The American Journal of Orthopedics

ABSTRACT

Despite advancements in surgical technique and understanding of throwing mechanics, controversy persists regarding the treatment of grade III acromioclavicular (AC) joint separations, particularly in throwing athletes. Twenty-eight major league baseball (MLB) orthopedic team physicians were surveyed to determine their definitive management of a grade III AC separation in the dominant arm of a professional baseball pitcher and their experience treating AC joint separations in starting pitchers and position players. Return-to-play outcomes were also evaluated. Twenty (71.4%) team physicians recommended nonoperative intervention compared to 8 (28.6%) who would have operated acutely. Eighteen (64.3%) team physicians had treated at least 1 professional pitcher with a grade III AC separation; 51 (77.3%) pitchers had been treated nonoperatively compared to 15 (22.7%) operatively. No difference was observed in the proportion of pitchers who returned to the same level of play (P = .54), had full, unrestricted range of motion (P = .23), or had full pain relief (P = .19) between the operatively and nonoperatively treated MLB pitchers. The majority (53.6%) of physicians would not include an injection if the injury was treated nonoperatively. Open coracoclavicular reconstruction (65.2%) was preferred for operative cases; 66.7% of surgeons would also include distal clavicle excision as an adjunct procedure. About 90% of physicians would return pitchers to throwing >12 weeks after surgery compared to after 4 to 6 weeks in nonoperatively treated cases. In conclusion, MLB team physicians preferred nonoperative management for an acute grade III AC joint separation in professional pitchers. If operative intervention is required, ligament reconstruction with adjunct distal clavicle excision were the most commonly performed procedures.

Continue to: Despite advancements in surgucal technique...

Despite advancements in surgical technique and improved understanding of the physiology of throwing mechanics, controversy persists regarding the preferred treatment for grade III acromioclavicular (AC) joint separations.^1-6 Nonsurgical management has demonstrated return to prior function with fewer complications.⁷ However, there is a growing body of evidence demonstrating that surgical intervention is associated with more favorable outcomes⁸ and should be considered in patients who place high functional demands on their shoulders.⁹

The reported results on professional athletes in the literature remain ambivalent. Multiple small case reports/series have reported successful nonoperative treatment of elite athletes.^10-12 Not surprisingly, McFarland and colleagues¹³ reported in 1997 that 69% of major league baseball (MLB) team physicians preferred nonoperative treatment for a theoretical starting pitcher sustaining a grade III AC separation 1 week prior to the start of the season. In contrast, reports of an inability to throw at a pre-injury level are equally commonplace.^14,15 Nevertheless, all of these studies were limited to small cohorts, as the incidence of grade III AC separations in elite throwing athletes is relatively uncommon.^13,16

In this study, we re-evaluated the study performed by McFarland and colleagues¹³ in 1997 by surveying all active MLB team orthopedic surgeons. We asked them how they would treat a grade III AC separation in a starting professional baseball pitcher. The physicians were also asked about their personal experience evaluating outcomes in these elite athletes. Given our improved understanding of the anatomy, pathophysiology, and surgical techniques for treating grade III AC separations, we hypothesize that more MLB team physicians would favor operative intervention treatment in professional baseball pitchers, as their vocation places higher demands on their shoulders.

MATERIALS AND METHODS

A questionnaire (Appendix A) was distributed to the team physicians of all 30 MLB teams. In addition to surgeon demographics, including age, years in practice, and years of taking care of an MLB team, the initial section of the questionnaire asked orthopedic surgeons how they would treat a theoretical starting pitcher who sustained a grade III AC joint separation of the dominant throwing arm 1 week prior to the start of the season. Physicians who preferred nonoperative treatment were asked whether they would use an injection (and what type), as well as when they would allow the pitcher to start a progressive interval throwing program. Physicians who preferred operative treatment were asked to rank their indications for operating, what procedure they would use (eg, open vs arthroscopic or coracoclavicular ligament repair vs reconstruction), and whether the surgical intervention would include distal clavicle excision. Both groups of physicians were also asked if their preferred treatment would change if the injury were to occur at the end of the season.

The second portion of the questionnaire asked surgeons about their experience treating AC joint separations in both starting pitchers and position players, as well as to describe the long-term outcomes of their preferred treatment, including time to return to full clearance for pitching, whether their patients returned to their prior level of play, and whether these patients had full pain relief. Finally, physicians were asked if any of the nonoperatively treated players ultimately crossed over and required operative intervention.

Continue to: Statistics...

STATISTICS

Descriptive statistics were used for continuous variables, and frequencies were used for categorical variables. Linear regression was performed to determine the correlation between the physician’s training or experience in treating AC joint separations and their recommended treatment. Fischer’s exact test/chi-square analysis was used to compare categorical variables. All tests were conducted using 2-sided hypothesis testing with statistical significance set at P < .05. All statistical analyses were conducted with SPSS 21.0 software (IBM Corporation).

RESULTS

A total of 28 MLB team physicians completed the questionnaires from 18 of the 30 MLB teams. The average age of the responders was 50.5 years (range, 34-60 years), with an average of 18.2 years in practice (range, 2-30 years) and 10.8 years (range, 1-24 years) taking care of their current professional baseball team. About 82% of the team physicians completed a sports medicine fellowship. On average, physicians saw 16.6 (range, 5-50) grade III or higher AC joint separations per year, and operated on 4.6 (range, 0-10) per year.

Nonoperative treatment was the preferred treatment for a grade III AC joint separation in a starting professional baseball pitcher for the majority of team physicians (20/28). No correlation was observed between the physician’s age (P = .881), years in practice (P = .915), years taking care of their professional team (P = .989), percentage of practice focused on shoulders (P = .986), number of AC joint injuries seen (P = .325), or number of surgeries performed per year (P = .807) with the team physician’s preferred treatment. Compared to the proportion reported originally by McFarland and colleagues¹³ in 1997 (69%), there was no difference in the proportion of team physicians that recommended nonoperative treatment (P = 1).

If treating this injury nonoperatively, 46.4% of physicians would also use an injection, with orthobiologics (eg, platelet-rich plasma) as the most popular choice (Table 1). No consensus was provided on the timeframe to return pitchers back to a progressive interval throwing program; however, 46.67% of physicians would return pitchers 4 to 6 weeks after a nonoperatively treated injury, while 35.7% would return pitchers 7 to 12 weeks after the initial injury.

Table 1. Treatment Preferences of Grade III AC Separation by MLB Team Physicians

^aRespondents were allowed to choose more than 1 treatment in each category. ^bChosen as an adjunct treatment.

Abbreviations: AC, acromioclavicular; MLB, major league baseball.

Most physicians (64.3%) cited functional limitations as the most important reason for indicating operative treatment, followed by pain (21.4%), and a deformity (14.3%). About 65% preferred open coracoclavicular ligament reconstruction. No physician recommended the Weaver-Dunn procedure or use of hardware (eg, hook plate). Of those who preferred an operative intervention, 66.7% would also include a distal clavicle excision, which is significantly higher than the proportion reported by McFarland and colleagues¹³ (23%, P = .0170). About 90% of physicians would return pitchers to play >12 weeks after operative treatment.

Continue to: If the injury occurred at the end ...

If the injury occurred at the end of the season, 7 of the 20 orthopedists (35%) who recommended nonoperative treatment said they would change to an operative intervention. Eighteen of 28 responders would have the same algorithm for MLB position players. Team physicians were less likely to recommend operative intervention in position players due to less demand on the arm and increased ability to accommodate the injury by altering their throwing mechanics.

Eighteen (64%) of the team physicians had treated at least 1 professional pitcher with a grade III AC separation in his dominant arm, and 11 (39.3%) had treated >1. Collectively, team physicians had treated 15 professional pitchers operatively, and 51 nonoperatively; only 3 patients converted to operative intervention after a failed nonoperative treatment.

Of the pitchers treated operatively, 93.3% (14) of pitchers returned to their prior level of pitching. The 1 patient who failed to return to the same level of pitching retired instead of returning to play. About 80% (12) of the pitchers had full pain relief, and 93.3% (14) had full range of motion (ROM). The pitcher who failed to regain full ROM also had a concomitant rotator cuff repair. The only complication reported from an operative intervention was a pitcher who sustained a coracoid fracture 10 months postoperatively while throwing 100 mph. Of the pitchers treated nonoperatively, 96% returned to their prior level of pitching, 92.2% (47) had full complete pain relief when throwing, and 100% had full ROM. No differences were observed between the proportion of pitchers who returned to their prior level of pitching, regained full ROM, or had full pain relief in the operative and nonoperative groups (Table 2).

Table 2. Outcomes of Treatment of Grade III AC Separation in 58 Professional Baseball Players

Abbreviations: AC, acromioclavicular; ROM, range of motion.

DISCUSSION 

Controversy persists regarding the optimal management of acute grade III AC separations, with the current available evidence potentially suggesting better cosmetic and radiological results but no definite differences in clinical results.^1-6,17,18 In the absence of formal clinical practice guidelines, surgeons rely on their own experience or defer to the anecdotal experience of experts in the field. Our initial hypothesis was false in this survey of MLB team physicians taking care of overhead throwing athletes at the highest level. Our results demonstrate that despite improved techniques and an increased understanding of the pathophysiology of AC joint separations, conservative management is still the preferred treatment for acute grade III AC joint separations in professional baseball pitchers. The proportion of team physicians recommending nonoperative treatment in our series was essentially equivalent to the results reported by McFarland and colleagues¹³ in 1997, suggesting that the pendulum continues to favor conservative management initially. This status quo likely reflects both the dearth of literature suggesting a substantial benefit of acute operative repair, as well as the ability to accommodate with conservative measures after most grade III AC injuries, even at the highest level of athletic competition.

These results are also consistent with trends from the last few decades. In the 1970s, the overwhelming preference for treating an acute complete AC joint separation was surgical repair, with Powers and Bach¹⁰ reporting in a 1974 survey of 163 chairmen of orthopedic programs around the country that 91.5% advocated surgical treatment. However, surgical preference had reversed by the 1990s. Of the 187 chairmen and 59 team physicians surveyed by Cox¹⁹ in 1992, 72% and 86% respectively preferred nonoperative treatment in a theoretical 21-year-old athlete with a grade III AC separation. Nissen and Chatterjee²⁰ reported in 2007 on a survey of all American Orthopaedic Society for Sports Medicine surgeons (N = 577) and Accreditation Council for Graduate Medical Education orthopedic program residency directors (N = 87) that >80% of responders preferred conservative measures for this acute injury. The reversal of trends has also been corroborated by recent multicenter trials demonstrating no difference in clinical outcomes between operative and nonoperative treatment of high grade AC joint dislocations, albeit these patients were not all high level overhead throwing athletes.^17,18

Continue to: The trends in surgical interventions are notable...

The trends in surgical interventions are notable within the smaller subset of patients who are indicated for operative repair. Use of hardware and primary ligament repair, while popular in the surveys conducted in the 1970s¹⁰ and 1990s¹³ and even present in Nissen and Chatterjee’s²⁰ 2007 survey, were noticeably absent from our survey results, with the majority of respondents preferring open coracoclavicular ligament reconstruction. The role of distal clavicle excision has also expanded, from 23% of team physicians recommending it in 1997¹³ to 57% to 59% in Nissen and Chatterjee’s²⁰ 2007 survey, to 66.7% in our series. This trend is not surprising as several recent cadaveric biomechanical studies have demonstrated that not only do peak graft forces not increase significantly,²¹ the anterior-posterior and superior-inferior motion at the AC joint following ligament reconstruction is maintained despite resection of the lateral clavicle.²² Additionally, primary distal clavicle excision may prevent the development of post-traumatic arthritis at the AC joint and osteolysis of the distal clavicle as a possible pain generator in the future.²³ However, some respondents cautioned against performing a concomitant distal clavicle excision, as some biomechanical data demonstrate that resecting the distal clavicle may lead to increased horizontal translation at the AC joint despite intact superior and posterior AC capsules.²⁴ Professional baseball pitchers may also be more lax and thus prone to more instability. Primary repair or reconstruction may not always lead to complete pre-injury stability in these individuals. This subtle unrecognized instability is hard to diagnosis and may be a persistent source of pain; thus, adding a distal clavicle excision may actually exacerbate the instability.

The nuanced indications for operative intervention, such as the presence of associated lesions were not captured by our survey.²⁵ While most team physicians cited functional limitations as their most common reason for offering surgery, several MLB orthopedic surgeons also commented on evaluating the stability of the AC joint after a grade III injury, akin to the consensus statement from the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) Upper Extremity Committee²⁶ in 2014 that diversified the Rockwood Grade III AC joint separation into its IIIA and IIIB classifications. The ISAKOS recommendations include initial conservative management and a second evaluation (both clinical and radiographic) for grade III lesions 3 to 6 weeks after the injury. However, as professional baseball is an incredibly profitable sport with an annual revenue approaching $9.5 billion²⁷ and pitching salaries up to $32.5 million in 2015, serious financial considerations must be given to players who wish to avoid undergoing delayed surgery.

This study has shortcomings typical of expert opinion papers. The retrospective nature of this study places the data at risk of recall bias. Objective data (eg, terminal ROM, pain relief, and return to play) were obtained from a retrospective chart review; however, no standard documentation or collection method was used given the number of surgeons involved and, thus, conclusions based on treatment outcomes are imperfect. Another major weakness of this survey is the relatively small number of patients and respondents. An a priori power analysis was not available, as this was a retrospective review. A comparative trial will be necessary to definitively support one treatment over another. Assuming a 95% return to play in the nonoperatively treated group, approximately 300 patients would be needed in a prospective 2-armed study with 80% power to detect a 10% reduction in the incidence of return to play using an alpha level of 0.05 and assuming no loss to follow-up. This sample size would be difficult to achieve in this patient population.

However, compared to past series,¹³ the number of professional baseball players treated by the collective experience of these MLB team physicians is the largest reported to date. As suggested above, the rarity of this condition in elite athletes precludes the ability to have matched controls to definitively determine the optimal treatment, which may explain the lack of difference in the return to play, ROM, and pain relief outcomes. Instead, we can only extrapolate based on the collective anecdotal experience of the MLB team physicians.

CONCLUSION

Despite advances in surgical technique and understanding of throwing mechanics, the majority of MLB team physicians preferred nonoperative management for an acute grade III AC joint separation in a professional baseball pitcher. Open coracoclavicular ligament reconstruction was preferred for those who preferred operative intervention. An increasing number of orthopedic surgeons now consider a distal clavicle excision as an adjunct procedure.

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

ABSTRACT

Despite advancements in surgical technique and understanding of throwing mechanics, controversy persists regarding the treatment of grade III acromioclavicular (AC) joint separations, particularly in throwing athletes. Twenty-eight major league baseball (MLB) orthopedic team physicians were surveyed to determine their definitive management of a grade III AC separation in the dominant arm of a professional baseball pitcher and their experience treating AC joint separations in starting pitchers and position players. Return-to-play outcomes were also evaluated. Twenty (71.4%) team physicians recommended nonoperative intervention compared to 8 (28.6%) who would have operated acutely. Eighteen (64.3%) team physicians had treated at least 1 professional pitcher with a grade III AC separation; 51 (77.3%) pitchers had been treated nonoperatively compared to 15 (22.7%) operatively. No difference was observed in the proportion of pitchers who returned to the same level of play (P = .54), had full, unrestricted range of motion (P = .23), or had full pain relief (P = .19) between the operatively and nonoperatively treated MLB pitchers. The majority (53.6%) of physicians would not include an injection if the injury was treated nonoperatively. Open coracoclavicular reconstruction (65.2%) was preferred for operative cases; 66.7% of surgeons would also include distal clavicle excision as an adjunct procedure. About 90% of physicians would return pitchers to throwing >12 weeks after surgery compared to after 4 to 6 weeks in nonoperatively treated cases. In conclusion, MLB team physicians preferred nonoperative management for an acute grade III AC joint separation in professional pitchers. If operative intervention is required, ligament reconstruction with adjunct distal clavicle excision were the most commonly performed procedures.

Continue to: Despite advancements in surgucal technique...

