Original Research

ABSTRACT

We evaluated postoperative pain control and narcotic usage after thumb carpometacarpal (CMC) arthroplasty or open reduction and internal fixation (ORIF) of the distal radius in patients given opiates with or without other non-opiate medication using a specific dosing regimen. A prospective, randomized study of 79 patients undergoing elective CMC arthroplasty or ORIF of the distal radius evaluated postoperative pain in the first 5 postoperative days. Patients were divided into 4 groups: Group 1, oxycodone and acetaminophen PRN; Group 2, oxycodone and acetaminophen with specific dosing; Group 3, oxycodone, acetaminophen, and OxyContin with specific dosing; and Group 4, oxycodone, acetaminophen, and ketorolac with specific dosing. During the first 5 postoperative days, we recorded pain levels according to a numeric pain scale, opioid usage, and complications. Although differences in our data did not reach statistical significance, overall pain scores, opioid usage, and complication rates were less prevalent in the oxycodone, acetaminophen, and ketorolac group. Postoperative pain following ambulatory hand and wrist surgery under regional anesthesia was more effectively controlled with fewer complications using a combination of oxycodone, acetaminophen, and ketorolac with a specific dosing regimen.

Continue to: Regional anesthesia...

Regional anesthesia is a safe and effective modality of perioperative pain control in patients undergoing ambulatory hand procedures.^1-10 Often, as the regional block wears off, patients experience a rebound pain effect that can be challenging to manage.

We sought to determine if an organized, multimodal approach in patients undergoing thumb carpometacarpal (CMC) arthroplasty or open reduction and internal fixation (ORIF) of distal radius fractures would provide better postoperative pain control. We hypothesized that this approach would significantly reduce postoperative pain and the need for narcotic pain medication compared with PRN dosing of oxycodone/acetaminophen alone.^11-14

MATERIALS AND METHODS

Our study was approved by our Institutional Review Board. Informed consent was obtained from each patient. Patients presenting for elective thumb CMC arthroplasty or ORIF of the distal radius were screened for inclusion in a prospective, randomized study. Inclusion criteria included patients aged 18 to 65 years who could provide informed consent. Patients with chronic pain syndromes, long-term narcotic usage, chronic medical conditions precluding the use of opiates or nonsteroidal anti-inflammatory drugs (NSAIDs), and those who did not have a complete sensory and motor block postoperatively were excluded.

Patients were randomly divided into 1 of 4 study arms. Randomization was performed via sealed envelopes, which were opened in the recovery area when postoperative prescriptions were written. The group distribution was as follows: Group 1, Percocet 5 mg/325 mg alone (control); Group 2, oxycodone 5 mg, acetaminophen 325 mg administered separately; Group 3, oxycodone 5 mg, acetaminophen 325 mg, and oxycodone SR (OxyContin) 10 mg; and Group 4, oxycodone 5 mg, acetaminophen 325 mg, and ketorolac (Toradol) 10 mg (Table 1). Patients in the control group were instructed to take 1 or 2 tablets every 4 to 6 hours as needed for pain. Patients in the 3 experimental groups were given detailed instructions regarding when and how to take their medications. All patients were instructed to take 650 mg of acetaminophen every 6 hours. Patients were provided a sliding scale to assist in dosing their opioid medications according to their numeric pain score (NPS) (Table 2). Group 2 patients were given oxycodone 10 mg in the postanesthesia care unit (PACU) and instructed to take oxycodone 10 mg with acetaminophen 650 mg every 6 hours on a scheduled basis until their block wore off, then dose themselves using the NPS.

Table 1. Patient Groups

Table 2. Sliding Scale for Pain Control in the Experimental Groups

Group 3 patients were given oxycodone 10 mg in the PACU and instructed to take oxycodone 10 mg with acetaminophen 650 mg every 6 hours and OxyContin 10 mg every 12 hours on a scheduled basis until their block wore off, then dose themselves using NPS. Group 4 patients were given oxycodone 10 mg postoperatively and ketorolac 30 mg intravenously in the PACU and instructed to take oxycodone 10 mg, acetaminophen 650 mg, and ketorolac 10 mg every 6 hours on a scheduled basis until their block wore off, then dose themselves using the NPS.

Patients were provided with a journal and asked to record their medication usage, NPS, and any adverse effects (nausea, vomiting, and uncontrolled pain were specifically mentioned) or complications for 5 days after their procedure. We also attempted to contact patients by telephone on each of the 5 days after their procedure to remind them to complete their logs. They were asked specifically if they were having difficulty with their medications. They were also asked specifically about nausea, vomiting, and over-sedation. If patients requested additional medication to help treat their pain, they were instructed to add an over-the-counter NSAID of their choice based on the label’s suggested dosing.

Continue to: All patients received a supraclavicular...

All patients received a supraclavicular brachial plexus block using 0.75% ropivacaine under the supervision of an attending anesthesiologist experienced in regional anesthesia. Patients underwent thumb CMC arthroplasty utilizing complete resection of the trapezium followed by abductor pollicis longus suspensionplasty under the supervision of 1 of 3 fellowship-trained hand surgeons. ORIF of the distal radius was completed utilizing a volar approach and distal radius locking plate under the supervision of 1 of 3 fellowship-trained hand surgeons.

Primary outcome measures were the total number of oxycodone tablets taken daily and the average daily NPS. Secondary outcomes measured included adverse effects as noted above and the need for a trip to the emergency department for unrelieved pain.

A power analysis was completed prior to the beginning of the study. To detect a difference of at least 1 on the NPS, we determined that 18 patients per group would provide 80% power. This was based on literature utilizing the visual analog scale (VAS), a 100-mm line on which patients can place a mark to describe the intensity of their pain. The standard deviation on the VAS is approximately 15 mm. To account for potential dropout, we elected to recruit 20 patients per group. Non-paired t tests were used to compare groups.

RESULTS

One hundred and eighteen patients enrolled in the study. Of those, 79 patients completed and returned their summary logs (by group: 18 control, 20 oxycodone, 17 OxyContin, and 24 ketorolac). The remaining patients were excluded from the final analysis because they did not return their summary logs. Only 1 patient was excluded from the analysis because he did not have adequate regional anesthesia. Demographic data were analyzed and showed no significant differences between groups at the P < .05 level of significance. Surgical procedures were completed by 3 fellowship-trained hand surgeons. Distal radius fractures were performed using a volar approach. CMC arthroplasty was performed using a procedure that was standardized across surgeons. There were no between-surgeon differences in outcomes.

Average daily NPS (Figure 1) and the total number of oxycodone tablets taken (Figure 2) over the 5-day study period were recorded. Patients in the ketorolac group used fewer oxycodone tablets (19.3) than patients in the other 3 groups (24.4), P =.11, but the difference was not statistically significant. The maximum number of oxycodone tablets used was 71 in the Percocet group, 57 in the oxycodone and ketorolac groups, and 73 in the OxyContin group. The average daily NPS was lower in the ketorolac group during the period of medication use. This value only reached statistical significance on postoperative day 0 when the ketorolac group was compared with the OxyContin group (P = .01) and on postoperative day 1 when the ketorolac group was compared with the oxycodone group (P = .04). Complications (Figure 3) were greater in the non-ketorolac groups. One patient each in the oxycodone and OxyContin groups required a trip to the emergency department for pain control after their block wore off. Nausea and vomiting were present in each of the 4 groups but to a much greater degree in the Percocet and OxyContin groups; however, these results did not reach statistical significance (P = .129). Eleven of the 18 patients in the Percocet group required an additional NSAID (naproxen) and still did not achieve pain control similar to the other groups. This may explain why the average daily pain score in the Percocet group was lower than that in the oxycodone group, in which only 4 of the 20 patients supplemented with naproxen. Patients did, however, require many more oxycodone tablets to achieve pain control in the Percocet group. Over-sedation was reported in 3 patients in the oxycodone group and in 1 patient in the OxyContin group. No patients were found to have bleeding, renal, or other systemic complications.

Continue to: Discussion...

DISCUSSION

In this prospective, randomized study, we sought to determine whether a more organized approach to treating postoperative pain using a specific dosing regimen or opiates in conjunction with non-opiate medications would lead to improved pain control and a decreased need for opiates. We found that adding ketorolac to the postoperative pain regimen and outlining a more detailed set of instructions could lower narcotic usage in the first 4 postoperative days. In addition, adding ketorolac decreased other complications commonly seen with narcotic usage and was shown to be safe in our patient population.

Ketorolac has been shown to decrease narcotic pain medication usage in several surgical settings and across different surgical specialties. It is hypothesized that ketorolac potentiates the effects of narcotics.¹¹ Ketorolac given alone has a potent analgesic effect by acting as a strong non-selective cyclooxygenase inhibitor. The major drawback to ketorolac use has been its well-known side-effect profile. Ketorolac is renally excreted, and as such, should not be used in patients with renal insufficiency. In addition, ketorolac has been shown to cause increased gastrointestinal bleeding when used for >5 days.¹⁵ Caution should be taken when combining ketorolac with thromboprophylactic medications, especially in older patients.

Many surgeons use NSAIDs along with narcotics as part of a postoperative pain regimen. While this is often adequate for some procedures, when the surgery involves manipulating fractures, internal fixation, or resection arthroplasty, the variation in individual patient pain may call for a more robust protocol. Additionally, as surgeons expand to more complex procedures performed in the outpatient setting, evaluating different combinations of analgesics taken in a more structured manner may provide for improved pain control.

A major component of patient satisfaction is postoperative pain control.^3-8,12,16,17 Regional anesthesia is an important tool that allows patients to undergo a surgical procedure with a greatly reduced amount of opioid pain medications. In addition, regional anesthesia can provide significant pain control after the patient has left the ambulatory surgery center, but this relief is short-lived because the medication is designed to lose effectiveness over time. As the effects of regional anesthesia wear off, patients can experience “rebound pain” with severe levels of pain that, on occasion, cannot be controlled with oral analgesics alone. The addition of ketorolac provided improved pain control when compared with the other regimens during this transition period when the regional anesthesia was becoming ineffective. In addition, because patients taking ketorolac used less narcotic medication, they experienced less nausea, vomiting, and over-sedation.

Additionally, patients were instructed to record their medication usage and pain scores on a prospective basis, with the hope of eliminating recall bias. A potential weakness is the inability to show significance for pain relief and reduced narcotic usage with the addition of ketorolac, although there was a trend toward significance. Many of the patients who enrolled in the trial did not return their medication logs. While these patients had to be excluded from data analysis, we continued enrollment until we obtained an adequate number of patients in each group. In addition, in the OxyContin group (Group 3), we could only recruit 17 participants, instead of the 18 needed based on our power study. Although this has a potential to alter the significance of our results, we do not feel this had a substantial impact on our results.

Many patients in the non-ketorolac groups supplemented their medication regimens with NSAIDs, which may have falsely lowered pain scores and narcotic usage. While this confounds our study results, we do not believe that it invalidates the conclusion that ketorolac can be an effective adjunct pain medication for use in patients undergoing ambulatory hand surgery.

The study examined postoperative pain control for only 2 procedures, thumb basal joint arthroplasty and distal radius fracture fixation, both commonly performed in the outpatient setting under regional anesthesia and both typically requiring narcotic pain medication. Perhaps the utilization of these medication regimens with different surgical procedures would have differing results.

We conclude that ketorolac potentially provides patients with improved pain control over the use of narcotic pain medications alone in the setting of ambulatory hand surgery.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

We evaluated postoperative pain control and narcotic usage after thumb carpometacarpal (CMC) arthroplasty or open reduction and internal fixation (ORIF) of the distal radius in patients given opiates with or without other non-opiate medication using a specific dosing regimen. A prospective, randomized study of 79 patients undergoing elective CMC arthroplasty or ORIF of the distal radius evaluated postoperative pain in the first 5 postoperative days. Patients were divided into 4 groups: Group 1, oxycodone and acetaminophen PRN; Group 2, oxycodone and acetaminophen with specific dosing; Group 3, oxycodone, acetaminophen, and OxyContin with specific dosing; and Group 4, oxycodone, acetaminophen, and ketorolac with specific dosing. During the first 5 postoperative days, we recorded pain levels according to a numeric pain scale, opioid usage, and complications. Although differences in our data did not reach statistical significance, overall pain scores, opioid usage, and complication rates were less prevalent in the oxycodone, acetaminophen, and ketorolac group. Postoperative pain following ambulatory hand and wrist surgery under regional anesthesia was more effectively controlled with fewer complications using a combination of oxycodone, acetaminophen, and ketorolac with a specific dosing regimen.

Continue to: Regional anesthesia...

Regional anesthesia is a safe and effective modality of perioperative pain control in patients undergoing ambulatory hand procedures.^1-10 Often, as the regional block wears off, patients experience a rebound pain effect that can be challenging to manage.

We sought to determine if an organized, multimodal approach in patients undergoing thumb carpometacarpal (CMC) arthroplasty or open reduction and internal fixation (ORIF) of distal radius fractures would provide better postoperative pain control. We hypothesized that this approach would significantly reduce postoperative pain and the need for narcotic pain medication compared with PRN dosing of oxycodone/acetaminophen alone.^11-14

MATERIALS AND METHODS

Our study was approved by our Institutional Review Board. Informed consent was obtained from each patient. Patients presenting for elective thumb CMC arthroplasty or ORIF of the distal radius were screened for inclusion in a prospective, randomized study. Inclusion criteria included patients aged 18 to 65 years who could provide informed consent. Patients with chronic pain syndromes, long-term narcotic usage, chronic medical conditions precluding the use of opiates or nonsteroidal anti-inflammatory drugs (NSAIDs), and those who did not have a complete sensory and motor block postoperatively were excluded.

Patients were randomly divided into 1 of 4 study arms. Randomization was performed via sealed envelopes, which were opened in the recovery area when postoperative prescriptions were written. The group distribution was as follows: Group 1, Percocet 5 mg/325 mg alone (control); Group 2, oxycodone 5 mg, acetaminophen 325 mg administered separately; Group 3, oxycodone 5 mg, acetaminophen 325 mg, and oxycodone SR (OxyContin) 10 mg; and Group 4, oxycodone 5 mg, acetaminophen 325 mg, and ketorolac (Toradol) 10 mg (Table 1). Patients in the control group were instructed to take 1 or 2 tablets every 4 to 6 hours as needed for pain. Patients in the 3 experimental groups were given detailed instructions regarding when and how to take their medications. All patients were instructed to take 650 mg of acetaminophen every 6 hours. Patients were provided a sliding scale to assist in dosing their opioid medications according to their numeric pain score (NPS) (Table 2). Group 2 patients were given oxycodone 10 mg in the postanesthesia care unit (PACU) and instructed to take oxycodone 10 mg with acetaminophen 650 mg every 6 hours on a scheduled basis until their block wore off, then dose themselves using the NPS.

Table 1. Patient Groups

Table 2. Sliding Scale for Pain Control in the Experimental Groups

Group 3 patients were given oxycodone 10 mg in the PACU and instructed to take oxycodone 10 mg with acetaminophen 650 mg every 6 hours and OxyContin 10 mg every 12 hours on a scheduled basis until their block wore off, then dose themselves using NPS. Group 4 patients were given oxycodone 10 mg postoperatively and ketorolac 30 mg intravenously in the PACU and instructed to take oxycodone 10 mg, acetaminophen 650 mg, and ketorolac 10 mg every 6 hours on a scheduled basis until their block wore off, then dose themselves using the NPS.

Patients were provided with a journal and asked to record their medication usage, NPS, and any adverse effects (nausea, vomiting, and uncontrolled pain were specifically mentioned) or complications for 5 days after their procedure. We also attempted to contact patients by telephone on each of the 5 days after their procedure to remind them to complete their logs. They were asked specifically if they were having difficulty with their medications. They were also asked specifically about nausea, vomiting, and over-sedation. If patients requested additional medication to help treat their pain, they were instructed to add an over-the-counter NSAID of their choice based on the label’s suggested dosing.

Continue to: All patients received a supraclavicular...

All patients received a supraclavicular brachial plexus block using 0.75% ropivacaine under the supervision of an attending anesthesiologist experienced in regional anesthesia. Patients underwent thumb CMC arthroplasty utilizing complete resection of the trapezium followed by abductor pollicis longus suspensionplasty under the supervision of 1 of 3 fellowship-trained hand surgeons. ORIF of the distal radius was completed utilizing a volar approach and distal radius locking plate under the supervision of 1 of 3 fellowship-trained hand surgeons.

Primary outcome measures were the total number of oxycodone tablets taken daily and the average daily NPS. Secondary outcomes measured included adverse effects as noted above and the need for a trip to the emergency department for unrelieved pain.

A power analysis was completed prior to the beginning of the study. To detect a difference of at least 1 on the NPS, we determined that 18 patients per group would provide 80% power. This was based on literature utilizing the visual analog scale (VAS), a 100-mm line on which patients can place a mark to describe the intensity of their pain. The standard deviation on the VAS is approximately 15 mm. To account for potential dropout, we elected to recruit 20 patients per group. Non-paired t tests were used to compare groups.

RESULTS

One hundred and eighteen patients enrolled in the study. Of those, 79 patients completed and returned their summary logs (by group: 18 control, 20 oxycodone, 17 OxyContin, and 24 ketorolac). The remaining patients were excluded from the final analysis because they did not return their summary logs. Only 1 patient was excluded from the analysis because he did not have adequate regional anesthesia. Demographic data were analyzed and showed no significant differences between groups at the P < .05 level of significance. Surgical procedures were completed by 3 fellowship-trained hand surgeons. Distal radius fractures were performed using a volar approach. CMC arthroplasty was performed using a procedure that was standardized across surgeons. There were no between-surgeon differences in outcomes.

Average daily NPS (Figure 1) and the total number of oxycodone tablets taken (Figure 2) over the 5-day study period were recorded. Patients in the ketorolac group used fewer oxycodone tablets (19.3) than patients in the other 3 groups (24.4), P =.11, but the difference was not statistically significant. The maximum number of oxycodone tablets used was 71 in the Percocet group, 57 in the oxycodone and ketorolac groups, and 73 in the OxyContin group. The average daily NPS was lower in the ketorolac group during the period of medication use. This value only reached statistical significance on postoperative day 0 when the ketorolac group was compared with the OxyContin group (P = .01) and on postoperative day 1 when the ketorolac group was compared with the oxycodone group (P = .04). Complications (Figure 3) were greater in the non-ketorolac groups. One patient each in the oxycodone and OxyContin groups required a trip to the emergency department for pain control after their block wore off. Nausea and vomiting were present in each of the 4 groups but to a much greater degree in the Percocet and OxyContin groups; however, these results did not reach statistical significance (P = .129). Eleven of the 18 patients in the Percocet group required an additional NSAID (naproxen) and still did not achieve pain control similar to the other groups. This may explain why the average daily pain score in the Percocet group was lower than that in the oxycodone group, in which only 4 of the 20 patients supplemented with naproxen. Patients did, however, require many more oxycodone tablets to achieve pain control in the Percocet group. Over-sedation was reported in 3 patients in the oxycodone group and in 1 patient in the OxyContin group. No patients were found to have bleeding, renal, or other systemic complications.

Continue to: Discussion...

DISCUSSION

In this prospective, randomized study, we sought to determine whether a more organized approach to treating postoperative pain using a specific dosing regimen or opiates in conjunction with non-opiate medications would lead to improved pain control and a decreased need for opiates. We found that adding ketorolac to the postoperative pain regimen and outlining a more detailed set of instructions could lower narcotic usage in the first 4 postoperative days. In addition, adding ketorolac decreased other complications commonly seen with narcotic usage and was shown to be safe in our patient population.

Ketorolac has been shown to decrease narcotic pain medication usage in several surgical settings and across different surgical specialties. It is hypothesized that ketorolac potentiates the effects of narcotics.¹¹ Ketorolac given alone has a potent analgesic effect by acting as a strong non-selective cyclooxygenase inhibitor. The major drawback to ketorolac use has been its well-known side-effect profile. Ketorolac is renally excreted, and as such, should not be used in patients with renal insufficiency. In addition, ketorolac has been shown to cause increased gastrointestinal bleeding when used for >5 days.¹⁵ Caution should be taken when combining ketorolac with thromboprophylactic medications, especially in older patients.

Many surgeons use NSAIDs along with narcotics as part of a postoperative pain regimen. While this is often adequate for some procedures, when the surgery involves manipulating fractures, internal fixation, or resection arthroplasty, the variation in individual patient pain may call for a more robust protocol. Additionally, as surgeons expand to more complex procedures performed in the outpatient setting, evaluating different combinations of analgesics taken in a more structured manner may provide for improved pain control.

A major component of patient satisfaction is postoperative pain control.^3-8,12,16,17 Regional anesthesia is an important tool that allows patients to undergo a surgical procedure with a greatly reduced amount of opioid pain medications. In addition, regional anesthesia can provide significant pain control after the patient has left the ambulatory surgery center, but this relief is short-lived because the medication is designed to lose effectiveness over time. As the effects of regional anesthesia wear off, patients can experience “rebound pain” with severe levels of pain that, on occasion, cannot be controlled with oral analgesics alone. The addition of ketorolac provided improved pain control when compared with the other regimens during this transition period when the regional anesthesia was becoming ineffective. In addition, because patients taking ketorolac used less narcotic medication, they experienced less nausea, vomiting, and over-sedation.

Additionally, patients were instructed to record their medication usage and pain scores on a prospective basis, with the hope of eliminating recall bias. A potential weakness is the inability to show significance for pain relief and reduced narcotic usage with the addition of ketorolac, although there was a trend toward significance. Many of the patients who enrolled in the trial did not return their medication logs. While these patients had to be excluded from data analysis, we continued enrollment until we obtained an adequate number of patients in each group. In addition, in the OxyContin group (Group 3), we could only recruit 17 participants, instead of the 18 needed based on our power study. Although this has a potential to alter the significance of our results, we do not feel this had a substantial impact on our results.

Many patients in the non-ketorolac groups supplemented their medication regimens with NSAIDs, which may have falsely lowered pain scores and narcotic usage. While this confounds our study results, we do not believe that it invalidates the conclusion that ketorolac can be an effective adjunct pain medication for use in patients undergoing ambulatory hand surgery.

The study examined postoperative pain control for only 2 procedures, thumb basal joint arthroplasty and distal radius fracture fixation, both commonly performed in the outpatient setting under regional anesthesia and both typically requiring narcotic pain medication. Perhaps the utilization of these medication regimens with different surgical procedures would have differing results.

We conclude that ketorolac potentially provides patients with improved pain control over the use of narcotic pain medications alone in the setting of ambulatory hand surgery.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

We evaluated postoperative pain control and narcotic usage after thumb carpometacarpal (CMC) arthroplasty or open reduction and internal fixation (ORIF) of the distal radius in patients given opiates with or without other non-opiate medication using a specific dosing regimen. A prospective, randomized study of 79 patients undergoing elective CMC arthroplasty or ORIF of the distal radius evaluated postoperative pain in the first 5 postoperative days. Patients were divided into 4 groups: Group 1, oxycodone and acetaminophen PRN; Group 2, oxycodone and acetaminophen with specific dosing; Group 3, oxycodone, acetaminophen, and OxyContin with specific dosing; and Group 4, oxycodone, acetaminophen, and ketorolac with specific dosing. During the first 5 postoperative days, we recorded pain levels according to a numeric pain scale, opioid usage, and complications. Although differences in our data did not reach statistical significance, overall pain scores, opioid usage, and complication rates were less prevalent in the oxycodone, acetaminophen, and ketorolac group. Postoperative pain following ambulatory hand and wrist surgery under regional anesthesia was more effectively controlled with fewer complications using a combination of oxycodone, acetaminophen, and ketorolac with a specific dosing regimen.

Continue to: Regional anesthesia...

Regional anesthesia is a safe and effective modality of perioperative pain control in patients undergoing ambulatory hand procedures.^1-10 Often, as the regional block wears off, patients experience a rebound pain effect that can be challenging to manage.

We sought to determine if an organized, multimodal approach in patients undergoing thumb carpometacarpal (CMC) arthroplasty or open reduction and internal fixation (ORIF) of distal radius fractures would provide better postoperative pain control. We hypothesized that this approach would significantly reduce postoperative pain and the need for narcotic pain medication compared with PRN dosing of oxycodone/acetaminophen alone.^11-14

MATERIALS AND METHODS

Our study was approved by our Institutional Review Board. Informed consent was obtained from each patient. Patients presenting for elective thumb CMC arthroplasty or ORIF of the distal radius were screened for inclusion in a prospective, randomized study. Inclusion criteria included patients aged 18 to 65 years who could provide informed consent. Patients with chronic pain syndromes, long-term narcotic usage, chronic medical conditions precluding the use of opiates or nonsteroidal anti-inflammatory drugs (NSAIDs), and those who did not have a complete sensory and motor block postoperatively were excluded.

