Abstract
Background:
The number of ulnar collateral ligament (UCL) tears in professional baseball players is increasing. UCL reconstruction (UCLR) is the treatment of choice in players with failed nonoperative treatment who wish to return to sports (RTS). It is unknown if UCL tear location influences the ability of players to RTS or affects their performance upon RTS.
Purpose/Hypothesis:
The purpose was to compare the RTS rate and performance upon RTS in professional baseball players who underwent UCLR based on UCL tear location (proximal vs distal). It was hypothesized that no difference in RTS rate or performance upon RTS will exist between players with proximal or distal UCL tears.
Study Design:
Cohort study; Level of evidence, 3.
Methods:
All professional baseball players who underwent primary UCLR by a single surgeon between 2016 and 2018 were eligible for inclusion. Players with purely midsubstance tears or revision UCLR were excluded. Tear location was determined based on preoperative magnetic resonance imaging (MRI) and intraoperative findings. RTS rate and performance were compared between players with proximal versus distal UCL tears.
Results:
Overall, 25 pitchers (15 proximal and 10 distal tears) and 5 position players (2 proximal and 3 distal) underwent primary UCLR between 2016 and 2018. Of the 25 pitchers, 84% were able to RTS. Of the 5 position players, 80% were able to RTS. Among the total cohort of pitchers and position players, 12 out of 17 (71%) players with proximal tears were able to RTS, while of the 13 distal tears, 13 out of 13 (100%) players were able to RTS (P = .05). With regard to performance data, pitchers with distal tears had higher utilization postoperatively and, as such, allowed statistically more hits (P = .03), runs (P = .015), and walks (P = .021) postoperatively. However, the WHIP ([walks + hits]/innings pitched) was not different between players with proximal or distal tears, indicating that efficacy in games was not significantly different between groups.
Conclusion:
Professional baseball players who sustain a distal UCL tear and undergo UCLR may be more likely to RTS than those who sustain a proximal UCL tear and undergo UCLR. Players with distal UCL tears who underwent UCLR saw higher utilization postoperatively than those with proximal UCL tears. Further work is needed in this area to confirm this result.
Keywords
The number of ulnar collateral ligament (UCL) injuries in baseball players of all levels has continued to rise over the past 10 years.1,2,5,11,12,16 Nonoperative management is typically attempted in the majority of patients depending on tear location (proximal, midsubstance, or distal), tissue quality, level of play, and other factors. Several studies have evaluated the ability of athletes to return to sports (RTS) after nonoperative management of UCL tears. Several authors have noted a higher RTS rate in patients when the UCL tear is proximal (at the level of the medial epicondyle) as opposed to distal (at the level of the sublime tubercle).6,14,15 This could be due to many factors, including a more robust blood supply to the proximal aspect of the UCL. 3
While nonoperative management is effective in some athletes, those with failed nonoperative management who wish to RTS are offered surgical intervention with either UCL repair or UCL reconstruction (UCLR). 4 UCLR involves re-creating the anterior bundle of the UCL with a graft, typically a palmaris longus or gracilis autograft, and allowing this tendon to convert to a ligament over time to withstand the stress created on the medial elbow during the overhead throwing motion. Several UCLR techniques exist with minor variation, but the overall procedure involves creation of a tunnel or socket on the ulna and humerus and the use of a graft to re-create the UCL. Intraoperatively, when performing a UCLR, the native UCL is split in line with its fibers to access the joint and to allow for accurate placement of the proximal and distal socket/tunnel. Most surgeons repair the split that is made in the native ligament during surgery in a side-to-side fashion. Reported rates of RTS after UCLR have been good, with most studies citing an RTS rate of >80% regardless of surgical technique and graft type.1,5,8,9,18,19 However, no study to date has compared players with distal UCL tears with those with proximal UCL tears to determine if there is a difference in RTS rate or performance upon RTS. While the new UCL graft is the backbone of the surgery, there may be a difference in the ability of the native UCL to heal and/or scar, depending on where the tear is.
Therefore, the purpose of this study was to compare the RTS rate and performance upon RTS in professional baseball players who underwent UCLR based on UCL tear location (proximal vs distal). The authors hypothesized there would be no difference in RTS rate or performance upon RTS between players with proximal or distal UCL tears after UCLR.