Despite advancements in surgical technique and improved understanding of the physiology of throwing mechanics, controversy persists regarding the preferred treatment for grade III acromioclavicular (AC) joint separations.^1-6 Nonsurgical management has demonstrated return to prior function with fewer complications.⁷ However, there is a growing body of evidence demonstrating that surgical intervention is associated with more favorable outcomes⁸ and should be considered in patients who place high functional demands on their shoulders.⁹

The reported results on professional athletes in the literature remain ambivalent. Multiple small case reports/series have reported successful nonoperative treatment of elite athletes.^10-12 Not surprisingly, McFarland and colleagues¹³ reported in 1997 that 69% of major league baseball (MLB) team physicians preferred nonoperative treatment for a theoretical starting pitcher sustaining a grade III AC separation 1 week prior to the start of the season. In contrast, reports of an inability to throw at a pre-injury level are equally commonplace.^14,15 Nevertheless, all of these studies were limited to small cohorts, as the incidence of grade III AC separations in elite throwing athletes is relatively uncommon.^13,16

In this study, we re-evaluated the study performed by McFarland and colleagues¹³ in 1997 by surveying all active MLB team orthopedic surgeons. We asked them how they would treat a grade III AC separation in a starting professional baseball pitcher. The physicians were also asked about their personal experience evaluating outcomes in these elite athletes. Given our improved understanding of the anatomy, pathophysiology, and surgical techniques for treating grade III AC separations, we hypothesize that more MLB team physicians would favor operative intervention treatment in professional baseball pitchers, as their vocation places higher demands on their shoulders.

MATERIALS AND METHODS

A questionnaire (Appendix A) was distributed to the team physicians of all 30 MLB teams. In addition to surgeon demographics, including age, years in practice, and years of taking care of an MLB team, the initial section of the questionnaire asked orthopedic surgeons how they would treat a theoretical starting pitcher who sustained a grade III AC joint separation of the dominant throwing arm 1 week prior to the start of the season. Physicians who preferred nonoperative treatment were asked whether they would use an injection (and what type), as well as when they would allow the pitcher to start a progressive interval throwing program. Physicians who preferred operative treatment were asked to rank their indications for operating, what procedure they would use (eg, open vs arthroscopic or coracoclavicular ligament repair vs reconstruction), and whether the surgical intervention would include distal clavicle excision. Both groups of physicians were also asked if their preferred treatment would change if the injury were to occur at the end of the season.

The second portion of the questionnaire asked surgeons about their experience treating AC joint separations in both starting pitchers and position players, as well as to describe the long-term outcomes of their preferred treatment, including time to return to full clearance for pitching, whether their patients returned to their prior level of play, and whether these patients had full pain relief. Finally, physicians were asked if any of the nonoperatively treated players ultimately crossed over and required operative intervention.

Continue to: Statistics...

STATISTICS

Descriptive statistics were used for continuous variables, and frequencies were used for categorical variables. Linear regression was performed to determine the correlation between the physician’s training or experience in treating AC joint separations and their recommended treatment. Fischer’s exact test/chi-square analysis was used to compare categorical variables. All tests were conducted using 2-sided hypothesis testing with statistical significance set at P < .05. All statistical analyses were conducted with SPSS 21.0 software (IBM Corporation).

RESULTS

A total of 28 MLB team physicians completed the questionnaires from 18 of the 30 MLB teams. The average age of the responders was 50.5 years (range, 34-60 years), with an average of 18.2 years in practice (range, 2-30 years) and 10.8 years (range, 1-24 years) taking care of their current professional baseball team. About 82% of the team physicians completed a sports medicine fellowship. On average, physicians saw 16.6 (range, 5-50) grade III or higher AC joint separations per year, and operated on 4.6 (range, 0-10) per year.

Nonoperative treatment was the preferred treatment for a grade III AC joint separation in a starting professional baseball pitcher for the majority of team physicians (20/28). No correlation was observed between the physician’s age (P = .881), years in practice (P = .915), years taking care of their professional team (P = .989), percentage of practice focused on shoulders (P = .986), number of AC joint injuries seen (P = .325), or number of surgeries performed per year (P = .807) with the team physician’s preferred treatment. Compared to the proportion reported originally by McFarland and colleagues¹³ in 1997 (69%), there was no difference in the proportion of team physicians that recommended nonoperative treatment (P = 1).

If treating this injury nonoperatively, 46.4% of physicians would also use an injection, with orthobiologics (eg, platelet-rich plasma) as the most popular choice (Table 1). No consensus was provided on the timeframe to return pitchers back to a progressive interval throwing program; however, 46.67% of physicians would return pitchers 4 to 6 weeks after a nonoperatively treated injury, while 35.7% would return pitchers 7 to 12 weeks after the initial injury.

Table 1. Treatment Preferences of Grade III AC Separation by MLB Team Physicians

^aRespondents were allowed to choose more than 1 treatment in each category. ^bChosen as an adjunct treatment.

Abbreviations: AC, acromioclavicular; MLB, major league baseball.

Most physicians (64.3%) cited functional limitations as the most important reason for indicating operative treatment, followed by pain (21.4%), and a deformity (14.3%). About 65% preferred open coracoclavicular ligament reconstruction. No physician recommended the Weaver-Dunn procedure or use of hardware (eg, hook plate). Of those who preferred an operative intervention, 66.7% would also include a distal clavicle excision, which is significantly higher than the proportion reported by McFarland and colleagues¹³ (23%, P = .0170). About 90% of physicians would return pitchers to play >12 weeks after operative treatment.

Continue to: If the injury occurred at the end ...

If the injury occurred at the end of the season, 7 of the 20 orthopedists (35%) who recommended nonoperative treatment said they would change to an operative intervention. Eighteen of 28 responders would have the same algorithm for MLB position players. Team physicians were less likely to recommend operative intervention in position players due to less demand on the arm and increased ability to accommodate the injury by altering their throwing mechanics.

Eighteen (64%) of the team physicians had treated at least 1 professional pitcher with a grade III AC separation in his dominant arm, and 11 (39.3%) had treated >1. Collectively, team physicians had treated 15 professional pitchers operatively, and 51 nonoperatively; only 3 patients converted to operative intervention after a failed nonoperative treatment.

Of the pitchers treated operatively, 93.3% (14) of pitchers returned to their prior level of pitching. The 1 patient who failed to return to the same level of pitching retired instead of returning to play. About 80% (12) of the pitchers had full pain relief, and 93.3% (14) had full range of motion (ROM). The pitcher who failed to regain full ROM also had a concomitant rotator cuff repair. The only complication reported from an operative intervention was a pitcher who sustained a coracoid fracture 10 months postoperatively while throwing 100 mph. Of the pitchers treated nonoperatively, 96% returned to their prior level of pitching, 92.2% (47) had full complete pain relief when throwing, and 100% had full ROM. No differences were observed between the proportion of pitchers who returned to their prior level of pitching, regained full ROM, or had full pain relief in the operative and nonoperative groups (Table 2).

Table 2. Outcomes of Treatment of Grade III AC Separation in 58 Professional Baseball Players

Abbreviations: AC, acromioclavicular; ROM, range of motion.

DISCUSSION 

Controversy persists regarding the optimal management of acute grade III AC separations, with the current available evidence potentially suggesting better cosmetic and radiological results but no definite differences in clinical results.^1-6,17,18 In the absence of formal clinical practice guidelines, surgeons rely on their own experience or defer to the anecdotal experience of experts in the field. Our initial hypothesis was false in this survey of MLB team physicians taking care of overhead throwing athletes at the highest level. Our results demonstrate that despite improved techniques and an increased understanding of the pathophysiology of AC joint separations, conservative management is still the preferred treatment for acute grade III AC joint separations in professional baseball pitchers. The proportion of team physicians recommending nonoperative treatment in our series was essentially equivalent to the results reported by McFarland and colleagues¹³ in 1997, suggesting that the pendulum continues to favor conservative management initially. This status quo likely reflects both the dearth of literature suggesting a substantial benefit of acute operative repair, as well as the ability to accommodate with conservative measures after most grade III AC injuries, even at the highest level of athletic competition.

These results are also consistent with trends from the last few decades. In the 1970s, the overwhelming preference for treating an acute complete AC joint separation was surgical repair, with Powers and Bach¹⁰ reporting in a 1974 survey of 163 chairmen of orthopedic programs around the country that 91.5% advocated surgical treatment. However, surgical preference had reversed by the 1990s. Of the 187 chairmen and 59 team physicians surveyed by Cox¹⁹ in 1992, 72% and 86% respectively preferred nonoperative treatment in a theoretical 21-year-old athlete with a grade III AC separation. Nissen and Chatterjee²⁰ reported in 2007 on a survey of all American Orthopaedic Society for Sports Medicine surgeons (N = 577) and Accreditation Council for Graduate Medical Education orthopedic program residency directors (N = 87) that >80% of responders preferred conservative measures for this acute injury. The reversal of trends has also been corroborated by recent multicenter trials demonstrating no difference in clinical outcomes between operative and nonoperative treatment of high grade AC joint dislocations, albeit these patients were not all high level overhead throwing athletes.^17,18

Continue to: The trends in surgical interventions are notable...

The trends in surgical interventions are notable within the smaller subset of patients who are indicated for operative repair. Use of hardware and primary ligament repair, while popular in the surveys conducted in the 1970s¹⁰ and 1990s¹³ and even present in Nissen and Chatterjee’s²⁰ 2007 survey, were noticeably absent from our survey results, with the majority of respondents preferring open coracoclavicular ligament reconstruction. The role of distal clavicle excision has also expanded, from 23% of team physicians recommending it in 1997¹³ to 57% to 59% in Nissen and Chatterjee’s²⁰ 2007 survey, to 66.7% in our series. This trend is not surprising as several recent cadaveric biomechanical studies have demonstrated that not only do peak graft forces not increase significantly,²¹ the anterior-posterior and superior-inferior motion at the AC joint following ligament reconstruction is maintained despite resection of the lateral clavicle.²² Additionally, primary distal clavicle excision may prevent the development of post-traumatic arthritis at the AC joint and osteolysis of the distal clavicle as a possible pain generator in the future.²³ However, some respondents cautioned against performing a concomitant distal clavicle excision, as some biomechanical data demonstrate that resecting the distal clavicle may lead to increased horizontal translation at the AC joint despite intact superior and posterior AC capsules.²⁴ Professional baseball pitchers may also be more lax and thus prone to more instability. Primary repair or reconstruction may not always lead to complete pre-injury stability in these individuals. This subtle unrecognized instability is hard to diagnosis and may be a persistent source of pain; thus, adding a distal clavicle excision may actually exacerbate the instability.

The nuanced indications for operative intervention, such as the presence of associated lesions were not captured by our survey.²⁵ While most team physicians cited functional limitations as their most common reason for offering surgery, several MLB orthopedic surgeons also commented on evaluating the stability of the AC joint after a grade III injury, akin to the consensus statement from the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) Upper Extremity Committee²⁶ in 2014 that diversified the Rockwood Grade III AC joint separation into its IIIA and IIIB classifications. The ISAKOS recommendations include initial conservative management and a second evaluation (both clinical and radiographic) for grade III lesions 3 to 6 weeks after the injury. However, as professional baseball is an incredibly profitable sport with an annual revenue approaching $9.5 billion²⁷ and pitching salaries up to $32.5 million in 2015, serious financial considerations must be given to players who wish to avoid undergoing delayed surgery.

This study has shortcomings typical of expert opinion papers. The retrospective nature of this study places the data at risk of recall bias. Objective data (eg, terminal ROM, pain relief, and return to play) were obtained from a retrospective chart review; however, no standard documentation or collection method was used given the number of surgeons involved and, thus, conclusions based on treatment outcomes are imperfect. Another major weakness of this survey is the relatively small number of patients and respondents. An a priori power analysis was not available, as this was a retrospective review. A comparative trial will be necessary to definitively support one treatment over another. Assuming a 95% return to play in the nonoperatively treated group, approximately 300 patients would be needed in a prospective 2-armed study with 80% power to detect a 10% reduction in the incidence of return to play using an alpha level of 0.05 and assuming no loss to follow-up. This sample size would be difficult to achieve in this patient population.

However, compared to past series,¹³ the number of professional baseball players treated by the collective experience of these MLB team physicians is the largest reported to date. As suggested above, the rarity of this condition in elite athletes precludes the ability to have matched controls to definitively determine the optimal treatment, which may explain the lack of difference in the return to play, ROM, and pain relief outcomes. Instead, we can only extrapolate based on the collective anecdotal experience of the MLB team physicians.

CONCLUSION

Despite advances in surgical technique and understanding of throwing mechanics, the majority of MLB team physicians preferred nonoperative management for an acute grade III AC joint separation in a professional baseball pitcher. Open coracoclavicular ligament reconstruction was preferred for those who preferred operative intervention. An increasing number of orthopedic surgeons now consider a distal clavicle excision as an adjunct procedure.

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

ABSTRACT

Despite advancements in surgical technique and understanding of throwing mechanics, controversy persists regarding the treatment of grade III acromioclavicular (AC) joint separations, particularly in throwing athletes. Twenty-eight major league baseball (MLB) orthopedic team physicians were surveyed to determine their definitive management of a grade III AC separation in the dominant arm of a professional baseball pitcher and their experience treating AC joint separations in starting pitchers and position players. Return-to-play outcomes were also evaluated. Twenty (71.4%) team physicians recommended nonoperative intervention compared to 8 (28.6%) who would have operated acutely. Eighteen (64.3%) team physicians had treated at least 1 professional pitcher with a grade III AC separation; 51 (77.3%) pitchers had been treated nonoperatively compared to 15 (22.7%) operatively. No difference was observed in the proportion of pitchers who returned to the same level of play (P = .54), had full, unrestricted range of motion (P = .23), or had full pain relief (P = .19) between the operatively and nonoperatively treated MLB pitchers. The majority (53.6%) of physicians would not include an injection if the injury was treated nonoperatively. Open coracoclavicular reconstruction (65.2%) was preferred for operative cases; 66.7% of surgeons would also include distal clavicle excision as an adjunct procedure. About 90% of physicians would return pitchers to throwing >12 weeks after surgery compared to after 4 to 6 weeks in nonoperatively treated cases. In conclusion, MLB team physicians preferred nonoperative management for an acute grade III AC joint separation in professional pitchers. If operative intervention is required, ligament reconstruction with adjunct distal clavicle excision were the most commonly performed procedures.

Continue to: Despite advancements in surgucal technique...

Despite advancements in surgical technique and improved understanding of the physiology of throwing mechanics, controversy persists regarding the preferred treatment for grade III acromioclavicular (AC) joint separations.^1-6 Nonsurgical management has demonstrated return to prior function with fewer complications.⁷ However, there is a growing body of evidence demonstrating that surgical intervention is associated with more favorable outcomes⁸ and should be considered in patients who place high functional demands on their shoulders.⁹

The reported results on professional athletes in the literature remain ambivalent. Multiple small case reports/series have reported successful nonoperative treatment of elite athletes.^10-12 Not surprisingly, McFarland and colleagues¹³ reported in 1997 that 69% of major league baseball (MLB) team physicians preferred nonoperative treatment for a theoretical starting pitcher sustaining a grade III AC separation 1 week prior to the start of the season. In contrast, reports of an inability to throw at a pre-injury level are equally commonplace.^14,15 Nevertheless, all of these studies were limited to small cohorts, as the incidence of grade III AC separations in elite throwing athletes is relatively uncommon.^13,16

In this study, we re-evaluated the study performed by McFarland and colleagues¹³ in 1997 by surveying all active MLB team orthopedic surgeons. We asked them how they would treat a grade III AC separation in a starting professional baseball pitcher. The physicians were also asked about their personal experience evaluating outcomes in these elite athletes. Given our improved understanding of the anatomy, pathophysiology, and surgical techniques for treating grade III AC separations, we hypothesize that more MLB team physicians would favor operative intervention treatment in professional baseball pitchers, as their vocation places higher demands on their shoulders.

MATERIALS AND METHODS

A questionnaire (Appendix A) was distributed to the team physicians of all 30 MLB teams. In addition to surgeon demographics, including age, years in practice, and years of taking care of an MLB team, the initial section of the questionnaire asked orthopedic surgeons how they would treat a theoretical starting pitcher who sustained a grade III AC joint separation of the dominant throwing arm 1 week prior to the start of the season. Physicians who preferred nonoperative treatment were asked whether they would use an injection (and what type), as well as when they would allow the pitcher to start a progressive interval throwing program. Physicians who preferred operative treatment were asked to rank their indications for operating, what procedure they would use (eg, open vs arthroscopic or coracoclavicular ligament repair vs reconstruction), and whether the surgical intervention would include distal clavicle excision. Both groups of physicians were also asked if their preferred treatment would change if the injury were to occur at the end of the season.