Patients were randomly divided into 1 of 4 study arms. Randomization was performed via sealed envelopes, which were opened in the recovery area when postoperative prescriptions were written. The group distribution was as follows: Group 1, Percocet 5 mg/325 mg alone (control); Group 2, oxycodone 5 mg, acetaminophen 325 mg administered separately; Group 3, oxycodone 5 mg, acetaminophen 325 mg, and oxycodone SR (OxyContin) 10 mg; and Group 4, oxycodone 5 mg, acetaminophen 325 mg, and ketorolac (Toradol) 10 mg (Table 1). Patients in the control group were instructed to take 1 or 2 tablets every 4 to 6 hours as needed for pain. Patients in the 3 experimental groups were given detailed instructions regarding when and how to take their medications. All patients were instructed to take 650 mg of acetaminophen every 6 hours. Patients were provided a sliding scale to assist in dosing their opioid medications according to their numeric pain score (NPS) (Table 2). Group 2 patients were given oxycodone 10 mg in the postanesthesia care unit (PACU) and instructed to take oxycodone 10 mg with acetaminophen 650 mg every 6 hours on a scheduled basis until their block wore off, then dose themselves using the NPS.

Table 1. Patient Groups

Table 2. Sliding Scale for Pain Control in the Experimental Groups

Group 3 patients were given oxycodone 10 mg in the PACU and instructed to take oxycodone 10 mg with acetaminophen 650 mg every 6 hours and OxyContin 10 mg every 12 hours on a scheduled basis until their block wore off, then dose themselves using NPS. Group 4 patients were given oxycodone 10 mg postoperatively and ketorolac 30 mg intravenously in the PACU and instructed to take oxycodone 10 mg, acetaminophen 650 mg, and ketorolac 10 mg every 6 hours on a scheduled basis until their block wore off, then dose themselves using the NPS.

Patients were provided with a journal and asked to record their medication usage, NPS, and any adverse effects (nausea, vomiting, and uncontrolled pain were specifically mentioned) or complications for 5 days after their procedure. We also attempted to contact patients by telephone on each of the 5 days after their procedure to remind them to complete their logs. They were asked specifically if they were having difficulty with their medications. They were also asked specifically about nausea, vomiting, and over-sedation. If patients requested additional medication to help treat their pain, they were instructed to add an over-the-counter NSAID of their choice based on the label’s suggested dosing.

Continue to: All patients received a supraclavicular...

All patients received a supraclavicular brachial plexus block using 0.75% ropivacaine under the supervision of an attending anesthesiologist experienced in regional anesthesia. Patients underwent thumb CMC arthroplasty utilizing complete resection of the trapezium followed by abductor pollicis longus suspensionplasty under the supervision of 1 of 3 fellowship-trained hand surgeons. ORIF of the distal radius was completed utilizing a volar approach and distal radius locking plate under the supervision of 1 of 3 fellowship-trained hand surgeons.

Primary outcome measures were the total number of oxycodone tablets taken daily and the average daily NPS. Secondary outcomes measured included adverse effects as noted above and the need for a trip to the emergency department for unrelieved pain.

A power analysis was completed prior to the beginning of the study. To detect a difference of at least 1 on the NPS, we determined that 18 patients per group would provide 80% power. This was based on literature utilizing the visual analog scale (VAS), a 100-mm line on which patients can place a mark to describe the intensity of their pain. The standard deviation on the VAS is approximately 15 mm. To account for potential dropout, we elected to recruit 20 patients per group. Non-paired t tests were used to compare groups.

RESULTS

One hundred and eighteen patients enrolled in the study. Of those, 79 patients completed and returned their summary logs (by group: 18 control, 20 oxycodone, 17 OxyContin, and 24 ketorolac). The remaining patients were excluded from the final analysis because they did not return their summary logs. Only 1 patient was excluded from the analysis because he did not have adequate regional anesthesia. Demographic data were analyzed and showed no significant differences between groups at the P < .05 level of significance. Surgical procedures were completed by 3 fellowship-trained hand surgeons. Distal radius fractures were performed using a volar approach. CMC arthroplasty was performed using a procedure that was standardized across surgeons. There were no between-surgeon differences in outcomes.

Average daily NPS (Figure 1) and the total number of oxycodone tablets taken (Figure 2) over the 5-day study period were recorded. Patients in the ketorolac group used fewer oxycodone tablets (19.3) than patients in the other 3 groups (24.4), P =.11, but the difference was not statistically significant. The maximum number of oxycodone tablets used was 71 in the Percocet group, 57 in the oxycodone and ketorolac groups, and 73 in the OxyContin group. The average daily NPS was lower in the ketorolac group during the period of medication use. This value only reached statistical significance on postoperative day 0 when the ketorolac group was compared with the OxyContin group (P = .01) and on postoperative day 1 when the ketorolac group was compared with the oxycodone group (P = .04). Complications (Figure 3) were greater in the non-ketorolac groups. One patient each in the oxycodone and OxyContin groups required a trip to the emergency department for pain control after their block wore off. Nausea and vomiting were present in each of the 4 groups but to a much greater degree in the Percocet and OxyContin groups; however, these results did not reach statistical significance (P = .129). Eleven of the 18 patients in the Percocet group required an additional NSAID (naproxen) and still did not achieve pain control similar to the other groups. This may explain why the average daily pain score in the Percocet group was lower than that in the oxycodone group, in which only 4 of the 20 patients supplemented with naproxen. Patients did, however, require many more oxycodone tablets to achieve pain control in the Percocet group. Over-sedation was reported in 3 patients in the oxycodone group and in 1 patient in the OxyContin group. No patients were found to have bleeding, renal, or other systemic complications.

Continue to: Discussion...

DISCUSSION

In this prospective, randomized study, we sought to determine whether a more organized approach to treating postoperative pain using a specific dosing regimen or opiates in conjunction with non-opiate medications would lead to improved pain control and a decreased need for opiates. We found that adding ketorolac to the postoperative pain regimen and outlining a more detailed set of instructions could lower narcotic usage in the first 4 postoperative days. In addition, adding ketorolac decreased other complications commonly seen with narcotic usage and was shown to be safe in our patient population.

Ketorolac has been shown to decrease narcotic pain medication usage in several surgical settings and across different surgical specialties. It is hypothesized that ketorolac potentiates the effects of narcotics.¹¹ Ketorolac given alone has a potent analgesic effect by acting as a strong non-selective cyclooxygenase inhibitor. The major drawback to ketorolac use has been its well-known side-effect profile. Ketorolac is renally excreted, and as such, should not be used in patients with renal insufficiency. In addition, ketorolac has been shown to cause increased gastrointestinal bleeding when used for >5 days.¹⁵ Caution should be taken when combining ketorolac with thromboprophylactic medications, especially in older patients.

Many surgeons use NSAIDs along with narcotics as part of a postoperative pain regimen. While this is often adequate for some procedures, when the surgery involves manipulating fractures, internal fixation, or resection arthroplasty, the variation in individual patient pain may call for a more robust protocol. Additionally, as surgeons expand to more complex procedures performed in the outpatient setting, evaluating different combinations of analgesics taken in a more structured manner may provide for improved pain control.

A major component of patient satisfaction is postoperative pain control.^3-8,12,16,17 Regional anesthesia is an important tool that allows patients to undergo a surgical procedure with a greatly reduced amount of opioid pain medications. In addition, regional anesthesia can provide significant pain control after the patient has left the ambulatory surgery center, but this relief is short-lived because the medication is designed to lose effectiveness over time. As the effects of regional anesthesia wear off, patients can experience “rebound pain” with severe levels of pain that, on occasion, cannot be controlled with oral analgesics alone. The addition of ketorolac provided improved pain control when compared with the other regimens during this transition period when the regional anesthesia was becoming ineffective. In addition, because patients taking ketorolac used less narcotic medication, they experienced less nausea, vomiting, and over-sedation.

Additionally, patients were instructed to record their medication usage and pain scores on a prospective basis, with the hope of eliminating recall bias. A potential weakness is the inability to show significance for pain relief and reduced narcotic usage with the addition of ketorolac, although there was a trend toward significance. Many of the patients who enrolled in the trial did not return their medication logs. While these patients had to be excluded from data analysis, we continued enrollment until we obtained an adequate number of patients in each group. In addition, in the OxyContin group (Group 3), we could only recruit 17 participants, instead of the 18 needed based on our power study. Although this has a potential to alter the significance of our results, we do not feel this had a substantial impact on our results.

Many patients in the non-ketorolac groups supplemented their medication regimens with NSAIDs, which may have falsely lowered pain scores and narcotic usage. While this confounds our study results, we do not believe that it invalidates the conclusion that ketorolac can be an effective adjunct pain medication for use in patients undergoing ambulatory hand surgery.

The study examined postoperative pain control for only 2 procedures, thumb basal joint arthroplasty and distal radius fracture fixation, both commonly performed in the outpatient setting under regional anesthesia and both typically requiring narcotic pain medication. Perhaps the utilization of these medication regimens with different surgical procedures would have differing results.

We conclude that ketorolac potentially provides patients with improved pain control over the use of narcotic pain medications alone in the setting of ambulatory hand surgery.

This paper will be judged for the Resident Writer’s Award.

Methicillin, cloxacillin, flucloxacillin, and cefoxitin are stable, penicillinase-producing β-lactam antibiotics; Staphylococcus aureus strains resistant to these agents are designated as methicillin-resistant S aureus (MRSA). Based on genotypic and phenotypic differences there are 2 strains of MRSA: hospital acquired and community acquired.

The potential for nosocomial transmission and the limited number of antibiotics available to treat MRSA are problematic. Moreover, MRSA has emerged worldwide as a major nosocomial pathogen that contributes to morbidity and mortality. Methicillin-resistant S aureus infection in vesiculobullous disorders such as pemphigus vulgaris (PV) and toxic epidermal necrolysis (TEN) is known to contribute to mortality.¹

The reported prevalence of MRSA in India ranges from 12% to 38.44%.^2-4 We frequently encounter MRSA in dermatology inpatients, especially those with a vesiculobullous disorder. The primary objective of this study was to determine the prevalence of MRSA in dermatology inpatients with a vesiculobullous disorder; the secondary objective was to determine if MRSA contributes to mortality.

Materials and Methods

A 1-year prospective, cross-sectional, descriptive study was conducted in a tertiary-care center. The study population included all dermatology inpatients with a vesiculobullous disorder. Patients with a vesiculobullous disorder secondary to a primary viral or bacterial disorder were excluded. Permission to conduct the study was granted by the institution’s Human Ethics Committee.

All patients underwent a detailed history and clinical examination. Routine hematology testing, urinalysis, measurement of the blood glucose level, and other investigations relevant to the vesiculobullous disorder were performed. Special investigations were Gram staining, culture, and susceptibility testing of material from a nasal swab and a swab of a representative skin lesion.

Detection of MRSA
Skin lesions were thoroughly cleaned with sterile normal saline. Specimens of pus were drawn with a sterile swab for Gram staining, culture, and susceptibility testing and were analyzed in the institution’s microbiology department. A direct colony suspension (equivalent to McFarland Standard No. 0.5) was inoculated on a Mueller-Hinton agar plate, incorporating cefoxitin, linezolid, vancomycin, amikacin, and rifampicin supplemented with sodium chloride 2% and incubated at 37°C for 24 hours. Staphylococcus aureus colonies were identified by their smooth, convex, shiny, and opaque appearance with a golden yellow pigment, as well as by coagulase positivity, mannitol fermentation, and production of phosphatase.

Methicillin-resistant S aureus was defined as an isolate having a minimum inhibitory concentration of more than 2 μg/mL of cefoxitin; a methicillin-sensitive S aureus isolate was defined as having a minimum inhibitory concentration of less than or equal to 2 μg/mL of cefoxitin. Specimens showing moderate to heavy growth of MRSA were included in the study. For specimens showing mild growth, testing was repeated; if no growth was seen on repeat testing, results were interpreted as negative.

Data were collected and analyzed for frequency and percentage; P<.05 was considered significant.

Results

The number of patients analyzed in the study period was 43. Table 1 shows their salient demographic characteristics, clinical features, and findings of the investigation. The youngest patient was aged 13 years; the oldest was aged 80 years. The male to female ratio was 0.65 to 1. The most common primary lesion was a combined vesicle and bulla (34 patients [79.1%]); the most common secondary lesion was a combination of erosion with crusting (22 patients [51.2%]).

Table 2 lists the types of vesiculobullous disorders seen in this study. Pemphigus vulgaris was the most common (21 patients [48.8%])(Figure 1). Drug-induced vesiculobullous disorders (eg, TEN) were noted in 11 patients (25.6%)(Figure 2).

Table 2 also lists pathogens cultured in the study group. There were 24 bacterial isolates, of which S aureus accounted for 22 (91.7%). Methicillin-resistant S aureus was cultured in 14 patients (32.6%); culture was sterile in 19 patients (44.2%).

Among the 22 cultured staphylococcal species, MRSA accounted for 14 (63.6%) and constituted 58.3% (14/24) of all bacterial isolates. The nasal swab for MRSA was positive in 4 PV patients (9.3%), 2 TEN patients (4.6%), and 1 bullous pemphigoid patient (2.3%). Methicillin-resistant S aureus was most commonly cultured in PV patients (8/14 [57.1%]).

All MRSA strains (100%) were sensitive to vancomycin and linezolid; 34 (79.1%) were sensitive to amikacin. Additionally, 100% of MRSA strains were resistant to oxacillin, cloxacillin, and cefoxitin.

Three patients with PV (7.0%) and 1 patient with TEN (2.3%) died during the course of the study; only 1 death (2.3%) occurred in a patient who had a positive MRSA culture.

Comment

In this 1-year study, we tested and followed 43 patients with autoimmune and drug-induced vesiculobullous disorders. Vesiculobullous disorders in dermatology inpatients are a cause of great concern. When lesions rupture, they leave behind a large area of erosion that forms a nidus of bacterial colonization; often, these bacteria cause severe infection, including septicemia, and result in death.⁵ Moreover, autoimmune bullous disorders usually require a prolonged hospital stay and powerful immunosuppressive drugs, which contributes to bacterial infection, especially MRSA.⁶

The age of patients in this study ranged from 13 to 80 years; most patients were in the 6th decade, a pattern seen in studies worldwide.⁵ In a study by Kanwar and De,⁷ however, most cases were aged 20 to 40 years.⁷ In our study, there was a female preponderance (male to female ratio of 0.65 to 1).

Studies have shown that the duration of illness in vesiculobullous disorder is directly associated with MRSA infection. However, in our study with MRSA detected in 14 patients, most patients had a duration of illness less than 1 year (statistically insignificant [P>.05]), a finding similar to Shafi et al.⁸

The symptomatic nature of these diseases, their unsightly appearance, and mucous-membrane involvement of vesiculobullous disorders prompts these patients to present to the hospital early. However, a prolonged hospital stay by patients with an autoimmune vesiculobullous disorders sets the stage for MRSA colonization.

In this study, diabetes mellitus (DM) was seen in 15 patients (34.9%); 5 of them had MRSA infection (statistically insignificant [P>.05]). Diabetes mellitus contributing to sepsis and MRSA infection, which in turn contributes to morbidity and mortality, has been well-documented.^2,4,9

Methicillin-resistant S aureus in this study was isolated most often from blisters and erosions. Vesiculobullous disorders and drug reactions (eg, Stevens-Johnson syndrome, TEN) are characterized by blisters that rupture to form erosions and crusting, which form fissures in the epidermal barrier function that are nidi for colonization by microbes, especially S aureus and MRSA in particular; later, these bacteria can enter dermal vessels and then the bloodstream, leading to septicemia.¹⁰

The prevalence of MRSA in this study was 32.6% (14/43), which is high compared to other studies.^2-4 Pemphigus vulgaris was the most common disorder infected by MRSA in this study (57.1% [8/14] of MRSA isolates)(Table 1), a finding that reveals that the incidence of MRSA is high among staphylococcal isolates in vesiculobullous disorders. However, the high incidence of MRSA in this study could be a reflection of the number of patients with a severe and chronic vesiculobullous disorder, such as PV, and serious drug reactions such as TEN referred to our tertiary-care center, where we get a large number of patients affected by autoimmune and drug-induced vesiculobullous disorders. Similar findings have been reported by Stryjewski et al.¹¹

A high prevalence of MRSA in a dermatology unit has grave consequences, contributing to morbidity and mortality in particular among patients with a vesiculobullous disorder. Immunosuppressive therapy and comorbidities such as DM contribute to MRSA colonization in vesiculobullous disorders.¹² Overcrowding and poor sterilization techniques in public hospitals in India may contribute to the high prevalence of MRSA seen in hospital units.

Patients with a vesiculobullous disorder who are chronic nasal carriers of MRSA are at risk for cutaneous MRSA infection, which in turn can lead to MRSA septicemia and an elevated risk of death. In this study, however, a nasal swab was positive for MRSA in only 7 patients. One patient with MRSA colonization died, which was statistically insignificant (P=1).

In this study, all MRSA strains (100%) were resistant to first-line antibiotics, such as oxacillin, cloxacillin, and cefoxitin; all strains were susceptible to vancomycin and linezolid. This finding is similar to prior studies.^13,14 A distinctive finding in this study is that 34 (79.1%) of MRSA isolates were susceptible to amikacin. This finding has practical significance. Amikacin, an inexpensive antibiotic that is readily available in most units, can be used to treat MRSA infection in resource-poor settings where vancomycin and linezolid are unavailable.

Conclusion

Our study shows that MRSA is becoming the prominent pathogen in nosocomial infections, especially in bedridden patients, which has grave implications. The use of a prophylactic S aureus conjugate vaccine in patients with a chronic vesiculobullous disorder might be justified in the future.¹⁵ We found a high prevalence (32.6%) of MRSA in vesiculobullous disorders, no relationship between DM and MRSA colonization, PV was the most common disorder complicated by MRSA, no relationship between nasal colonization and MRSA infection, no relationship between death during the study period and MRSA infection, 100% of MRSA strains were susceptible to vancomycin and linezolid, and 79.1% of MRSA strains were susceptible to amikacin.

Methicillin, cloxacillin, flucloxacillin, and cefoxitin are stable, penicillinase-producing β-lactam antibiotics; Staphylococcus aureus strains resistant to these agents are designated as methicillin-resistant S aureus (MRSA). Based on genotypic and phenotypic differences there are 2 strains of MRSA: hospital acquired and community acquired.

The potential for nosocomial transmission and the limited number of antibiotics available to treat MRSA are problematic. Moreover, MRSA has emerged worldwide as a major nosocomial pathogen that contributes to morbidity and mortality. Methicillin-resistant S aureus infection in vesiculobullous disorders such as pemphigus vulgaris (PV) and toxic epidermal necrolysis (TEN) is known to contribute to mortality.¹

The reported prevalence of MRSA in India ranges from 12% to 38.44%.^2-4 We frequently encounter MRSA in dermatology inpatients, especially those with a vesiculobullous disorder. The primary objective of this study was to determine the prevalence of MRSA in dermatology inpatients with a vesiculobullous disorder; the secondary objective was to determine if MRSA contributes to mortality.

Materials and Methods

A 1-year prospective, cross-sectional, descriptive study was conducted in a tertiary-care center. The study population included all dermatology inpatients with a vesiculobullous disorder. Patients with a vesiculobullous disorder secondary to a primary viral or bacterial disorder were excluded. Permission to conduct the study was granted by the institution’s Human Ethics Committee.

All patients underwent a detailed history and clinical examination. Routine hematology testing, urinalysis, measurement of the blood glucose level, and other investigations relevant to the vesiculobullous disorder were performed. Special investigations were Gram staining, culture, and susceptibility testing of material from a nasal swab and a swab of a representative skin lesion.

Detection of MRSA
Skin lesions were thoroughly cleaned with sterile normal saline. Specimens of pus were drawn with a sterile swab for Gram staining, culture, and susceptibility testing and were analyzed in the institution’s microbiology department. A direct colony suspension (equivalent to McFarland Standard No. 0.5) was inoculated on a Mueller-Hinton agar plate, incorporating cefoxitin, linezolid, vancomycin, amikacin, and rifampicin supplemented with sodium chloride 2% and incubated at 37°C for 24 hours. Staphylococcus aureus colonies were identified by their smooth, convex, shiny, and opaque appearance with a golden yellow pigment, as well as by coagulase positivity, mannitol fermentation, and production of phosphatase.

Methicillin-resistant S aureus was defined as an isolate having a minimum inhibitory concentration of more than 2 μg/mL of cefoxitin; a methicillin-sensitive S aureus isolate was defined as having a minimum inhibitory concentration of less than or equal to 2 μg/mL of cefoxitin. Specimens showing moderate to heavy growth of MRSA were included in the study. For specimens showing mild growth, testing was repeated; if no growth was seen on repeat testing, results were interpreted as negative.

Data were collected and analyzed for frequency and percentage; P<.05 was considered significant.

Results

The number of patients analyzed in the study period was 43. Table 1 shows their salient demographic characteristics, clinical features, and findings of the investigation. The youngest patient was aged 13 years; the oldest was aged 80 years. The male to female ratio was 0.65 to 1. The most common primary lesion was a combined vesicle and bulla (34 patients [79.1%]); the most common secondary lesion was a combination of erosion with crusting (22 patients [51.2%]).

Table 2 lists the types of vesiculobullous disorders seen in this study. Pemphigus vulgaris was the most common (21 patients [48.8%])(Figure 1). Drug-induced vesiculobullous disorders (eg, TEN) were noted in 11 patients (25.6%)(Figure 2).

Table 2 also lists pathogens cultured in the study group. There were 24 bacterial isolates, of which S aureus accounted for 22 (91.7%). Methicillin-resistant S aureus was cultured in 14 patients (32.6%); culture was sterile in 19 patients (44.2%).

Among the 22 cultured staphylococcal species, MRSA accounted for 14 (63.6%) and constituted 58.3% (14/24) of all bacterial isolates. The nasal swab for MRSA was positive in 4 PV patients (9.3%), 2 TEN patients (4.6%), and 1 bullous pemphigoid patient (2.3%). Methicillin-resistant S aureus was most commonly cultured in PV patients (8/14 [57.1%]).

All MRSA strains (100%) were sensitive to vancomycin and linezolid; 34 (79.1%) were sensitive to amikacin. Additionally, 100% of MRSA strains were resistant to oxacillin, cloxacillin, and cefoxitin.

Three patients with PV (7.0%) and 1 patient with TEN (2.3%) died during the course of the study; only 1 death (2.3%) occurred in a patient who had a positive MRSA culture.

Comment

In this 1-year study, we tested and followed 43 patients with autoimmune and drug-induced vesiculobullous disorders. Vesiculobullous disorders in dermatology inpatients are a cause of great concern. When lesions rupture, they leave behind a large area of erosion that forms a nidus of bacterial colonization; often, these bacteria cause severe infection, including septicemia, and result in death.⁵ Moreover, autoimmune bullous disorders usually require a prolonged hospital stay and powerful immunosuppressive drugs, which contributes to bacterial infection, especially MRSA.⁶

The age of patients in this study ranged from 13 to 80 years; most patients were in the 6th decade, a pattern seen in studies worldwide.⁵ In a study by Kanwar and De,⁷ however, most cases were aged 20 to 40 years.⁷ In our study, there was a female preponderance (male to female ratio of 0.65 to 1).

Studies have shown that the duration of illness in vesiculobullous disorder is directly associated with MRSA infection. However, in our study with MRSA detected in 14 patients, most patients had a duration of illness less than 1 year (statistically insignificant [P>.05]), a finding similar to Shafi et al.⁸

The symptomatic nature of these diseases, their unsightly appearance, and mucous-membrane involvement of vesiculobullous disorders prompts these patients to present to the hospital early. However, a prolonged hospital stay by patients with an autoimmune vesiculobullous disorders sets the stage for MRSA colonization.

