable in predicting the longevity of modern TKA. In addition, they suggested that factors apart from mechanical alignment may have a more profound impact on implant durability.
Several studies27-31 that compared the joint line changes or ligament balance between navigated and conventional TKA, report no substantial differences in the maintenance of the joint line, quality of life, and functional outcomes. Despite claims of decreased blood loss, length-of stay, cardiac complications, and lower risks of fat embolism with computer-assisted navigation by some authors, other reports have failed to demonstrate any substantial advantages, therefore, it is controversial if any clear benefit exists.6,32-34 It is postulated that the high initial institutional costs of navigation can even out in the long run if the goals of improved survivorship and functional outcomes are achieved.35 However, as mid-term follow-up studies have failed to show a survival or functional benefit, the purported costs savings from computer navigation may not be accurate. Navigated TKA has been reported to increase operative time by about 15 to 20 minutes, compared with conventional TKA. Although, this increases operative time, it has not been reported to increase the risk of deep prosthetic joint infections.
Navigation provides some benefits in terms of radiological alignment. However, the clinical advantages are yet to be defined. Currently, there are many unanswered ques- tions concerning alignment in TKA, such as having a more individual approach based on the patients’ own anatomic variations including considerations about the presence of constitutional varus in patients. Navigation may have a role when TKA is performed for complex deformities, fractures, or in the presence of retained implants that prevent the use of conventional guides. Nevertheless, one should always keep in mind cost considerations. This has been true with any technological advancement we have had in the past and will be of concern in the future as well, especially with rising healthcare costs. When analyzing costs with naviga- tion, one must take in to account not only the overall costs of technology, but also the added costs of training, increased operating room times, and disposables when performing these procedures. Although we are advocates of change and are excited about this technology, the cost-benefit ratio for computer navigated TKA needs to be reconciled.
Phialophora verrucosa as a Cause of Deep Infection Following Total Knee Arthroplasty
Osteolytic Psuedotumor After Cemented Total Knee Arthroplasty
Usefulness of Intraoperative Radiographs in Reducing Errors of Cup Placement and Leg Length During Total Hip Arthroplasty
The Economic Recession and Its Effect on Utilization of Elective Total Joint Arthroplasty
Acute Compartment Syndrome Following Distal Biceps Tendon Rupture in an Otherwise Healthy Male
Bracing lessened patellofemoral pain in OA
SAN DIEGO – Patients with osteoarthritis of the knee who wore a patellofemoral brace for 6 weeks experienced a significant reduction in pain and in bone marrow lesion volumes in the patellofemoral region, compared with those who did not wear the brace, a multicenter trial showed.
"There’s a pressing need for nonsurgical intervention for knee osteoarthritis," Dr. David T. Felson said in a press briefing at the annual meeting of the American College of Rheumatology.
"There are no currently approved structure-modifying treatments. This has been a focus of studies that have been testing modifying treatments on hyaline cartilage, which changes slowly, necessitating expensive, long-term, large trials. Even so, mechanopathology such as that caused by malalignment or meniscal tears may make it impossible to protect cartilage in existing OA," he noted.
Dr. Felson, director of the Research in Osteoarthritis in Manchester group at the University of Manchester (England) and professor of medicine at Boston University, went on to note that bone marrow lesions (BMLs) "have been well shown to predict later cartilage loss in that location and correlate with pain and its severity. Recently, we showed that BMLs fluctuate in volume in as little as 6 weeks. Further, one small trial has suggested that zoledronic acid may shrink BMLs and reduce knee pain. That leads us to suggest that BMLs may be a viable treatment target in OA."
The patellofemoral joint "is a major source of knee pain in OA, and there has been little study of the efficacy of PF braces," he continued. "In a body mechanics study, PF bracing has been shown to increase the contact area of the PF joint. It may thereby lower the contact stress and shrink BMLs."
He and his associates set out to determine whether bracing would improve pain and lessen the volume of BMLs in patients with knee OA. They enrolled 126 patients with a mean age of 55 years whose knee pain had been present daily for the previous 3 months. Half of the patients wore a soft neoprene PF brace for a mean of 7.3 hours per day, while the other half did not.