The second portion of the questionnaire asked surgeons about their experience treating AC joint separations in both starting pitchers and position players, as well as to describe the long-term outcomes of their preferred treatment, including time to return to full clearance for pitching, whether their patients returned to their prior level of play, and whether these patients had full pain relief. Finally, physicians were asked if any of the nonoperatively treated players ultimately crossed over and required operative intervention.

Continue to: Statistics...

STATISTICS

Descriptive statistics were used for continuous variables, and frequencies were used for categorical variables. Linear regression was performed to determine the correlation between the physician’s training or experience in treating AC joint separations and their recommended treatment. Fischer’s exact test/chi-square analysis was used to compare categorical variables. All tests were conducted using 2-sided hypothesis testing with statistical significance set at P < .05. All statistical analyses were conducted with SPSS 21.0 software (IBM Corporation).

RESULTS

A total of 28 MLB team physicians completed the questionnaires from 18 of the 30 MLB teams. The average age of the responders was 50.5 years (range, 34-60 years), with an average of 18.2 years in practice (range, 2-30 years) and 10.8 years (range, 1-24 years) taking care of their current professional baseball team. About 82% of the team physicians completed a sports medicine fellowship. On average, physicians saw 16.6 (range, 5-50) grade III or higher AC joint separations per year, and operated on 4.6 (range, 0-10) per year.

Nonoperative treatment was the preferred treatment for a grade III AC joint separation in a starting professional baseball pitcher for the majority of team physicians (20/28). No correlation was observed between the physician’s age (P = .881), years in practice (P = .915), years taking care of their professional team (P = .989), percentage of practice focused on shoulders (P = .986), number of AC joint injuries seen (P = .325), or number of surgeries performed per year (P = .807) with the team physician’s preferred treatment. Compared to the proportion reported originally by McFarland and colleagues¹³ in 1997 (69%), there was no difference in the proportion of team physicians that recommended nonoperative treatment (P = 1).

If treating this injury nonoperatively, 46.4% of physicians would also use an injection, with orthobiologics (eg, platelet-rich plasma) as the most popular choice (Table 1). No consensus was provided on the timeframe to return pitchers back to a progressive interval throwing program; however, 46.67% of physicians would return pitchers 4 to 6 weeks after a nonoperatively treated injury, while 35.7% would return pitchers 7 to 12 weeks after the initial injury.

Table 1. Treatment Preferences of Grade III AC Separation by MLB Team Physicians

^aRespondents were allowed to choose more than 1 treatment in each category. ^bChosen as an adjunct treatment.

Abbreviations: AC, acromioclavicular; MLB, major league baseball.

Most physicians (64.3%) cited functional limitations as the most important reason for indicating operative treatment, followed by pain (21.4%), and a deformity (14.3%). About 65% preferred open coracoclavicular ligament reconstruction. No physician recommended the Weaver-Dunn procedure or use of hardware (eg, hook plate). Of those who preferred an operative intervention, 66.7% would also include a distal clavicle excision, which is significantly higher than the proportion reported by McFarland and colleagues¹³ (23%, P = .0170). About 90% of physicians would return pitchers to play >12 weeks after operative treatment.

Continue to: If the injury occurred at the end ...

If the injury occurred at the end of the season, 7 of the 20 orthopedists (35%) who recommended nonoperative treatment said they would change to an operative intervention. Eighteen of 28 responders would have the same algorithm for MLB position players. Team physicians were less likely to recommend operative intervention in position players due to less demand on the arm and increased ability to accommodate the injury by altering their throwing mechanics.

Eighteen (64%) of the team physicians had treated at least 1 professional pitcher with a grade III AC separation in his dominant arm, and 11 (39.3%) had treated >1. Collectively, team physicians had treated 15 professional pitchers operatively, and 51 nonoperatively; only 3 patients converted to operative intervention after a failed nonoperative treatment.

Of the pitchers treated operatively, 93.3% (14) of pitchers returned to their prior level of pitching. The 1 patient who failed to return to the same level of pitching retired instead of returning to play. About 80% (12) of the pitchers had full pain relief, and 93.3% (14) had full range of motion (ROM). The pitcher who failed to regain full ROM also had a concomitant rotator cuff repair. The only complication reported from an operative intervention was a pitcher who sustained a coracoid fracture 10 months postoperatively while throwing 100 mph. Of the pitchers treated nonoperatively, 96% returned to their prior level of pitching, 92.2% (47) had full complete pain relief when throwing, and 100% had full ROM. No differences were observed between the proportion of pitchers who returned to their prior level of pitching, regained full ROM, or had full pain relief in the operative and nonoperative groups (Table 2).

Table 2. Outcomes of Treatment of Grade III AC Separation in 58 Professional Baseball Players

Abbreviations: AC, acromioclavicular; ROM, range of motion.

DISCUSSION 

Controversy persists regarding the optimal management of acute grade III AC separations, with the current available evidence potentially suggesting better cosmetic and radiological results but no definite differences in clinical results.^1-6,17,18 In the absence of formal clinical practice guidelines, surgeons rely on their own experience or defer to the anecdotal experience of experts in the field. Our initial hypothesis was false in this survey of MLB team physicians taking care of overhead throwing athletes at the highest level. Our results demonstrate that despite improved techniques and an increased understanding of the pathophysiology of AC joint separations, conservative management is still the preferred treatment for acute grade III AC joint separations in professional baseball pitchers. The proportion of team physicians recommending nonoperative treatment in our series was essentially equivalent to the results reported by McFarland and colleagues¹³ in 1997, suggesting that the pendulum continues to favor conservative management initially. This status quo likely reflects both the dearth of literature suggesting a substantial benefit of acute operative repair, as well as the ability to accommodate with conservative measures after most grade III AC injuries, even at the highest level of athletic competition.

These results are also consistent with trends from the last few decades. In the 1970s, the overwhelming preference for treating an acute complete AC joint separation was surgical repair, with Powers and Bach¹⁰ reporting in a 1974 survey of 163 chairmen of orthopedic programs around the country that 91.5% advocated surgical treatment. However, surgical preference had reversed by the 1990s. Of the 187 chairmen and 59 team physicians surveyed by Cox¹⁹ in 1992, 72% and 86% respectively preferred nonoperative treatment in a theoretical 21-year-old athlete with a grade III AC separation. Nissen and Chatterjee²⁰ reported in 2007 on a survey of all American Orthopaedic Society for Sports Medicine surgeons (N = 577) and Accreditation Council for Graduate Medical Education orthopedic program residency directors (N = 87) that >80% of responders preferred conservative measures for this acute injury. The reversal of trends has also been corroborated by recent multicenter trials demonstrating no difference in clinical outcomes between operative and nonoperative treatment of high grade AC joint dislocations, albeit these patients were not all high level overhead throwing athletes.^17,18

Continue to: The trends in surgical interventions are notable...

The trends in surgical interventions are notable within the smaller subset of patients who are indicated for operative repair. Use of hardware and primary ligament repair, while popular in the surveys conducted in the 1970s¹⁰ and 1990s¹³ and even present in Nissen and Chatterjee’s²⁰ 2007 survey, were noticeably absent from our survey results, with the majority of respondents preferring open coracoclavicular ligament reconstruction. The role of distal clavicle excision has also expanded, from 23% of team physicians recommending it in 1997¹³ to 57% to 59% in Nissen and Chatterjee’s²⁰ 2007 survey, to 66.7% in our series. This trend is not surprising as several recent cadaveric biomechanical studies have demonstrated that not only do peak graft forces not increase significantly,²¹ the anterior-posterior and superior-inferior motion at the AC joint following ligament reconstruction is maintained despite resection of the lateral clavicle.²² Additionally, primary distal clavicle excision may prevent the development of post-traumatic arthritis at the AC joint and osteolysis of the distal clavicle as a possible pain generator in the future.²³ However, some respondents cautioned against performing a concomitant distal clavicle excision, as some biomechanical data demonstrate that resecting the distal clavicle may lead to increased horizontal translation at the AC joint despite intact superior and posterior AC capsules.²⁴ Professional baseball pitchers may also be more lax and thus prone to more instability. Primary repair or reconstruction may not always lead to complete pre-injury stability in these individuals. This subtle unrecognized instability is hard to diagnosis and may be a persistent source of pain; thus, adding a distal clavicle excision may actually exacerbate the instability.

The nuanced indications for operative intervention, such as the presence of associated lesions were not captured by our survey.²⁵ While most team physicians cited functional limitations as their most common reason for offering surgery, several MLB orthopedic surgeons also commented on evaluating the stability of the AC joint after a grade III injury, akin to the consensus statement from the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) Upper Extremity Committee²⁶ in 2014 that diversified the Rockwood Grade III AC joint separation into its IIIA and IIIB classifications. The ISAKOS recommendations include initial conservative management and a second evaluation (both clinical and radiographic) for grade III lesions 3 to 6 weeks after the injury. However, as professional baseball is an incredibly profitable sport with an annual revenue approaching $9.5 billion²⁷ and pitching salaries up to $32.5 million in 2015, serious financial considerations must be given to players who wish to avoid undergoing delayed surgery.

This study has shortcomings typical of expert opinion papers. The retrospective nature of this study places the data at risk of recall bias. Objective data (eg, terminal ROM, pain relief, and return to play) were obtained from a retrospective chart review; however, no standard documentation or collection method was used given the number of surgeons involved and, thus, conclusions based on treatment outcomes are imperfect. Another major weakness of this survey is the relatively small number of patients and respondents. An a priori power analysis was not available, as this was a retrospective review. A comparative trial will be necessary to definitively support one treatment over another. Assuming a 95% return to play in the nonoperatively treated group, approximately 300 patients would be needed in a prospective 2-armed study with 80% power to detect a 10% reduction in the incidence of return to play using an alpha level of 0.05 and assuming no loss to follow-up. This sample size would be difficult to achieve in this patient population.

However, compared to past series,¹³ the number of professional baseball players treated by the collective experience of these MLB team physicians is the largest reported to date. As suggested above, the rarity of this condition in elite athletes precludes the ability to have matched controls to definitively determine the optimal treatment, which may explain the lack of difference in the return to play, ROM, and pain relief outcomes. Instead, we can only extrapolate based on the collective anecdotal experience of the MLB team physicians.

CONCLUSION

Despite advances in surgical technique and understanding of throwing mechanics, the majority of MLB team physicians preferred nonoperative management for an acute grade III AC joint separation in a professional baseball pitcher. Open coracoclavicular ligament reconstruction was preferred for those who preferred operative intervention. An increasing number of orthopedic surgeons now consider a distal clavicle excision as an adjunct procedure.

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

ABSTRACT

The traditional technique for patella fracture fixation utilizes prominent hardware. Prominent hardware use, however, results in a high rate of reoperation for symptomatic implant removal. This biomechanical study evaluates the effectiveness of a novel patella fixation technique that minimizes implant prominence.

Patellar transverse osteotomies were created in 13 pairs of cadaveric knees. Paired knees were assigned to either standard fixation (SF) using cannulated partially threaded screws and stainless steel wire tension band, or buried fixation (BF) using headless compression screws with a No. 2 FiberWire tension band and a No. 5 FiberWire cerclage suture. Quadriceps tendons were cyclically loaded to full extension followed by load to failure. The gap across the fracture site, stiffness, and load to failure were measured.

The differences in stiffness and load to failure between the 2 groups were not statistically significant. During cyclic loading, significantly greater gapping was observed across the fracture site in the BF group compared with SF group (P < .05).

Both constructs failed under loads that exceeded typical loads experienced during the postoperative rehabilitation period. Nevertheless, the BF technique demonstrated larger gap formation and a reduced load to failure than the SF technique. Further clinical studies are therefore underway to determine whether the use of constructs with decreased stability but increased patient comfort could improve clinical outcomes and reduce reoperation rates.

Continue to: Patella fractures are common...

Patella fractures are common injuries that can cause considerable disability to the knee extensor apparatus.^1-3 Transverse patella fractures are the most common fracture pattern associated with patella fractures.{Harrell, 2003 #3}² Given that the patella plays a crucial role in knee extensor biomechanics, its proper integrity is vital for physiological knee motion and ambulation.⁴ Traditionally, patella fractures with >2 mm of displacement have been managed with cannulated screws or Kirschner wires (K-wires) and a stainless-steel wire tension band.^5-9 The goal in the treatment of patellar fractures is to reduce fracture fragments accurately and to minimize additional insults to the articular cartilage.¹⁰

Despite advances in surgical protocols and acceptable radiographic outcomes, functional impairment remains common after the treatment of patella fractures. Functional impairment includes knee pain, screw head pain, implant removal, wire breakage, and patella baja.¹ The need for implant removal is one of the most common complications following the open reduction internal fixation of patella fractures.^2,11 The subcutaneous and exposed nature of the patella in conjunction with soft tissue irritation resulting from standard fixation (SF) predisposes the patient toward prominence and discomfort with the retained implant. Although nonunion rates are low, the rate of implant removal can reach as high as 52%.^2,10-12 To overcome some of these complications, we designed a novel buried fixation (BF) method for the treatment of transverse fractures. Our method minimizes the amount of exposed implant to improve patient comfort and potentially reduce the need for future implant removal. These effects are achieved by using headless compression screws and nonabsorbable sutures to attenuate the soft tissue irritation associated with traditional fixation.¹³ While our novel technique has demonstrated improved clinical results, it has not been tested biomechanically against a traditional fixation technique. Therefore, this study aims to evaluate and compare the structural integrity of our novel BF technique with that of the standard technique that uses cannulated screws and wire tension band. We hypothesized that the stability provided by our technique would be similar to that provided by SF for transverse patella fractures.

MATERIALS AND METHODS

SPECIMEN PREPARATION

Thirteen matched pairs of fresh-frozen human cadaveric knees were obtained from a Cedars-Sinai approved tissue bank. Specimens were cut midfemur and were intact to the foot. Legs with major structural bony or ligamentous abnormalities, extensor mechanism disruption, or septic knees were excluded from testing. To assess the bone quality of each specimen prior to testing, dual-energy X-ray absorptiometry was performed using a GE Lunar iDXA scanner (GE Healthcare). Specimens were stored at −30°C and thawed at room temperature for 24 hours prior to biomechanical testing.

A midline anterior approach to the patella was performed, and the extensor retinaculum, quadriceps tendon, and patellar tendon were exposed. A digital caliper was used to measure the craniocaudal and mediolateral dimensions of the patella, and a transverse osteotomy (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association [AO/OTA] type 34-C1) was created at the midway point between superior and inferior poles by using an oscillating saw. The retinaculum was then incised to the level of the midaxial line of the femur. One leg from each matched pair was allocated to the SF group, and the other was allocated to the BF group. Left and right legs were alternately assigned to each group to ensure that laterality was balanced between the 2 groups.

SURGICAL TECHNIQUE

The repair of the specimens in the SF group involved the use of 2 parallel 4.0-mm partially threaded cannulated screws (Acumed) and an 18-gauge monofilament steel wire (Ethicon) in a figure-eight tension band (Figure 1A). The repair of the specimens in the BF group involved the use of 2 parallel standard Acutrak headless compression screws (Acumed), a No. 2 FiberWire (Arthrex) in a figure-eight tension band, and a No. 5 FiberWire (Arthrex) was applied as cerclage around the patella (Figure 1B).

Continue to: Mechanical testing...

MECHANICAL TESTING

Mechanical testing was performed on a biaxial 370.02 Bionix Testing System (MTS Systems Corp.). The femur was rigidly and horizontally secured to a custom-built test frame, and the lower leg was left free to move. The quadriceps tendon was secured in a freeze clamp and was attached to the MTS actuator for loading via a pulley system such that raising the actuator was translated into a simulated quadriceps extensor force.

A differential variable reluctance transducer (DVRT) (Lord MicroStrain) was placed across the osteotomy site to measure the distraction, or gap, across the fracture line. The minimum load to full extension for each specimen was then determined under a slow, controlled increase in load until the leg was in a fully extended position. Any distraction across the fracture line during the initial loading phase was determined by using digital calipers. The specimen was then subjected to a preconditioning phase with 10 cycles from 0 N to full extension under the previously determined load, which was applied at the rate of 5 N/s. Meanwhile, displacement across the fracture site was recorded via the DVRT. Following the preconditioning phase, each specimen was then tested to failure in displacement control at the rate of 1.5 mm/s. Failure was defined as implant failure (screw pullout) or DVRT gapping across the osteotomy site >3 mm.^10,14

Outcome measures included stiffness (N/mm), which was calculated as the slope of the linear change in load from full extension to failure vs DVRT displacement during the final loading phase; failure load (N); gapping (mm) across the osteotomy site at each cycle during the preconditioning phase; and failure mode (pullout vs >3.0 mm gap).