In this study, diabetes mellitus (DM) was seen in 15 patients (34.9%); 5 of them had MRSA infection (statistically insignificant [P>.05]). Diabetes mellitus contributing to sepsis and MRSA infection, which in turn contributes to morbidity and mortality, has been well-documented.^2,4,9

Methicillin-resistant S aureus in this study was isolated most often from blisters and erosions. Vesiculobullous disorders and drug reactions (eg, Stevens-Johnson syndrome, TEN) are characterized by blisters that rupture to form erosions and crusting, which form fissures in the epidermal barrier function that are nidi for colonization by microbes, especially S aureus and MRSA in particular; later, these bacteria can enter dermal vessels and then the bloodstream, leading to septicemia.¹⁰

The prevalence of MRSA in this study was 32.6% (14/43), which is high compared to other studies.^2-4 Pemphigus vulgaris was the most common disorder infected by MRSA in this study (57.1% [8/14] of MRSA isolates)(Table 1), a finding that reveals that the incidence of MRSA is high among staphylococcal isolates in vesiculobullous disorders. However, the high incidence of MRSA in this study could be a reflection of the number of patients with a severe and chronic vesiculobullous disorder, such as PV, and serious drug reactions such as TEN referred to our tertiary-care center, where we get a large number of patients affected by autoimmune and drug-induced vesiculobullous disorders. Similar findings have been reported by Stryjewski et al.¹¹

A high prevalence of MRSA in a dermatology unit has grave consequences, contributing to morbidity and mortality in particular among patients with a vesiculobullous disorder. Immunosuppressive therapy and comorbidities such as DM contribute to MRSA colonization in vesiculobullous disorders.¹² Overcrowding and poor sterilization techniques in public hospitals in India may contribute to the high prevalence of MRSA seen in hospital units.

Patients with a vesiculobullous disorder who are chronic nasal carriers of MRSA are at risk for cutaneous MRSA infection, which in turn can lead to MRSA septicemia and an elevated risk of death. In this study, however, a nasal swab was positive for MRSA in only 7 patients. One patient with MRSA colonization died, which was statistically insignificant (P=1).

In this study, all MRSA strains (100%) were resistant to first-line antibiotics, such as oxacillin, cloxacillin, and cefoxitin; all strains were susceptible to vancomycin and linezolid. This finding is similar to prior studies.^13,14 A distinctive finding in this study is that 34 (79.1%) of MRSA isolates were susceptible to amikacin. This finding has practical significance. Amikacin, an inexpensive antibiotic that is readily available in most units, can be used to treat MRSA infection in resource-poor settings where vancomycin and linezolid are unavailable.

Conclusion

Our study shows that MRSA is becoming the prominent pathogen in nosocomial infections, especially in bedridden patients, which has grave implications. The use of a prophylactic S aureus conjugate vaccine in patients with a chronic vesiculobullous disorder might be justified in the future.¹⁵ We found a high prevalence (32.6%) of MRSA in vesiculobullous disorders, no relationship between DM and MRSA colonization, PV was the most common disorder complicated by MRSA, no relationship between nasal colonization and MRSA infection, no relationship between death during the study period and MRSA infection, 100% of MRSA strains were susceptible to vancomycin and linezolid, and 79.1% of MRSA strains were susceptible to amikacin.

Methicillin, cloxacillin, flucloxacillin, and cefoxitin are stable, penicillinase-producing β-lactam antibiotics; Staphylococcus aureus strains resistant to these agents are designated as methicillin-resistant S aureus (MRSA). Based on genotypic and phenotypic differences there are 2 strains of MRSA: hospital acquired and community acquired.

The potential for nosocomial transmission and the limited number of antibiotics available to treat MRSA are problematic. Moreover, MRSA has emerged worldwide as a major nosocomial pathogen that contributes to morbidity and mortality. Methicillin-resistant S aureus infection in vesiculobullous disorders such as pemphigus vulgaris (PV) and toxic epidermal necrolysis (TEN) is known to contribute to mortality.¹

The reported prevalence of MRSA in India ranges from 12% to 38.44%.^2-4 We frequently encounter MRSA in dermatology inpatients, especially those with a vesiculobullous disorder. The primary objective of this study was to determine the prevalence of MRSA in dermatology inpatients with a vesiculobullous disorder; the secondary objective was to determine if MRSA contributes to mortality.

Materials and Methods

A 1-year prospective, cross-sectional, descriptive study was conducted in a tertiary-care center. The study population included all dermatology inpatients with a vesiculobullous disorder. Patients with a vesiculobullous disorder secondary to a primary viral or bacterial disorder were excluded. Permission to conduct the study was granted by the institution’s Human Ethics Committee.

All patients underwent a detailed history and clinical examination. Routine hematology testing, urinalysis, measurement of the blood glucose level, and other investigations relevant to the vesiculobullous disorder were performed. Special investigations were Gram staining, culture, and susceptibility testing of material from a nasal swab and a swab of a representative skin lesion.

Detection of MRSA
Skin lesions were thoroughly cleaned with sterile normal saline. Specimens of pus were drawn with a sterile swab for Gram staining, culture, and susceptibility testing and were analyzed in the institution’s microbiology department. A direct colony suspension (equivalent to McFarland Standard No. 0.5) was inoculated on a Mueller-Hinton agar plate, incorporating cefoxitin, linezolid, vancomycin, amikacin, and rifampicin supplemented with sodium chloride 2% and incubated at 37°C for 24 hours. Staphylococcus aureus colonies were identified by their smooth, convex, shiny, and opaque appearance with a golden yellow pigment, as well as by coagulase positivity, mannitol fermentation, and production of phosphatase.

Methicillin-resistant S aureus was defined as an isolate having a minimum inhibitory concentration of more than 2 μg/mL of cefoxitin; a methicillin-sensitive S aureus isolate was defined as having a minimum inhibitory concentration of less than or equal to 2 μg/mL of cefoxitin. Specimens showing moderate to heavy growth of MRSA were included in the study. For specimens showing mild growth, testing was repeated; if no growth was seen on repeat testing, results were interpreted as negative.

Data were collected and analyzed for frequency and percentage; P<.05 was considered significant.

Results

The number of patients analyzed in the study period was 43. Table 1 shows their salient demographic characteristics, clinical features, and findings of the investigation. The youngest patient was aged 13 years; the oldest was aged 80 years. The male to female ratio was 0.65 to 1. The most common primary lesion was a combined vesicle and bulla (34 patients [79.1%]); the most common secondary lesion was a combination of erosion with crusting (22 patients [51.2%]).

Table 2 lists the types of vesiculobullous disorders seen in this study. Pemphigus vulgaris was the most common (21 patients [48.8%])(Figure 1). Drug-induced vesiculobullous disorders (eg, TEN) were noted in 11 patients (25.6%)(Figure 2).

Table 2 also lists pathogens cultured in the study group. There were 24 bacterial isolates, of which S aureus accounted for 22 (91.7%). Methicillin-resistant S aureus was cultured in 14 patients (32.6%); culture was sterile in 19 patients (44.2%).

Among the 22 cultured staphylococcal species, MRSA accounted for 14 (63.6%) and constituted 58.3% (14/24) of all bacterial isolates. The nasal swab for MRSA was positive in 4 PV patients (9.3%), 2 TEN patients (4.6%), and 1 bullous pemphigoid patient (2.3%). Methicillin-resistant S aureus was most commonly cultured in PV patients (8/14 [57.1%]).

All MRSA strains (100%) were sensitive to vancomycin and linezolid; 34 (79.1%) were sensitive to amikacin. Additionally, 100% of MRSA strains were resistant to oxacillin, cloxacillin, and cefoxitin.

Three patients with PV (7.0%) and 1 patient with TEN (2.3%) died during the course of the study; only 1 death (2.3%) occurred in a patient who had a positive MRSA culture.

Comment

In this 1-year study, we tested and followed 43 patients with autoimmune and drug-induced vesiculobullous disorders. Vesiculobullous disorders in dermatology inpatients are a cause of great concern. When lesions rupture, they leave behind a large area of erosion that forms a nidus of bacterial colonization; often, these bacteria cause severe infection, including septicemia, and result in death.⁵ Moreover, autoimmune bullous disorders usually require a prolonged hospital stay and powerful immunosuppressive drugs, which contributes to bacterial infection, especially MRSA.⁶

The age of patients in this study ranged from 13 to 80 years; most patients were in the 6th decade, a pattern seen in studies worldwide.⁵ In a study by Kanwar and De,⁷ however, most cases were aged 20 to 40 years.⁷ In our study, there was a female preponderance (male to female ratio of 0.65 to 1).

Studies have shown that the duration of illness in vesiculobullous disorder is directly associated with MRSA infection. However, in our study with MRSA detected in 14 patients, most patients had a duration of illness less than 1 year (statistically insignificant [P>.05]), a finding similar to Shafi et al.⁸

The symptomatic nature of these diseases, their unsightly appearance, and mucous-membrane involvement of vesiculobullous disorders prompts these patients to present to the hospital early. However, a prolonged hospital stay by patients with an autoimmune vesiculobullous disorders sets the stage for MRSA colonization.

In this study, diabetes mellitus (DM) was seen in 15 patients (34.9%); 5 of them had MRSA infection (statistically insignificant [P>.05]). Diabetes mellitus contributing to sepsis and MRSA infection, which in turn contributes to morbidity and mortality, has been well-documented.^2,4,9

Methicillin-resistant S aureus in this study was isolated most often from blisters and erosions. Vesiculobullous disorders and drug reactions (eg, Stevens-Johnson syndrome, TEN) are characterized by blisters that rupture to form erosions and crusting, which form fissures in the epidermal barrier function that are nidi for colonization by microbes, especially S aureus and MRSA in particular; later, these bacteria can enter dermal vessels and then the bloodstream, leading to septicemia.¹⁰

The prevalence of MRSA in this study was 32.6% (14/43), which is high compared to other studies.^2-4 Pemphigus vulgaris was the most common disorder infected by MRSA in this study (57.1% [8/14] of MRSA isolates)(Table 1), a finding that reveals that the incidence of MRSA is high among staphylococcal isolates in vesiculobullous disorders. However, the high incidence of MRSA in this study could be a reflection of the number of patients with a severe and chronic vesiculobullous disorder, such as PV, and serious drug reactions such as TEN referred to our tertiary-care center, where we get a large number of patients affected by autoimmune and drug-induced vesiculobullous disorders. Similar findings have been reported by Stryjewski et al.¹¹

A high prevalence of MRSA in a dermatology unit has grave consequences, contributing to morbidity and mortality in particular among patients with a vesiculobullous disorder. Immunosuppressive therapy and comorbidities such as DM contribute to MRSA colonization in vesiculobullous disorders.¹² Overcrowding and poor sterilization techniques in public hospitals in India may contribute to the high prevalence of MRSA seen in hospital units.

Patients with a vesiculobullous disorder who are chronic nasal carriers of MRSA are at risk for cutaneous MRSA infection, which in turn can lead to MRSA septicemia and an elevated risk of death. In this study, however, a nasal swab was positive for MRSA in only 7 patients. One patient with MRSA colonization died, which was statistically insignificant (P=1).

In this study, all MRSA strains (100%) were resistant to first-line antibiotics, such as oxacillin, cloxacillin, and cefoxitin; all strains were susceptible to vancomycin and linezolid. This finding is similar to prior studies.^13,14 A distinctive finding in this study is that 34 (79.1%) of MRSA isolates were susceptible to amikacin. This finding has practical significance. Amikacin, an inexpensive antibiotic that is readily available in most units, can be used to treat MRSA infection in resource-poor settings where vancomycin and linezolid are unavailable.

Conclusion

Our study shows that MRSA is becoming the prominent pathogen in nosocomial infections, especially in bedridden patients, which has grave implications. The use of a prophylactic S aureus conjugate vaccine in patients with a chronic vesiculobullous disorder might be justified in the future.¹⁵ We found a high prevalence (32.6%) of MRSA in vesiculobullous disorders, no relationship between DM and MRSA colonization, PV was the most common disorder complicated by MRSA, no relationship between nasal colonization and MRSA infection, no relationship between death during the study period and MRSA infection, 100% of MRSA strains were susceptible to vancomycin and linezolid, and 79.1% of MRSA strains were susceptible to amikacin.

ABSTRACT

Standard 2-dimensional (2-D) computed tomography (CT) scans of the shoulder are often aligned to the plane of the body as opposed to the plane of the scapula, which may challenge the ability to accurately measure glenoid width and glenoid bone loss (GBL). The purpose of this study is to determine the effect of sagittal rotation of the glenoid on axial anterior-posterior (AP) glenoid width measurements in the setting of anterior GBL.

Forty-three CT scans from consecutive patients with anterior GBL (minimum 10%) were reformatted utilizing open-source DICOM software (OsiriX MD). Patients were grouped according to extent of GBL: I, 10% to 14.9% (N = 12); II, 15% to 19.9% (N = 16); and III, >20% (N = 15). The uncorrected (UNCORR) and corrected (CORR) images were assessed in the axial plane at 5 standardized cuts and measured for AP glenoid width.

For groups I and III, UNCORR scans underestimated axial AP width (and thus overestimated anterior GBL) in cuts 1 and 2, while in cuts 3 to 5, the axial AP width was overestimated (GBL was underestimated). In Group II, axial AP width was underestimated (GBL was overestimated), while in cuts 2 to 5, the axial AP width was overestimated (GBL was underestimated). Overall, AP glenoid width was consistently underestimated in cut 1, the most caudal cut; while AP glenoid width was consistently overestimated in cuts 3 to 5, the more cephalad cuts.

UNCORR 2-D CT scans inaccurately estimated glenoid width and the degree of anterior GBL. This data suggests that corrected 2D CT scans or a 3-dimensional (3-D) reconstruction can help in accurately defining the anterior GBL in patients with shoulder instability.

The treatment of glenohumeral instability has substantially evolved over the past several decades. The understanding of glenoid bone loss (GBL), in particular, has advanced to such a level that we utilize the quantification of GBL for surgical decision-making. Unrecognized and/or untreated GBL is associated with recurrent instability, pain, and disability. Controversy exists, however, regarding the precise amount of anterior GBL that is significant enough to warrant surgical treatment. While historically, 25%^1,2 of anterior GBL was thought to be the critical number required to warrant osseous augmentation, studies that are more recent have highlighted the need to perform osseous glenoid reconstruction with lesser degrees of GBL, particularly in the contact athlete.^3-9 As small differences in the amount of GBL can change surgical decision-making from an all-soft tissue repair to an osseous reconstruction, it is paramount that we have accurate, valid, and reproducible methods for calculating GBL.

Continue to: Historically, plain radiographs...

Computed tomography (CT) of the shoulder has become the most commonly utilized imaging modality in the evaluation of patients with shoulder instability associated with GBL. Standard 2-dimensional (2-D) CT scans of the shoulder are often aligned to the plane of the body as opposed to the plane of the scapula/glenoid, as standard protocols often fail to account for the anterior sagittal rotation of the scapula/glenoid, similar to the disadvantage of standard radiographs. While 3-dimensional (3-D) CT reconstructions eliminate the effect of gantry angles, and thus allow for an en face view of the glenoid, 3-D reconstructions are not always available, and cannot always be measured.^12-14 Thus, improved methodology for utilizing standard 2D scans is warranted, as the ability to correctly align the axial CT scan to the axis of the glenoid may allow for more accurate GBL measurements, which will ultimately impact surgical decision-making. Recently, Gross and colleagues¹⁵ reported the effect of sagittal rotation of the glenoid on axial measurements of anterior-posterior (AP) glenoid width and glenoid version in normal glenoids, without bone loss, and found that the mean angle of correction needed to align the sagittal plane was 20.1° ± 1.2° of rotation. To the authors’ knowledge, this same methodology has not been applied to patients with clinically meaningful anterior GBL. Given that the average glenoid width in human shoulders is 24.4 mm ± 2.9 mm,¹⁶ 1 mm of glenoid bone loss (GBL) corresponds to approximately 4% of the glenoid width, and thus even subtle differences in the interpretation of GBL may have substantial clinical implications. Therefore, the purpose of this study is to determine the effect of sagittal rotation of the glenoid on axial AP glenoid width measurements in the setting of clinically significant anterior GBL.

METHODS

This study was approved by Massachusetts General Hospital Institutional Review Board. A retrospective review of consecutive patients with a diagnosis of anterior shoulder instability between 2009 and 2013 was conducted. Inclusion criteria comprised patients with a minimum of 10% anterior GBL, an available CT scan of the affected shoulder, and no history of prior ipsilateral surgeries. Exclusion criteria comprised evidence of degenerative changes to the glenoid and/or humeral head, as well as prior ipsilateral shoulder surgery. Sixty consecutive patients were originally identified as having anterior shoulder instability, and 17 were excluded based on the inclusion/exclusion criteria, leaving 43 patients (43 shoulders) available for inclusion. Shoulder CT scans from all 43 patients were reformatted utilizing open-source DICOM software (OsiriX MD, version 2.5.1 65-bit) multi-planar reconstruction (MPR).

CT PROTOCOL

All patients underwent a standard glenohumeral CT scan using a Siemens Sensation 64 Scanner (Siemens), a 64-detector scanner. Scans were acquired with 0.6 mm of collimation, 140 kV, and 300 mA-seconds. Slice thickness was set to 2 mm. All patient information was de-identified for analysis.

The uncorrected (UNCORR) scans were defined as the default orientation on the scanner. In the UNCORR scans, the axial, coronal, and sagittal views were oriented relative to the scanner gantry table, as opposed to the anatomy of the glenoid. The corrected (CORR) CT scans were aligned in all 3 planes relative to the glenoid face, and thus the cuts were perpendicular to the long axis of the glenoid.¹⁵ This resulted in sagittal cuts perpendicular to the 12-o’clock to 6-o’clock axis in the sagittal plane (Figure 1).

Continue to: In a de-identified fashion...

IMAGE ANALYSIS AND REFORMATTING

In a de-identified fashion, all CT scans were imported and analyzed using open-source Digital Imaging and Communications in Medicine (DICOM) software (OsiriX MD, version 2.5.1 64-bit). By following a previously developed method, CT scans were reformatted using OsiriX MPR. The OsiriX software has an MPR function that allows simultaneous manipulation of 2-D CT scans in 3 orthogonal planes: axial, sagittal, and coronal. In the MPR mode, the alternation of 1 plane directly affects the orientation of the remaining 2 planes. Thus, by using an MPR, one can analyze the impact that a default CT scan performed relative to the gantry of the table, UNCORR, has on the axial images.

First, the en face view was obtained via a 2-step process: alignment of the axial plane to account for the scapular angle, followed by alignment of the coronal plane to adjust for the glenoid inclination.¹⁵ These 2 adjustments provided a true en face sagittal glenoid view. The final adjustment step was a sagittal en face rotation of the glenoid such that the superior and inferior glenoid tubercles were placed on the 12-o’clock to 6-o’clock axis (CORR scan). Previous studies have identified a central longitudinal axis that was used in this method to align the supraglenoid tubercle with the 12-o’clock to 6-o’clock axis on the glenoid face.^15,17,18 The standard error of mean was 1.21^°. This new CORR view resulted in axial cuts through the glenoid that were oriented perpendicular to the 12-o’clock to 6-o’clock axis. The UNCORR and CORR images were assessed in the axial plane at 5 standardized cuts and measured for AP glenoid width by 2 independent observers in a blinded, randomized fashion. When the measured AP width of the UNCORR scan was less than that measured on the CORR scan, the AP width of the glenoid was considered underestimated, and the degree of GBL was considered overestimated (Figure 2).

SCAPULAR ANGLE

Scapular angle measurements were performed on the axial view as the angle between a line through the long axis of the body of the scapula, and a line parallel to the CT gantry table.^15,19 Subsequently, the axial plane was aligned to the glenoid surface.

CORONAL INCLINATION

Coronal inclination measurements were performed on the sagittal view as the angle between a line tangential to the face of the glenoid and a line perpendicular to the CT gantry table. Positive values represented superior inclination, while negative values represented inferior glenoid inclination.¹⁵

SAGITTAL ROTATION

Sagittal rotation measurements were performed using the built-in angle measurement tool in OsiriX in the sagittal plane since the degree of rotation required aligning the long axis of the glenoid to the 12-o’clock to 6-o’clock axis. The amount of rotation was defined as the rotation angle.¹⁵

Continue to: Similarly, as described by Gross...

GLENOID WIDTH

Similarly, as described by Gross and colleagues,¹⁵ the sagittal en face view was divided via 5 cuts, throughout a superimposed best-fit circle that closely represents the glenoid.^9,15,20 For both the UNCORR and CORR, glenoid width (AP distance) was measured on the axial image at the widest point from AP cortex across the glenoid face.

PATIENT GROUPS

Utilizing the en face 3-D CT reconstruction view of the glenoid as the gold standard, patients were placed into 1 of 3 groups according to the degree of anterior GBL measured via the surface method.^9,20 The groups were as follows:

I. 10% to 14.9% (N = 12)

II. 15% to 19.9% (N = 16)

III. >20% (N = 15)

STATISTICAL METHODS

Paired t-tests were used to compare all measurements between CORR and UNCORR scans for each of the 5 cuts. A P-value of .05 was used as the threshold for statistical significance in 2-tailed comparisons. Mean and standard errors are presented with standard deviations throughout the study. For interobserver reliability, the measurements between the observers, the intraclass correlation coefficient was calculated. All statistics were performed with SPSS (Version 22).

RESULTS

The study cohort was comprised of 19 left shoulders (44%) and 24 right shoulders (56%), including 36 male patients (84%) and 7 female patients (16%). The average age was 27.8 years (range, 21-40 years). The variability in measured difference, with respect to AP width, was 1.05 mm. The UNCORR CT scans required a mean correction for coronal inclination of 7.0° ± 5.8° (range, -8°-6°). The UNCORR CT scans required a mean correction for scapular angle of 30.2° ± 8.0° (range, 15°-49°). The mean angle of sagittal rotation required to align the glenoid face with the 12-o’clock to 6-o’clock axis was 24.2° ± 5.1 ° (range, 13°-30°). These results are summarized in Table 1. 

For all measurements, the intraclass correlation coefficient for independent observers for all cuts within the 3 groups was r >.900 in all cases.

On an optimized CT scan, over 5 standardized cuts across a best-fit circle of the inferior glenoid, there was a statistically significant absolute mean difference of 12.6% in axial AP glenoid width (2.86 mm ± 2.00 mm, P =.016) when compared with the UNCORR scan. This corresponds to a 3% to 21% error in measurement of the AP width of the glenoid.

Continue to: For the entire cohort...

For groups I (10%-14.9% GBL) and III (>20% GBL), the UNCORR scans underestimated the axial AP width (and thus overestimated anterior GBL) in cuts 1 and 2, while in cuts 3 to 5, the axial AP width was overestimated (GBL was underestimated) (Tables 2, 3). In Group II (15%-19.9% GBL), the axial AP width was underestimated (GBL was overestimated), while in cuts 2 to 5, the axial AP width was overestimated (GBL was underestimated). Overall, AP glenoid width was consistently underestimated in cut 1, the most caudal cut, while AP glenoid width was consistently overestimated in cuts 3 to 5, the more cephalad cuts.

Abbreviations: AP, anterior-posterior; GBL, glenoid bone loss.

Abbreviations: AP, anterior-posterior; CORR, corrected; UNCORR, uncorrected.

DISCUSSION

The principle findings of this study demonstrate that UNCORR conventional 2-D CT scans inaccurately estimate glenoid width as well as inaccurately quantify the degree of anterior GBL. Underestimations of GBL may lead to insufficient treatment of clinically meaningful GBL, thereby increasing the risk of instability recurrence; whereas overestimations of GBL may lead to unnecessary treatment, subjecting patients to increased surgical morbidity. Therefore, the authors recommend correcting the orientation of the scapula in cases wherein clinical decisions are entirely based on 2-D CT, or using alternative methods for quantifying GBL, specifically in the form of 3-D reconstructions.