Methods
This study was approved by the institutional review board of the Hospital for Special Surgery (IRB No. 2015-221). All professional baseball players who underwent a UCLR with a single surgeon (D.W.A.) at a single institution (Hospital for Special Surgery) between October 2016 and April 2018 were eligible for inclusion. The senior author (D.W.A.) uses the docking technique for UCLR. The medical record was updated in October 2016, allowing for accurate reporting of clinical information from this point forward. April 2018 was chosen as the end date to allow players time to RTS and participate in a season after their surgery. Players were excluded if they were playing in high school or college at the time of their surgery or if their medical record was incomplete. Players who had a previous UCLR were excluded. There were 26 pitchers and 7 position players who underwent UCLR between 2016 and 2018. One position player was excluded as his tear was purely midsubstance, 1 position player was excluded as he had a previous UCLR and this was a revision surgery, and 1 pitcher was excluded as he had a previous UCLR and this was a revision surgery. This left 25 pitchers and 5 position players who were included in the final analysis. No player was excluded because of an incomplete medical record. All players underwent the same rehabilitation protocol. Date of surgery, side of surgery, UCL tear location, ability to RTS (defined as ability to participate in a minimum of 5 games postoperatively), level of play, and preoperative and postoperative performance data were recorded for each player. This information was obtained from patient charts and from https://www.baseball-reference.com. Players were then divided into 2 groups, proximal or distal, based on their tear location. Tear location was determined by preoperative magnetic resonance imaging (MRI) and intraoperative findings. Tear location was recorded for all players. The ability to RTS was recorded for all players and was compared between the 2 groups. Preoperative and postoperative performance were recorded for all players with a minimum of 2 years of follow-up who were able to RTS. As there were significantly fewer position players than pitchers, position players were included in the study with regard to RTS rate but were not included in the performance portion.
Statistics
All analyses were performed in Excel X (Microsoft) and SPSS Version 21 (IBM Corp). As this was a retrospective study of an uncommon procedure in a specific population subgroup, no a priori power analysis was conducted and all available patients were included. Descriptive statistics were calculated. Performance outcomes were averaged before the injury and postoperatively/after the injury. Performance data within a year of surgery were discarded because of potential variations in injury chronicity and rehabilitation variations. Baseball performance data are reported as both counts and percentages. For the former, preoperative and postoperative counts per season were calculated. Pre- and postoperative data were then compared using paired Student t tests and related-samples Wilcoxon signed-rank tests as appropriate based on data normality. RTS and postoperative performance data were compared between players with proximal and distal tears using Fisher exact tests, Student t tests, and Mann-Whitney U tests as appropriate, based on data normality.
Results
Overall, 25 pitchers (15 proximal and 10 distal tears) and 5 position players (2 proximal and 3 distal) underwent primary UCLR between 2016 and 2018. Of the 25 pitchers, 84% were able to RTS. Of the 5 position players, 80% were able to RTS. Among the 17 players with proximal tears, 12 (71%) RTS, while of the 13 players with distal tears, 13 (100%) RTS (P = .050). For the 12 players with proximal tears who were able to RTS, 9 (75%) were able to RTS at the same or higher level of play while 3 (25%) RTS at a lower level of play. For the 13 players with distal tears that were able to RTS, 13 (100%) were able to RTS at the same or higher level of play. Seven players underwent concomitant elbow arthroscopy, 6 underwent concomitant ulnar nerve decompression and transposition, and 1 underwent concomitant flexor-pronator repair (some players had more than 1 concomitant procedure). Among players with concomitant procedures, 6 had distal tears (all 6 RTS) and 10 players had proximal tears (7 RTS). The right elbow was operated on in 77% (23/30) of the cases. The included players had played for an average of 3.7 ± 1.7 years in professional baseball before surgery.
For the performance portion of the study, of the 25 pitchers who met inclusion criteria, 8 had fewer than 2 years of follow-up available, leaving 17 pitchers within the performance portion of the study. Of these 17 pitchers, 35% (n = 6) had distal tears and 65% (n = 11) had proximal tears. Players with distal tears tended toward higher utilization postoperatively and, as such, allowed more hits, runs, and walks (Table 1). However, the WHIP ([walks + hits]/innings pitched) was no different between players with proximal or distal tears, indicating that efficacy in games not was significantly different between groups.
Performance Data a
Data are presented as mean ± SD. Boldface type indicates statistical significance. CG, complete games; ERA, earned run average; HB, hits batted in; HR, home runs; IP, innings pitched; SHO, shutouts; SO, strikeouts; SV, saves; WHIP, walks and hits per innings pitched.