STATISTICAL ANALYSIS

An a priori power analysis revealed that 13 knees per group would be required to obtain an α of 0.05 and a power of 0.80. This calculation was based on a 20% difference in fracture displacement calculated by using the standard deviation and mean previously reported for cannulated screws with nonabsorbable sutures.¹⁴

Means and standard deviations for all dependent outcome measures were computed and compared across the independent measure of fixation type (BF vs SF) through repeated measures Analysis of variance (ANOVA-GLM, SAS 9.3, SAS Institute, Inc.) after controlling for bone mineral density (BMD), gender, and age. Multivariate repeated-measures ANOVA with Tukey's studentized range was applied to cyclic gap data. The mode of failure was compared across fixation type (BF vs SF) for matched data using McNemar’s test. Intracorrelations were computed and examined over all data and separately on the basis of screw fixation type (BF vs SF). All tests were considered statistically significant when P < .05.

Continue to: Results...

RESULTS

Specimen donors were 46% (6/13) male with an average age of 78.5 years (±13.77; range, 56-91 years) and 54% (7/13) female with an average age of 76.57 years (±14.37; range, 59-102 years). Average BMD was significantly lower in female (0.71 ± 0.18) than in male specimens (1.15 ± 0.33) (P < .05).

The average load to full extension across all specimens was 272 N (±54; range, 160-360 N) and was well balanced across matched pairs (270 ± 56 N for BF and 273 ± 54 N for SF). Of the 13 BF specimens, 4 experienced distraction across the fracture line during the determination of the minimum load to full extension. This initial pretest gap was measured with digital calipers (average, 1.5 mm; range, 0.90-1.85 mm) and added as an offset to the respective DVRT displacement data recorded during testing.

The total number of specimens included in the displacement data calculations decreased from 13 to 11 per group because DVRT data were not recorded during cyclic loading for 1 specimen and were considered unreliable in another. The maximum displacement measured across the fracture site during cyclic loading was significantly higher in the BF (0.94 ± 1.21) group than in the SF group (0.19 ± 0.26) as shown in the Table. The average slope of the gap per cycle for each specimen was calculated and compared between the BF and SF groups. The BF group demonstrated a significantly greater increase in gap per cycle than the SF group (Figure 2). Stiffness during load to failure was calculated for all but 1 specimen that did not display any measurable displacement during the final loading cycle. The average final stiffness and failure load between the BF and SF groups were not significantly different (Table). An equal number of specimens in both groups failed through gapping (6/13) and pullout (7/13).

Table. Means and Standard Deviations of the Main Outcome Measures

^aIndicates statistical significance (P < .05).

Abbreviation: NS, not significant.

Failure load was significantly positively correlated with BMD (R = 0.62, P < .001) when all specimens were grouped together. When analyzed separately, the SF group was significantly correlated with BMD (P < .01), whereas the BF group had a marginally significant correlation (P = .06) with BMD (Figure 3). In both groups, BMD was positively correlated with stiffness and negatively correlated with gapping. Neither of these trends, however, was significant.

Continue to: Discussion...

DISCUSSION

We proposed a novel BF technique for the treatment of noncomminuted transverse patella fractures. Our technique utilizes headless cannulated compression screws and nonabsorbable suture tension bands. We then biomechanically compared our proposed technique with an established fixation technique that uses partially threaded cannulated screws and stainless steel wire tension bands. We hypothesized that the mechanical response of the BF technique to cyclic and failure loading would be similar to that of the SF technique. Our results demonstrate a significant increase in gap formation across the fracture site among knees and an overall reduced load to failure in the BF group (Figure 2). Whether these inferior results manifest clinically is not yet established. Both constructs could withstand forces that are typically experienced during the postoperative period. Given the high rate of symptomatic implant removal associated with the traditional technique, the low-profile buried technique might be an attractive alternative that provides increased patient comfort but may require an extended period of postoperative protection against bony ingrowths.

Patellar fixation constructs that use a combination of cannulated screws and a wire tension band provide the best resistance to patella fracture displacement when compared with screws or wires alone.^4,15 Although this combination is biomechanically favorable, the steel wire often causes the painful irritation of the surrounding soft tissues and can break or migrate, thus increasing the rates of implant removal surgery to as high as 52%.^4,10,12,15 We developed our novel BF technique, which uses headless compression screws and a No. 2 FiberWire tension band, to address the high rates of reoperation and patient dissatisfaction associated with the SF technique.

Headless compression screws have been successfully used in the reduction and fixation of scaphoid fractures and sesamoid fractures.^16,17 The pull-out strengths of these screws are comparable with those of other commonly used screws, such as Twinfix and Herbert-Whipple screws.¹⁶ Similarly, the strength of a No. 5 FiberWire is comparable with that of an 18-gauge stainless-steel wire.^14,18 Several studies have also obtained good outcomes with nonmetallic constructs that use nonabsorbable sutures alone.^19,20 In this study, we utilized a No. 2 FiberWire as the tension band. The use of the No. 2 FiberWire facilitated threading through headless cannulated screws and created a low-profile knot. However, the use of thin FiberWire, despite a No. 5 FiberWire cerclage, likely contributed to the increase in distraction across the fracture.

The highest patellofemoral joint reaction force during level walking is approximately 35 kg (half body weight), which is equivalent to 350 N.^15,21,22 This force is similar to the average cyclic load used in this experiment (272 ± 54 N). Gapping increased in the BF group but did not reach the defined failure value of 3 mm, and the ultimate load to failure was relatively high across both groups (SF, 1123 N; BF, 973 N). These results suggest that both fixation methods can withstand the typical patellofemoral joint forces that are experienced during the postoperative period.⁴ In addition, in a clinical setting, patients are placed in hinged knee braces for at least 2 weeks to limit their flexion angle and to allow for healing and bony ingrowth. Postoperative knee-brace protection presumably increases the overall strength of the fixation.

The number of specimens (n = 26) evaluated in this study was greater than that used in other biomechanical patella fracture studies.¹⁴ Furthermore, none of our specimens were reused. Our study design was further strengthened given that fellowship-trained trauma surgeons performed all surgical procedures. Finally, the data collection and analysis of numerous clinically relevant factors, such as BMD, age, and cyclical loading, contributed to the comprehensive description of each technique with respect to patient-specific criteria.

Similar to all cadaveric studies, our data only represent the immediate postoperative condition and does not represent any healing that would occur during postoperative rehabilitation. Postoperative knee-brace protection and bone healing across the fracture site would likely strengthen both constructs in a clinical setting. In addition, the average age of our specimens is 77.5 years, and therefore does not best represent the age range (20-50 years) of the typical adult population affected by patella fractures.^3,23,24 Finally, postsurgical reduction was confirmed through visual inspection and not through fluoroscopy as in a clinical setting. Radiographic images were obtained after each experiment only to confirm screw placement post facto (Figures 4A, 4B).

CONCLUSION

This study demonstrates the utility of a novel BF technique. Nevertheless, the proposed technique exhibited increased gapping and a lower load to failure than the current gold standard. The significance of these inferior results in clinical and functional settings has not been established. The proposed BF technique may be an appealing alternative to the SF technique given its low profile and potential to reduce the rates of future implant removal. Further studies on the long-term outcomes of patients treated through the BF technique are currently under way and will ultimately determine the utility of the proposed construct.

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

ABSTRACT

The traditional technique for patella fracture fixation utilizes prominent hardware. Prominent hardware use, however, results in a high rate of reoperation for symptomatic implant removal. This biomechanical study evaluates the effectiveness of a novel patella fixation technique that minimizes implant prominence.

Patellar transverse osteotomies were created in 13 pairs of cadaveric knees. Paired knees were assigned to either standard fixation (SF) using cannulated partially threaded screws and stainless steel wire tension band, or buried fixation (BF) using headless compression screws with a No. 2 FiberWire tension band and a No. 5 FiberWire cerclage suture. Quadriceps tendons were cyclically loaded to full extension followed by load to failure. The gap across the fracture site, stiffness, and load to failure were measured.

The differences in stiffness and load to failure between the 2 groups were not statistically significant. During cyclic loading, significantly greater gapping was observed across the fracture site in the BF group compared with SF group (P < .05).

Both constructs failed under loads that exceeded typical loads experienced during the postoperative rehabilitation period. Nevertheless, the BF technique demonstrated larger gap formation and a reduced load to failure than the SF technique. Further clinical studies are therefore underway to determine whether the use of constructs with decreased stability but increased patient comfort could improve clinical outcomes and reduce reoperation rates.

Continue to: Patella fractures are common...

Patella fractures are common injuries that can cause considerable disability to the knee extensor apparatus.^1-3 Transverse patella fractures are the most common fracture pattern associated with patella fractures.{Harrell, 2003 #3}² Given that the patella plays a crucial role in knee extensor biomechanics, its proper integrity is vital for physiological knee motion and ambulation.⁴ Traditionally, patella fractures with >2 mm of displacement have been managed with cannulated screws or Kirschner wires (K-wires) and a stainless-steel wire tension band.^5-9 The goal in the treatment of patellar fractures is to reduce fracture fragments accurately and to minimize additional insults to the articular cartilage.¹⁰

Despite advances in surgical protocols and acceptable radiographic outcomes, functional impairment remains common after the treatment of patella fractures. Functional impairment includes knee pain, screw head pain, implant removal, wire breakage, and patella baja.¹ The need for implant removal is one of the most common complications following the open reduction internal fixation of patella fractures.^2,11 The subcutaneous and exposed nature of the patella in conjunction with soft tissue irritation resulting from standard fixation (SF) predisposes the patient toward prominence and discomfort with the retained implant. Although nonunion rates are low, the rate of implant removal can reach as high as 52%.^2,10-12 To overcome some of these complications, we designed a novel buried fixation (BF) method for the treatment of transverse fractures. Our method minimizes the amount of exposed implant to improve patient comfort and potentially reduce the need for future implant removal. These effects are achieved by using headless compression screws and nonabsorbable sutures to attenuate the soft tissue irritation associated with traditional fixation.¹³ While our novel technique has demonstrated improved clinical results, it has not been tested biomechanically against a traditional fixation technique. Therefore, this study aims to evaluate and compare the structural integrity of our novel BF technique with that of the standard technique that uses cannulated screws and wire tension band. We hypothesized that the stability provided by our technique would be similar to that provided by SF for transverse patella fractures.

MATERIALS AND METHODS

SPECIMEN PREPARATION

Thirteen matched pairs of fresh-frozen human cadaveric knees were obtained from a Cedars-Sinai approved tissue bank. Specimens were cut midfemur and were intact to the foot. Legs with major structural bony or ligamentous abnormalities, extensor mechanism disruption, or septic knees were excluded from testing. To assess the bone quality of each specimen prior to testing, dual-energy X-ray absorptiometry was performed using a GE Lunar iDXA scanner (GE Healthcare). Specimens were stored at −30°C and thawed at room temperature for 24 hours prior to biomechanical testing.

A midline anterior approach to the patella was performed, and the extensor retinaculum, quadriceps tendon, and patellar tendon were exposed. A digital caliper was used to measure the craniocaudal and mediolateral dimensions of the patella, and a transverse osteotomy (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association [AO/OTA] type 34-C1) was created at the midway point between superior and inferior poles by using an oscillating saw. The retinaculum was then incised to the level of the midaxial line of the femur. One leg from each matched pair was allocated to the SF group, and the other was allocated to the BF group. Left and right legs were alternately assigned to each group to ensure that laterality was balanced between the 2 groups.

SURGICAL TECHNIQUE

The repair of the specimens in the SF group involved the use of 2 parallel 4.0-mm partially threaded cannulated screws (Acumed) and an 18-gauge monofilament steel wire (Ethicon) in a figure-eight tension band (Figure 1A). The repair of the specimens in the BF group involved the use of 2 parallel standard Acutrak headless compression screws (Acumed), a No. 2 FiberWire (Arthrex) in a figure-eight tension band, and a No. 5 FiberWire (Arthrex) was applied as cerclage around the patella (Figure 1B).

Continue to: Mechanical testing...

MECHANICAL TESTING

Mechanical testing was performed on a biaxial 370.02 Bionix Testing System (MTS Systems Corp.). The femur was rigidly and horizontally secured to a custom-built test frame, and the lower leg was left free to move. The quadriceps tendon was secured in a freeze clamp and was attached to the MTS actuator for loading via a pulley system such that raising the actuator was translated into a simulated quadriceps extensor force.

A differential variable reluctance transducer (DVRT) (Lord MicroStrain) was placed across the osteotomy site to measure the distraction, or gap, across the fracture line. The minimum load to full extension for each specimen was then determined under a slow, controlled increase in load until the leg was in a fully extended position. Any distraction across the fracture line during the initial loading phase was determined by using digital calipers. The specimen was then subjected to a preconditioning phase with 10 cycles from 0 N to full extension under the previously determined load, which was applied at the rate of 5 N/s. Meanwhile, displacement across the fracture site was recorded via the DVRT. Following the preconditioning phase, each specimen was then tested to failure in displacement control at the rate of 1.5 mm/s. Failure was defined as implant failure (screw pullout) or DVRT gapping across the osteotomy site >3 mm.^10,14

Outcome measures included stiffness (N/mm), which was calculated as the slope of the linear change in load from full extension to failure vs DVRT displacement during the final loading phase; failure load (N); gapping (mm) across the osteotomy site at each cycle during the preconditioning phase; and failure mode (pullout vs >3.0 mm gap).

STATISTICAL ANALYSIS

An a priori power analysis revealed that 13 knees per group would be required to obtain an α of 0.05 and a power of 0.80. This calculation was based on a 20% difference in fracture displacement calculated by using the standard deviation and mean previously reported for cannulated screws with nonabsorbable sutures.¹⁴

Means and standard deviations for all dependent outcome measures were computed and compared across the independent measure of fixation type (BF vs SF) through repeated measures Analysis of variance (ANOVA-GLM, SAS 9.3, SAS Institute, Inc.) after controlling for bone mineral density (BMD), gender, and age. Multivariate repeated-measures ANOVA with Tukey's studentized range was applied to cyclic gap data. The mode of failure was compared across fixation type (BF vs SF) for matched data using McNemar’s test. Intracorrelations were computed and examined over all data and separately on the basis of screw fixation type (BF vs SF). All tests were considered statistically significant when P < .05.

Continue to: Results...

RESULTS

Specimen donors were 46% (6/13) male with an average age of 78.5 years (±13.77; range, 56-91 years) and 54% (7/13) female with an average age of 76.57 years (±14.37; range, 59-102 years). Average BMD was significantly lower in female (0.71 ± 0.18) than in male specimens (1.15 ± 0.33) (P < .05).

The average load to full extension across all specimens was 272 N (±54; range, 160-360 N) and was well balanced across matched pairs (270 ± 56 N for BF and 273 ± 54 N for SF). Of the 13 BF specimens, 4 experienced distraction across the fracture line during the determination of the minimum load to full extension. This initial pretest gap was measured with digital calipers (average, 1.5 mm; range, 0.90-1.85 mm) and added as an offset to the respective DVRT displacement data recorded during testing.

The total number of specimens included in the displacement data calculations decreased from 13 to 11 per group because DVRT data were not recorded during cyclic loading for 1 specimen and were considered unreliable in another. The maximum displacement measured across the fracture site during cyclic loading was significantly higher in the BF (0.94 ± 1.21) group than in the SF group (0.19 ± 0.26) as shown in the Table. The average slope of the gap per cycle for each specimen was calculated and compared between the BF and SF groups. The BF group demonstrated a significantly greater increase in gap per cycle than the SF group (Figure 2). Stiffness during load to failure was calculated for all but 1 specimen that did not display any measurable displacement during the final loading cycle. The average final stiffness and failure load between the BF and SF groups were not significantly different (Table). An equal number of specimens in both groups failed through gapping (6/13) and pullout (7/13).

Table. Means and Standard Deviations of the Main Outcome Measures

^aIndicates statistical significance (P < .05).

Abbreviation: NS, not significant.

Failure load was significantly positively correlated with BMD (R = 0.62, P < .001) when all specimens were grouped together. When analyzed separately, the SF group was significantly correlated with BMD (P < .01), whereas the BF group had a marginally significant correlation (P = .06) with BMD (Figure 3). In both groups, BMD was positively correlated with stiffness and negatively correlated with gapping. Neither of these trends, however, was significant.