All study participants "had to have at least a score of 40 on a 0-100 mm visual analogue scale (VAS) for nominated aggravating activity likely to originate in the PF joint," Dr. Felson said. "They had to have pain with activities such as stair climbing, kneeling, prolonged sitting or squatting, [and] they also had to have a radiographic KL [Kellgren-Lawrence] score of grade 2 or 3 in the PF joint. That score had to be greater than the KL score for the tibiofemoral compartments. They also had to undergo a clinical exam by a trained physiotherapist to confirm PF joint tenderness."
The researchers performed contrast-enhanced knee MRIs at baseline and at 6 weeks. The primary symptom outcome measure was VAS pain during the patients’ nominated aggravating activity, while the primary structural outcome measure was BML volume in the PF joint as assessed on sagittal precontrast view.
At 6 weeks, Dr. Felson reported that patients in the no-brace group had a mean reduction in their VAS pain of 1.3, compared with a reduction of 18.2 in the braced group, a mean between-group difference of 16.9 that reached statistical significance (P less than .001).
As for PF BML volume, patients in the no-brace group showed a slight increase in volume (mean, 102.7 mm3), while the braced group showed a significant decrease in PF BML volume (mean, –554.9 mm3), for a mean between-group difference of 657.6 mm3 that reached statistical significance (P = .02). "That represents about a 25% decrease in volume," Dr. Felson said.
No differences were observed between the two groups in terms of tibiofemoral BML volume or in synovitis volume.
Dr. Felson acknowledged certain limitations of the study, including its 6-week design. "OA is a long-term chronic disease," he said. "We don’t know what relevance our findings have for longer-term structure changes of the knee."
The researchers stated that they had no relevant financial conflicts to disclose.
SAN DIEGO – Patients with osteoarthritis of the knee who wore a patellofemoral brace for 6 weeks experienced a significant reduction in pain and in bone marrow lesion volumes in the patellofemoral region, compared with those who did not wear the brace, a multicenter trial showed.
"There’s a pressing need for nonsurgical intervention for knee osteoarthritis," Dr. David T. Felson said in a press briefing at the annual meeting of the American College of Rheumatology.
"There are no currently approved structure-modifying treatments. This has been a focus of studies that have been testing modifying treatments on hyaline cartilage, which changes slowly, necessitating expensive, long-term, large trials. Even so, mechanopathology such as that caused by malalignment or meniscal tears may make it impossible to protect cartilage in existing OA," he noted.
Dr. Felson, director of the Research in Osteoarthritis in Manchester group at the University of Manchester (England) and professor of medicine at Boston University, went on to note that bone marrow lesions (BMLs) "have been well shown to predict later cartilage loss in that location and correlate with pain and its severity. Recently, we showed that BMLs fluctuate in volume in as little as 6 weeks. Further, one small trial has suggested that zoledronic acid may shrink BMLs and reduce knee pain. That leads us to suggest that BMLs may be a viable treatment target in OA."
The patellofemoral joint "is a major source of knee pain in OA, and there has been little study of the efficacy of PF braces," he continued. "In a body mechanics study, PF bracing has been shown to increase the contact area of the PF joint. It may thereby lower the contact stress and shrink BMLs."
He and his associates set out to determine whether bracing would improve pain and lessen the volume of BMLs in patients with knee OA. They enrolled 126 patients with a mean age of 55 years whose knee pain had been present daily for the previous 3 months. Half of the patients wore a soft neoprene PF brace for a mean of 7.3 hours per day, while the other half did not.
All study participants "had to have at least a score of 40 on a 0-100 mm visual analogue scale (VAS) for nominated aggravating activity likely to originate in the PF joint," Dr. Felson said. "They had to have pain with activities such as stair climbing, kneeling, prolonged sitting or squatting, [and] they also had to have a radiographic KL [Kellgren-Lawrence] score of grade 2 or 3 in the PF joint. That score had to be greater than the KL score for the tibiofemoral compartments. They also had to undergo a clinical exam by a trained physiotherapist to confirm PF joint tenderness."