The use of axial imaging, with CT scans and/or magnetic resonance imaging, is growing in popularity for evaluation of both glenoid anatomy and GBL. Nevertheless, despite our improved ability to critically evaluate the glenoid using these advanced imaging modalities, the images themselves require scrutiny by clinicians to determine if the images accurately depict the true anatomy of the glenoid. As demonstrated by Gross and colleagues,¹⁵ conventional 2D CT scan protocols are not optimized to the anatomy of the glenohumeral joint, even in patients without GBL. Due to the alignment of the image relative to the plane of the scapula as opposed to the plane of the glenoid, UNCORR scans result in significantly different measurements of glenoid version (2.0° ± 0.1°) and AP glenoid width (1.2 mm  ± 0.42 mm) compared with corrected scans, requiring an average 20.1° ± 1.2° of correction to align the sagittal plane. In the present study involving the patients with GBL, we also found that conventional, UNCORR 2-D CT scan protocols inaccurately estimate glenoid width and the degree of anterior GBL. In particular, AP glenoid width was consistently underestimated in the more caudal cuts, while AP glenoid width was consistently overestimated in the more cephalad cuts. Thus, anterior GBL was overestimated (AP glenoid width was underestimated) in the more caudal cuts, whereas anterior GBL was underestimated in the more cranial cuts (AP glenoid width was overestimated). Given that approximately 1 mm of glenoid bone corresponds to approximately 4% of glenoid width,¹⁶ even subtle differences in the interpretation of GBL may lead to gross overestimation/underestimation of bone loss, with significant clinical implications.

In the anterior instability patient population, clinical decision-making is often based on the degree of GBL as determined by advanced imaging modalities. In addition to other patient-specific factors, including age, gender, activity level, type of sport, and number of prior dislocations and/or prior surgeries, the quantity of GBL will often determine which surgical procedure needs to be performed. Typically, patients with >20% to 25% anterior GBL are indicated for a glenoid reconstruction procedure, most commonly via the Latarjet procedure (coracoid transfer).^21-27 The Latarjet procedure remains an excellent technique for appropriately indicated patients, with historically good clinical outcomes and low recurrence rates. Complications associated with the Latarjet procedure, however, are not uncommon, including devastating neuropraxia of the axillary and musculocutaneous nerves, and occasionally permanent neurologic deficits.²⁸ Thus, it is critical to avoid overtreating patients with recurrent instability and GBL. As demonstrated by this study, depending on the cranial-to-caudal location on the glenoid, current 2-D CT techniques may underestimate AP glenoid width, resulting in an overestimation of GBL, potentially leading to the decision to proceed with glenoid bone reconstruction when such a procedure is not required. On the contrary, overestimation of AP glenoid width, which occurs in the more cephalad cuts of the glenoid, is perhaps more worrisome, as the resulting underestimation of GBL may lead to inadequate treatment of patients with recurrent instability. Certainly, one of the main risk factors for failed soft tissue shoulder stabilization is a failure to address GBL. If clinical decisions are made based on UNCORR 2-D CT scans, which are often inaccurate with respect to AP glenoid width by an average 2.86 mm ± 2.00 mm (equivalent to 12.6% ± 6.9% GBL) as determined in this study, patients who truly require osseous glenoid reconstructions may be indicated for only soft tissue stabilization, based on the underestimation of GBL.

Continue to: The current gold standard...

LIMITATIONS

This study has limitations, such as the relatively small sample size and the selection bias by the reviewers with potential differences in interobserver reliability. Further, minor modifications during the reformatting process may be found with each attempt to manipulate the images and may result in minor, insignificant differences in AP width measurements. Performing 1 or more additional CT scans on the same cohort of patients would have been helpful; however, due to the increased risk of radiation exposure, this was not performed. Performing CT scans on cadaveric specimens with GBL and applying the study methodology would also have been helpful to provide independent verification of our clinical findings; however, specimens were not available for this study. Another limitation of this study is that we did not compare our findings with the findings of glenoid width, and bone loss, as determined using the circle method, which is commonly utilized when 3-D reconstructions are available. In this study, the purpose was to utilize only the 2-D reformatted images, with the assumption that 3-D reconstructions are not always available, and cannot always be measured. To minimize selection bias, the investigators measured the correction effects within groups of patients with similar degrees of GBL (10%-14.9%, 15%-19.9%, and >20%). In addition, not all the selected patients showed degenerative glenoid changes or irregular glenoid shape indicating previous bone augmentation.

CONCLUSIONS

UNCORR 2D CT scans inaccurately estimate glenoid width and the degree of anterior GBL. The clinical implications of these findings are profound and suggest corrected 2D CT scans or 3D reconstruction allow measurements to be taken in the axis of the glenoid to accurately define the anatomy and quantity of anterior GBL in patients with shoulder instability.

ABSTRACT

Standard 2-dimensional (2-D) computed tomography (CT) scans of the shoulder are often aligned to the plane of the body as opposed to the plane of the scapula, which may challenge the ability to accurately measure glenoid width and glenoid bone loss (GBL). The purpose of this study is to determine the effect of sagittal rotation of the glenoid on axial anterior-posterior (AP) glenoid width measurements in the setting of anterior GBL.

Forty-three CT scans from consecutive patients with anterior GBL (minimum 10%) were reformatted utilizing open-source DICOM software (OsiriX MD). Patients were grouped according to extent of GBL: I, 10% to 14.9% (N = 12); II, 15% to 19.9% (N = 16); and III, >20% (N = 15). The uncorrected (UNCORR) and corrected (CORR) images were assessed in the axial plane at 5 standardized cuts and measured for AP glenoid width.

For groups I and III, UNCORR scans underestimated axial AP width (and thus overestimated anterior GBL) in cuts 1 and 2, while in cuts 3 to 5, the axial AP width was overestimated (GBL was underestimated). In Group II, axial AP width was underestimated (GBL was overestimated), while in cuts 2 to 5, the axial AP width was overestimated (GBL was underestimated). Overall, AP glenoid width was consistently underestimated in cut 1, the most caudal cut; while AP glenoid width was consistently overestimated in cuts 3 to 5, the more cephalad cuts.

UNCORR 2-D CT scans inaccurately estimated glenoid width and the degree of anterior GBL. This data suggests that corrected 2D CT scans or a 3-dimensional (3-D) reconstruction can help in accurately defining the anterior GBL in patients with shoulder instability.

The treatment of glenohumeral instability has substantially evolved over the past several decades. The understanding of glenoid bone loss (GBL), in particular, has advanced to such a level that we utilize the quantification of GBL for surgical decision-making. Unrecognized and/or untreated GBL is associated with recurrent instability, pain, and disability. Controversy exists, however, regarding the precise amount of anterior GBL that is significant enough to warrant surgical treatment. While historically, 25%^1,2 of anterior GBL was thought to be the critical number required to warrant osseous augmentation, studies that are more recent have highlighted the need to perform osseous glenoid reconstruction with lesser degrees of GBL, particularly in the contact athlete.^3-9 As small differences in the amount of GBL can change surgical decision-making from an all-soft tissue repair to an osseous reconstruction, it is paramount that we have accurate, valid, and reproducible methods for calculating GBL.

Continue to: Historically, plain radiographs...

Computed tomography (CT) of the shoulder has become the most commonly utilized imaging modality in the evaluation of patients with shoulder instability associated with GBL. Standard 2-dimensional (2-D) CT scans of the shoulder are often aligned to the plane of the body as opposed to the plane of the scapula/glenoid, as standard protocols often fail to account for the anterior sagittal rotation of the scapula/glenoid, similar to the disadvantage of standard radiographs. While 3-dimensional (3-D) CT reconstructions eliminate the effect of gantry angles, and thus allow for an en face view of the glenoid, 3-D reconstructions are not always available, and cannot always be measured.^12-14 Thus, improved methodology for utilizing standard 2D scans is warranted, as the ability to correctly align the axial CT scan to the axis of the glenoid may allow for more accurate GBL measurements, which will ultimately impact surgical decision-making. Recently, Gross and colleagues¹⁵ reported the effect of sagittal rotation of the glenoid on axial measurements of anterior-posterior (AP) glenoid width and glenoid version in normal glenoids, without bone loss, and found that the mean angle of correction needed to align the sagittal plane was 20.1° ± 1.2° of rotation. To the authors’ knowledge, this same methodology has not been applied to patients with clinically meaningful anterior GBL. Given that the average glenoid width in human shoulders is 24.4 mm ± 2.9 mm,¹⁶ 1 mm of glenoid bone loss (GBL) corresponds to approximately 4% of the glenoid width, and thus even subtle differences in the interpretation of GBL may have substantial clinical implications. Therefore, the purpose of this study is to determine the effect of sagittal rotation of the glenoid on axial AP glenoid width measurements in the setting of clinically significant anterior GBL.

METHODS

This study was approved by Massachusetts General Hospital Institutional Review Board. A retrospective review of consecutive patients with a diagnosis of anterior shoulder instability between 2009 and 2013 was conducted. Inclusion criteria comprised patients with a minimum of 10% anterior GBL, an available CT scan of the affected shoulder, and no history of prior ipsilateral surgeries. Exclusion criteria comprised evidence of degenerative changes to the glenoid and/or humeral head, as well as prior ipsilateral shoulder surgery. Sixty consecutive patients were originally identified as having anterior shoulder instability, and 17 were excluded based on the inclusion/exclusion criteria, leaving 43 patients (43 shoulders) available for inclusion. Shoulder CT scans from all 43 patients were reformatted utilizing open-source DICOM software (OsiriX MD, version 2.5.1 65-bit) multi-planar reconstruction (MPR).

CT PROTOCOL

All patients underwent a standard glenohumeral CT scan using a Siemens Sensation 64 Scanner (Siemens), a 64-detector scanner. Scans were acquired with 0.6 mm of collimation, 140 kV, and 300 mA-seconds. Slice thickness was set to 2 mm. All patient information was de-identified for analysis.

The uncorrected (UNCORR) scans were defined as the default orientation on the scanner. In the UNCORR scans, the axial, coronal, and sagittal views were oriented relative to the scanner gantry table, as opposed to the anatomy of the glenoid. The corrected (CORR) CT scans were aligned in all 3 planes relative to the glenoid face, and thus the cuts were perpendicular to the long axis of the glenoid.¹⁵ This resulted in sagittal cuts perpendicular to the 12-o’clock to 6-o’clock axis in the sagittal plane (Figure 1).

Continue to: In a de-identified fashion...

IMAGE ANALYSIS AND REFORMATTING

In a de-identified fashion, all CT scans were imported and analyzed using open-source Digital Imaging and Communications in Medicine (DICOM) software (OsiriX MD, version 2.5.1 64-bit). By following a previously developed method, CT scans were reformatted using OsiriX MPR. The OsiriX software has an MPR function that allows simultaneous manipulation of 2-D CT scans in 3 orthogonal planes: axial, sagittal, and coronal. In the MPR mode, the alternation of 1 plane directly affects the orientation of the remaining 2 planes. Thus, by using an MPR, one can analyze the impact that a default CT scan performed relative to the gantry of the table, UNCORR, has on the axial images.

First, the en face view was obtained via a 2-step process: alignment of the axial plane to account for the scapular angle, followed by alignment of the coronal plane to adjust for the glenoid inclination.¹⁵ These 2 adjustments provided a true en face sagittal glenoid view. The final adjustment step was a sagittal en face rotation of the glenoid such that the superior and inferior glenoid tubercles were placed on the 12-o’clock to 6-o’clock axis (CORR scan). Previous studies have identified a central longitudinal axis that was used in this method to align the supraglenoid tubercle with the 12-o’clock to 6-o’clock axis on the glenoid face.^15,17,18 The standard error of mean was 1.21^°. This new CORR view resulted in axial cuts through the glenoid that were oriented perpendicular to the 12-o’clock to 6-o’clock axis. The UNCORR and CORR images were assessed in the axial plane at 5 standardized cuts and measured for AP glenoid width by 2 independent observers in a blinded, randomized fashion. When the measured AP width of the UNCORR scan was less than that measured on the CORR scan, the AP width of the glenoid was considered underestimated, and the degree of GBL was considered overestimated (Figure 2).

SCAPULAR ANGLE

Scapular angle measurements were performed on the axial view as the angle between a line through the long axis of the body of the scapula, and a line parallel to the CT gantry table.^15,19 Subsequently, the axial plane was aligned to the glenoid surface.

CORONAL INCLINATION

Coronal inclination measurements were performed on the sagittal view as the angle between a line tangential to the face of the glenoid and a line perpendicular to the CT gantry table. Positive values represented superior inclination, while negative values represented inferior glenoid inclination.¹⁵

SAGITTAL ROTATION

Sagittal rotation measurements were performed using the built-in angle measurement tool in OsiriX in the sagittal plane since the degree of rotation required aligning the long axis of the glenoid to the 12-o’clock to 6-o’clock axis. The amount of rotation was defined as the rotation angle.¹⁵

Continue to: Similarly, as described by Gross...

GLENOID WIDTH

Similarly, as described by Gross and colleagues,¹⁵ the sagittal en face view was divided via 5 cuts, throughout a superimposed best-fit circle that closely represents the glenoid.^9,15,20 For both the UNCORR and CORR, glenoid width (AP distance) was measured on the axial image at the widest point from AP cortex across the glenoid face.

PATIENT GROUPS

Utilizing the en face 3-D CT reconstruction view of the glenoid as the gold standard, patients were placed into 1 of 3 groups according to the degree of anterior GBL measured via the surface method.^9,20 The groups were as follows:

I. 10% to 14.9% (N = 12)

II. 15% to 19.9% (N = 16)

III. >20% (N = 15)

STATISTICAL METHODS

Paired t-tests were used to compare all measurements between CORR and UNCORR scans for each of the 5 cuts. A P-value of .05 was used as the threshold for statistical significance in 2-tailed comparisons. Mean and standard errors are presented with standard deviations throughout the study. For interobserver reliability, the measurements between the observers, the intraclass correlation coefficient was calculated. All statistics were performed with SPSS (Version 22).

RESULTS

The study cohort was comprised of 19 left shoulders (44%) and 24 right shoulders (56%), including 36 male patients (84%) and 7 female patients (16%). The average age was 27.8 years (range, 21-40 years). The variability in measured difference, with respect to AP width, was 1.05 mm. The UNCORR CT scans required a mean correction for coronal inclination of 7.0° ± 5.8° (range, -8°-6°). The UNCORR CT scans required a mean correction for scapular angle of 30.2° ± 8.0° (range, 15°-49°). The mean angle of sagittal rotation required to align the glenoid face with the 12-o’clock to 6-o’clock axis was 24.2° ± 5.1 ° (range, 13°-30°). These results are summarized in Table 1. 

For all measurements, the intraclass correlation coefficient for independent observers for all cuts within the 3 groups was r >.900 in all cases.

On an optimized CT scan, over 5 standardized cuts across a best-fit circle of the inferior glenoid, there was a statistically significant absolute mean difference of 12.6% in axial AP glenoid width (2.86 mm ± 2.00 mm, P =.016) when compared with the UNCORR scan. This corresponds to a 3% to 21% error in measurement of the AP width of the glenoid.

Continue to: For the entire cohort...

For groups I (10%-14.9% GBL) and III (>20% GBL), the UNCORR scans underestimated the axial AP width (and thus overestimated anterior GBL) in cuts 1 and 2, while in cuts 3 to 5, the axial AP width was overestimated (GBL was underestimated) (Tables 2, 3). In Group II (15%-19.9% GBL), the axial AP width was underestimated (GBL was overestimated), while in cuts 2 to 5, the axial AP width was overestimated (GBL was underestimated). Overall, AP glenoid width was consistently underestimated in cut 1, the most caudal cut, while AP glenoid width was consistently overestimated in cuts 3 to 5, the more cephalad cuts.

Abbreviations: AP, anterior-posterior; GBL, glenoid bone loss.

Abbreviations: AP, anterior-posterior; CORR, corrected; UNCORR, uncorrected.

DISCUSSION

The principle findings of this study demonstrate that UNCORR conventional 2-D CT scans inaccurately estimate glenoid width as well as inaccurately quantify the degree of anterior GBL. Underestimations of GBL may lead to insufficient treatment of clinically meaningful GBL, thereby increasing the risk of instability recurrence; whereas overestimations of GBL may lead to unnecessary treatment, subjecting patients to increased surgical morbidity. Therefore, the authors recommend correcting the orientation of the scapula in cases wherein clinical decisions are entirely based on 2-D CT, or using alternative methods for quantifying GBL, specifically in the form of 3-D reconstructions.

The use of axial imaging, with CT scans and/or magnetic resonance imaging, is growing in popularity for evaluation of both glenoid anatomy and GBL. Nevertheless, despite our improved ability to critically evaluate the glenoid using these advanced imaging modalities, the images themselves require scrutiny by clinicians to determine if the images accurately depict the true anatomy of the glenoid. As demonstrated by Gross and colleagues,¹⁵ conventional 2D CT scan protocols are not optimized to the anatomy of the glenohumeral joint, even in patients without GBL. Due to the alignment of the image relative to the plane of the scapula as opposed to the plane of the glenoid, UNCORR scans result in significantly different measurements of glenoid version (2.0° ± 0.1°) and AP glenoid width (1.2 mm  ± 0.42 mm) compared with corrected scans, requiring an average 20.1° ± 1.2° of correction to align the sagittal plane. In the present study involving the patients with GBL, we also found that conventional, UNCORR 2-D CT scan protocols inaccurately estimate glenoid width and the degree of anterior GBL. In particular, AP glenoid width was consistently underestimated in the more caudal cuts, while AP glenoid width was consistently overestimated in the more cephalad cuts. Thus, anterior GBL was overestimated (AP glenoid width was underestimated) in the more caudal cuts, whereas anterior GBL was underestimated in the more cranial cuts (AP glenoid width was overestimated). Given that approximately 1 mm of glenoid bone corresponds to approximately 4% of glenoid width,¹⁶ even subtle differences in the interpretation of GBL may lead to gross overestimation/underestimation of bone loss, with significant clinical implications.

In the anterior instability patient population, clinical decision-making is often based on the degree of GBL as determined by advanced imaging modalities. In addition to other patient-specific factors, including age, gender, activity level, type of sport, and number of prior dislocations and/or prior surgeries, the quantity of GBL will often determine which surgical procedure needs to be performed. Typically, patients with >20% to 25% anterior GBL are indicated for a glenoid reconstruction procedure, most commonly via the Latarjet procedure (coracoid transfer).^21-27 The Latarjet procedure remains an excellent technique for appropriately indicated patients, with historically good clinical outcomes and low recurrence rates. Complications associated with the Latarjet procedure, however, are not uncommon, including devastating neuropraxia of the axillary and musculocutaneous nerves, and occasionally permanent neurologic deficits.²⁸ Thus, it is critical to avoid overtreating patients with recurrent instability and GBL. As demonstrated by this study, depending on the cranial-to-caudal location on the glenoid, current 2-D CT techniques may underestimate AP glenoid width, resulting in an overestimation of GBL, potentially leading to the decision to proceed with glenoid bone reconstruction when such a procedure is not required. On the contrary, overestimation of AP glenoid width, which occurs in the more cephalad cuts of the glenoid, is perhaps more worrisome, as the resulting underestimation of GBL may lead to inadequate treatment of patients with recurrent instability. Certainly, one of the main risk factors for failed soft tissue shoulder stabilization is a failure to address GBL. If clinical decisions are made based on UNCORR 2-D CT scans, which are often inaccurate with respect to AP glenoid width by an average 2.86 mm ± 2.00 mm (equivalent to 12.6% ± 6.9% GBL) as determined in this study, patients who truly require osseous glenoid reconstructions may be indicated for only soft tissue stabilization, based on the underestimation of GBL.

Continue to: The current gold standard...

LIMITATIONS

This study has limitations, such as the relatively small sample size and the selection bias by the reviewers with potential differences in interobserver reliability. Further, minor modifications during the reformatting process may be found with each attempt to manipulate the images and may result in minor, insignificant differences in AP width measurements. Performing 1 or more additional CT scans on the same cohort of patients would have been helpful; however, due to the increased risk of radiation exposure, this was not performed. Performing CT scans on cadaveric specimens with GBL and applying the study methodology would also have been helpful to provide independent verification of our clinical findings; however, specimens were not available for this study. Another limitation of this study is that we did not compare our findings with the findings of glenoid width, and bone loss, as determined using the circle method, which is commonly utilized when 3-D reconstructions are available. In this study, the purpose was to utilize only the 2-D reformatted images, with the assumption that 3-D reconstructions are not always available, and cannot always be measured. To minimize selection bias, the investigators measured the correction effects within groups of patients with similar degrees of GBL (10%-14.9%, 15%-19.9%, and >20%). In addition, not all the selected patients showed degenerative glenoid changes or irregular glenoid shape indicating previous bone augmentation.

CONCLUSIONS

UNCORR 2D CT scans inaccurately estimate glenoid width and the degree of anterior GBL. The clinical implications of these findings are profound and suggest corrected 2D CT scans or 3D reconstruction allow measurements to be taken in the axis of the glenoid to accurately define the anatomy and quantity of anterior GBL in patients with shoulder instability.

ABSTRACT

Standard 2-dimensional (2-D) computed tomography (CT) scans of the shoulder are often aligned to the plane of the body as opposed to the plane of the scapula, which may challenge the ability to accurately measure glenoid width and glenoid bone loss (GBL). The purpose of this study is to determine the effect of sagittal rotation of the glenoid on axial anterior-posterior (AP) glenoid width measurements in the setting of anterior GBL.

Forty-three CT scans from consecutive patients with anterior GBL (minimum 10%) were reformatted utilizing open-source DICOM software (OsiriX MD). Patients were grouped according to extent of GBL: I, 10% to 14.9% (N = 12); II, 15% to 19.9% (N = 16); and III, >20% (N = 15). The uncorrected (UNCORR) and corrected (CORR) images were assessed in the axial plane at 5 standardized cuts and measured for AP glenoid width.

For groups I and III, UNCORR scans underestimated axial AP width (and thus overestimated anterior GBL) in cuts 1 and 2, while in cuts 3 to 5, the axial AP width was overestimated (GBL was underestimated). In Group II, axial AP width was underestimated (GBL was overestimated), while in cuts 2 to 5, the axial AP width was overestimated (GBL was underestimated). Overall, AP glenoid width was consistently underestimated in cut 1, the most caudal cut; while AP glenoid width was consistently overestimated in cuts 3 to 5, the more cephalad cuts.

UNCORR 2-D CT scans inaccurately estimated glenoid width and the degree of anterior GBL. This data suggests that corrected 2D CT scans or a 3-dimensional (3-D) reconstruction can help in accurately defining the anterior GBL in patients with shoulder instability.

The treatment of glenohumeral instability has substantially evolved over the past several decades. The understanding of glenoid bone loss (GBL), in particular, has advanced to such a level that we utilize the quantification of GBL for surgical decision-making. Unrecognized and/or untreated GBL is associated with recurrent instability, pain, and disability. Controversy exists, however, regarding the precise amount of anterior GBL that is significant enough to warrant surgical treatment. While historically, 25%^1,2 of anterior GBL was thought to be the critical number required to warrant osseous augmentation, studies that are more recent have highlighted the need to perform osseous glenoid reconstruction with lesser degrees of GBL, particularly in the contact athlete.^3-9 As small differences in the amount of GBL can change surgical decision-making from an all-soft tissue repair to an osseous reconstruction, it is paramount that we have accurate, valid, and reproducible methods for calculating GBL.

Continue to: Historically, plain radiographs...

Computed tomography (CT) of the shoulder has become the most commonly utilized imaging modality in the evaluation of patients with shoulder instability associated with GBL. Standard 2-dimensional (2-D) CT scans of the shoulder are often aligned to the plane of the body as opposed to the plane of the scapula/glenoid, as standard protocols often fail to account for the anterior sagittal rotation of the scapula/glenoid, similar to the disadvantage of standard radiographs. While 3-dimensional (3-D) CT reconstructions eliminate the effect of gantry angles, and thus allow for an en face view of the glenoid, 3-D reconstructions are not always available, and cannot always be measured.^12-14 Thus, improved methodology for utilizing standard 2D scans is warranted, as the ability to correctly align the axial CT scan to the axis of the glenoid may allow for more accurate GBL measurements, which will ultimately impact surgical decision-making. Recently, Gross and colleagues¹⁵ reported the effect of sagittal rotation of the glenoid on axial measurements of anterior-posterior (AP) glenoid width and glenoid version in normal glenoids, without bone loss, and found that the mean angle of correction needed to align the sagittal plane was 20.1° ± 1.2° of rotation. To the authors’ knowledge, this same methodology has not been applied to patients with clinically meaningful anterior GBL. Given that the average glenoid width in human shoulders is 24.4 mm ± 2.9 mm,¹⁶ 1 mm of glenoid bone loss (GBL) corresponds to approximately 4% of the glenoid width, and thus even subtle differences in the interpretation of GBL may have substantial clinical implications. Therefore, the purpose of this study is to determine the effect of sagittal rotation of the glenoid on axial AP glenoid width measurements in the setting of clinically significant anterior GBL.