Continue to: Discussion...

DISCUSSION

We proposed a novel BF technique for the treatment of noncomminuted transverse patella fractures. Our technique utilizes headless cannulated compression screws and nonabsorbable suture tension bands. We then biomechanically compared our proposed technique with an established fixation technique that uses partially threaded cannulated screws and stainless steel wire tension bands. We hypothesized that the mechanical response of the BF technique to cyclic and failure loading would be similar to that of the SF technique. Our results demonstrate a significant increase in gap formation across the fracture site among knees and an overall reduced load to failure in the BF group (Figure 2). Whether these inferior results manifest clinically is not yet established. Both constructs could withstand forces that are typically experienced during the postoperative period. Given the high rate of symptomatic implant removal associated with the traditional technique, the low-profile buried technique might be an attractive alternative that provides increased patient comfort but may require an extended period of postoperative protection against bony ingrowths.

Patellar fixation constructs that use a combination of cannulated screws and a wire tension band provide the best resistance to patella fracture displacement when compared with screws or wires alone.^4,15 Although this combination is biomechanically favorable, the steel wire often causes the painful irritation of the surrounding soft tissues and can break or migrate, thus increasing the rates of implant removal surgery to as high as 52%.^4,10,12,15 We developed our novel BF technique, which uses headless compression screws and a No. 2 FiberWire tension band, to address the high rates of reoperation and patient dissatisfaction associated with the SF technique.

Headless compression screws have been successfully used in the reduction and fixation of scaphoid fractures and sesamoid fractures.^16,17 The pull-out strengths of these screws are comparable with those of other commonly used screws, such as Twinfix and Herbert-Whipple screws.¹⁶ Similarly, the strength of a No. 5 FiberWire is comparable with that of an 18-gauge stainless-steel wire.^14,18 Several studies have also obtained good outcomes with nonmetallic constructs that use nonabsorbable sutures alone.^19,20 In this study, we utilized a No. 2 FiberWire as the tension band. The use of the No. 2 FiberWire facilitated threading through headless cannulated screws and created a low-profile knot. However, the use of thin FiberWire, despite a No. 5 FiberWire cerclage, likely contributed to the increase in distraction across the fracture.

The highest patellofemoral joint reaction force during level walking is approximately 35 kg (half body weight), which is equivalent to 350 N.^15,21,22 This force is similar to the average cyclic load used in this experiment (272 ± 54 N). Gapping increased in the BF group but did not reach the defined failure value of 3 mm, and the ultimate load to failure was relatively high across both groups (SF, 1123 N; BF, 973 N). These results suggest that both fixation methods can withstand the typical patellofemoral joint forces that are experienced during the postoperative period.⁴ In addition, in a clinical setting, patients are placed in hinged knee braces for at least 2 weeks to limit their flexion angle and to allow for healing and bony ingrowth. Postoperative knee-brace protection presumably increases the overall strength of the fixation.

The number of specimens (n = 26) evaluated in this study was greater than that used in other biomechanical patella fracture studies.¹⁴ Furthermore, none of our specimens were reused. Our study design was further strengthened given that fellowship-trained trauma surgeons performed all surgical procedures. Finally, the data collection and analysis of numerous clinically relevant factors, such as BMD, age, and cyclical loading, contributed to the comprehensive description of each technique with respect to patient-specific criteria.

Similar to all cadaveric studies, our data only represent the immediate postoperative condition and does not represent any healing that would occur during postoperative rehabilitation. Postoperative knee-brace protection and bone healing across the fracture site would likely strengthen both constructs in a clinical setting. In addition, the average age of our specimens is 77.5 years, and therefore does not best represent the age range (20-50 years) of the typical adult population affected by patella fractures.^3,23,24 Finally, postsurgical reduction was confirmed through visual inspection and not through fluoroscopy as in a clinical setting. Radiographic images were obtained after each experiment only to confirm screw placement post facto (Figures 4A, 4B).

CONCLUSION

This study demonstrates the utility of a novel BF technique. Nevertheless, the proposed technique exhibited increased gapping and a lower load to failure than the current gold standard. The significance of these inferior results in clinical and functional settings has not been established. The proposed BF technique may be an appealing alternative to the SF technique given its low profile and potential to reduce the rates of future implant removal. Further studies on the long-term outcomes of patients treated through the BF technique are currently under way and will ultimately determine the utility of the proposed construct.

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

ABSTRACT

The traditional technique for patella fracture fixation utilizes prominent hardware. Prominent hardware use, however, results in a high rate of reoperation for symptomatic implant removal. This biomechanical study evaluates the effectiveness of a novel patella fixation technique that minimizes implant prominence.

Patellar transverse osteotomies were created in 13 pairs of cadaveric knees. Paired knees were assigned to either standard fixation (SF) using cannulated partially threaded screws and stainless steel wire tension band, or buried fixation (BF) using headless compression screws with a No. 2 FiberWire tension band and a No. 5 FiberWire cerclage suture. Quadriceps tendons were cyclically loaded to full extension followed by load to failure. The gap across the fracture site, stiffness, and load to failure were measured.

The differences in stiffness and load to failure between the 2 groups were not statistically significant. During cyclic loading, significantly greater gapping was observed across the fracture site in the BF group compared with SF group (P < .05).

Both constructs failed under loads that exceeded typical loads experienced during the postoperative rehabilitation period. Nevertheless, the BF technique demonstrated larger gap formation and a reduced load to failure than the SF technique. Further clinical studies are therefore underway to determine whether the use of constructs with decreased stability but increased patient comfort could improve clinical outcomes and reduce reoperation rates.

Continue to: Patella fractures are common...

Patella fractures are common injuries that can cause considerable disability to the knee extensor apparatus.^1-3 Transverse patella fractures are the most common fracture pattern associated with patella fractures.{Harrell, 2003 #3}² Given that the patella plays a crucial role in knee extensor biomechanics, its proper integrity is vital for physiological knee motion and ambulation.⁴ Traditionally, patella fractures with >2 mm of displacement have been managed with cannulated screws or Kirschner wires (K-wires) and a stainless-steel wire tension band.^5-9 The goal in the treatment of patellar fractures is to reduce fracture fragments accurately and to minimize additional insults to the articular cartilage.¹⁰

Despite advances in surgical protocols and acceptable radiographic outcomes, functional impairment remains common after the treatment of patella fractures. Functional impairment includes knee pain, screw head pain, implant removal, wire breakage, and patella baja.¹ The need for implant removal is one of the most common complications following the open reduction internal fixation of patella fractures.^2,11 The subcutaneous and exposed nature of the patella in conjunction with soft tissue irritation resulting from standard fixation (SF) predisposes the patient toward prominence and discomfort with the retained implant. Although nonunion rates are low, the rate of implant removal can reach as high as 52%.^2,10-12 To overcome some of these complications, we designed a novel buried fixation (BF) method for the treatment of transverse fractures. Our method minimizes the amount of exposed implant to improve patient comfort and potentially reduce the need for future implant removal. These effects are achieved by using headless compression screws and nonabsorbable sutures to attenuate the soft tissue irritation associated with traditional fixation.¹³ While our novel technique has demonstrated improved clinical results, it has not been tested biomechanically against a traditional fixation technique. Therefore, this study aims to evaluate and compare the structural integrity of our novel BF technique with that of the standard technique that uses cannulated screws and wire tension band. We hypothesized that the stability provided by our technique would be similar to that provided by SF for transverse patella fractures.

MATERIALS AND METHODS

SPECIMEN PREPARATION

Thirteen matched pairs of fresh-frozen human cadaveric knees were obtained from a Cedars-Sinai approved tissue bank. Specimens were cut midfemur and were intact to the foot. Legs with major structural bony or ligamentous abnormalities, extensor mechanism disruption, or septic knees were excluded from testing. To assess the bone quality of each specimen prior to testing, dual-energy X-ray absorptiometry was performed using a GE Lunar iDXA scanner (GE Healthcare). Specimens were stored at −30°C and thawed at room temperature for 24 hours prior to biomechanical testing.

A midline anterior approach to the patella was performed, and the extensor retinaculum, quadriceps tendon, and patellar tendon were exposed. A digital caliper was used to measure the craniocaudal and mediolateral dimensions of the patella, and a transverse osteotomy (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association [AO/OTA] type 34-C1) was created at the midway point between superior and inferior poles by using an oscillating saw. The retinaculum was then incised to the level of the midaxial line of the femur. One leg from each matched pair was allocated to the SF group, and the other was allocated to the BF group. Left and right legs were alternately assigned to each group to ensure that laterality was balanced between the 2 groups.

SURGICAL TECHNIQUE

The repair of the specimens in the SF group involved the use of 2 parallel 4.0-mm partially threaded cannulated screws (Acumed) and an 18-gauge monofilament steel wire (Ethicon) in a figure-eight tension band (Figure 1A). The repair of the specimens in the BF group involved the use of 2 parallel standard Acutrak headless compression screws (Acumed), a No. 2 FiberWire (Arthrex) in a figure-eight tension band, and a No. 5 FiberWire (Arthrex) was applied as cerclage around the patella (Figure 1B).

Continue to: Mechanical testing...

MECHANICAL TESTING

Mechanical testing was performed on a biaxial 370.02 Bionix Testing System (MTS Systems Corp.). The femur was rigidly and horizontally secured to a custom-built test frame, and the lower leg was left free to move. The quadriceps tendon was secured in a freeze clamp and was attached to the MTS actuator for loading via a pulley system such that raising the actuator was translated into a simulated quadriceps extensor force.

A differential variable reluctance transducer (DVRT) (Lord MicroStrain) was placed across the osteotomy site to measure the distraction, or gap, across the fracture line. The minimum load to full extension for each specimen was then determined under a slow, controlled increase in load until the leg was in a fully extended position. Any distraction across the fracture line during the initial loading phase was determined by using digital calipers. The specimen was then subjected to a preconditioning phase with 10 cycles from 0 N to full extension under the previously determined load, which was applied at the rate of 5 N/s. Meanwhile, displacement across the fracture site was recorded via the DVRT. Following the preconditioning phase, each specimen was then tested to failure in displacement control at the rate of 1.5 mm/s. Failure was defined as implant failure (screw pullout) or DVRT gapping across the osteotomy site >3 mm.^10,14

Outcome measures included stiffness (N/mm), which was calculated as the slope of the linear change in load from full extension to failure vs DVRT displacement during the final loading phase; failure load (N); gapping (mm) across the osteotomy site at each cycle during the preconditioning phase; and failure mode (pullout vs >3.0 mm gap).

STATISTICAL ANALYSIS

An a priori power analysis revealed that 13 knees per group would be required to obtain an α of 0.05 and a power of 0.80. This calculation was based on a 20% difference in fracture displacement calculated by using the standard deviation and mean previously reported for cannulated screws with nonabsorbable sutures.¹⁴

Means and standard deviations for all dependent outcome measures were computed and compared across the independent measure of fixation type (BF vs SF) through repeated measures Analysis of variance (ANOVA-GLM, SAS 9.3, SAS Institute, Inc.) after controlling for bone mineral density (BMD), gender, and age. Multivariate repeated-measures ANOVA with Tukey's studentized range was applied to cyclic gap data. The mode of failure was compared across fixation type (BF vs SF) for matched data using McNemar’s test. Intracorrelations were computed and examined over all data and separately on the basis of screw fixation type (BF vs SF). All tests were considered statistically significant when P < .05.

Continue to: Results...

RESULTS

Specimen donors were 46% (6/13) male with an average age of 78.5 years (±13.77; range, 56-91 years) and 54% (7/13) female with an average age of 76.57 years (±14.37; range, 59-102 years). Average BMD was significantly lower in female (0.71 ± 0.18) than in male specimens (1.15 ± 0.33) (P < .05).

The average load to full extension across all specimens was 272 N (±54; range, 160-360 N) and was well balanced across matched pairs (270 ± 56 N for BF and 273 ± 54 N for SF). Of the 13 BF specimens, 4 experienced distraction across the fracture line during the determination of the minimum load to full extension. This initial pretest gap was measured with digital calipers (average, 1.5 mm; range, 0.90-1.85 mm) and added as an offset to the respective DVRT displacement data recorded during testing.

The total number of specimens included in the displacement data calculations decreased from 13 to 11 per group because DVRT data were not recorded during cyclic loading for 1 specimen and were considered unreliable in another. The maximum displacement measured across the fracture site during cyclic loading was significantly higher in the BF (0.94 ± 1.21) group than in the SF group (0.19 ± 0.26) as shown in the Table. The average slope of the gap per cycle for each specimen was calculated and compared between the BF and SF groups. The BF group demonstrated a significantly greater increase in gap per cycle than the SF group (Figure 2). Stiffness during load to failure was calculated for all but 1 specimen that did not display any measurable displacement during the final loading cycle. The average final stiffness and failure load between the BF and SF groups were not significantly different (Table). An equal number of specimens in both groups failed through gapping (6/13) and pullout (7/13).

Table. Means and Standard Deviations of the Main Outcome Measures

^aIndicates statistical significance (P < .05).

Abbreviation: NS, not significant.

Failure load was significantly positively correlated with BMD (R = 0.62, P < .001) when all specimens were grouped together. When analyzed separately, the SF group was significantly correlated with BMD (P < .01), whereas the BF group had a marginally significant correlation (P = .06) with BMD (Figure 3). In both groups, BMD was positively correlated with stiffness and negatively correlated with gapping. Neither of these trends, however, was significant.

Continue to: Discussion...

DISCUSSION

We proposed a novel BF technique for the treatment of noncomminuted transverse patella fractures. Our technique utilizes headless cannulated compression screws and nonabsorbable suture tension bands. We then biomechanically compared our proposed technique with an established fixation technique that uses partially threaded cannulated screws and stainless steel wire tension bands. We hypothesized that the mechanical response of the BF technique to cyclic and failure loading would be similar to that of the SF technique. Our results demonstrate a significant increase in gap formation across the fracture site among knees and an overall reduced load to failure in the BF group (Figure 2). Whether these inferior results manifest clinically is not yet established. Both constructs could withstand forces that are typically experienced during the postoperative period. Given the high rate of symptomatic implant removal associated with the traditional technique, the low-profile buried technique might be an attractive alternative that provides increased patient comfort but may require an extended period of postoperative protection against bony ingrowths.

Patellar fixation constructs that use a combination of cannulated screws and a wire tension band provide the best resistance to patella fracture displacement when compared with screws or wires alone.^4,15 Although this combination is biomechanically favorable, the steel wire often causes the painful irritation of the surrounding soft tissues and can break or migrate, thus increasing the rates of implant removal surgery to as high as 52%.^4,10,12,15 We developed our novel BF technique, which uses headless compression screws and a No. 2 FiberWire tension band, to address the high rates of reoperation and patient dissatisfaction associated with the SF technique.

Headless compression screws have been successfully used in the reduction and fixation of scaphoid fractures and sesamoid fractures.^16,17 The pull-out strengths of these screws are comparable with those of other commonly used screws, such as Twinfix and Herbert-Whipple screws.¹⁶ Similarly, the strength of a No. 5 FiberWire is comparable with that of an 18-gauge stainless-steel wire.^14,18 Several studies have also obtained good outcomes with nonmetallic constructs that use nonabsorbable sutures alone.^19,20 In this study, we utilized a No. 2 FiberWire as the tension band. The use of the No. 2 FiberWire facilitated threading through headless cannulated screws and created a low-profile knot. However, the use of thin FiberWire, despite a No. 5 FiberWire cerclage, likely contributed to the increase in distraction across the fracture.

The highest patellofemoral joint reaction force during level walking is approximately 35 kg (half body weight), which is equivalent to 350 N.^15,21,22 This force is similar to the average cyclic load used in this experiment (272 ± 54 N). Gapping increased in the BF group but did not reach the defined failure value of 3 mm, and the ultimate load to failure was relatively high across both groups (SF, 1123 N; BF, 973 N). These results suggest that both fixation methods can withstand the typical patellofemoral joint forces that are experienced during the postoperative period.⁴ In addition, in a clinical setting, patients are placed in hinged knee braces for at least 2 weeks to limit their flexion angle and to allow for healing and bony ingrowth. Postoperative knee-brace protection presumably increases the overall strength of the fixation.