The researchers performed contrast-enhanced knee MRIs at baseline and at 6 weeks. The primary symptom outcome measure was VAS pain during the patients’ nominated aggravating activity, while the primary structural outcome measure was BML volume in the PF joint as assessed on sagittal precontrast view.
At 6 weeks, Dr. Felson reported that patients in the no-brace group had a mean reduction in their VAS pain of 1.3, compared with a reduction of 18.2 in the braced group, a mean between-group difference of 16.9 that reached statistical significance (P less than .001).
As for PF BML volume, patients in the no-brace group showed a slight increase in volume (mean, 102.7 mm3), while the braced group showed a significant decrease in PF BML volume (mean, –554.9 mm3), for a mean between-group difference of 657.6 mm3 that reached statistical significance (P = .02). "That represents about a 25% decrease in volume," Dr. Felson said.
No differences were observed between the two groups in terms of tibiofemoral BML volume or in synovitis volume.
Dr. Felson acknowledged certain limitations of the study, including its 6-week design. "OA is a long-term chronic disease," he said. "We don’t know what relevance our findings have for longer-term structure changes of the knee."
The researchers stated that they had no relevant financial conflicts to disclose.
SAN DIEGO – Patients with osteoarthritis of the knee who wore a patellofemoral brace for 6 weeks experienced a significant reduction in pain and in bone marrow lesion volumes in the patellofemoral region, compared with those who did not wear the brace, a multicenter trial showed.
"There’s a pressing need for nonsurgical intervention for knee osteoarthritis," Dr. David T. Felson said in a press briefing at the annual meeting of the American College of Rheumatology.
"There are no currently approved structure-modifying treatments. This has been a focus of studies that have been testing modifying treatments on hyaline cartilage, which changes slowly, necessitating expensive, long-term, large trials. Even so, mechanopathology such as that caused by malalignment or meniscal tears may make it impossible to protect cartilage in existing OA," he noted.
Dr. Felson, director of the Research in Osteoarthritis in Manchester group at the University of Manchester (England) and professor of medicine at Boston University, went on to note that bone marrow lesions (BMLs) "have been well shown to predict later cartilage loss in that location and correlate with pain and its severity. Recently, we showed that BMLs fluctuate in volume in as little as 6 weeks. Further, one small trial has suggested that zoledronic acid may shrink BMLs and reduce knee pain. That leads us to suggest that BMLs may be a viable treatment target in OA."
The patellofemoral joint "is a major source of knee pain in OA, and there has been little study of the efficacy of PF braces," he continued. "In a body mechanics study, PF bracing has been shown to increase the contact area of the PF joint. It may thereby lower the contact stress and shrink BMLs."
He and his associates set out to determine whether bracing would improve pain and lessen the volume of BMLs in patients with knee OA. They enrolled 126 patients with a mean age of 55 years whose knee pain had been present daily for the previous 3 months. Half of the patients wore a soft neoprene PF brace for a mean of 7.3 hours per day, while the other half did not.
All study participants "had to have at least a score of 40 on a 0-100 mm visual analogue scale (VAS) for nominated aggravating activity likely to originate in the PF joint," Dr. Felson said. "They had to have pain with activities such as stair climbing, kneeling, prolonged sitting or squatting, [and] they also had to have a radiographic KL [Kellgren-Lawrence] score of grade 2 or 3 in the PF joint. That score had to be greater than the KL score for the tibiofemoral compartments. They also had to undergo a clinical exam by a trained physiotherapist to confirm PF joint tenderness."
The researchers performed contrast-enhanced knee MRIs at baseline and at 6 weeks. The primary symptom outcome measure was VAS pain during the patients’ nominated aggravating activity, while the primary structural outcome measure was BML volume in the PF joint as assessed on sagittal precontrast view.
At 6 weeks, Dr. Felson reported that patients in the no-brace group had a mean reduction in their VAS pain of 1.3, compared with a reduction of 18.2 in the braced group, a mean between-group difference of 16.9 that reached statistical significance (P less than .001).