METHODS

This study was approved by Massachusetts General Hospital Institutional Review Board. A retrospective review of consecutive patients with a diagnosis of anterior shoulder instability between 2009 and 2013 was conducted. Inclusion criteria comprised patients with a minimum of 10% anterior GBL, an available CT scan of the affected shoulder, and no history of prior ipsilateral surgeries. Exclusion criteria comprised evidence of degenerative changes to the glenoid and/or humeral head, as well as prior ipsilateral shoulder surgery. Sixty consecutive patients were originally identified as having anterior shoulder instability, and 17 were excluded based on the inclusion/exclusion criteria, leaving 43 patients (43 shoulders) available for inclusion. Shoulder CT scans from all 43 patients were reformatted utilizing open-source DICOM software (OsiriX MD, version 2.5.1 65-bit) multi-planar reconstruction (MPR).

CT PROTOCOL

All patients underwent a standard glenohumeral CT scan using a Siemens Sensation 64 Scanner (Siemens), a 64-detector scanner. Scans were acquired with 0.6 mm of collimation, 140 kV, and 300 mA-seconds. Slice thickness was set to 2 mm. All patient information was de-identified for analysis.

The uncorrected (UNCORR) scans were defined as the default orientation on the scanner. In the UNCORR scans, the axial, coronal, and sagittal views were oriented relative to the scanner gantry table, as opposed to the anatomy of the glenoid. The corrected (CORR) CT scans were aligned in all 3 planes relative to the glenoid face, and thus the cuts were perpendicular to the long axis of the glenoid.¹⁵ This resulted in sagittal cuts perpendicular to the 12-o’clock to 6-o’clock axis in the sagittal plane (Figure 1).

Continue to: In a de-identified fashion...

IMAGE ANALYSIS AND REFORMATTING

In a de-identified fashion, all CT scans were imported and analyzed using open-source Digital Imaging and Communications in Medicine (DICOM) software (OsiriX MD, version 2.5.1 64-bit). By following a previously developed method, CT scans were reformatted using OsiriX MPR. The OsiriX software has an MPR function that allows simultaneous manipulation of 2-D CT scans in 3 orthogonal planes: axial, sagittal, and coronal. In the MPR mode, the alternation of 1 plane directly affects the orientation of the remaining 2 planes. Thus, by using an MPR, one can analyze the impact that a default CT scan performed relative to the gantry of the table, UNCORR, has on the axial images.

First, the en face view was obtained via a 2-step process: alignment of the axial plane to account for the scapular angle, followed by alignment of the coronal plane to adjust for the glenoid inclination.¹⁵ These 2 adjustments provided a true en face sagittal glenoid view. The final adjustment step was a sagittal en face rotation of the glenoid such that the superior and inferior glenoid tubercles were placed on the 12-o’clock to 6-o’clock axis (CORR scan). Previous studies have identified a central longitudinal axis that was used in this method to align the supraglenoid tubercle with the 12-o’clock to 6-o’clock axis on the glenoid face.^15,17,18 The standard error of mean was 1.21^°. This new CORR view resulted in axial cuts through the glenoid that were oriented perpendicular to the 12-o’clock to 6-o’clock axis. The UNCORR and CORR images were assessed in the axial plane at 5 standardized cuts and measured for AP glenoid width by 2 independent observers in a blinded, randomized fashion. When the measured AP width of the UNCORR scan was less than that measured on the CORR scan, the AP width of the glenoid was considered underestimated, and the degree of GBL was considered overestimated (Figure 2).

SCAPULAR ANGLE

Scapular angle measurements were performed on the axial view as the angle between a line through the long axis of the body of the scapula, and a line parallel to the CT gantry table.^15,19 Subsequently, the axial plane was aligned to the glenoid surface.

CORONAL INCLINATION

Coronal inclination measurements were performed on the sagittal view as the angle between a line tangential to the face of the glenoid and a line perpendicular to the CT gantry table. Positive values represented superior inclination, while negative values represented inferior glenoid inclination.¹⁵

SAGITTAL ROTATION

Sagittal rotation measurements were performed using the built-in angle measurement tool in OsiriX in the sagittal plane since the degree of rotation required aligning the long axis of the glenoid to the 12-o’clock to 6-o’clock axis. The amount of rotation was defined as the rotation angle.¹⁵

Continue to: Similarly, as described by Gross...

GLENOID WIDTH

Similarly, as described by Gross and colleagues,¹⁵ the sagittal en face view was divided via 5 cuts, throughout a superimposed best-fit circle that closely represents the glenoid.^9,15,20 For both the UNCORR and CORR, glenoid width (AP distance) was measured on the axial image at the widest point from AP cortex across the glenoid face.

PATIENT GROUPS

Utilizing the en face 3-D CT reconstruction view of the glenoid as the gold standard, patients were placed into 1 of 3 groups according to the degree of anterior GBL measured via the surface method.^9,20 The groups were as follows:

I. 10% to 14.9% (N = 12)

II. 15% to 19.9% (N = 16)

III. >20% (N = 15)

STATISTICAL METHODS

Paired t-tests were used to compare all measurements between CORR and UNCORR scans for each of the 5 cuts. A P-value of .05 was used as the threshold for statistical significance in 2-tailed comparisons. Mean and standard errors are presented with standard deviations throughout the study. For interobserver reliability, the measurements between the observers, the intraclass correlation coefficient was calculated. All statistics were performed with SPSS (Version 22).

RESULTS

The study cohort was comprised of 19 left shoulders (44%) and 24 right shoulders (56%), including 36 male patients (84%) and 7 female patients (16%). The average age was 27.8 years (range, 21-40 years). The variability in measured difference, with respect to AP width, was 1.05 mm. The UNCORR CT scans required a mean correction for coronal inclination of 7.0° ± 5.8° (range, -8°-6°). The UNCORR CT scans required a mean correction for scapular angle of 30.2° ± 8.0° (range, 15°-49°). The mean angle of sagittal rotation required to align the glenoid face with the 12-o’clock to 6-o’clock axis was 24.2° ± 5.1 ° (range, 13°-30°). These results are summarized in Table 1. 

For all measurements, the intraclass correlation coefficient for independent observers for all cuts within the 3 groups was r >.900 in all cases.

On an optimized CT scan, over 5 standardized cuts across a best-fit circle of the inferior glenoid, there was a statistically significant absolute mean difference of 12.6% in axial AP glenoid width (2.86 mm ± 2.00 mm, P =.016) when compared with the UNCORR scan. This corresponds to a 3% to 21% error in measurement of the AP width of the glenoid.

Continue to: For the entire cohort...

For groups I (10%-14.9% GBL) and III (>20% GBL), the UNCORR scans underestimated the axial AP width (and thus overestimated anterior GBL) in cuts 1 and 2, while in cuts 3 to 5, the axial AP width was overestimated (GBL was underestimated) (Tables 2, 3). In Group II (15%-19.9% GBL), the axial AP width was underestimated (GBL was overestimated), while in cuts 2 to 5, the axial AP width was overestimated (GBL was underestimated). Overall, AP glenoid width was consistently underestimated in cut 1, the most caudal cut, while AP glenoid width was consistently overestimated in cuts 3 to 5, the more cephalad cuts.

Abbreviations: AP, anterior-posterior; GBL, glenoid bone loss.

Abbreviations: AP, anterior-posterior; CORR, corrected; UNCORR, uncorrected.

DISCUSSION

The principle findings of this study demonstrate that UNCORR conventional 2-D CT scans inaccurately estimate glenoid width as well as inaccurately quantify the degree of anterior GBL. Underestimations of GBL may lead to insufficient treatment of clinically meaningful GBL, thereby increasing the risk of instability recurrence; whereas overestimations of GBL may lead to unnecessary treatment, subjecting patients to increased surgical morbidity. Therefore, the authors recommend correcting the orientation of the scapula in cases wherein clinical decisions are entirely based on 2-D CT, or using alternative methods for quantifying GBL, specifically in the form of 3-D reconstructions.

The use of axial imaging, with CT scans and/or magnetic resonance imaging, is growing in popularity for evaluation of both glenoid anatomy and GBL. Nevertheless, despite our improved ability to critically evaluate the glenoid using these advanced imaging modalities, the images themselves require scrutiny by clinicians to determine if the images accurately depict the true anatomy of the glenoid. As demonstrated by Gross and colleagues,¹⁵ conventional 2D CT scan protocols are not optimized to the anatomy of the glenohumeral joint, even in patients without GBL. Due to the alignment of the image relative to the plane of the scapula as opposed to the plane of the glenoid, UNCORR scans result in significantly different measurements of glenoid version (2.0° ± 0.1°) and AP glenoid width (1.2 mm  ± 0.42 mm) compared with corrected scans, requiring an average 20.1° ± 1.2° of correction to align the sagittal plane. In the present study involving the patients with GBL, we also found that conventional, UNCORR 2-D CT scan protocols inaccurately estimate glenoid width and the degree of anterior GBL. In particular, AP glenoid width was consistently underestimated in the more caudal cuts, while AP glenoid width was consistently overestimated in the more cephalad cuts. Thus, anterior GBL was overestimated (AP glenoid width was underestimated) in the more caudal cuts, whereas anterior GBL was underestimated in the more cranial cuts (AP glenoid width was overestimated). Given that approximately 1 mm of glenoid bone corresponds to approximately 4% of glenoid width,¹⁶ even subtle differences in the interpretation of GBL may lead to gross overestimation/underestimation of bone loss, with significant clinical implications.

In the anterior instability patient population, clinical decision-making is often based on the degree of GBL as determined by advanced imaging modalities. In addition to other patient-specific factors, including age, gender, activity level, type of sport, and number of prior dislocations and/or prior surgeries, the quantity of GBL will often determine which surgical procedure needs to be performed. Typically, patients with >20% to 25% anterior GBL are indicated for a glenoid reconstruction procedure, most commonly via the Latarjet procedure (coracoid transfer).^21-27 The Latarjet procedure remains an excellent technique for appropriately indicated patients, with historically good clinical outcomes and low recurrence rates. Complications associated with the Latarjet procedure, however, are not uncommon, including devastating neuropraxia of the axillary and musculocutaneous nerves, and occasionally permanent neurologic deficits.²⁸ Thus, it is critical to avoid overtreating patients with recurrent instability and GBL. As demonstrated by this study, depending on the cranial-to-caudal location on the glenoid, current 2-D CT techniques may underestimate AP glenoid width, resulting in an overestimation of GBL, potentially leading to the decision to proceed with glenoid bone reconstruction when such a procedure is not required. On the contrary, overestimation of AP glenoid width, which occurs in the more cephalad cuts of the glenoid, is perhaps more worrisome, as the resulting underestimation of GBL may lead to inadequate treatment of patients with recurrent instability. Certainly, one of the main risk factors for failed soft tissue shoulder stabilization is a failure to address GBL. If clinical decisions are made based on UNCORR 2-D CT scans, which are often inaccurate with respect to AP glenoid width by an average 2.86 mm ± 2.00 mm (equivalent to 12.6% ± 6.9% GBL) as determined in this study, patients who truly require osseous glenoid reconstructions may be indicated for only soft tissue stabilization, based on the underestimation of GBL.

Continue to: The current gold standard...

LIMITATIONS

This study has limitations, such as the relatively small sample size and the selection bias by the reviewers with potential differences in interobserver reliability. Further, minor modifications during the reformatting process may be found with each attempt to manipulate the images and may result in minor, insignificant differences in AP width measurements. Performing 1 or more additional CT scans on the same cohort of patients would have been helpful; however, due to the increased risk of radiation exposure, this was not performed. Performing CT scans on cadaveric specimens with GBL and applying the study methodology would also have been helpful to provide independent verification of our clinical findings; however, specimens were not available for this study. Another limitation of this study is that we did not compare our findings with the findings of glenoid width, and bone loss, as determined using the circle method, which is commonly utilized when 3-D reconstructions are available. In this study, the purpose was to utilize only the 2-D reformatted images, with the assumption that 3-D reconstructions are not always available, and cannot always be measured. To minimize selection bias, the investigators measured the correction effects within groups of patients with similar degrees of GBL (10%-14.9%, 15%-19.9%, and >20%). In addition, not all the selected patients showed degenerative glenoid changes or irregular glenoid shape indicating previous bone augmentation.

CONCLUSIONS

UNCORR 2D CT scans inaccurately estimate glenoid width and the degree of anterior GBL. The clinical implications of these findings are profound and suggest corrected 2D CT scans or 3D reconstruction allow measurements to be taken in the axis of the glenoid to accurately define the anatomy and quantity of anterior GBL in patients with shoulder instability.

ABSTRACT

The importance of cost control in total knee arthroplasty is increasing in the United States secondary to both changing economic realities of healthcare and the increasing prevalence of joint replacement.

Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. The purpose of this study is to examine the cost-effectiveness of all-polyethylene tibial (APT) components and determine what difference in revision rate would make modular metal-backed tibial (MBT) implants a more cost-effective intervention.

Markov models were constructed using variable implant failure rates and previously published probabilities. Cost data were obtained from both our institution and published United States implant list prices, and modeled with a 3.0% discount rate. The decision tree was continued over a 20-year timeframe.

Using our institutional cost data and model assumptions with a 1.0% annual failure rate for MBT components, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components. A sensitivity analysis was performed with different assumptions for MBT annual failure rates.

Given our assumptions, the APT component is cost-saving if the excess cumulative revision rate increases by <9% in 20 years compared with that of the MBT implant. Surgeons, payers, and hospitals should consider this approach when evaluating implants. Consideration should also be given to the decreased utility associated with revision surgery.

Continue to: All-polythylene tibial implants...

All-polyethylene tibial (APT) implants have been available for use in total knee arthroplasty (TKA) for decades. Except for one particular implant design, APT implants have shown equivalent functional outcome and survivorship to metal-backed tibial (MBT) components.¹ Two recent systematic reviews have demonstrated no difference in durability or functional outcome between APT and MBT components.^1,2 Despite this data, APT components continue to be used uncommonly in the United States. Improved technical ease and the theoretical advantages of modularity are likely responsible for the continued popularity of MBT implants despite the fact that APT implants cost considerably less than their MBT counterparts.

The importance of cost control in TKA is increasing secondary to changing economic realities of healthcare and increasing prevalence of joint replacement. Payers are seeking ways to ensure quality care at more affordable reimbursement rates. Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. Implants account for a substantial portion of hospital costs for knee replacement and have been suggested as an essential part of cost control.³ As such, surgeons in the United States will probably need to factor in value when selecting implants and be required to justify the additional cost of “premium” implants.

Given recent systemic reviews concluding both equivalent effectiveness and survivorship, the APT component would appear to be inherently cost-effective when compared with an MBT design. However, the degree to which this implant is cost-effective has been difficult to quantify. The purpose of this study is to take a novel approach to examine the cost-effectiveness of APT components by determining what theoretical difference in revision rate would make modular MBT implants a more cost-effective intervention using our institutional cost data.

MATERIALS AND METHODS

A Markov decision model was used to evaluate the cost-effectiveness of APT components.⁴ A Markov decision model is a mathematical framework for modeling decision making in situations where outcomes are partly random and partly under the control of a decision maker. They are powerful tools for determining the best solution from all feasible solutions to a given problem. A decision model was constructed (Figure 1) to depict patients with arthritis of the knee being treated with either APT or MBT implants in a fashion similar to previously published models.⁵ At each point of a patient’s health status in the 20 years following surgery, they are either considered well after total knee replacement, well after revision surgery, or dead. Patients transition through the decision tree and pass through different states according to the probability of each event occurring, a process that is discussed further below. A utility value, measured in quality-adjusted life years (QALYs), and a cost are assigned to every health state and both primary and revision procedures within the model. The model is designed to determine the maximum failure rate for which the APT is the more cost-effective option.

We assumed the age at the initial surgery to be 65 years. Age-specific mortality rates were taken from the 2007 United States Life Tables published by the Centers for Disease Control and Prevention.⁶ An additional probability of .007 of dying during the surgery or postoperative from the initial surgery and a probability of .011 from the revision was included.

Costs for the surgery were obtained from the University of Virginia’s billing department. We obtained the average cost for the diagnosis-related group in 2012. The cost of primary knee replacement was $17,578.06 with MBT implants. We subtracted institutional cost savings for the APT that could be achieved to obtain a cost of $16,272.10 for the APT. The cost of revision was $21,650.34 and assumed to be the same regardless of the type of initial surgery. A 3% discount rate was used.

The costs, QALYs, and probabilities were then used to compute cost-effectiveness ratios, or the cost per additional QALY, of the 2 options. Unlike previous models published in the orthopedic literature, we assumed a constant probability of revision for the MBT. We initially assumed a 1.0% probability of failure per year for the MBT implant. We then determined what revision rate for the APT would be necessary to be cost equivalent with the MBT. A sensitivity analysis was performed to examine the impact of varying assumptions regarding the rate of revision.

Continue to: Results...

RESULTS

Under our institutional cost data and model assumptions with a 1% annual failure rate for MBT implants, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components.

A two-way sensitivity analysis for probabilities of failure was performed to compare revision probabilities of the APT with those of MBT components. The preferred strategy graph is included in Figure 2. This graph shows how varying annual revision rates for both the APT and MBT would impact which option would be preferable. For example, on the graph, an annual failure rate of 1.6% for APT implants would be cost equivalent to a 0.1% annual failure rate for MBT implants at 20 years. A 2.0% annual failure rate for the APT would be equivalent to a 1.4% annual failure rate for the MBT, and a 2.5% failure rate for the APT would be equivalent to a 1.8% MBT failure rate. Holding the APT failure rate constant at 2.5%, any MBT failure rate <1.8% would make the MBT the more cost-effective option, whereas a failure rate >1.8% would make the MBT less cost-effective than the APT. For probability combinations that fall in the lower right area of Figure 2, the APT is preferable, and for probability combinations that fall in the upper left area, the MBT is preferable. The line separating the 2 areas is where 1 would be indifferent, such that the cost per additional QALY is the same for both procedures.

DISCUSSION

In light of the current economic climate and push for cost savings in the United States healthcare system, orthopedic surgeons must increasingly understand the realities of cost and the role it plays in the assessment of new technology. This concept is especially true of TKA as it becomes an increasingly common operative intervention. Utilizing cost savings techniques while ensuring quality outcomes is something that needs to be championed by healthcare providers.

Ideally, the introduction of a new medical technology that is more expensive than preexisting technology should lead to improved outcomes. Multiple randomized radiostereometric and clinical outcome studies looking at failure rates of APT compared with MBT have consistently suggested equivalence or superiority of the APT design when modern round-on-round implant designs are utilized.^7-17 Two recent systematic reviews demonstrated that APT components were equivalent to MBT components regarding both revision rates and clinical scores.^1,18 Given these results, it seems that the increased use of the APT design could save the healthcare system substantial amounts of money without compromising outcomes. For example, in 2006 Muller and colleagues^19. proposed a possible cost savings of approximately 39 million dollars per year across England and Wales, if just 50% of the 70,000 TKAs performed annually used APTs. Our study, which helps quantify the potential cost-effectiveness of the APT design in terms of revision rates, should help further support this debate and provide a framework for the evaluation of new technology.

It should be noted that the results of this current study are based on both assumptions and generalizations. Institutional cost data is known to vary widely among institutions and our conclusions regarding comparable revision rates would change with different cost inputs. We are also unable to take into account individual patients, surgeons, or specific implant factors. It is very difficult to place a price on quality-adjusted life years and negative repercussions with revision surgery. Furthermore, speaking specifically about surgical technique, each surgeon has his/her own preference when performing TKA. There is a lack of intraoperative flexibility when using monoblock tibial components that many surgeons may find undesirable. A surgeon is unable to adjust the thickness of the polyethylene insert after cementation of metal implants. Finally, we are aware that cost-effectiveness analyses cannot take the place of rational clinical decision making when evaluating an individual patient for TKA. Patient age, body mass index, and deformity are all factors that may dictate the use of MBTs in an attempt to improve outcomes.

The results of this analysis help quantify the cost-effectiveness of the APT. Given the additional cost, the MBT design would have to lower revision rates substantially when compared with the APT design to be considered cost-effective. Multiple clinical studies have not shown this to be the case. Further studies are required to help guide clinical decision making and define the role of APT components in TKA.

ABSTRACT

The importance of cost control in total knee arthroplasty is increasing in the United States secondary to both changing economic realities of healthcare and the increasing prevalence of joint replacement.

Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. The purpose of this study is to examine the cost-effectiveness of all-polyethylene tibial (APT) components and determine what difference in revision rate would make modular metal-backed tibial (MBT) implants a more cost-effective intervention.

Markov models were constructed using variable implant failure rates and previously published probabilities. Cost data were obtained from both our institution and published United States implant list prices, and modeled with a 3.0% discount rate. The decision tree was continued over a 20-year timeframe.

Using our institutional cost data and model assumptions with a 1.0% annual failure rate for MBT components, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components. A sensitivity analysis was performed with different assumptions for MBT annual failure rates.

Given our assumptions, the APT component is cost-saving if the excess cumulative revision rate increases by <9% in 20 years compared with that of the MBT implant. Surgeons, payers, and hospitals should consider this approach when evaluating implants. Consideration should also be given to the decreased utility associated with revision surgery.

Continue to: All-polythylene tibial implants...

All-polyethylene tibial (APT) implants have been available for use in total knee arthroplasty (TKA) for decades. Except for one particular implant design, APT implants have shown equivalent functional outcome and survivorship to metal-backed tibial (MBT) components.¹ Two recent systematic reviews have demonstrated no difference in durability or functional outcome between APT and MBT components.^1,2 Despite this data, APT components continue to be used uncommonly in the United States. Improved technical ease and the theoretical advantages of modularity are likely responsible for the continued popularity of MBT implants despite the fact that APT implants cost considerably less than their MBT counterparts.

The importance of cost control in TKA is increasing secondary to changing economic realities of healthcare and increasing prevalence of joint replacement. Payers are seeking ways to ensure quality care at more affordable reimbursement rates. Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. Implants account for a substantial portion of hospital costs for knee replacement and have been suggested as an essential part of cost control.³ As such, surgeons in the United States will probably need to factor in value when selecting implants and be required to justify the additional cost of “premium” implants.

Given recent systemic reviews concluding both equivalent effectiveness and survivorship, the APT component would appear to be inherently cost-effective when compared with an MBT design. However, the degree to which this implant is cost-effective has been difficult to quantify. The purpose of this study is to take a novel approach to examine the cost-effectiveness of APT components by determining what theoretical difference in revision rate would make modular MBT implants a more cost-effective intervention using our institutional cost data.

MATERIALS AND METHODS

A Markov decision model was used to evaluate the cost-effectiveness of APT components.⁴ A Markov decision model is a mathematical framework for modeling decision making in situations where outcomes are partly random and partly under the control of a decision maker. They are powerful tools for determining the best solution from all feasible solutions to a given problem. A decision model was constructed (Figure 1) to depict patients with arthritis of the knee being treated with either APT or MBT implants in a fashion similar to previously published models.⁵ At each point of a patient’s health status in the 20 years following surgery, they are either considered well after total knee replacement, well after revision surgery, or dead. Patients transition through the decision tree and pass through different states according to the probability of each event occurring, a process that is discussed further below. A utility value, measured in quality-adjusted life years (QALYs), and a cost are assigned to every health state and both primary and revision procedures within the model. The model is designed to determine the maximum failure rate for which the APT is the more cost-effective option.

We assumed the age at the initial surgery to be 65 years. Age-specific mortality rates were taken from the 2007 United States Life Tables published by the Centers for Disease Control and Prevention.⁶ An additional probability of .007 of dying during the surgery or postoperative from the initial surgery and a probability of .011 from the revision was included.

Costs for the surgery were obtained from the University of Virginia’s billing department. We obtained the average cost for the diagnosis-related group in 2012. The cost of primary knee replacement was $17,578.06 with MBT implants. We subtracted institutional cost savings for the APT that could be achieved to obtain a cost of $16,272.10 for the APT. The cost of revision was $21,650.34 and assumed to be the same regardless of the type of initial surgery. A 3% discount rate was used.

The costs, QALYs, and probabilities were then used to compute cost-effectiveness ratios, or the cost per additional QALY, of the 2 options. Unlike previous models published in the orthopedic literature, we assumed a constant probability of revision for the MBT. We initially assumed a 1.0% probability of failure per year for the MBT implant. We then determined what revision rate for the APT would be necessary to be cost equivalent with the MBT. A sensitivity analysis was performed to examine the impact of varying assumptions regarding the rate of revision.