The number of specimens (n = 26) evaluated in this study was greater than that used in other biomechanical patella fracture studies.¹⁴ Furthermore, none of our specimens were reused. Our study design was further strengthened given that fellowship-trained trauma surgeons performed all surgical procedures. Finally, the data collection and analysis of numerous clinically relevant factors, such as BMD, age, and cyclical loading, contributed to the comprehensive description of each technique with respect to patient-specific criteria.

Similar to all cadaveric studies, our data only represent the immediate postoperative condition and does not represent any healing that would occur during postoperative rehabilitation. Postoperative knee-brace protection and bone healing across the fracture site would likely strengthen both constructs in a clinical setting. In addition, the average age of our specimens is 77.5 years, and therefore does not best represent the age range (20-50 years) of the typical adult population affected by patella fractures.^3,23,24 Finally, postsurgical reduction was confirmed through visual inspection and not through fluoroscopy as in a clinical setting. Radiographic images were obtained after each experiment only to confirm screw placement post facto (Figures 4A, 4B).

CONCLUSION

This study demonstrates the utility of a novel BF technique. Nevertheless, the proposed technique exhibited increased gapping and a lower load to failure than the current gold standard. The significance of these inferior results in clinical and functional settings has not been established. The proposed BF technique may be an appealing alternative to the SF technique given its low profile and potential to reduce the rates of future implant removal. Further studies on the long-term outcomes of patients treated through the BF technique are currently under way and will ultimately determine the utility of the proposed construct.

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

ABSTRACT

An increasing interest focuses on the rates and risk factors for hospital readmission. However, little is known regarding the readmission following total shoulder arthroplasty (TSA). This study aims to determine the rates, risk factors, and reasons for hospital readmission following primary TSA. Patients undergoing TSA (anatomic or reverse) as part of the American College of Surgeons National Surgical Quality Improvement Program in 2011 to 2013 were identified. The rate of unplanned readmission to the hospital within 30 postoperative days was characterized. Using multivariate regression, demographic and comorbidity factors were tested for independent association with readmission. Finally, the reasons for readmission were characterized. A total of 3627 patients were identified. Among the admitted patients, 93 (2.56%) were readmitted within 30 days of surgery. The independent risk factors for readmission included old age (for age 60-69 years, relative risk [RR] = 1.6; for age 70-79 years, RR = 2.3; for age ≥80 years, RR = 23.1; P = .042), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). The reasons for readmission were available for 84 of the 93 readmitted patients. The most common reasons for readmission comprised pneumonia (14 cases, 16.7%), dislocation (7 cases, 8.3%), pulmonary embolism (7 cases, 8.3%), and surgical site infection (6 cases, 7.1%). Unplanned readmission occurs following about 1 in 40 cases of TSA. The most common causes of readmission include pneumonia, dislocation, pulmonary embolism, and surgical site infection. Patients with old age, male sex, anemia, and dependent functional status are at higher risk for readmission and should be counseled and monitored accordingly.

Continue to: Total shoulder arthroplasty...

Total shoulder arthroplasty (TSA) is performed with increasing frequency in the United States and is considered to be cost-effective.^1-4 Following the procedure, patients generally achieve shoulder function and pain relief.^5-8 Despite the success of the procedure, the growing literature on TSA has also reported rates of complications between 3.6% and 25% of the treated patients.^9-16

In recent years, an increasing interest has focused on the rates and risk factors for unplanned hospital readmissions; these variables may not only reflect the quality of patient care but also result in considerable costs to the healthcare system. For instance, among Medicare patients, readmissions within 30 days of discharge occur in almost 20% of cases, costing $17.4 billion per year.¹⁷ Readmission rates increasingly factor into hospital performance metrics and reimbursement, including the Hospital Readmissions Reduction Program of the Patient Protection and Affordable Care Act that reduces Centers for Medicare and Medicaid Services payments to hospitals with high 30-day readmission rates.¹⁸

To date, only a few studies have evaluated readmission following TSA, with 30- to 90-day readmission rates ranging from 4.5% to 7.3%.^19-23 These studies comprised single institution series^20,22 and analyses of administrative databases.^19,21,23 Most studies have shown that readmission occurs more often for medical than surgical reasons, with surgical reasons most commonly including infection and dislocation.^19-23 However, only limited analyses have been conducted regarding risk factors for readmission.^21,23 To date and to our knowledge, no study has investigated reasons for readmission following TSA using nationwide data.

This study aims to determine the rates, risk factors, and reasons for hospital readmission following primary TSA in the United States using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database.

METHODS

DATA SOURCE

The NSQIP database was utilized to address the study purpose. NSQIP is a nationwide prospective surgical registry established by the American College of Surgeons and reports data from academic and community hospitals across the United States.²⁴ Patients undertaking surgery at these centers are followed by the surgical clinical reviewers at the participating NSQIP sites prospectively for 30 days following the procedure to record complications including readmission. Preoperative and surgical data, such as demographics, medical comorbid diseases, and operative time, are also included. Previous studies have analyzed the complications of various orthopedic surgeries using the NSQIP data.^14,16,25-30

DATA COLLECTION

We retrospectively identified from NSQIP the patients who underwent primary TSA (anatomic or reverse) in 2013 to 2014. The timeframe 2013 to 2014 was used because NSQIP only began recording reasons for readmission in 2013. The inclusion criteria were as follows: Current Procedural Terminology (CPT) code for TSA (23472); preoperative diagnosis according to the International Classification of Diseases, Ninth Revision (ICD-9) codes 714.0, 715.11, 715.31, 715.91, 715.21, 715.89, 716.xx 718.xx, 719.xx, 726.x, 727.xx, and 733.41 (where x is a wild card digit); and no missing demographic, comorbidity, or outcome data. Anatomic and reverse TSA were analyzed together because they share the same CPT code, and the NSQIP database prevents searching by the ICD-9 procedure code.

The rate of unplanned readmission to the hospital within 30 postoperative days was characterized. The reasons for readmission in this 30-day period were only available in 2013 and were determined using the ICD-9 diagnosis codes. Patient demographics were recorded for use in identifying potential risk factors for readmission; the demographic data included sex, age, smoking status, body mass index (BMI), and comorbidities, including end-stage renal disease, dyspnea on exertion, congestive heart failure, diabetes mellitus, hypertension, and chronic obstructive pulmonary disease (COPD).

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analyses were performed using Stata version 13.1 (StataCorp). First, using bivariate and multivariate regression, demographic and comorbidity factors were tested for independent association with readmission to the hospital within 30 days of surgery. Second, among the readmitted patients, the reasons for readmission were tabulated. Of note, the reasons for readmission were only documented for the procedures performed in 2013. All tests were 2-tailed and conducted at an α level of 0.05.

RESTULTS

A total of 3627 TSA patients were identified. The mean age (± standard deviation) was 69.4 ± 9.5 years, 55.8% of patients were female, and mean BMI was 30.1 ± 7.0 years. Table 1 provides the additional demographic data. Of the 3627 included patients, 93 (2.56%) were readmitted within 30 days of surgery. The 95% confidence interval for the estimated rate of readmission reached 2.05% to 3.08%.

Table 1. Patient Population

Abbreviation: COPD, chronic obstructive pulmonary disease.

In the bivariate analyses (Table 2), the following factors were positively associated readmission: older age (60-69 years, relative risk [RR] = 1.6; 70-79 years, RR = 2.2; ≥80 years, RR = 3.3; P = .011), dependent functional status (RR = 2.9, P = .008), and anemia (RR = 2.2, P < .001).

Table 2. Bivariate Analysis of Risk Factors for Readmission

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.

In the multivariate analyses (Table 3), the following factors were independent risk factors for readmission: older age (60-69 years, RR = 1.6; 70-79 years, RR = 2.3; ≥80 years, RR = 3.1; P =.027), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). Interestingly, readmission showed no independent association with diabetes, dyspnea on exertion, BMI, COPD, hypertension, or current smoking status (P > .05 for each).

Table 3. Independent Risk Factors for Readmission on Multivariate Analysis

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.

Continue to: Table 4...

The reasons for readmission were available for 84 of the 93 readmitted patients. The most common reasons for readmission included pneumonia (14 cases, 16.7%), dislocation (7 cases, 8.3%), pulmonary embolism (7 cases, 8.3%), and surgical site infection (6 cases, 7.1%) (Table 4).

Table 4. Reasons for Readmission

DISCUSSION

Our analysis of 3042 TSAs from the NSQIP database suggests that unplanned readmission to the hospital occurs following about 1 in 40 cases of TSA. The study also suggests that the most common reasons for readmission encompass pneumonia, dislocation, pulmonary embolism, and surgical site infection. Old age, male sex, anemia, and dependent functional status serve as risk factors for readmission, and patients with such factors should be counseled and monitored accordingly.

In recent years, an increasing emphasis has centered on reducing rates of hospital readmission, with programs such as the Hospital Readmissions Reduction Program of the Affordable Care Act cutting reimbursements for hospitals with high 30-day readmission rates.^17,18 To date, only a few studies have evaluated the reasons for readmission and readmission rates for TSA.^19-23 Initial reports consisted of single-institution TSA registry reviews. For example, Mahoney and colleagues²⁰ retrospectively evaluated shoulder arthroplasty procedures at their institution to document the readmission rates, finding a 5.9% readmission rate at 30 days. Readmission occurred more frequently in the first 30 days following discharge than in the 30- to 90-day period, with the most common reasons for readmission including medical complications, infection, and dislocation. Streubel and colleagues²² evaluated reoperation rates from their institution’s TSA registry, finding a 0.6% reoperation rate for primary TSA at 30 days and 1.5% for revision TSA. Instability and infection were the most common indications for reoperation. Our findings confirm these single-institution results and demonstrate their application to a nationwide sample of TSA, not just to high-volume academic centers. We similarly observed that dislocation, surgical site infection, and medical complications (mostly pneumonia and pulmonary embolism) were common causes of readmission, and that the 30-day readmission rate was about 1 in 40.

Several authors have since used statewide databases to analyze and determine risk factors for readmission following TSA. Lyman and colleagues¹⁹ used the New York State Database to show that higher hospital TSA surgical volume was associated with a lower rate of readmission when age and comorbidities were controlled for in a multivariate model. Old age was also associated with an increased readmission rate in their multivariate analysis, but comorbidities (as measured by the Charlson comorbidity index) presented a nonsignificant associative trend. These authors opted not to determine specific causes of readmission. Schairer and colleagues²¹ used State Inpatient Databases from 7 states, finding a 90-day readmission rate of 7.3%, 82% of which were due to medical complications and 18% of which were due to surgical complications (mostly infection and dislocation). Their multivariate regression revealed that male sex, reverse TSA, Medicaid insurance, patients discharged to inpatient rehabilitation or nursing facilities, medical comorbidities, and low-volume TSA hospitals were associated with readmission. Zhang and colleagues²³ used the same source to show that the 90-day readmission rate reached 14% for surgically treated proximal humerus fractures and higher for patients who underwent open reduction internal fixation, were female, were African American, were discharged to a nursing facility, possessed Medicaid insurance, or experienced medical comorbidities. Most recently, Basques and colleagues³¹ analyzed 1505 TSA cases from 2011 and 2012 in the NSQIP database, finding a 3.3% rate of readmission, with heart disease and hypertension as risk factors for readmission. Although the limitations of the NSQIP database prevented us from analyzing surgeon and hospital TSA volume or reverse vs anatomic TSA, our results confirm that the findings from statewide database studies apply to the United States nationwide NSQIP database. Old patient age, male sex, and medical comorbidities (anemia and dependent functional status) are independent risk factors for TSA readmission. We identified pneumonia, dislocation, pulmonary embolism, and surgical site infection as the most common reasons for readmission.

This study features several limitations that should be considered when interpreting the results. Anatomic and reverse TSA share a CPT code and were not separated using NSQIP data. A number of studies have reported that reverse TSA may place patients at higher risk for readmission;^20,21 however, confounding by other patient factors could play a role in this finding. The 30-day timeframe for readmission is another potential limitation; however, this timeframe is frequently used in other studies and is the relevant timeframe for the reduced reimbursement penalties from the Hospital Readmissions Reduction Program of the Affordable Care Act.¹⁸ Furthermore, the NSQIP database contains no information on surgeon or hospital TSA volume, which is a result of safeguards for patient and provider privacy. Additionally, readmission data were only available for 2011 to 2013, with causes of readmission only present in 2013. Although provided with such current information, we cannot analyze readmission trends over time, such as in response to the Affordable Care Act of 2010. Finally, although NSQIP surgical clinical reviewers strive to identify readmissions to other hospitals during their reviews of outpatient medical records, proportions of these readmissions are possibly missed. Therefore, our 30-day readmission rate may slightly underestimate the true rate.

Despite these limitations, the NSQIP database offers a unique opportunity to examine risk factors and reasons for readmission following TSA. The prior literature on readmission following TSA stemmed either from limited samples or administrative data, which feature known limitations.³² By utilizing a large, prospective, non-administrative, nationwide sample, our findings are probably both more reliable and generalizable to the country as a whole.

CONCLUSION

Unplanned readmission occurs following about 1 in 40 cases of TSA. The most common causes of readmission include pneumonia, dislocation, pulmonary embolism, and surgical site infection. Patients with old age, male sex, anemia, and dependent functional status are at a higher risk for readmission and should be counseled and monitored accordingly.

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

ABSTRACT

An increasing interest focuses on the rates and risk factors for hospital readmission. However, little is known regarding the readmission following total shoulder arthroplasty (TSA). This study aims to determine the rates, risk factors, and reasons for hospital readmission following primary TSA. Patients undergoing TSA (anatomic or reverse) as part of the American College of Surgeons National Surgical Quality Improvement Program in 2011 to 2013 were identified. The rate of unplanned readmission to the hospital within 30 postoperative days was characterized. Using multivariate regression, demographic and comorbidity factors were tested for independent association with readmission. Finally, the reasons for readmission were characterized. A total of 3627 patients were identified. Among the admitted patients, 93 (2.56%) were readmitted within 30 days of surgery. The independent risk factors for readmission included old age (for age 60-69 years, relative risk [RR] = 1.6; for age 70-79 years, RR = 2.3; for age ≥80 years, RR = 23.1; P = .042), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). The reasons for readmission were available for 84 of the 93 readmitted patients. The most common reasons for readmission comprised pneumonia (14 cases, 16.7%), dislocation (7 cases, 8.3%), pulmonary embolism (7 cases, 8.3%), and surgical site infection (6 cases, 7.1%). Unplanned readmission occurs following about 1 in 40 cases of TSA. The most common causes of readmission include pneumonia, dislocation, pulmonary embolism, and surgical site infection. Patients with old age, male sex, anemia, and dependent functional status are at higher risk for readmission and should be counseled and monitored accordingly.

Continue to: Total shoulder arthroplasty...

Total shoulder arthroplasty (TSA) is performed with increasing frequency in the United States and is considered to be cost-effective.^1-4 Following the procedure, patients generally achieve shoulder function and pain relief.^5-8 Despite the success of the procedure, the growing literature on TSA has also reported rates of complications between 3.6% and 25% of the treated patients.^9-16

In recent years, an increasing interest has focused on the rates and risk factors for unplanned hospital readmissions; these variables may not only reflect the quality of patient care but also result in considerable costs to the healthcare system. For instance, among Medicare patients, readmissions within 30 days of discharge occur in almost 20% of cases, costing $17.4 billion per year.¹⁷ Readmission rates increasingly factor into hospital performance metrics and reimbursement, including the Hospital Readmissions Reduction Program of the Patient Protection and Affordable Care Act that reduces Centers for Medicare and Medicaid Services payments to hospitals with high 30-day readmission rates.¹⁸

To date, only a few studies have evaluated readmission following TSA, with 30- to 90-day readmission rates ranging from 4.5% to 7.3%.^19-23 These studies comprised single institution series^20,22 and analyses of administrative databases.^19,21,23 Most studies have shown that readmission occurs more often for medical than surgical reasons, with surgical reasons most commonly including infection and dislocation.^19-23 However, only limited analyses have been conducted regarding risk factors for readmission.^21,23 To date and to our knowledge, no study has investigated reasons for readmission following TSA using nationwide data.

This study aims to determine the rates, risk factors, and reasons for hospital readmission following primary TSA in the United States using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database.