As for PF BML volume, patients in the no-brace group showed a slight increase in volume (mean, 102.7 mm3), while the braced group showed a significant decrease in PF BML volume (mean, –554.9 mm3), for a mean between-group difference of 657.6 mm3 that reached statistical significance (P = .02). "That represents about a 25% decrease in volume," Dr. Felson said.
No differences were observed between the two groups in terms of tibiofemoral BML volume or in synovitis volume.
Dr. Felson acknowledged certain limitations of the study, including its 6-week design. "OA is a long-term chronic disease," he said. "We don’t know what relevance our findings have for longer-term structure changes of the knee."
The researchers stated that they had no relevant financial conflicts to disclose.
AT THE ACR ANNUAL MEETING
Major finding: Patients who wore a patellofemoral brace over the course of 6 weeks had a significant reduction in patellofemoral pain as measured by a visual analogue scale compared with those who did not wear a brace (reductions of 18.2 and 1.3, respectively; P less than .001).
Data source: 126 patients with a mean age of 55 years who had knee pain present daily for the previous 3 months. Half of the patients wore a soft neoprene PF brace for a mean of 7.3 hours per day, while the other half did not.
Disclosures: The researchers had no relevant financial conflicts to disclose.
Knee replacement delayed by hyaluronic acid injections
SAN DIEGO – Viscosupplementation using hyaluronic acid injections delayed total knee replacement for patients with knee osteoarthritis by up to a median 2.6 years in a retrospective observational study.
The study, involving analysis of a large commercial health insurance claims database (Truven MarketScan), included all 16,529 patients with knee osteoarthritis (OA) who made their first visit to a specialist for the condition in 2008-2011 and who eventually went on to total knee replacement surgery.
Among this group were 4,178 knee OA patients who underwent one or more courses of treatment with any of the Food and Drug Administration–approved injectable hyaluronic acid products. A total of 3,647 of these patients were successfully matched to controls with knee OA who had total knee replacement surgery without any prior hyaluronic acid injections, Dr. Roy D. Altman explained at the annual meeting of the American College of Rheumatology.
The matching process relied upon propensity scores based on age, sex, physician specialty, diagnosis at the first specialist visit, and year. Therein lays a significant study limitation: These variables provide only limited ability to adjust for any differences in baseline knee OA severity that might have existed between patients who did or didn’t receive hyaluronic acid injections. Nor can an observational study establish causality, observed Dr. Altman, professor emeritus of medicine at the University of California, Los Angeles.
That being said, the study demonstrated a strong dose-dependent relationship between viscosupplementation and time from first specialist visit to knee replacement surgery, he noted.
Seventy-nine percent of patients who got hyaluronic acid injections received a single course consisting of either one injection or a series of injections, depending upon the specific product. Those patients experienced a median 233-day increase in the time to surgery, compared with matched controls who didn’t get hyaluronic acid injections.
Moreover, the 16% of viscosupplementation recipients who underwent a second round of treatment further delayed their median time from first specialist visit to total knee replacement by an additional 7 months. And that pattern continued in the relatively small numbers of patients who underwent three or more courses of viscosupplementation: Each round of hyaluronic acid injections brought a roughly 7-month further delay in time to surgery, out to a total of 2.6 years.
The study was sponsored by Johnson & Johnson. Dr. Altman reported having no financial conflicts.
SAN DIEGO – Viscosupplementation using hyaluronic acid injections delayed total knee replacement for patients with knee osteoarthritis by up to a median 2.6 years in a retrospective observational study.
The study, involving analysis of a large commercial health insurance claims database (Truven MarketScan), included all 16,529 patients with knee osteoarthritis (OA) who made their first visit to a specialist for the condition in 2008-2011 and who eventually went on to total knee replacement surgery.
Among this group were 4,178 knee OA patients who underwent one or more courses of treatment with any of the Food and Drug Administration–approved injectable hyaluronic acid products. A total of 3,647 of these patients were successfully matched to controls with knee OA who had total knee replacement surgery without any prior hyaluronic acid injections, Dr. Roy D. Altman explained at the annual meeting of the American College of Rheumatology.