Continue to: Results...

RESULTS

Under our institutional cost data and model assumptions with a 1% annual failure rate for MBT implants, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components.

A two-way sensitivity analysis for probabilities of failure was performed to compare revision probabilities of the APT with those of MBT components. The preferred strategy graph is included in Figure 2. This graph shows how varying annual revision rates for both the APT and MBT would impact which option would be preferable. For example, on the graph, an annual failure rate of 1.6% for APT implants would be cost equivalent to a 0.1% annual failure rate for MBT implants at 20 years. A 2.0% annual failure rate for the APT would be equivalent to a 1.4% annual failure rate for the MBT, and a 2.5% failure rate for the APT would be equivalent to a 1.8% MBT failure rate. Holding the APT failure rate constant at 2.5%, any MBT failure rate <1.8% would make the MBT the more cost-effective option, whereas a failure rate >1.8% would make the MBT less cost-effective than the APT. For probability combinations that fall in the lower right area of Figure 2, the APT is preferable, and for probability combinations that fall in the upper left area, the MBT is preferable. The line separating the 2 areas is where 1 would be indifferent, such that the cost per additional QALY is the same for both procedures.

DISCUSSION

In light of the current economic climate and push for cost savings in the United States healthcare system, orthopedic surgeons must increasingly understand the realities of cost and the role it plays in the assessment of new technology. This concept is especially true of TKA as it becomes an increasingly common operative intervention. Utilizing cost savings techniques while ensuring quality outcomes is something that needs to be championed by healthcare providers.

Ideally, the introduction of a new medical technology that is more expensive than preexisting technology should lead to improved outcomes. Multiple randomized radiostereometric and clinical outcome studies looking at failure rates of APT compared with MBT have consistently suggested equivalence or superiority of the APT design when modern round-on-round implant designs are utilized.^7-17 Two recent systematic reviews demonstrated that APT components were equivalent to MBT components regarding both revision rates and clinical scores.^1,18 Given these results, it seems that the increased use of the APT design could save the healthcare system substantial amounts of money without compromising outcomes. For example, in 2006 Muller and colleagues^19. proposed a possible cost savings of approximately 39 million dollars per year across England and Wales, if just 50% of the 70,000 TKAs performed annually used APTs. Our study, which helps quantify the potential cost-effectiveness of the APT design in terms of revision rates, should help further support this debate and provide a framework for the evaluation of new technology.

It should be noted that the results of this current study are based on both assumptions and generalizations. Institutional cost data is known to vary widely among institutions and our conclusions regarding comparable revision rates would change with different cost inputs. We are also unable to take into account individual patients, surgeons, or specific implant factors. It is very difficult to place a price on quality-adjusted life years and negative repercussions with revision surgery. Furthermore, speaking specifically about surgical technique, each surgeon has his/her own preference when performing TKA. There is a lack of intraoperative flexibility when using monoblock tibial components that many surgeons may find undesirable. A surgeon is unable to adjust the thickness of the polyethylene insert after cementation of metal implants. Finally, we are aware that cost-effectiveness analyses cannot take the place of rational clinical decision making when evaluating an individual patient for TKA. Patient age, body mass index, and deformity are all factors that may dictate the use of MBTs in an attempt to improve outcomes.

The results of this analysis help quantify the cost-effectiveness of the APT. Given the additional cost, the MBT design would have to lower revision rates substantially when compared with the APT design to be considered cost-effective. Multiple clinical studies have not shown this to be the case. Further studies are required to help guide clinical decision making and define the role of APT components in TKA.

ABSTRACT

The importance of cost control in total knee arthroplasty is increasing in the United States secondary to both changing economic realities of healthcare and the increasing prevalence of joint replacement.

Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. The purpose of this study is to examine the cost-effectiveness of all-polyethylene tibial (APT) components and determine what difference in revision rate would make modular metal-backed tibial (MBT) implants a more cost-effective intervention.

Markov models were constructed using variable implant failure rates and previously published probabilities. Cost data were obtained from both our institution and published United States implant list prices, and modeled with a 3.0% discount rate. The decision tree was continued over a 20-year timeframe.

Using our institutional cost data and model assumptions with a 1.0% annual failure rate for MBT components, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components. A sensitivity analysis was performed with different assumptions for MBT annual failure rates.

Given our assumptions, the APT component is cost-saving if the excess cumulative revision rate increases by <9% in 20 years compared with that of the MBT implant. Surgeons, payers, and hospitals should consider this approach when evaluating implants. Consideration should also be given to the decreased utility associated with revision surgery.

Continue to: All-polythylene tibial implants...

All-polyethylene tibial (APT) implants have been available for use in total knee arthroplasty (TKA) for decades. Except for one particular implant design, APT implants have shown equivalent functional outcome and survivorship to metal-backed tibial (MBT) components.¹ Two recent systematic reviews have demonstrated no difference in durability or functional outcome between APT and MBT components.^1,2 Despite this data, APT components continue to be used uncommonly in the United States. Improved technical ease and the theoretical advantages of modularity are likely responsible for the continued popularity of MBT implants despite the fact that APT implants cost considerably less than their MBT counterparts.

The importance of cost control in TKA is increasing secondary to changing economic realities of healthcare and increasing prevalence of joint replacement. Payers are seeking ways to ensure quality care at more affordable reimbursement rates. Surgeons play a critical role in cost containment and may soon be incentivized to make cost-effective decisions under proposed gainsharing programs. Implants account for a substantial portion of hospital costs for knee replacement and have been suggested as an essential part of cost control.³ As such, surgeons in the United States will probably need to factor in value when selecting implants and be required to justify the additional cost of “premium” implants.

Given recent systemic reviews concluding both equivalent effectiveness and survivorship, the APT component would appear to be inherently cost-effective when compared with an MBT design. However, the degree to which this implant is cost-effective has been difficult to quantify. The purpose of this study is to take a novel approach to examine the cost-effectiveness of APT components by determining what theoretical difference in revision rate would make modular MBT implants a more cost-effective intervention using our institutional cost data.

MATERIALS AND METHODS

A Markov decision model was used to evaluate the cost-effectiveness of APT components.⁴ A Markov decision model is a mathematical framework for modeling decision making in situations where outcomes are partly random and partly under the control of a decision maker. They are powerful tools for determining the best solution from all feasible solutions to a given problem. A decision model was constructed (Figure 1) to depict patients with arthritis of the knee being treated with either APT or MBT implants in a fashion similar to previously published models.⁵ At each point of a patient’s health status in the 20 years following surgery, they are either considered well after total knee replacement, well after revision surgery, or dead. Patients transition through the decision tree and pass through different states according to the probability of each event occurring, a process that is discussed further below. A utility value, measured in quality-adjusted life years (QALYs), and a cost are assigned to every health state and both primary and revision procedures within the model. The model is designed to determine the maximum failure rate for which the APT is the more cost-effective option.

We assumed the age at the initial surgery to be 65 years. Age-specific mortality rates were taken from the 2007 United States Life Tables published by the Centers for Disease Control and Prevention.⁶ An additional probability of .007 of dying during the surgery or postoperative from the initial surgery and a probability of .011 from the revision was included.

Costs for the surgery were obtained from the University of Virginia’s billing department. We obtained the average cost for the diagnosis-related group in 2012. The cost of primary knee replacement was $17,578.06 with MBT implants. We subtracted institutional cost savings for the APT that could be achieved to obtain a cost of $16,272.10 for the APT. The cost of revision was $21,650.34 and assumed to be the same regardless of the type of initial surgery. A 3% discount rate was used.

The costs, QALYs, and probabilities were then used to compute cost-effectiveness ratios, or the cost per additional QALY, of the 2 options. Unlike previous models published in the orthopedic literature, we assumed a constant probability of revision for the MBT. We initially assumed a 1.0% probability of failure per year for the MBT implant. We then determined what revision rate for the APT would be necessary to be cost equivalent with the MBT. A sensitivity analysis was performed to examine the impact of varying assumptions regarding the rate of revision.

Continue to: Results...

RESULTS

Under our institutional cost data and model assumptions with a 1% annual failure rate for MBT implants, an annual failure rate of 1.6% for APT components would be required to achieve equivalency in cost. Over a 20-year period, a failure rate of >27% for the APT component would be necessary to achieve equivalent cost compared with the proposed failure rate of 18% with MBT components.

A two-way sensitivity analysis for probabilities of failure was performed to compare revision probabilities of the APT with those of MBT components. The preferred strategy graph is included in Figure 2. This graph shows how varying annual revision rates for both the APT and MBT would impact which option would be preferable. For example, on the graph, an annual failure rate of 1.6% for APT implants would be cost equivalent to a 0.1% annual failure rate for MBT implants at 20 years. A 2.0% annual failure rate for the APT would be equivalent to a 1.4% annual failure rate for the MBT, and a 2.5% failure rate for the APT would be equivalent to a 1.8% MBT failure rate. Holding the APT failure rate constant at 2.5%, any MBT failure rate <1.8% would make the MBT the more cost-effective option, whereas a failure rate >1.8% would make the MBT less cost-effective than the APT. For probability combinations that fall in the lower right area of Figure 2, the APT is preferable, and for probability combinations that fall in the upper left area, the MBT is preferable. The line separating the 2 areas is where 1 would be indifferent, such that the cost per additional QALY is the same for both procedures.

DISCUSSION

In light of the current economic climate and push for cost savings in the United States healthcare system, orthopedic surgeons must increasingly understand the realities of cost and the role it plays in the assessment of new technology. This concept is especially true of TKA as it becomes an increasingly common operative intervention. Utilizing cost savings techniques while ensuring quality outcomes is something that needs to be championed by healthcare providers.

Ideally, the introduction of a new medical technology that is more expensive than preexisting technology should lead to improved outcomes. Multiple randomized radiostereometric and clinical outcome studies looking at failure rates of APT compared with MBT have consistently suggested equivalence or superiority of the APT design when modern round-on-round implant designs are utilized.^7-17 Two recent systematic reviews demonstrated that APT components were equivalent to MBT components regarding both revision rates and clinical scores.^1,18 Given these results, it seems that the increased use of the APT design could save the healthcare system substantial amounts of money without compromising outcomes. For example, in 2006 Muller and colleagues^19. proposed a possible cost savings of approximately 39 million dollars per year across England and Wales, if just 50% of the 70,000 TKAs performed annually used APTs. Our study, which helps quantify the potential cost-effectiveness of the APT design in terms of revision rates, should help further support this debate and provide a framework for the evaluation of new technology.

It should be noted that the results of this current study are based on both assumptions and generalizations. Institutional cost data is known to vary widely among institutions and our conclusions regarding comparable revision rates would change with different cost inputs. We are also unable to take into account individual patients, surgeons, or specific implant factors. It is very difficult to place a price on quality-adjusted life years and negative repercussions with revision surgery. Furthermore, speaking specifically about surgical technique, each surgeon has his/her own preference when performing TKA. There is a lack of intraoperative flexibility when using monoblock tibial components that many surgeons may find undesirable. A surgeon is unable to adjust the thickness of the polyethylene insert after cementation of metal implants. Finally, we are aware that cost-effectiveness analyses cannot take the place of rational clinical decision making when evaluating an individual patient for TKA. Patient age, body mass index, and deformity are all factors that may dictate the use of MBTs in an attempt to improve outcomes.

The results of this analysis help quantify the cost-effectiveness of the APT. Given the additional cost, the MBT design would have to lower revision rates substantially when compared with the APT design to be considered cost-effective. Multiple clinical studies have not shown this to be the case. Further studies are required to help guide clinical decision making and define the role of APT components in TKA.

ABSTRACT

The purpose of this study is to describe the rate of return to the operating room (OR) following microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral autograft transplantation (OATS), and osteochondral allograft (OCA) procedures at 90 days, 1 year, and 2 years. Current Procedural Terminology codes for all patients undergoing MFX, ACI, OATS, and OCA were used to search a prospectively collected, commercially available private payer insurance company database from 2007 to 2011. Within 90 days, 1 year, and 2 years after surgery, the database was searched for the occurrence of these same patients undergoing knee diagnostic arthroscopy with biopsy, lysis of adhesions, synovectomy, arthroscopy for infection or lavage, arthroscopy for removal of loose bodies, chondroplasty, MFX, ACI, OATS, OCA, and/or knee arthroplasty. Descriptive statistical analysis and contingency table analysis were performed. A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX, 640 ACI, 386 open OATS, 997 arthroscopic OATS, 714 open OCA, and 894 arthroscopic OCA procedures. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. At 2 years, patients who underwent MFX, ACI, OATS, OCA had reoperation rates of 14.65%, 29.69%, 8.82%, and 12.22%, respectively. There was a statistically significantly increased risk for ACI return to OR within all intervals (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty. There was no difference in failure/revision rates between the restorative treatment options. With a large US commercial insurance database from 2007 to 2011, reparative procedures were favored for chondral injuries, but yielded an increased risk for conversion to arthroplasty. There was no difference in failure/revision rates between the restorative approaches, yet cell-based approaches yielded a significantly increased risk for a return to the OR.

Continue to: Symptomatic, full-thickness articular cartilage

Symptomatic, full-thickness articular cartilage defects in the knee are difficult to manage, particularly in the young, athletic patient population. Fortunately, a variety of cartilage repair (direct repair of the cartilage or those procedures which attempt to generate fibrocartilage) and restoration (those aimed at restoring hyaline cartilage) procedures are available, with encouraging short- and long-term clinical outcomes. After failure of nonoperative management, several surgical options are available for treating symptomatic focal chondral defects, including microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral autograft transplantation (OATS), and open and arthroscopic osteochondral allograft (OCA) transplantation procedures.^1,2 When appropriately indicated, each of these techniques has demonstrated good to excellent clinical outcomes with respect to reducing pain and improving function.^3-5

While major complications following cartilage surgery are uncommon, the need for reoperation following an index articular cartilage operation is poorly understood. Recently, McCormick and colleagues6 found that reoperation within the first 2 years following meniscus allograft transplantation (MAT) is associated with an increased likelihood of revision MAT or future arthroplasty. Given the association between early reoperation following meniscus restoration surgery and subsequent failure, an improved understanding of the epidemiology and implications of reoperations following cartilage restoration surgery is warranted. Further, in deciding which treatment option is best suited to a particular patient, the rate of return to the operating room (OR) should be taken into consideration, as this could potentially influence surgical decision-making as to which procedure to perform, especially in value-based care decision-making environments.

The purpose of this study is to describe the rate of return to the OR for knee procedures following cartilage restoration at intervals of 90 days, 1 year, and 2 years across a large-scale US patient database. The authors hypothesize that the rate of return to the OR following knee cartilage repair or restoration procedures will be under 20% during the first post-operative year, with increasing reoperation rates over time. A secondary hypothesis is that there will be no difference in reoperation rates according to sex, but that younger patients (those younger than 40 years) will have higher reoperation rates than older patients.

METHODS

We performed a retrospective analysis of a prospectively collected, large-scale, and commercially available private payer insurance company database (PearlDiver) from 2007 to 2011. The PearlDiver database is a Health Insurance Portability and Accountability Act (HIPAA) compliant, publicly available national database consisting of a collection of private payer records, with United Health Group representing the contributing health plan. The database has more than 30 million patient records and contains Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth Revision (ICD-9) codes related to orthopedic procedures. From 2007 to 2011, the private payer database captured between 5.9 million and 6.2 million patients per year.

Our search was based on the CPT codes for MFX (29879), ACI (27412), OATS (29866, 29867), and OCA (27415, 27416). Return to the OR for revision surgery for the above-mentioned procedures was classified as patients with a diagnosis of diagnostic arthroscopy with biopsy (CPT 29870), lysis of adhesions (CPT 29884), synovectomy (29875, 29876), arthroscopy for infection or lavage (CPT 29871), arthroscopy for removal of loose bodies (29874), chondroplasty (29877), unicompartmental knee arthroplasty (27446), total knee arthroplasty (27447), and/or patellar arthroplasty (27438). Patient records were followed for reoperations occurring within 90 days, 1 year, and 2 years after the index cartilage procedure. All data were compared based on patient age and sex.

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analysis of this study was primarily descriptive to demonstrate the incidence for each code at each time interval. One-way analysis of variance, Chi-square analysis, and contingency tables were used to compare the incidence of each type of procedure throughout the various time intervals. A P-value of < 0.05 was considered statistically significant. Statistical analysis was performed using SPSS v.20 (International Business Machines).

RESULTS

A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX (92.3%) 640 ACI (1.4%), 386 open OATS (0.82%), 997 arthroscopic OATS (2.11%), 714 open OCA (1.51%), and 894 arthroscopic OCA (1.89%) procedures. A summary of the procedures performed, broken down by age and sex, is provided in Tables 1 and 2. A total of 25,149 male patients (53.3%) underwent surgical procedures compared to 22,058 female patients (46.7%). For each category of procedure (MFX, ACI, OATS, OCA), there was a significantly higher proportion of males than females undergoing surgery (P < .0001 for all). Surgical treatment with MFX was consistently the most frequently performed surgery across all age groups (92.31%), while cell-based therapy with ACI was the least frequently performed procedure across all age ranges (1.36%). Restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not utilized in patients over 64 years of age (Table 2).

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.

A summary of all reoperation data is provided in Tables 3 to 7 and Figures 1 and 2. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. Patients who underwent MFX had reoperation rates of 6.05% at 90 days, 11.80% at 1 year, and 14.65% at 2 years. Patients who underwent ACI had reoperation rates of 4.53% at 90 days, 23.28% at 1 year, and 29.69% at 2 years. Patients who had open and arthroscopic OATS had reoperation rates of 3.122% and 5.12% at 90 days, 6.74% and 8.53% at 1 year, and 7.51% and 10.13% at 2 years, respectively. Patients who underwent open and arthroscopic OCA had reoperation rates of 2.52% and 3.91% at 90 days, 7.14% and 6.60% at 1 year, and 13.59% and 10.85% at 2 years (Table 3). There was a statistically significantly increased risk for reoperation following ACI within all intervals compared to all other surgical techniques (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty at 6.70%. There was no significant difference between failure rates (revision OATS/OCA or conversion to arthroplasty) between the restorative treatment options, with 14 failures for OATS (9.52% of reoperations at 2 years) compared to 22 failures for OCA (12.7% of reoperations at 2 years, P = .358). Among the entire cohort of cartilage surgery patients, arthroscopic chondroplasty was the most frequent procedure performed at the time of reoperation at all time points assessed, notably accounting for 33.08% of reoperations 2 years following microfracture, 51.58% of reoperations at 2 years following ACI, 53.06% of reoperations at 2 years following OATS, and 54.07% of reoperations at 2 years following OCA (Figure 3, Tables 4–7).

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; MFX, microfracture; OR, operating room.

^aA -1 denotes No. <11 within the PearlDiver database, and exact numbers are not reported due to patient privacy considerations.

Abbreviations: ACI, autologous chondrocyte implantation; CPT, Current Procedural Terminology; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; OATS, osteochondral autograft transplantation; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; OCA, osteochondral allograft; OR, operating room.

Continue to: Discussion...

DISCUSSION

The principle findings of this study demonstrate that there is an overall reoperation rate of 14.90% at 2 years following cartilage repair/restoration surgery, with the highest reoperation rates following MFX at 90 days, and ACI at both 1 year and 2 years following the index procedure. Also, patients undergoing index MFX as the index procedure have the highest risk for conversion to arthroplasty, reoperation rates for all cartilage surgeries increase over time, and arthroscopic chondroplasty is the most frequent procedure performed at the time of reoperation.

The management of symptomatic articular cartilage knee pathology is extremely challenging. With improvements in surgical technique, instrumentation, and clinical decision-making, indications are constantly evolving. Techniques that may work for “small” defects, though there is some debate as to what constitutes a “small” defect, are not necessarily going to be successful for larger defects, and this certainly varies depending on where the defect is located within the knee joint (distal femur vs patella vs trochlea, etc.). Recently, in a 2015 analysis of 3 level I or II studies, Miller and colleagues⁷ demonstrated both MFX and OATS to be viable, cost-effective, first-line treatment options for articular cartilage injuries, with similar clinical outcomes at 8.7 years. The authors noted cumulative reoperation rates of 29% among patients undergoing MFX compared to 13% among patients undergoing OATS. While ACI and OCA procedures were not included in their study, the reported reoperation rates of 29% following MFX and 13% following OATS at nearly 10 years suggest a possible increased need for reoperation following MFX over time (approximately 15% at 2 years in our study) and a stable rate of reoperation following OATS (approximately 11% at 2 years in our study). This finding is significant, as one of the goals with these procedures is to deliver effective, long-lasting pain relief and restoration of function. Interestingly, in this study, restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not performed in patients older than 64 years. This may be explained by the higher prevalence of acute traumatic injuries and osteochondritis dissecans diagnoses in younger patients compared with older patients, as these diagnoses are more often indicated to undergo restorative procedures as opposed to marrow stimulation.

In a 2016 systematic review of 20 studies incorporating 1117 patients, Campbell and colleagues⁸ assessed return-to-play rates following MFX, ACI, OATS, and OCA. The authors noted that return to sport (RTS) rates were greatest following OATS (89%), followed by OCA (88%), ACI (84%), and MFX (75%). Positive prognostic factors for RTS included younger age, shorter duration of preoperative symptoms, no history of prior ipsilateral knee surgery, and smaller chondral defects. Reoperation rates between the 4 techniques were not statistically compared in their study. Interestingly, in 2013, Chalmers and colleagues⁹ conducted a separate systematic review of 20 studies comprising 1375 patients undergoing MFX, ACI, or OATS. In their study, the authors found significant advantages following ACI and OATS compared to MFX with respect to patient-reported outcome scores but noted significantly faster RTS rates with MFX. Reoperation rates were noted to be similar between the 3 procedures (25% for ACI, 21% for MFX, and 28% for OATS) at an average 3.7 years following the index procedure. When considering these 2 systematic reviews together, despite a faster RTS rate following MFX, a greater proportion of patients seem to be able to RTS over time following other procedures such as OATS, OCA, and ACI. Unfortunately, these reviews do not provide insight as to the role, if any, of reoperation on return to play rates nor on overall clinical outcome scores on patients undergoing articular cartilage surgery. However, this information is valuable when counseling athletes who are in season and would like to RTS as soon as possible as opposed to those who do not have tight time constraints for when they need to RTS.

Regardless of the cartilage technique chosen, the goals of surgery remain similar—to reduce pain and improve function. For athletes, the ultimate goal is to return to the same level of play that the athlete was able to achieve prior to injury. Certainly, the need for reoperation following a cartilage surgery has implications on pain, function, and ability to RTS. Our review of nearly 50,000 cartilage surgeries demonstrates that reoperations following cartilage repair surgery are not uncommon, with a rate of 14.90% at 2 years, and that while reoperation rates are the highest following ACI, the rate of conversion to knee arthroplasty is highest following MFX. Due to the limitations of the PearlDiver database, it is not possible to determine the clinical outcomes of patients undergoing reoperation following cartilage surgery, but certainly, given these data, reoperation is clearly not necessarily indicative of clinical failure. This is highlighted by the fact that the most common procedure performed at the time of reoperation is arthroscopic chondroplasty, which, despite being an additional surgical procedure, may be acceptable for patients who wish to RTS, particularly in the setting of an index ACI in which there may be graft hypertrophy. Ideally, additional studies incorporating a cost-effectiveness analysis of each of the procedures, incorporating reoperation rates as well as patient-reported clinical outcomes, would be helpful to truly determine the patient and societal implications of reoperation following cartilage repair/restoration.

Many of the advantages and disadvantages of the described cartilage repair/restoration procedures have been well described.^10-17 Microfracture is the most commonly utilized first-line repair/restoration option for small articular cartilage lesions, mainly due to its low cost, low morbidity, and relatively low level of difficulty.18 Despite these advantages, MFX is not without limitations, and the need for revision cartilage restoration and/or conversion to arthroplasty is concerning. In 2013, Salzmann and colleagues19 evaluated a cohort of 454 patients undergoing MFX for a symptomatic knee defect and noted a reoperation rate of 26.9% (n = 123) within 2 years of the index surgery, with risk factors for reoperation noted to include an increased number of pre-MFX ipsilateral knee surgeries, patellofemoral lesions, smoking, and lower preoperative numeric analog scale scores. The definition of reoperation in their study is unfortunately not described, and thus the extent of reoperation (arthroscopy to arthroplasty) is unclear. In a 2009 systematic review of 3122 patients (28 studies) undergoing MFX conducted by Mithoefer and colleagues,²⁰ revision rates were noted to range from 2% to 31% depending on the study analyzed, with increasing revision rates after 2 years. Unfortunately, the heterogeneity of the included studies makes it difficult to determine which patients tend to fail over time.