METHODS

DATA SOURCE

The NSQIP database was utilized to address the study purpose. NSQIP is a nationwide prospective surgical registry established by the American College of Surgeons and reports data from academic and community hospitals across the United States.²⁴ Patients undertaking surgery at these centers are followed by the surgical clinical reviewers at the participating NSQIP sites prospectively for 30 days following the procedure to record complications including readmission. Preoperative and surgical data, such as demographics, medical comorbid diseases, and operative time, are also included. Previous studies have analyzed the complications of various orthopedic surgeries using the NSQIP data.^14,16,25-30

DATA COLLECTION

We retrospectively identified from NSQIP the patients who underwent primary TSA (anatomic or reverse) in 2013 to 2014. The timeframe 2013 to 2014 was used because NSQIP only began recording reasons for readmission in 2013. The inclusion criteria were as follows: Current Procedural Terminology (CPT) code for TSA (23472); preoperative diagnosis according to the International Classification of Diseases, Ninth Revision (ICD-9) codes 714.0, 715.11, 715.31, 715.91, 715.21, 715.89, 716.xx 718.xx, 719.xx, 726.x, 727.xx, and 733.41 (where x is a wild card digit); and no missing demographic, comorbidity, or outcome data. Anatomic and reverse TSA were analyzed together because they share the same CPT code, and the NSQIP database prevents searching by the ICD-9 procedure code.

The rate of unplanned readmission to the hospital within 30 postoperative days was characterized. The reasons for readmission in this 30-day period were only available in 2013 and were determined using the ICD-9 diagnosis codes. Patient demographics were recorded for use in identifying potential risk factors for readmission; the demographic data included sex, age, smoking status, body mass index (BMI), and comorbidities, including end-stage renal disease, dyspnea on exertion, congestive heart failure, diabetes mellitus, hypertension, and chronic obstructive pulmonary disease (COPD).

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analyses were performed using Stata version 13.1 (StataCorp). First, using bivariate and multivariate regression, demographic and comorbidity factors were tested for independent association with readmission to the hospital within 30 days of surgery. Second, among the readmitted patients, the reasons for readmission were tabulated. Of note, the reasons for readmission were only documented for the procedures performed in 2013. All tests were 2-tailed and conducted at an α level of 0.05.

RESTULTS

A total of 3627 TSA patients were identified. The mean age (± standard deviation) was 69.4 ± 9.5 years, 55.8% of patients were female, and mean BMI was 30.1 ± 7.0 years. Table 1 provides the additional demographic data. Of the 3627 included patients, 93 (2.56%) were readmitted within 30 days of surgery. The 95% confidence interval for the estimated rate of readmission reached 2.05% to 3.08%.

Table 1. Patient Population

Abbreviation: COPD, chronic obstructive pulmonary disease.

In the bivariate analyses (Table 2), the following factors were positively associated readmission: older age (60-69 years, relative risk [RR] = 1.6; 70-79 years, RR = 2.2; ≥80 years, RR = 3.3; P = .011), dependent functional status (RR = 2.9, P = .008), and anemia (RR = 2.2, P < .001).

Table 2. Bivariate Analysis of Risk Factors for Readmission

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.

In the multivariate analyses (Table 3), the following factors were independent risk factors for readmission: older age (60-69 years, RR = 1.6; 70-79 years, RR = 2.3; ≥80 years, RR = 3.1; P =.027), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). Interestingly, readmission showed no independent association with diabetes, dyspnea on exertion, BMI, COPD, hypertension, or current smoking status (P > .05 for each).

Table 3. Independent Risk Factors for Readmission on Multivariate Analysis

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.

Continue to: Table 4...

The reasons for readmission were available for 84 of the 93 readmitted patients. The most common reasons for readmission included pneumonia (14 cases, 16.7%), dislocation (7 cases, 8.3%), pulmonary embolism (7 cases, 8.3%), and surgical site infection (6 cases, 7.1%) (Table 4).

Table 4. Reasons for Readmission

DISCUSSION

Our analysis of 3042 TSAs from the NSQIP database suggests that unplanned readmission to the hospital occurs following about 1 in 40 cases of TSA. The study also suggests that the most common reasons for readmission encompass pneumonia, dislocation, pulmonary embolism, and surgical site infection. Old age, male sex, anemia, and dependent functional status serve as risk factors for readmission, and patients with such factors should be counseled and monitored accordingly.

In recent years, an increasing emphasis has centered on reducing rates of hospital readmission, with programs such as the Hospital Readmissions Reduction Program of the Affordable Care Act cutting reimbursements for hospitals with high 30-day readmission rates.^17,18 To date, only a few studies have evaluated the reasons for readmission and readmission rates for TSA.^19-23 Initial reports consisted of single-institution TSA registry reviews. For example, Mahoney and colleagues²⁰ retrospectively evaluated shoulder arthroplasty procedures at their institution to document the readmission rates, finding a 5.9% readmission rate at 30 days. Readmission occurred more frequently in the first 30 days following discharge than in the 30- to 90-day period, with the most common reasons for readmission including medical complications, infection, and dislocation. Streubel and colleagues²² evaluated reoperation rates from their institution’s TSA registry, finding a 0.6% reoperation rate for primary TSA at 30 days and 1.5% for revision TSA. Instability and infection were the most common indications for reoperation. Our findings confirm these single-institution results and demonstrate their application to a nationwide sample of TSA, not just to high-volume academic centers. We similarly observed that dislocation, surgical site infection, and medical complications (mostly pneumonia and pulmonary embolism) were common causes of readmission, and that the 30-day readmission rate was about 1 in 40.

Several authors have since used statewide databases to analyze and determine risk factors for readmission following TSA. Lyman and colleagues¹⁹ used the New York State Database to show that higher hospital TSA surgical volume was associated with a lower rate of readmission when age and comorbidities were controlled for in a multivariate model. Old age was also associated with an increased readmission rate in their multivariate analysis, but comorbidities (as measured by the Charlson comorbidity index) presented a nonsignificant associative trend. These authors opted not to determine specific causes of readmission. Schairer and colleagues²¹ used State Inpatient Databases from 7 states, finding a 90-day readmission rate of 7.3%, 82% of which were due to medical complications and 18% of which were due to surgical complications (mostly infection and dislocation). Their multivariate regression revealed that male sex, reverse TSA, Medicaid insurance, patients discharged to inpatient rehabilitation or nursing facilities, medical comorbidities, and low-volume TSA hospitals were associated with readmission. Zhang and colleagues²³ used the same source to show that the 90-day readmission rate reached 14% for surgically treated proximal humerus fractures and higher for patients who underwent open reduction internal fixation, were female, were African American, were discharged to a nursing facility, possessed Medicaid insurance, or experienced medical comorbidities. Most recently, Basques and colleagues³¹ analyzed 1505 TSA cases from 2011 and 2012 in the NSQIP database, finding a 3.3% rate of readmission, with heart disease and hypertension as risk factors for readmission. Although the limitations of the NSQIP database prevented us from analyzing surgeon and hospital TSA volume or reverse vs anatomic TSA, our results confirm that the findings from statewide database studies apply to the United States nationwide NSQIP database. Old patient age, male sex, and medical comorbidities (anemia and dependent functional status) are independent risk factors for TSA readmission. We identified pneumonia, dislocation, pulmonary embolism, and surgical site infection as the most common reasons for readmission.

This study features several limitations that should be considered when interpreting the results. Anatomic and reverse TSA share a CPT code and were not separated using NSQIP data. A number of studies have reported that reverse TSA may place patients at higher risk for readmission;^20,21 however, confounding by other patient factors could play a role in this finding. The 30-day timeframe for readmission is another potential limitation; however, this timeframe is frequently used in other studies and is the relevant timeframe for the reduced reimbursement penalties from the Hospital Readmissions Reduction Program of the Affordable Care Act.¹⁸ Furthermore, the NSQIP database contains no information on surgeon or hospital TSA volume, which is a result of safeguards for patient and provider privacy. Additionally, readmission data were only available for 2011 to 2013, with causes of readmission only present in 2013. Although provided with such current information, we cannot analyze readmission trends over time, such as in response to the Affordable Care Act of 2010. Finally, although NSQIP surgical clinical reviewers strive to identify readmissions to other hospitals during their reviews of outpatient medical records, proportions of these readmissions are possibly missed. Therefore, our 30-day readmission rate may slightly underestimate the true rate.

Despite these limitations, the NSQIP database offers a unique opportunity to examine risk factors and reasons for readmission following TSA. The prior literature on readmission following TSA stemmed either from limited samples or administrative data, which feature known limitations.³² By utilizing a large, prospective, non-administrative, nationwide sample, our findings are probably both more reliable and generalizable to the country as a whole.

CONCLUSION

Unplanned readmission occurs following about 1 in 40 cases of TSA. The most common causes of readmission include pneumonia, dislocation, pulmonary embolism, and surgical site infection. Patients with old age, male sex, anemia, and dependent functional status are at a higher risk for readmission and should be counseled and monitored accordingly.

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

ABSTRACT

An increasing interest focuses on the rates and risk factors for hospital readmission. However, little is known regarding the readmission following total shoulder arthroplasty (TSA). This study aims to determine the rates, risk factors, and reasons for hospital readmission following primary TSA. Patients undergoing TSA (anatomic or reverse) as part of the American College of Surgeons National Surgical Quality Improvement Program in 2011 to 2013 were identified. The rate of unplanned readmission to the hospital within 30 postoperative days was characterized. Using multivariate regression, demographic and comorbidity factors were tested for independent association with readmission. Finally, the reasons for readmission were characterized. A total of 3627 patients were identified. Among the admitted patients, 93 (2.56%) were readmitted within 30 days of surgery. The independent risk factors for readmission included old age (for age 60-69 years, relative risk [RR] = 1.6; for age 70-79 years, RR = 2.3; for age ≥80 years, RR = 23.1; P = .042), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). The reasons for readmission were available for 84 of the 93 readmitted patients. The most common reasons for readmission comprised pneumonia (14 cases, 16.7%), dislocation (7 cases, 8.3%), pulmonary embolism (7 cases, 8.3%), and surgical site infection (6 cases, 7.1%). Unplanned readmission occurs following about 1 in 40 cases of TSA. The most common causes of readmission include pneumonia, dislocation, pulmonary embolism, and surgical site infection. Patients with old age, male sex, anemia, and dependent functional status are at higher risk for readmission and should be counseled and monitored accordingly.

Continue to: Total shoulder arthroplasty...

Total shoulder arthroplasty (TSA) is performed with increasing frequency in the United States and is considered to be cost-effective.^1-4 Following the procedure, patients generally achieve shoulder function and pain relief.^5-8 Despite the success of the procedure, the growing literature on TSA has also reported rates of complications between 3.6% and 25% of the treated patients.^9-16

In recent years, an increasing interest has focused on the rates and risk factors for unplanned hospital readmissions; these variables may not only reflect the quality of patient care but also result in considerable costs to the healthcare system. For instance, among Medicare patients, readmissions within 30 days of discharge occur in almost 20% of cases, costing $17.4 billion per year.¹⁷ Readmission rates increasingly factor into hospital performance metrics and reimbursement, including the Hospital Readmissions Reduction Program of the Patient Protection and Affordable Care Act that reduces Centers for Medicare and Medicaid Services payments to hospitals with high 30-day readmission rates.¹⁸

To date, only a few studies have evaluated readmission following TSA, with 30- to 90-day readmission rates ranging from 4.5% to 7.3%.^19-23 These studies comprised single institution series^20,22 and analyses of administrative databases.^19,21,23 Most studies have shown that readmission occurs more often for medical than surgical reasons, with surgical reasons most commonly including infection and dislocation.^19-23 However, only limited analyses have been conducted regarding risk factors for readmission.^21,23 To date and to our knowledge, no study has investigated reasons for readmission following TSA using nationwide data.

This study aims to determine the rates, risk factors, and reasons for hospital readmission following primary TSA in the United States using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database.

METHODS

DATA SOURCE

The NSQIP database was utilized to address the study purpose. NSQIP is a nationwide prospective surgical registry established by the American College of Surgeons and reports data from academic and community hospitals across the United States.²⁴ Patients undertaking surgery at these centers are followed by the surgical clinical reviewers at the participating NSQIP sites prospectively for 30 days following the procedure to record complications including readmission. Preoperative and surgical data, such as demographics, medical comorbid diseases, and operative time, are also included. Previous studies have analyzed the complications of various orthopedic surgeries using the NSQIP data.^14,16,25-30

DATA COLLECTION

We retrospectively identified from NSQIP the patients who underwent primary TSA (anatomic or reverse) in 2013 to 2014. The timeframe 2013 to 2014 was used because NSQIP only began recording reasons for readmission in 2013. The inclusion criteria were as follows: Current Procedural Terminology (CPT) code for TSA (23472); preoperative diagnosis according to the International Classification of Diseases, Ninth Revision (ICD-9) codes 714.0, 715.11, 715.31, 715.91, 715.21, 715.89, 716.xx 718.xx, 719.xx, 726.x, 727.xx, and 733.41 (where x is a wild card digit); and no missing demographic, comorbidity, or outcome data. Anatomic and reverse TSA were analyzed together because they share the same CPT code, and the NSQIP database prevents searching by the ICD-9 procedure code.

The rate of unplanned readmission to the hospital within 30 postoperative days was characterized. The reasons for readmission in this 30-day period were only available in 2013 and were determined using the ICD-9 diagnosis codes. Patient demographics were recorded for use in identifying potential risk factors for readmission; the demographic data included sex, age, smoking status, body mass index (BMI), and comorbidities, including end-stage renal disease, dyspnea on exertion, congestive heart failure, diabetes mellitus, hypertension, and chronic obstructive pulmonary disease (COPD).

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analyses were performed using Stata version 13.1 (StataCorp). First, using bivariate and multivariate regression, demographic and comorbidity factors were tested for independent association with readmission to the hospital within 30 days of surgery. Second, among the readmitted patients, the reasons for readmission were tabulated. Of note, the reasons for readmission were only documented for the procedures performed in 2013. All tests were 2-tailed and conducted at an α level of 0.05.

RESTULTS

A total of 3627 TSA patients were identified. The mean age (± standard deviation) was 69.4 ± 9.5 years, 55.8% of patients were female, and mean BMI was 30.1 ± 7.0 years. Table 1 provides the additional demographic data. Of the 3627 included patients, 93 (2.56%) were readmitted within 30 days of surgery. The 95% confidence interval for the estimated rate of readmission reached 2.05% to 3.08%.

Table 1. Patient Population

Abbreviation: COPD, chronic obstructive pulmonary disease.

In the bivariate analyses (Table 2), the following factors were positively associated readmission: older age (60-69 years, relative risk [RR] = 1.6; 70-79 years, RR = 2.2; ≥80 years, RR = 3.3; P = .011), dependent functional status (RR = 2.9, P = .008), and anemia (RR = 2.2, P < .001).

Table 2. Bivariate Analysis of Risk Factors for Readmission

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.

In the multivariate analyses (Table 3), the following factors were independent risk factors for readmission: older age (60-69 years, RR = 1.6; 70-79 years, RR = 2.3; ≥80 years, RR = 3.1; P =.027), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). Interestingly, readmission showed no independent association with diabetes, dyspnea on exertion, BMI, COPD, hypertension, or current smoking status (P > .05 for each).

Table 3. Independent Risk Factors for Readmission on Multivariate Analysis

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.

Continue to: Table 4...

The reasons for readmission were available for 84 of the 93 readmitted patients. The most common reasons for readmission included pneumonia (14 cases, 16.7%), dislocation (7 cases, 8.3%), pulmonary embolism (7 cases, 8.3%), and surgical site infection (6 cases, 7.1%) (Table 4).

Table 4. Reasons for Readmission

DISCUSSION

Our analysis of 3042 TSAs from the NSQIP database suggests that unplanned readmission to the hospital occurs following about 1 in 40 cases of TSA. The study also suggests that the most common reasons for readmission encompass pneumonia, dislocation, pulmonary embolism, and surgical site infection. Old age, male sex, anemia, and dependent functional status serve as risk factors for readmission, and patients with such factors should be counseled and monitored accordingly.