The matching process relied upon propensity scores based on age, sex, physician specialty, diagnosis at the first specialist visit, and year. Therein lays a significant study limitation: These variables provide only limited ability to adjust for any differences in baseline knee OA severity that might have existed between patients who did or didn’t receive hyaluronic acid injections. Nor can an observational study establish causality, observed Dr. Altman, professor emeritus of medicine at the University of California, Los Angeles.
That being said, the study demonstrated a strong dose-dependent relationship between viscosupplementation and time from first specialist visit to knee replacement surgery, he noted.
Seventy-nine percent of patients who got hyaluronic acid injections received a single course consisting of either one injection or a series of injections, depending upon the specific product. Those patients experienced a median 233-day increase in the time to surgery, compared with matched controls who didn’t get hyaluronic acid injections.
Moreover, the 16% of viscosupplementation recipients who underwent a second round of treatment further delayed their median time from first specialist visit to total knee replacement by an additional 7 months. And that pattern continued in the relatively small numbers of patients who underwent three or more courses of viscosupplementation: Each round of hyaluronic acid injections brought a roughly 7-month further delay in time to surgery, out to a total of 2.6 years.
The study was sponsored by Johnson & Johnson. Dr. Altman reported having no financial conflicts.
SAN DIEGO – Viscosupplementation using hyaluronic acid injections delayed total knee replacement for patients with knee osteoarthritis by up to a median 2.6 years in a retrospective observational study.
The study, involving analysis of a large commercial health insurance claims database (Truven MarketScan), included all 16,529 patients with knee osteoarthritis (OA) who made their first visit to a specialist for the condition in 2008-2011 and who eventually went on to total knee replacement surgery.
Among this group were 4,178 knee OA patients who underwent one or more courses of treatment with any of the Food and Drug Administration–approved injectable hyaluronic acid products. A total of 3,647 of these patients were successfully matched to controls with knee OA who had total knee replacement surgery without any prior hyaluronic acid injections, Dr. Roy D. Altman explained at the annual meeting of the American College of Rheumatology.
The matching process relied upon propensity scores based on age, sex, physician specialty, diagnosis at the first specialist visit, and year. Therein lays a significant study limitation: These variables provide only limited ability to adjust for any differences in baseline knee OA severity that might have existed between patients who did or didn’t receive hyaluronic acid injections. Nor can an observational study establish causality, observed Dr. Altman, professor emeritus of medicine at the University of California, Los Angeles.
That being said, the study demonstrated a strong dose-dependent relationship between viscosupplementation and time from first specialist visit to knee replacement surgery, he noted.
Seventy-nine percent of patients who got hyaluronic acid injections received a single course consisting of either one injection or a series of injections, depending upon the specific product. Those patients experienced a median 233-day increase in the time to surgery, compared with matched controls who didn’t get hyaluronic acid injections.
Moreover, the 16% of viscosupplementation recipients who underwent a second round of treatment further delayed their median time from first specialist visit to total knee replacement by an additional 7 months. And that pattern continued in the relatively small numbers of patients who underwent three or more courses of viscosupplementation: Each round of hyaluronic acid injections brought a roughly 7-month further delay in time to surgery, out to a total of 2.6 years.
The study was sponsored by Johnson & Johnson. Dr. Altman reported having no financial conflicts.
AT THE ACR ANNUAL MEETING
Major finding: Patients with knee osteoarthritis who eventually underwent total knee replacement had their surgery delayed by a median 233 days if they received one course of viscosupplementation using hyaluronic acid injections. For those who received more than one round of injections, each additional course brought a further average 7-month delay in time to surgery out to 2.6 years.
Data source: Retrospective observational study involving a large commercial health insurance claims database matched 3,647 patients with knee osteoarthritis who underwent total knee replacement after receiving one or more courses of hyaluronic acid injections to an equal number who didn’t get hyaluronic acid injections prior to surgery.
Disclosures: The study was sponsored by Johnson & Johnson. The presenter reported having no financial conflicts.