Continue to: OATS...

OATS is a promising cartilage restoration technique indicated for treatment of patients with large, uncontained chondral lesions, and/or lesions with both bone and cartilage loss.¹ OCA is similar to OATS but uses allograft tissue instead of autograft tissue and is typically considered a viable treatment option in larger lesions (>2 cm²).²¹ Cell-based ACI therapy has evolved substantially over the past decade and is now available as a third-generation model utilizing biodegradable 3-dimensional scaffolds seeded with chondrocytes. Reoperation rates following ACI can often be higher than those following other cartilage treatments, particularly given the known complication of graft hypertrophy and/or delamination. Harris and colleagues²² conducted a systematic review of 5276 subjects undergoing ACI (all generations), noting an overall reoperation rate of 33%, but a failure rate of 5.8% at an average of 22 months following ACI. Risk factors for reoperation included periosteal-based ACI as well as open (vs arthroscopic) ACI. In this study, we found a modestly lower return to OR rate of 29.69% at 2 years.

When the outcomes of patients undergoing OATS or OCA are compared to those of patients undergoing MFX or ACI, it can be difficult to interpret the results, as the indications for performing these procedures tend to be very different. Further, the reasons for reoperation, as well as the procedures performed at the time of reoperation, are often poorly described, making it difficult to truly quantify the risk of reoperation and the implications of reoperation for patients undergoing any of these index cartilage procedures.

Overall, in this database, the return to the OR rate approaches 15% at 2 years following cartilage surgery, with cell-based therapy demonstrating higher reoperation rates at 2 years, without the risk of conversion to arthroplasty. Reoperation rates appear to stabilize at 1 year following surgery and consist mostly of minor arthroscopic procedures. These findings can help surgeons counsel patients as to the rate and type of reoperations that can be expected following cartilage surgery. Additional research incorporating patient-reported outcomes and patient-specific risk factors are needed to complement these data as to the impact of reoperations on overall clinical outcomes. Further, studies incorporating 90-day, 1-year, and 2-year costs associated with cartilage surgery will help to determine which index procedure is the most cost effective over the short- and long-term.

LIMITATIONS

This study is not without limitations. The PearlDiver database is reliant upon accurate CPT and ICD-9 coding, which creates a potential for a reporting bias. The overall reliability of the analyses is dependent on the quality of the available data, which, as noted in previous PearlDiver studies,^18,23-28 may include inaccurate billing codes, miscoding, and/or non-coding by physicians as potential sources of error. At the time of this study, the PearlDiver database did not provide consistent data points on laterality, and thus it is possible that the reported rates of reoperation overestimate the true reoperation rate following a given procedure. Fortunately, the reoperation rates for each procedure analyzed in this database study are consistent with those previously presented in the literature. In addition, it is not uncommon for patients receiving one of these procedures to have previously been treated with one of the others. Due to the inherent limitations of the PearlDiver database, this study did not investigate concomitant procedures performed along with the index procedure, nor did it investigate confounding factors such as comorbidities. The PearlDiver database does not provide data on defect size, location within the knee, concomitant pathologies (eg, meniscus tear), prior surgeries, or patient comorbidities, and while important, these factors cannot be accounted for in our analysis. The inability to account for these important factors, particularly concomitant diagnoses, procedures, and lesion size/location, represents an important limitation of this study, as this is a source of selection bias and may influence the need for reoperation in a given patient. Despite these limitations, the results of this study are supported by previous and current literature. In addition, the PearlDiver database, as a HIPAA-compliant database, does not report exact numbers when the value of the outcome of interest is between 0 and 10, which prohibits analysis of any cartilage procedure performed in a cohort of patients greater than 1 and less than 11. Finally, while not necessarily a limitation, it should be noted that CPT 29879 is not specific for microfracture, as the code also includes abrasion arthroplasty and drilling. Due to the limitations of the methodology of searching the database for this code, it is unclear as to how many patients underwent actual microfracture vs abrasion arthroplasty.

CONCLUSION

Within a large US commercial insurance database from 2007 to 2011, reparative procedures were favored for chondral injuries, but yielded an increased risk for conversion to arthroplasty. There was no difference between failure/revision rates among the restorative approaches, yet cell-based approaches yielded a significantly increased risk for a return to the OR.

ABSTRACT

The purpose of this study is to describe the rate of return to the operating room (OR) following microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral autograft transplantation (OATS), and osteochondral allograft (OCA) procedures at 90 days, 1 year, and 2 years. Current Procedural Terminology codes for all patients undergoing MFX, ACI, OATS, and OCA were used to search a prospectively collected, commercially available private payer insurance company database from 2007 to 2011. Within 90 days, 1 year, and 2 years after surgery, the database was searched for the occurrence of these same patients undergoing knee diagnostic arthroscopy with biopsy, lysis of adhesions, synovectomy, arthroscopy for infection or lavage, arthroscopy for removal of loose bodies, chondroplasty, MFX, ACI, OATS, OCA, and/or knee arthroplasty. Descriptive statistical analysis and contingency table analysis were performed. A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX, 640 ACI, 386 open OATS, 997 arthroscopic OATS, 714 open OCA, and 894 arthroscopic OCA procedures. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. At 2 years, patients who underwent MFX, ACI, OATS, OCA had reoperation rates of 14.65%, 29.69%, 8.82%, and 12.22%, respectively. There was a statistically significantly increased risk for ACI return to OR within all intervals (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty. There was no difference in failure/revision rates between the restorative treatment options. With a large US commercial insurance database from 2007 to 2011, reparative procedures were favored for chondral injuries, but yielded an increased risk for conversion to arthroplasty. There was no difference in failure/revision rates between the restorative approaches, yet cell-based approaches yielded a significantly increased risk for a return to the OR.

Continue to: Symptomatic, full-thickness articular cartilage

Symptomatic, full-thickness articular cartilage defects in the knee are difficult to manage, particularly in the young, athletic patient population. Fortunately, a variety of cartilage repair (direct repair of the cartilage or those procedures which attempt to generate fibrocartilage) and restoration (those aimed at restoring hyaline cartilage) procedures are available, with encouraging short- and long-term clinical outcomes. After failure of nonoperative management, several surgical options are available for treating symptomatic focal chondral defects, including microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral autograft transplantation (OATS), and open and arthroscopic osteochondral allograft (OCA) transplantation procedures.^1,2 When appropriately indicated, each of these techniques has demonstrated good to excellent clinical outcomes with respect to reducing pain and improving function.^3-5

While major complications following cartilage surgery are uncommon, the need for reoperation following an index articular cartilage operation is poorly understood. Recently, McCormick and colleagues6 found that reoperation within the first 2 years following meniscus allograft transplantation (MAT) is associated with an increased likelihood of revision MAT or future arthroplasty. Given the association between early reoperation following meniscus restoration surgery and subsequent failure, an improved understanding of the epidemiology and implications of reoperations following cartilage restoration surgery is warranted. Further, in deciding which treatment option is best suited to a particular patient, the rate of return to the operating room (OR) should be taken into consideration, as this could potentially influence surgical decision-making as to which procedure to perform, especially in value-based care decision-making environments.

The purpose of this study is to describe the rate of return to the OR for knee procedures following cartilage restoration at intervals of 90 days, 1 year, and 2 years across a large-scale US patient database. The authors hypothesize that the rate of return to the OR following knee cartilage repair or restoration procedures will be under 20% during the first post-operative year, with increasing reoperation rates over time. A secondary hypothesis is that there will be no difference in reoperation rates according to sex, but that younger patients (those younger than 40 years) will have higher reoperation rates than older patients.

METHODS

We performed a retrospective analysis of a prospectively collected, large-scale, and commercially available private payer insurance company database (PearlDiver) from 2007 to 2011. The PearlDiver database is a Health Insurance Portability and Accountability Act (HIPAA) compliant, publicly available national database consisting of a collection of private payer records, with United Health Group representing the contributing health plan. The database has more than 30 million patient records and contains Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth Revision (ICD-9) codes related to orthopedic procedures. From 2007 to 2011, the private payer database captured between 5.9 million and 6.2 million patients per year.

Our search was based on the CPT codes for MFX (29879), ACI (27412), OATS (29866, 29867), and OCA (27415, 27416). Return to the OR for revision surgery for the above-mentioned procedures was classified as patients with a diagnosis of diagnostic arthroscopy with biopsy (CPT 29870), lysis of adhesions (CPT 29884), synovectomy (29875, 29876), arthroscopy for infection or lavage (CPT 29871), arthroscopy for removal of loose bodies (29874), chondroplasty (29877), unicompartmental knee arthroplasty (27446), total knee arthroplasty (27447), and/or patellar arthroplasty (27438). Patient records were followed for reoperations occurring within 90 days, 1 year, and 2 years after the index cartilage procedure. All data were compared based on patient age and sex.

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analysis of this study was primarily descriptive to demonstrate the incidence for each code at each time interval. One-way analysis of variance, Chi-square analysis, and contingency tables were used to compare the incidence of each type of procedure throughout the various time intervals. A P-value of < 0.05 was considered statistically significant. Statistical analysis was performed using SPSS v.20 (International Business Machines).

RESULTS

A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX (92.3%) 640 ACI (1.4%), 386 open OATS (0.82%), 997 arthroscopic OATS (2.11%), 714 open OCA (1.51%), and 894 arthroscopic OCA (1.89%) procedures. A summary of the procedures performed, broken down by age and sex, is provided in Tables 1 and 2. A total of 25,149 male patients (53.3%) underwent surgical procedures compared to 22,058 female patients (46.7%). For each category of procedure (MFX, ACI, OATS, OCA), there was a significantly higher proportion of males than females undergoing surgery (P < .0001 for all). Surgical treatment with MFX was consistently the most frequently performed surgery across all age groups (92.31%), while cell-based therapy with ACI was the least frequently performed procedure across all age ranges (1.36%). Restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not utilized in patients over 64 years of age (Table 2).

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.

A summary of all reoperation data is provided in Tables 3 to 7 and Figures 1 and 2. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. Patients who underwent MFX had reoperation rates of 6.05% at 90 days, 11.80% at 1 year, and 14.65% at 2 years. Patients who underwent ACI had reoperation rates of 4.53% at 90 days, 23.28% at 1 year, and 29.69% at 2 years. Patients who had open and arthroscopic OATS had reoperation rates of 3.122% and 5.12% at 90 days, 6.74% and 8.53% at 1 year, and 7.51% and 10.13% at 2 years, respectively. Patients who underwent open and arthroscopic OCA had reoperation rates of 2.52% and 3.91% at 90 days, 7.14% and 6.60% at 1 year, and 13.59% and 10.85% at 2 years (Table 3). There was a statistically significantly increased risk for reoperation following ACI within all intervals compared to all other surgical techniques (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty at 6.70%. There was no significant difference between failure rates (revision OATS/OCA or conversion to arthroplasty) between the restorative treatment options, with 14 failures for OATS (9.52% of reoperations at 2 years) compared to 22 failures for OCA (12.7% of reoperations at 2 years, P = .358). Among the entire cohort of cartilage surgery patients, arthroscopic chondroplasty was the most frequent procedure performed at the time of reoperation at all time points assessed, notably accounting for 33.08% of reoperations 2 years following microfracture, 51.58% of reoperations at 2 years following ACI, 53.06% of reoperations at 2 years following OATS, and 54.07% of reoperations at 2 years following OCA (Figure 3, Tables 4–7).

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; MFX, microfracture; OR, operating room.

^aA -1 denotes No. <11 within the PearlDiver database, and exact numbers are not reported due to patient privacy considerations.

Abbreviations: ACI, autologous chondrocyte implantation; CPT, Current Procedural Terminology; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; OATS, osteochondral autograft transplantation; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; OCA, osteochondral allograft; OR, operating room.

Continue to: Discussion...

DISCUSSION

The principle findings of this study demonstrate that there is an overall reoperation rate of 14.90% at 2 years following cartilage repair/restoration surgery, with the highest reoperation rates following MFX at 90 days, and ACI at both 1 year and 2 years following the index procedure. Also, patients undergoing index MFX as the index procedure have the highest risk for conversion to arthroplasty, reoperation rates for all cartilage surgeries increase over time, and arthroscopic chondroplasty is the most frequent procedure performed at the time of reoperation.

The management of symptomatic articular cartilage knee pathology is extremely challenging. With improvements in surgical technique, instrumentation, and clinical decision-making, indications are constantly evolving. Techniques that may work for “small” defects, though there is some debate as to what constitutes a “small” defect, are not necessarily going to be successful for larger defects, and this certainly varies depending on where the defect is located within the knee joint (distal femur vs patella vs trochlea, etc.). Recently, in a 2015 analysis of 3 level I or II studies, Miller and colleagues⁷ demonstrated both MFX and OATS to be viable, cost-effective, first-line treatment options for articular cartilage injuries, with similar clinical outcomes at 8.7 years. The authors noted cumulative reoperation rates of 29% among patients undergoing MFX compared to 13% among patients undergoing OATS. While ACI and OCA procedures were not included in their study, the reported reoperation rates of 29% following MFX and 13% following OATS at nearly 10 years suggest a possible increased need for reoperation following MFX over time (approximately 15% at 2 years in our study) and a stable rate of reoperation following OATS (approximately 11% at 2 years in our study). This finding is significant, as one of the goals with these procedures is to deliver effective, long-lasting pain relief and restoration of function. Interestingly, in this study, restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not performed in patients older than 64 years. This may be explained by the higher prevalence of acute traumatic injuries and osteochondritis dissecans diagnoses in younger patients compared with older patients, as these diagnoses are more often indicated to undergo restorative procedures as opposed to marrow stimulation.

In a 2016 systematic review of 20 studies incorporating 1117 patients, Campbell and colleagues⁸ assessed return-to-play rates following MFX, ACI, OATS, and OCA. The authors noted that return to sport (RTS) rates were greatest following OATS (89%), followed by OCA (88%), ACI (84%), and MFX (75%). Positive prognostic factors for RTS included younger age, shorter duration of preoperative symptoms, no history of prior ipsilateral knee surgery, and smaller chondral defects. Reoperation rates between the 4 techniques were not statistically compared in their study. Interestingly, in 2013, Chalmers and colleagues⁹ conducted a separate systematic review of 20 studies comprising 1375 patients undergoing MFX, ACI, or OATS. In their study, the authors found significant advantages following ACI and OATS compared to MFX with respect to patient-reported outcome scores but noted significantly faster RTS rates with MFX. Reoperation rates were noted to be similar between the 3 procedures (25% for ACI, 21% for MFX, and 28% for OATS) at an average 3.7 years following the index procedure. When considering these 2 systematic reviews together, despite a faster RTS rate following MFX, a greater proportion of patients seem to be able to RTS over time following other procedures such as OATS, OCA, and ACI. Unfortunately, these reviews do not provide insight as to the role, if any, of reoperation on return to play rates nor on overall clinical outcome scores on patients undergoing articular cartilage surgery. However, this information is valuable when counseling athletes who are in season and would like to RTS as soon as possible as opposed to those who do not have tight time constraints for when they need to RTS.

Regardless of the cartilage technique chosen, the goals of surgery remain similar—to reduce pain and improve function. For athletes, the ultimate goal is to return to the same level of play that the athlete was able to achieve prior to injury. Certainly, the need for reoperation following a cartilage surgery has implications on pain, function, and ability to RTS. Our review of nearly 50,000 cartilage surgeries demonstrates that reoperations following cartilage repair surgery are not uncommon, with a rate of 14.90% at 2 years, and that while reoperation rates are the highest following ACI, the rate of conversion to knee arthroplasty is highest following MFX. Due to the limitations of the PearlDiver database, it is not possible to determine the clinical outcomes of patients undergoing reoperation following cartilage surgery, but certainly, given these data, reoperation is clearly not necessarily indicative of clinical failure. This is highlighted by the fact that the most common procedure performed at the time of reoperation is arthroscopic chondroplasty, which, despite being an additional surgical procedure, may be acceptable for patients who wish to RTS, particularly in the setting of an index ACI in which there may be graft hypertrophy. Ideally, additional studies incorporating a cost-effectiveness analysis of each of the procedures, incorporating reoperation rates as well as patient-reported clinical outcomes, would be helpful to truly determine the patient and societal implications of reoperation following cartilage repair/restoration.

Many of the advantages and disadvantages of the described cartilage repair/restoration procedures have been well described.^10-17 Microfracture is the most commonly utilized first-line repair/restoration option for small articular cartilage lesions, mainly due to its low cost, low morbidity, and relatively low level of difficulty.18 Despite these advantages, MFX is not without limitations, and the need for revision cartilage restoration and/or conversion to arthroplasty is concerning. In 2013, Salzmann and colleagues19 evaluated a cohort of 454 patients undergoing MFX for a symptomatic knee defect and noted a reoperation rate of 26.9% (n = 123) within 2 years of the index surgery, with risk factors for reoperation noted to include an increased number of pre-MFX ipsilateral knee surgeries, patellofemoral lesions, smoking, and lower preoperative numeric analog scale scores. The definition of reoperation in their study is unfortunately not described, and thus the extent of reoperation (arthroscopy to arthroplasty) is unclear. In a 2009 systematic review of 3122 patients (28 studies) undergoing MFX conducted by Mithoefer and colleagues,²⁰ revision rates were noted to range from 2% to 31% depending on the study analyzed, with increasing revision rates after 2 years. Unfortunately, the heterogeneity of the included studies makes it difficult to determine which patients tend to fail over time.

Continue to: OATS...

OATS is a promising cartilage restoration technique indicated for treatment of patients with large, uncontained chondral lesions, and/or lesions with both bone and cartilage loss.¹ OCA is similar to OATS but uses allograft tissue instead of autograft tissue and is typically considered a viable treatment option in larger lesions (>2 cm²).²¹ Cell-based ACI therapy has evolved substantially over the past decade and is now available as a third-generation model utilizing biodegradable 3-dimensional scaffolds seeded with chondrocytes. Reoperation rates following ACI can often be higher than those following other cartilage treatments, particularly given the known complication of graft hypertrophy and/or delamination. Harris and colleagues²² conducted a systematic review of 5276 subjects undergoing ACI (all generations), noting an overall reoperation rate of 33%, but a failure rate of 5.8% at an average of 22 months following ACI. Risk factors for reoperation included periosteal-based ACI as well as open (vs arthroscopic) ACI. In this study, we found a modestly lower return to OR rate of 29.69% at 2 years.

When the outcomes of patients undergoing OATS or OCA are compared to those of patients undergoing MFX or ACI, it can be difficult to interpret the results, as the indications for performing these procedures tend to be very different. Further, the reasons for reoperation, as well as the procedures performed at the time of reoperation, are often poorly described, making it difficult to truly quantify the risk of reoperation and the implications of reoperation for patients undergoing any of these index cartilage procedures.

Overall, in this database, the return to the OR rate approaches 15% at 2 years following cartilage surgery, with cell-based therapy demonstrating higher reoperation rates at 2 years, without the risk of conversion to arthroplasty. Reoperation rates appear to stabilize at 1 year following surgery and consist mostly of minor arthroscopic procedures. These findings can help surgeons counsel patients as to the rate and type of reoperations that can be expected following cartilage surgery. Additional research incorporating patient-reported outcomes and patient-specific risk factors are needed to complement these data as to the impact of reoperations on overall clinical outcomes. Further, studies incorporating 90-day, 1-year, and 2-year costs associated with cartilage surgery will help to determine which index procedure is the most cost effective over the short- and long-term.

LIMITATIONS

This study is not without limitations. The PearlDiver database is reliant upon accurate CPT and ICD-9 coding, which creates a potential for a reporting bias. The overall reliability of the analyses is dependent on the quality of the available data, which, as noted in previous PearlDiver studies,^18,23-28 may include inaccurate billing codes, miscoding, and/or non-coding by physicians as potential sources of error. At the time of this study, the PearlDiver database did not provide consistent data points on laterality, and thus it is possible that the reported rates of reoperation overestimate the true reoperation rate following a given procedure. Fortunately, the reoperation rates for each procedure analyzed in this database study are consistent with those previously presented in the literature. In addition, it is not uncommon for patients receiving one of these procedures to have previously been treated with one of the others. Due to the inherent limitations of the PearlDiver database, this study did not investigate concomitant procedures performed along with the index procedure, nor did it investigate confounding factors such as comorbidities. The PearlDiver database does not provide data on defect size, location within the knee, concomitant pathologies (eg, meniscus tear), prior surgeries, or patient comorbidities, and while important, these factors cannot be accounted for in our analysis. The inability to account for these important factors, particularly concomitant diagnoses, procedures, and lesion size/location, represents an important limitation of this study, as this is a source of selection bias and may influence the need for reoperation in a given patient. Despite these limitations, the results of this study are supported by previous and current literature. In addition, the PearlDiver database, as a HIPAA-compliant database, does not report exact numbers when the value of the outcome of interest is between 0 and 10, which prohibits analysis of any cartilage procedure performed in a cohort of patients greater than 1 and less than 11. Finally, while not necessarily a limitation, it should be noted that CPT 29879 is not specific for microfracture, as the code also includes abrasion arthroplasty and drilling. Due to the limitations of the methodology of searching the database for this code, it is unclear as to how many patients underwent actual microfracture vs abrasion arthroplasty.

CONCLUSION

Within a large US commercial insurance database from 2007 to 2011, reparative procedures were favored for chondral injuries, but yielded an increased risk for conversion to arthroplasty. There was no difference between failure/revision rates among the restorative approaches, yet cell-based approaches yielded a significantly increased risk for a return to the OR.

ABSTRACT

The purpose of this study is to describe the rate of return to the operating room (OR) following microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral autograft transplantation (OATS), and osteochondral allograft (OCA) procedures at 90 days, 1 year, and 2 years. Current Procedural Terminology codes for all patients undergoing MFX, ACI, OATS, and OCA were used to search a prospectively collected, commercially available private payer insurance company database from 2007 to 2011. Within 90 days, 1 year, and 2 years after surgery, the database was searched for the occurrence of these same patients undergoing knee diagnostic arthroscopy with biopsy, lysis of adhesions, synovectomy, arthroscopy for infection or lavage, arthroscopy for removal of loose bodies, chondroplasty, MFX, ACI, OATS, OCA, and/or knee arthroplasty. Descriptive statistical analysis and contingency table analysis were performed. A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX, 640 ACI, 386 open OATS, 997 arthroscopic OATS, 714 open OCA, and 894 arthroscopic OCA procedures. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. At 2 years, patients who underwent MFX, ACI, OATS, OCA had reoperation rates of 14.65%, 29.69%, 8.82%, and 12.22%, respectively. There was a statistically significantly increased risk for ACI return to OR within all intervals (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty. There was no difference in failure/revision rates between the restorative treatment options. With a large US commercial insurance database from 2007 to 2011, reparative procedures were favored for chondral injuries, but yielded an increased risk for conversion to arthroplasty. There was no difference in failure/revision rates between the restorative approaches, yet cell-based approaches yielded a significantly increased risk for a return to the OR.

Continue to: Symptomatic, full-thickness articular cartilage

Symptomatic, full-thickness articular cartilage defects in the knee are difficult to manage, particularly in the young, athletic patient population. Fortunately, a variety of cartilage repair (direct repair of the cartilage or those procedures which attempt to generate fibrocartilage) and restoration (those aimed at restoring hyaline cartilage) procedures are available, with encouraging short- and long-term clinical outcomes. After failure of nonoperative management, several surgical options are available for treating symptomatic focal chondral defects, including microfracture (MFX), autologous chondrocyte implantation (ACI), osteochondral autograft transplantation (OATS), and open and arthroscopic osteochondral allograft (OCA) transplantation procedures.^1,2 When appropriately indicated, each of these techniques has demonstrated good to excellent clinical outcomes with respect to reducing pain and improving function.^3-5

While major complications following cartilage surgery are uncommon, the need for reoperation following an index articular cartilage operation is poorly understood. Recently, McCormick and colleagues6 found that reoperation within the first 2 years following meniscus allograft transplantation (MAT) is associated with an increased likelihood of revision MAT or future arthroplasty. Given the association between early reoperation following meniscus restoration surgery and subsequent failure, an improved understanding of the epidemiology and implications of reoperations following cartilage restoration surgery is warranted. Further, in deciding which treatment option is best suited to a particular patient, the rate of return to the operating room (OR) should be taken into consideration, as this could potentially influence surgical decision-making as to which procedure to perform, especially in value-based care decision-making environments.