In recent years, an increasing emphasis has centered on reducing rates of hospital readmission, with programs such as the Hospital Readmissions Reduction Program of the Affordable Care Act cutting reimbursements for hospitals with high 30-day readmission rates.^17,18 To date, only a few studies have evaluated the reasons for readmission and readmission rates for TSA.^19-23 Initial reports consisted of single-institution TSA registry reviews. For example, Mahoney and colleagues²⁰ retrospectively evaluated shoulder arthroplasty procedures at their institution to document the readmission rates, finding a 5.9% readmission rate at 30 days. Readmission occurred more frequently in the first 30 days following discharge than in the 30- to 90-day period, with the most common reasons for readmission including medical complications, infection, and dislocation. Streubel and colleagues²² evaluated reoperation rates from their institution’s TSA registry, finding a 0.6% reoperation rate for primary TSA at 30 days and 1.5% for revision TSA. Instability and infection were the most common indications for reoperation. Our findings confirm these single-institution results and demonstrate their application to a nationwide sample of TSA, not just to high-volume academic centers. We similarly observed that dislocation, surgical site infection, and medical complications (mostly pneumonia and pulmonary embolism) were common causes of readmission, and that the 30-day readmission rate was about 1 in 40.

Several authors have since used statewide databases to analyze and determine risk factors for readmission following TSA. Lyman and colleagues¹⁹ used the New York State Database to show that higher hospital TSA surgical volume was associated with a lower rate of readmission when age and comorbidities were controlled for in a multivariate model. Old age was also associated with an increased readmission rate in their multivariate analysis, but comorbidities (as measured by the Charlson comorbidity index) presented a nonsignificant associative trend. These authors opted not to determine specific causes of readmission. Schairer and colleagues²¹ used State Inpatient Databases from 7 states, finding a 90-day readmission rate of 7.3%, 82% of which were due to medical complications and 18% of which were due to surgical complications (mostly infection and dislocation). Their multivariate regression revealed that male sex, reverse TSA, Medicaid insurance, patients discharged to inpatient rehabilitation or nursing facilities, medical comorbidities, and low-volume TSA hospitals were associated with readmission. Zhang and colleagues²³ used the same source to show that the 90-day readmission rate reached 14% for surgically treated proximal humerus fractures and higher for patients who underwent open reduction internal fixation, were female, were African American, were discharged to a nursing facility, possessed Medicaid insurance, or experienced medical comorbidities. Most recently, Basques and colleagues³¹ analyzed 1505 TSA cases from 2011 and 2012 in the NSQIP database, finding a 3.3% rate of readmission, with heart disease and hypertension as risk factors for readmission. Although the limitations of the NSQIP database prevented us from analyzing surgeon and hospital TSA volume or reverse vs anatomic TSA, our results confirm that the findings from statewide database studies apply to the United States nationwide NSQIP database. Old patient age, male sex, and medical comorbidities (anemia and dependent functional status) are independent risk factors for TSA readmission. We identified pneumonia, dislocation, pulmonary embolism, and surgical site infection as the most common reasons for readmission.

This study features several limitations that should be considered when interpreting the results. Anatomic and reverse TSA share a CPT code and were not separated using NSQIP data. A number of studies have reported that reverse TSA may place patients at higher risk for readmission;^20,21 however, confounding by other patient factors could play a role in this finding. The 30-day timeframe for readmission is another potential limitation; however, this timeframe is frequently used in other studies and is the relevant timeframe for the reduced reimbursement penalties from the Hospital Readmissions Reduction Program of the Affordable Care Act.¹⁸ Furthermore, the NSQIP database contains no information on surgeon or hospital TSA volume, which is a result of safeguards for patient and provider privacy. Additionally, readmission data were only available for 2011 to 2013, with causes of readmission only present in 2013. Although provided with such current information, we cannot analyze readmission trends over time, such as in response to the Affordable Care Act of 2010. Finally, although NSQIP surgical clinical reviewers strive to identify readmissions to other hospitals during their reviews of outpatient medical records, proportions of these readmissions are possibly missed. Therefore, our 30-day readmission rate may slightly underestimate the true rate.

Despite these limitations, the NSQIP database offers a unique opportunity to examine risk factors and reasons for readmission following TSA. The prior literature on readmission following TSA stemmed either from limited samples or administrative data, which feature known limitations.³² By utilizing a large, prospective, non-administrative, nationwide sample, our findings are probably both more reliable and generalizable to the country as a whole.

CONCLUSION

Unplanned readmission occurs following about 1 in 40 cases of TSA. The most common causes of readmission include pneumonia, dislocation, pulmonary embolism, and surgical site infection. Patients with old age, male sex, anemia, and dependent functional status are at a higher risk for readmission and should be counseled and monitored accordingly.

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

ABSTRACT

Current literature regarding complications following total joint arthroplasty have primarily focused on patients with osteoarthritis (OA), with less emphasis on the trends and in-hospital outcomes of rheumatoid arthritis (RA) patients undergoing these procedures. The purpose of this study is to analyze the outcomes and trends of RA patients undergoing total knee arthroplasty (TKA) or total hip arthroplasty (THA) compared to OA patients.

Data from the Nationwide Inpatient Sample from 2006 to 2011 was extracted using the International Classification of Diseases, Ninth Revision codes for patients that received a TKA or THA. Outcome measures included cardiovascular complications, cerebrovascular complications, pulmonary complications, wound dehiscence, and infection. Inpatient and hospital demographics including primary diagnosis, age, gender, primary payer, hospital teaching status, Charlson Comorbidity Index score, hospital bed size, location, and median household income were analyzed.

Logistic regression analysis of OA vs RA patients with patient outcomes revealed that osteoarthritic THA candidates had lower risk for cardiovascular complications, pulmonary complications, wound dehiscence, infections, and systemic complications, compared to rheumatoid patients. There was a significantly elevated risk of cerebrovascular complication in osteoarthritic THA compared to RA THA. OA patients undergoing TKA had significantly higher risk for cardiovascular and cerebrovascular complications. There were significant decreases in mechanical wounds, infection, and systemic complications in the OA TKA patients.

RA patients are at higher risk for postoperative infection, wound dehiscence, and systemic complications after TKA and THA compared to OA patients. These findings highlight the importance of preoperative medical clearance and management to optimize RA patients and improve the postoperative outcomes.

Continue to: RA is a chronic systemic inflammatory disease...

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease that causes joint deterioration, leading to pain, disability, systemic complications, short lifespan, and decline in quality of life.^1-3 The deterioration primarily affects the synovial membranes of joints, causing arthritis and resulting in extra-articular sequelae such as cardiovascular disease,⁴ pulmonary disease,⁵ and increased infection rates.^3,6 RA is the most prevalent inflammatory arthritis worldwide and affects up to 50 cases per 100,000 in both the US and northern Europe.^2,7-9 Although the gold standard of care for these patients is medical management with immunosuppressant drugs such as disease-modifying anti-rheumatic drugs (DMARDs), total joint arthroplasty (TJA) remains an important tool in the management of joint deterioration in such patients.

Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are common procedures utilized to treat disorders that cause joint pain and hindered joint mobility, including osteoarthritis (OA) and RA. Given the aging population, the amount of TKAs and THAs performed in the US has consistently increased each year, with the vast majority of this increase composed of patients with OA.¹⁰ As a result, previous studies investigated the trends and outcomes of these procedures in patients with OA, but relatively less is known about the outcomes and trends of patients with RA undergoing the same surgeries.

Given that RA is a fundamentally different condition with its own pathological characteristics, an understanding of how these differences may impact postoperative outcomes in patients with RA is important. This study aims to present a comparative analysis of the trends and postoperative outcomes between patients with RA and OA undergoing TKA and THA (Figure 1, Tables 1 and 2).

Table 1. Demographics of Total Knee Arthroplasty Patients Based on Primary Diagnosis of Osteoarthritis

Abbreviations: OA, osteoarthritis; RA, rheumatoid arthritis.

Table 2. Demographics of Total Hip Arthroplasty Patients Based on Primary Diagnosis of Osteoarthritis or Rheumatoid Arthritis

Abbreviations: OA, osteoarthritis; RA, rheumatoid arthritis

Continue to: Methods...

METHODS

Exemptions were obtained from the Institutional Review Board. Data from the Nationwide Inpatient Sample (NIS) from 2006 to 2011 were extracted using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes for patients that received primary TKA or THA, as well as their comorbid conditions. No patients or populations were excluded from the sampling process. A list of all independent variables collected for analysis and provision of relevant ICD-9 codes is included in Figure 1. The NIS is the largest all-payer stratified survey of inpatient care in the US healthcare system. As of 2011, each year provides information on approximately 8 million inpatient stays from about 1000 hospitals in 46 states. All discharges from sampled hospitals are also represented in the database. All patient information is protected, and all methods were conducted in accordance with the highest ethical standards of Human and Animal Rights Research.

STATISTICAL ANALYSIS

SAS 9.2 and PROC FREQ statistics software were used to generate P values (chi square result) and analyze the trends (Cochran-Armitage). Results were weighted utilizing standard discharge weights from the NIS to ensure accurate comparison of data from different time points. P < .05 was considered statistically significant. Multivariable logistic regression analyses were performed to generate odds ratio and 95% confidence limits to assess outcomes across different demographic variables.

RESULTS

Data on 337,082 and 1,362,241 patients undergoing THA or TKA, respectively, between 2006 and 2011 were analyzed. Patients in both groups were further differentiated by a diagnosis of either OA or RA. OA was the most common diagnosis, constituting 96.8% of all arthritic THA and TKA patients. From 2006 to 2011, a 36% and 34% increase in total number of THAs and TKAs, respectively, were reported. The number of patients with OA undergoing THA and TKA steadily increased from 2006 to 2011 (Figure 2). The number of THA and TKA procedures in patients with RA followed a similar trend but at a comparatively slower rate (Figure 3). The TKA geographical trends mirrored those observed with THA. The majority of operations were performed at urban hospitals (89% THA, 87% TKA; P < .0001). Among patients with RA and OA, the majority of TKAs (47.77%; P < .0001) took place in urban non-teaching hospitals than in urban teaching hospitals (39.26%). This pattern was not the same for THA, with 44.94% being performed at urban teaching hospitals and 44.05% at urban non-teaching institutions (P < .0001). Rural hospitals accounted for a low percentage of operations for both procedures: 10.46% of THA and 12.36% of TKA (P < .0001). Large institutions (based on the number of beds) claimed the majority of cases (59% of THA and TKA).

Logistic regression analysis and odds ratios of patients with OA vs those with RA with patient outcomes adjusted for age, Charlson Comorbidity Index (CCI) score, and gender revealed that patients with OA undergoing THA had lower risk for cardiovascular (0.674; confidence interval (CI) 0.587-0.774) and pulmonary complications (0.416; CI 0.384-0.450), wound dehiscence (0.647; CI 0.561-0.747), infections (0.258; CI 0.221-0.301), and systemic complications (0.625; CI 0.562-0.695) than patients with RA. Patients with OA exhibited statistically significantly higher odds of experiencing cerebrovascular complications after THA than those with RA (1.946; CI 1.673-2.236) (Table 3). In a similar logistic regression analysis of OA vs RA in TKA, which was adjusted for age, CCI score, and gender, patients with OA had significantly higher risk for cardiovascular (1.329; CI 1.069-1.651) and cerebrovascular complications (1.635; CI 1.375-1.943) than patients with RA. Significant decreases in wound dehiscence (0.757; CI 0.639-0.896), infection (0.331; CI 0.286-0.383), and systemic complication (0.641; CI 0.565-0.729) were noted in the patients with OA and TKA (Table 4).

Table 3. Odds Ratio for In-Hospital Complications Following THA for OA Patients vs RA Patients

Abbreviations: OA, osteoarthritis; RA, rheumatoid arthritis; THA, total hip arthroplasty.

Table 4. Odds Ratio for In-Hospital Complications Following TKA for OA Patients vs RA Patients

Abbreviations: OA, osteoarthritis; RA, rheumatoid arthritis; TKA, total knee arthroplasty.

Continue to: Discussion...

DISCUSSION

Our results showed a continuous yearly increase from 2006 to 2011 in THA and TKA procedures at a rate of 36% and 34%, respectively; this result was consistent with existing literature.¹¹ Despite a substantial increase in the amount of total THA and TKA procedures, the ratio of patients with RA undergoing these operations has decreased or remained nearly the same. Similar effects were found in Japan and the US when examining patients with RA undergoing TJA procedures between 2001 and 2007 and between 1992 and 2005, respectively.^12-14 This observation may be explained by the advances and early initiation of pharmacologic treatment and the widespread use of DMARDs such as methotrexate (MTX), azathioprine, leflunomide, hydroxychloroquine, and biological response modifiers TNF-α and interleukin-1.¹⁵ These medications have drastically improved survival rates of patients with RA with impressive capabilities in symptom relief.¹⁵ With the increasing use of DMARDs and aggressive treatment early on in the disease process, patients with RA are showing markedly slow progression of joint deterioration, leading to a decreased need for orthopedic intervention compared with the general population.^13,15

When analyzing the complication rates for patients undergoing TKA and THA, we observed that patients with RA exhibited a significant increase in the rates of infections, wound dehiscence, and systemic complications prior to discharge from the hospital compared with the OA population. The increased risk of infections was reported in previous studies assessing postoperative complication rates in TJA.^16,17 A study utilizing the Norwegian Arthroplasty Registry noted an increased risk of late infection in patients with RA, leading to increased rates of revision TJA in comparison with patients with OA.¹⁶ Another study, which was based on the Canadian Institute for Health Information Discharge Abstract Database, showed that patients with RA are at an increased risk of infection only after THA and interestingly not after TKA.¹⁷ Although our study did not identify the causes of the increased infection rate, the inherent nature of the disease and the immunomodulatory drugs used to treat it may contribute to this increased infectious risk in patients with RA.^6,18 Immunosuppressive DMARDs are some of the widely used medications employed to treat RA and are prime suspects of causing increased infection rates.¹⁵ The perioperative use of MTX has not been shown to cause short-term increases in infection for patients undergoing orthopedic intervention, but leflunomide and TNF-α inhibitors have been shown to cause a significant several-fold increase in risk for surgical wound infections.^19,20

All patients with RA presented with significant increases for infection, wound dehiscence, and systemic complications, whereas only patients with RA undergoing THA showed increased risk of pulmonary and cardiovascular complications when compared with patients with OA. Surprisingly, in TKA, patients with RA were at a significantly decreased risk of cardiovascular complications. This observation was interesting due to cardiovascular disease being one of RA's most notable extra-articular features.^4,21

Patients with RA undergoing TJA also showed significantly lower cerebrovascular complications than patients with OA. The significant reduction in risk for these complications has not been previously reported in the current literature, and it was an unexpected finding as past studies have found an increased risk in cerebrovascular disease in patients with RA. RA is an inflammatory disease exhibiting the upregulation of procoagulation factors,²² so we expected patients with RA to be at an increased risk for cerebrovascular and cardiovascular complications over patients with OA. Although we are unsure why these results were observed, we postulate that pharmaceutical interventions may confer some protection to patients with RA. For example, aspirin is commonly utilized in RA for its protective anti-platelet effect²³ and may be a contributing factor to why we found low postoperative complication rates in cerebrovascular disease. However, the reason why aspirin may be protective against cerebrovascular and not cardiovascular complications remains unclear. Moreover, most guidelines suggest that aspirin be stopped prior to surgery.²⁴ Although patients with RA were younger than those with OA, age was accounted for when analyzing the data.

A major strength of the study was the large sample size and the adjustment of potential confounding variables when examining the difference in complications between RA and OA. It is also a national US study that utilizes a validated database. Given that the patient samples in the NIS are reported in a uniform and de-identified manner, the database is considered ideal and has been extensively used for retrospective large observational cohort studies.²⁵ However, the study also had some limitations due to the retrospective and administrative nature of the NIS database. Only data concerning patient complications during their inpatient stay at the hospital were available. Patients who may develop complications following discharge were not included in the data, providing a very small window of time for analysis. Another limitation with the database was its lack of ability to identify the severity of each patient's disease process or the medical treatment they received perioperatively. Finally, no patient-reported outcomes were determined, which would provide information on whether these complications affect the patients’ postoperational satisfaction in regard to their pain and disability.

CONCLUSION

As RA patients continue to utilize joint arthroplasty to repair deteriorated joints, understanding of how the disease process and its medical management may impact patient outcomes is important. This article reports significantly higher postoperational infection rates in RA than in patients with OA, which may be due to the medical management of the disease. Although new medications have been introduced and are being used to treat patients with RA, they have not altered the complication rate following TJA in this patient population. Thus, surgeons and other members of the management team should be familiar with the common medical conditions, co-morbidities, and medical treatments/side effects that are encountered in patients with RA. Future studies should delve into possible differences in long-term outcomes of patients with RA undergoing TKA and THA, as well as whether certain perioperative strategies and therapies (medical or physical) may decrease complications and improve outcomes.

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