The purpose of this study is to describe the rate of return to the OR for knee procedures following cartilage restoration at intervals of 90 days, 1 year, and 2 years across a large-scale US patient database. The authors hypothesize that the rate of return to the OR following knee cartilage repair or restoration procedures will be under 20% during the first post-operative year, with increasing reoperation rates over time. A secondary hypothesis is that there will be no difference in reoperation rates according to sex, but that younger patients (those younger than 40 years) will have higher reoperation rates than older patients.

METHODS

We performed a retrospective analysis of a prospectively collected, large-scale, and commercially available private payer insurance company database (PearlDiver) from 2007 to 2011. The PearlDiver database is a Health Insurance Portability and Accountability Act (HIPAA) compliant, publicly available national database consisting of a collection of private payer records, with United Health Group representing the contributing health plan. The database has more than 30 million patient records and contains Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth Revision (ICD-9) codes related to orthopedic procedures. From 2007 to 2011, the private payer database captured between 5.9 million and 6.2 million patients per year.

Our search was based on the CPT codes for MFX (29879), ACI (27412), OATS (29866, 29867), and OCA (27415, 27416). Return to the OR for revision surgery for the above-mentioned procedures was classified as patients with a diagnosis of diagnostic arthroscopy with biopsy (CPT 29870), lysis of adhesions (CPT 29884), synovectomy (29875, 29876), arthroscopy for infection or lavage (CPT 29871), arthroscopy for removal of loose bodies (29874), chondroplasty (29877), unicompartmental knee arthroplasty (27446), total knee arthroplasty (27447), and/or patellar arthroplasty (27438). Patient records were followed for reoperations occurring within 90 days, 1 year, and 2 years after the index cartilage procedure. All data were compared based on patient age and sex.

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analysis of this study was primarily descriptive to demonstrate the incidence for each code at each time interval. One-way analysis of variance, Chi-square analysis, and contingency tables were used to compare the incidence of each type of procedure throughout the various time intervals. A P-value of < 0.05 was considered statistically significant. Statistical analysis was performed using SPSS v.20 (International Business Machines).

RESULTS

A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX (92.3%) 640 ACI (1.4%), 386 open OATS (0.82%), 997 arthroscopic OATS (2.11%), 714 open OCA (1.51%), and 894 arthroscopic OCA (1.89%) procedures. A summary of the procedures performed, broken down by age and sex, is provided in Tables 1 and 2. A total of 25,149 male patients (53.3%) underwent surgical procedures compared to 22,058 female patients (46.7%). For each category of procedure (MFX, ACI, OATS, OCA), there was a significantly higher proportion of males than females undergoing surgery (P < .0001 for all). Surgical treatment with MFX was consistently the most frequently performed surgery across all age groups (92.31%), while cell-based therapy with ACI was the least frequently performed procedure across all age ranges (1.36%). Restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not utilized in patients over 64 years of age (Table 2).

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.

A summary of all reoperation data is provided in Tables 3 to 7 and Figures 1 and 2. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. Patients who underwent MFX had reoperation rates of 6.05% at 90 days, 11.80% at 1 year, and 14.65% at 2 years. Patients who underwent ACI had reoperation rates of 4.53% at 90 days, 23.28% at 1 year, and 29.69% at 2 years. Patients who had open and arthroscopic OATS had reoperation rates of 3.122% and 5.12% at 90 days, 6.74% and 8.53% at 1 year, and 7.51% and 10.13% at 2 years, respectively. Patients who underwent open and arthroscopic OCA had reoperation rates of 2.52% and 3.91% at 90 days, 7.14% and 6.60% at 1 year, and 13.59% and 10.85% at 2 years (Table 3). There was a statistically significantly increased risk for reoperation following ACI within all intervals compared to all other surgical techniques (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty at 6.70%. There was no significant difference between failure rates (revision OATS/OCA or conversion to arthroplasty) between the restorative treatment options, with 14 failures for OATS (9.52% of reoperations at 2 years) compared to 22 failures for OCA (12.7% of reoperations at 2 years, P = .358). Among the entire cohort of cartilage surgery patients, arthroscopic chondroplasty was the most frequent procedure performed at the time of reoperation at all time points assessed, notably accounting for 33.08% of reoperations 2 years following microfracture, 51.58% of reoperations at 2 years following ACI, 53.06% of reoperations at 2 years following OATS, and 54.07% of reoperations at 2 years following OCA (Figure 3, Tables 4–7).

Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; MFX, microfracture; OR, operating room.

^aA -1 denotes No. <11 within the PearlDiver database, and exact numbers are not reported due to patient privacy considerations.

Abbreviations: ACI, autologous chondrocyte implantation; CPT, Current Procedural Terminology; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; OATS, osteochondral autograft transplantation; OR, operating room.

Abbreviations: CPT, Current Procedural Terminology; OCA, osteochondral allograft; OR, operating room.

Continue to: Discussion...

DISCUSSION

The principle findings of this study demonstrate that there is an overall reoperation rate of 14.90% at 2 years following cartilage repair/restoration surgery, with the highest reoperation rates following MFX at 90 days, and ACI at both 1 year and 2 years following the index procedure. Also, patients undergoing index MFX as the index procedure have the highest risk for conversion to arthroplasty, reoperation rates for all cartilage surgeries increase over time, and arthroscopic chondroplasty is the most frequent procedure performed at the time of reoperation.

The management of symptomatic articular cartilage knee pathology is extremely challenging. With improvements in surgical technique, instrumentation, and clinical decision-making, indications are constantly evolving. Techniques that may work for “small” defects, though there is some debate as to what constitutes a “small” defect, are not necessarily going to be successful for larger defects, and this certainly varies depending on where the defect is located within the knee joint (distal femur vs patella vs trochlea, etc.). Recently, in a 2015 analysis of 3 level I or II studies, Miller and colleagues⁷ demonstrated both MFX and OATS to be viable, cost-effective, first-line treatment options for articular cartilage injuries, with similar clinical outcomes at 8.7 years. The authors noted cumulative reoperation rates of 29% among patients undergoing MFX compared to 13% among patients undergoing OATS. While ACI and OCA procedures were not included in their study, the reported reoperation rates of 29% following MFX and 13% following OATS at nearly 10 years suggest a possible increased need for reoperation following MFX over time (approximately 15% at 2 years in our study) and a stable rate of reoperation following OATS (approximately 11% at 2 years in our study). This finding is significant, as one of the goals with these procedures is to deliver effective, long-lasting pain relief and restoration of function. Interestingly, in this study, restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not performed in patients older than 64 years. This may be explained by the higher prevalence of acute traumatic injuries and osteochondritis dissecans diagnoses in younger patients compared with older patients, as these diagnoses are more often indicated to undergo restorative procedures as opposed to marrow stimulation.

In a 2016 systematic review of 20 studies incorporating 1117 patients, Campbell and colleagues⁸ assessed return-to-play rates following MFX, ACI, OATS, and OCA. The authors noted that return to sport (RTS) rates were greatest following OATS (89%), followed by OCA (88%), ACI (84%), and MFX (75%). Positive prognostic factors for RTS included younger age, shorter duration of preoperative symptoms, no history of prior ipsilateral knee surgery, and smaller chondral defects. Reoperation rates between the 4 techniques were not statistically compared in their study. Interestingly, in 2013, Chalmers and colleagues⁹ conducted a separate systematic review of 20 studies comprising 1375 patients undergoing MFX, ACI, or OATS. In their study, the authors found significant advantages following ACI and OATS compared to MFX with respect to patient-reported outcome scores but noted significantly faster RTS rates with MFX. Reoperation rates were noted to be similar between the 3 procedures (25% for ACI, 21% for MFX, and 28% for OATS) at an average 3.7 years following the index procedure. When considering these 2 systematic reviews together, despite a faster RTS rate following MFX, a greater proportion of patients seem to be able to RTS over time following other procedures such as OATS, OCA, and ACI. Unfortunately, these reviews do not provide insight as to the role, if any, of reoperation on return to play rates nor on overall clinical outcome scores on patients undergoing articular cartilage surgery. However, this information is valuable when counseling athletes who are in season and would like to RTS as soon as possible as opposed to those who do not have tight time constraints for when they need to RTS.

Regardless of the cartilage technique chosen, the goals of surgery remain similar—to reduce pain and improve function. For athletes, the ultimate goal is to return to the same level of play that the athlete was able to achieve prior to injury. Certainly, the need for reoperation following a cartilage surgery has implications on pain, function, and ability to RTS. Our review of nearly 50,000 cartilage surgeries demonstrates that reoperations following cartilage repair surgery are not uncommon, with a rate of 14.90% at 2 years, and that while reoperation rates are the highest following ACI, the rate of conversion to knee arthroplasty is highest following MFX. Due to the limitations of the PearlDiver database, it is not possible to determine the clinical outcomes of patients undergoing reoperation following cartilage surgery, but certainly, given these data, reoperation is clearly not necessarily indicative of clinical failure. This is highlighted by the fact that the most common procedure performed at the time of reoperation is arthroscopic chondroplasty, which, despite being an additional surgical procedure, may be acceptable for patients who wish to RTS, particularly in the setting of an index ACI in which there may be graft hypertrophy. Ideally, additional studies incorporating a cost-effectiveness analysis of each of the procedures, incorporating reoperation rates as well as patient-reported clinical outcomes, would be helpful to truly determine the patient and societal implications of reoperation following cartilage repair/restoration.

Many of the advantages and disadvantages of the described cartilage repair/restoration procedures have been well described.^10-17 Microfracture is the most commonly utilized first-line repair/restoration option for small articular cartilage lesions, mainly due to its low cost, low morbidity, and relatively low level of difficulty.18 Despite these advantages, MFX is not without limitations, and the need for revision cartilage restoration and/or conversion to arthroplasty is concerning. In 2013, Salzmann and colleagues19 evaluated a cohort of 454 patients undergoing MFX for a symptomatic knee defect and noted a reoperation rate of 26.9% (n = 123) within 2 years of the index surgery, with risk factors for reoperation noted to include an increased number of pre-MFX ipsilateral knee surgeries, patellofemoral lesions, smoking, and lower preoperative numeric analog scale scores. The definition of reoperation in their study is unfortunately not described, and thus the extent of reoperation (arthroscopy to arthroplasty) is unclear. In a 2009 systematic review of 3122 patients (28 studies) undergoing MFX conducted by Mithoefer and colleagues,²⁰ revision rates were noted to range from 2% to 31% depending on the study analyzed, with increasing revision rates after 2 years. Unfortunately, the heterogeneity of the included studies makes it difficult to determine which patients tend to fail over time.

Continue to: OATS...

OATS is a promising cartilage restoration technique indicated for treatment of patients with large, uncontained chondral lesions, and/or lesions with both bone and cartilage loss.¹ OCA is similar to OATS but uses allograft tissue instead of autograft tissue and is typically considered a viable treatment option in larger lesions (>2 cm²).²¹ Cell-based ACI therapy has evolved substantially over the past decade and is now available as a third-generation model utilizing biodegradable 3-dimensional scaffolds seeded with chondrocytes. Reoperation rates following ACI can often be higher than those following other cartilage treatments, particularly given the known complication of graft hypertrophy and/or delamination. Harris and colleagues²² conducted a systematic review of 5276 subjects undergoing ACI (all generations), noting an overall reoperation rate of 33%, but a failure rate of 5.8% at an average of 22 months following ACI. Risk factors for reoperation included periosteal-based ACI as well as open (vs arthroscopic) ACI. In this study, we found a modestly lower return to OR rate of 29.69% at 2 years.

When the outcomes of patients undergoing OATS or OCA are compared to those of patients undergoing MFX or ACI, it can be difficult to interpret the results, as the indications for performing these procedures tend to be very different. Further, the reasons for reoperation, as well as the procedures performed at the time of reoperation, are often poorly described, making it difficult to truly quantify the risk of reoperation and the implications of reoperation for patients undergoing any of these index cartilage procedures.

Overall, in this database, the return to the OR rate approaches 15% at 2 years following cartilage surgery, with cell-based therapy demonstrating higher reoperation rates at 2 years, without the risk of conversion to arthroplasty. Reoperation rates appear to stabilize at 1 year following surgery and consist mostly of minor arthroscopic procedures. These findings can help surgeons counsel patients as to the rate and type of reoperations that can be expected following cartilage surgery. Additional research incorporating patient-reported outcomes and patient-specific risk factors are needed to complement these data as to the impact of reoperations on overall clinical outcomes. Further, studies incorporating 90-day, 1-year, and 2-year costs associated with cartilage surgery will help to determine which index procedure is the most cost effective over the short- and long-term.

LIMITATIONS

This study is not without limitations. The PearlDiver database is reliant upon accurate CPT and ICD-9 coding, which creates a potential for a reporting bias. The overall reliability of the analyses is dependent on the quality of the available data, which, as noted in previous PearlDiver studies,^18,23-28 may include inaccurate billing codes, miscoding, and/or non-coding by physicians as potential sources of error. At the time of this study, the PearlDiver database did not provide consistent data points on laterality, and thus it is possible that the reported rates of reoperation overestimate the true reoperation rate following a given procedure. Fortunately, the reoperation rates for each procedure analyzed in this database study are consistent with those previously presented in the literature. In addition, it is not uncommon for patients receiving one of these procedures to have previously been treated with one of the others. Due to the inherent limitations of the PearlDiver database, this study did not investigate concomitant procedures performed along with the index procedure, nor did it investigate confounding factors such as comorbidities. The PearlDiver database does not provide data on defect size, location within the knee, concomitant pathologies (eg, meniscus tear), prior surgeries, or patient comorbidities, and while important, these factors cannot be accounted for in our analysis. The inability to account for these important factors, particularly concomitant diagnoses, procedures, and lesion size/location, represents an important limitation of this study, as this is a source of selection bias and may influence the need for reoperation in a given patient. Despite these limitations, the results of this study are supported by previous and current literature. In addition, the PearlDiver database, as a HIPAA-compliant database, does not report exact numbers when the value of the outcome of interest is between 0 and 10, which prohibits analysis of any cartilage procedure performed in a cohort of patients greater than 1 and less than 11. Finally, while not necessarily a limitation, it should be noted that CPT 29879 is not specific for microfracture, as the code also includes abrasion arthroplasty and drilling. Due to the limitations of the methodology of searching the database for this code, it is unclear as to how many patients underwent actual microfracture vs abrasion arthroplasty.

CONCLUSION

Within a large US commercial insurance database from 2007 to 2011, reparative procedures were favored for chondral injuries, but yielded an increased risk for conversion to arthroplasty. There was no difference between failure/revision rates among the restorative approaches, yet cell-based approaches yielded a significantly increased risk for a return to the OR.

Seventy-five percent of adults aged >75 years have hypertension.^1-3 According to the Joint National Commission 8 (JNC 8), the recommended target blood pressure (BP) is < 150/80 mm Hg for adults aged > 60 years.⁴ In 2016 the Systolic Blood Pressure Intervention Trial (SPRINT) suggested that more aggressive BP control with a goal of < 120/80 mm Hg reduced rates of cardiovascular disease and lowered the risk of death in adults aged > 50 years with hypertension.⁵ It is anticipated that as a result of the landmark SPRINT results, clinicians may attempt to treat hypertension more intensely in older patients with an increased risk of adverse consequences if BPs are not appropriately measured.

There is a standardized protocol for BP measurement, but these recommendations typically are not followed in routine office visits.^6,7 Some studies have noted that home BP measurement may be more accurate than office measurement.⁸ However, clinicians may not always trust the accuracy of home BP readings, and many patients are not adherent with home measurement. As a result, physicians usually manage hypertension in older patients based on office readings, though it is likely that most office measurements do not follow protocol on proper measurement. Office measurements have been noted to be inaccurate with high likelihood of overestimating or underestimating BP control.⁹

Office BP measurements demonstrate poor correlation with home measurements and have not been shown to be as good of a predictor for target organ damage or long-term cardiovascular outcomes compared with that of home measurements.^10,11 Although there have been studies comparing home and office BP measurements and comparing office and ambulatory BP measurement, no literature has been found that reports on the difference between routine office and standardized measurement of BP.^9,12-14

This study seeks to identify the magnitude of difference among BP measured according to a standardized protocol, routine clinical, and home BP. The authors hypothesized that there would be a significant, clinically relevant difference among the 3 BP measurement methods, especially between the routine office and standardized office measurements. This study has implications for implementing intensive treatment of hypertension based on office measurements.

Methods

Participants included 30 male veterans aged > 65 years who were actively participating in the Gerofit program at the VA Greater Los Angeles Healthcare System (VAGLAHS). The Gerofit program is a model clinical demonstration exercise and health promotion program targeting older and veterans at risk for falls or institutionalization. Gerofit was established in 1987 at the Durham VA Health System and successfully implemented in 2014 at VAGLAHS. Supervised exercise is offered 3 times per week and consists of individually tailored exercises aimed at reducing functional deficits that are identified and monitored by an initial and quarterly functional assessment. Blood pressures are checked routinely once a week as a part of the program. Gerofit was reviewed and approved by the institutional review board at VAGLAHS as a quality improvement/quality assurance project.

Data

Routine office and standardized protocol measurements were obtained by a single CasMED 740 (Branford, CT) automated BP machine and were conducted separately on different days. The CasMED 740 machine was not otherwise calibrated; however, a one-time correlation was performed between the CasMED 740 and the home BP monitor for each participant, when it was brought to VAGLAHS. Two measurements were made with the CasMed 740 automated BP machine on the arm that gave the higher BP reading throughout the standardized and routine protocol. Two subsequent measurements were made with the participant’s home automated BP cuff. Averages for the CasMED 740 and the home BP monitoring device were compared and assessed for significance by paired t test. No rest was scheduled prior to the first measurement, but there was a 1-minute rest after each subsequent measurement.

Mean values (SD) were used for participant characteristics and mean values (standard error [SE]) were used for BP measurements. Data were analyzed using Microsoft Excel (Redmond, WA) and GraphPad Prism version 7.03 (San Diego, CA). T tests were used for analysis of home BP measurements due to low sample size. Values of P < .05 were considered to be statistically significant.

Routine office protocol. Automated BP was measured to mimic routine office visits. Upon arrival, participants sat down, and the BP cuff was placed around their arm. Any rest before a measurement was incidental and not intentionally structured. Appropriate cuff size was determined by visual estimation of arm circumference. Only 1 measurement was made unless BP was > 150/90 mm Hg, in which case a repeat measurement was made after 2 to 4 minutes of rest. The BP was then determined based on the average of 2 or more readings. The BPs were recorded by hand in a weekly log. Participants had at least 12 weeks of BP readings measured by the routine method, and these BPs were averaged over 12 weeks to yield their average routine measured BP.

Standardized protocol. Automated BP was measured according to the 2015 USPSTF Guidelines and Look AHEAD trial protocol.^7,15 A participant’s arm circumference was measured, and appropriate cuff size was determined. The participant rested quietly in a chair for at least 5 minutes with feet flat on the floor and back supported. The cuff was snugly placed 2 to 3 cm above the antecubital fossa, and the arm was supported at the level of the right atrium during the measurement. Blood pressure was determined using the mean of 4 automated cuff readings, 2 on each arm, taken 1 minute apart. Participants did not necessarily have their BP measured by the standardized method immediately following the routine method but all measurements were performed during the same 12-week time period.

Home blood pressure protocol. Participants were given instructions according to the American Heart Association (AHA) recommendations for measuring home BP. Patients were instructed to use a calibrated, automated arm BP cuff. Home BP machines were not provided in advance, and each individual’s BP machine was not calibrated. They also were instructed to rest at least 5 minutes before measuring their BP. The mean home BP was determined by the cumulative average of 3 readings in the morning and evening, taken 1 minute between each reading, for a total of 6 readings/d. Participants recorded home BPs for 2 weeks before submitting their readings. Each participant affirmed clear understanding of how to measure BP by correctly demonstrating placement of the cuff 1 time under supervision.

Results

Thirty veterans aged > 65 years participated in the study. The average age (SD) was 82.7 (9.3) years. The average BMI (SD) was overweight at 29.7 kg/m² (5.7). Most (87.6%) of the study participants had been diagnosed with hypertension prior to the study, and no new diagnoses were made as a result of the study. 

Both systolic BP (SBP) and diastolic BPs (DBP) measured by the standardized method were significantly lower than those by the routine method (P < .01 and P < .01, respectively) (Figure 1). 

To determine the accuracy of the home BP monitors, the average routine VAGLAHS BP measure was compared with home BP results. For SBPs, there was a significant correlation coefficient of 0.91 (P < .01). 

Discussion

The present study demonstrated that standardized measurements of BP were lower than that of the routine method used in most office settings. These results suggest that there could be a risk of overtreatment for some patients those of whose results are higher than the SPRINT BP target of < 120/80 mm Hg. Clinicians might be treating BPs that are elevated due to improper measurement, which can lead to deleterious consequences in older adults, such as syncope and falls.¹⁶

Each participant exhibited a significantly lower BP reading with the standardized method than the routine method. The 20-point decrease in SBP and 10-point decrease in DBP are clinically significant. The routine method of measurement was intended to simulate BP measurement in outpatient settings. There is usually little time structured for rest, and because the protocol established by the AHA and other professional organizations is time consuming, it usually is not strictly followed. With guidelines proposed by JNC 8 and new findings from SPRINT, the method of BP readings should be reviewed in all clinical settings.

While changes in BP management are not necessarily immediate, the differences in recommendations proposed by SPRINT and JNC 8 can lead to confusion regarding how intensely to treat BP. These recommendations guide clinical practice, but clinicians’ best judgment ultimately determines BP management. Physicians who utilize routine office measurements likely rely on BP readings that are higher on average than are readings done under proper conditions. This leads to the prospect of overtreatment, where physicians attempt to control hypertension too aggressively, potentially leading to orthostatic hypotension, syncope, and increased risk for falls.¹⁶ With findings from SPRINT recommending even lower BPs than that by JNC 8, overtreatment risk becomes especially relevant. While BP protocol was strictly followed in SPRINT, some clinicians may not necessarily follow the same fastidious protocol.

The average differences between the home and standardized BPs were not statistically significant possibly due to the small sample size in the home BP measurements; however, the difference might represent some clinical relevance. There was a 15-point difference in SBP results between home (129 mm Hg) and standardized (115 mm Hg) measures. There also was a difference in DBP between home (69 mm Hg) and standardized (62 mm Hg) results. The close correlation between both home and BPs measured in VAGLAHS demonstrated that any difference was not due to variability in the measurement devices. Previous studies have demonstrated that home BPs are better indicators of cardiovascular risk than office BP.⁸

Despite lack of statistical significance, home BPs were lower than routine, which suggests that they still may be more reliable than routine office measurements. Definitive conclusions regarding the accuracy of the home BPs in the present study cannot be drawn due to the small sample size (n = 13). Further exploration with comparisons to ambulatory BP monitoring could yield more information on accuracy of home BP monitoring.

In this study’s cohort of older veterans, the average BMI was between 25 and 30 (overweight), which is a risk factor for hypertension.¹⁷ Every participant with hypertension was taking at least 1 antihypertensive medication and being actively managed. In this study, the authors accounted for other medications that may affect BP, such as α blockers used in patients with benign prostatic hyperplasia.¹⁸ These could have potential elevating or lowering effects on BP measurements.

An issue in this study was the lack of adherence to home BP monitoring. Many patients forgot to bring in their records or to measure their BPs at home. The difficulties highlight real-life issues. Clinicians often request that patients monitor their BP at home, but few may actually remember, let alone keep diligent records. There are many barriers between measuring and reporting home BPs, which may prevent the usefulness of monitoring BP at home.

Limitations

There were several limitations to the study. There was no specific protocol for the routine method of BP measurement, as it was intended to simulate the haphazard nature of office measurements. However, this approach limits its reproducibility. For home BP monitoring, it would have been ideal to provide the same calibrated, automated BP device to each participant. This study of older veterans may not be applicable to the general population. Finally, the relatively small number of participants in the study (n = 30) may have limited power in drawing definitive conclusions.

Future Directions

For future studies, comparing the standardized method to ambulatory BP monitoring would provide more information on accuracy. In addition, the authors would like to evaluate the effect of exercise on BP measurements in the different settings: home, standardized, and routine methods.