Discussion
The number of UCLRs in overhead athletes of all levels continues to rise. The authors’ hypothesis was partly confirmed, as there was no difference in performance between professional baseball pitchers who had a distal or proximal UCL tear and underwent UCLR, although those who had distal UCL tears saw more utilization and, as such, allowed more runs, hits, and walks postoperatively. However, significantly fewer players with proximal UCL tears were able to successfully RTS after UCLR than those with distal tears.
While this is the first study to report on the RTS rate and performance upon RTS after UCLR based on UCL tear location (proximal or distal), several previous studies have evaluated the success of nonoperative treatment based on UCL tear locations.14,15,17 Frangiamore et al 15 evaluated 32 professional baseball players who underwent initial nonoperative management of UCL injuries and compared the success of nonoperative management based on MRI-diagnosed tear location (proximal vs distal). In the authors’ cohort, 82% of players with failed nonoperative management had distal tears, while 81% who were successfully treated nonoperatively had proximal tears. Furthermore, after the authors adjusted for age, tear location, and evidence of chronic changes of the UCL on MRI, they reported that the likelihood of failing nonoperative treatment was 12.40 times higher when players had a distal tear. Similarly, Ramkumar et al 17 reported on 23 baseball players who underwent nonoperative management for UCL tears and found that players with distal tears were more likely to proceed to surgical management than those with proximal tears. 17 Conversely, Ford et al 14 reported on the nonoperative management of 35 incomplete UCL injuries in professional baseball players and evaluated their ability to RTS based on tear location (proximal vs distal). The authors found no significant difference in ability to RTS based on tear location. As several studies have found higher RTS rates with nonoperative management of proximal tears, this may preselect out those players who would have done well with operative treatment as they never progressed to UCLR. There may also be a different injury mechanism for proximal UCL tears than distal tears, causing inferior results with proximal tears after UCLR.
The increased failure of nonoperative management of distal UCL tears may be due to the UCL anatomy, as the distal aspect of the UCL has a long, narrow insertion with a poor blood supply, whereas the proximal UCL has a broad insertion with a more robust blood supply.3,13 Furthermore, only the proximal-most portion of the UCL insertion onto the sublime tubercle of the ulna contributes significantly to valgus stability of the elbow, indicating that there is a large amount of stress seen by a small area of the distal UCL insertion. 10 This is in contrast to the proximal insertion where the load is dispersed throughout the entire footprint. 13 However, during UCLR a distal tunnel and proximal socket are created and a graft is used to reconstruct the UCL. All patients included in this study underwent UCLR with the docking technique where a 3.0-mm bur was used to create an ulnar tunnel and a 4.0-mm bur was used to create a blind-ended humeral socket.
The senior author utilizes a technique where the native UCL is split in line with its fibers during exposure and is then repaired in a side-to-side manner before the final limb of the graft is docked into the ulna.7,18 Logistically, during repair of the native UCL intraoperatively, the distal and midportion of the UCL are easily repaired, as the graft does not interfere with the ability to repair these areas of the ligament. However, the most proximal aspect of the proximal UCL typically cannot be completely repaired since this area is covered by the graft and, if sewn together before the graft was docked into the humerus, would obstruct passage of the graft into the humeral socket. Hence, the repair of the distal UCL is more robust in the docking technique than the repair of the proximal UCL. This may have contributed to the trend toward a higher RTS rate in the distal UCL tear group compared with the proximal tear group. It is also possible that the proximal aspect of the UCLR is the weak point, as this is where the graft is fixed. In the authors’ experience, when a UCLR fails, it commonly fails proximally. In the docking technique for UCLR, the graft is simply passed through a tunnel in the ulna and therefore, barring a fracture of the ulnar tunnel, the weak point in the UCLR construct is proximal. As such, if a player has a proximal UCL tear and undergoes a UCLR where the weakest point in the reconstruction is in the same spot as the tear in the native ligament, it is possible that the reconstructed graft sees more load than if the tear in the native ligament were distal. A healthy proximal native UCL may be able to take stress off the proximal aspect of the reconstructed UCL, allowing for a better outcome after UCLR. Interestingly, performance data demonstrated that players with distal tears had more utilization postoperatively, while players with proximal tears had less utilization but better performance. Further work is needed to confirm the results of this study. However, if these results remain consistent, the surgical technique for UCLR may need to be modified based on location of the tear within the native UCL to allow for a more robust repair of the native UCL that can then maximize patient outcomes.
Limitations
This was a retrospective cohort study of baseball players treated by a single surgeon who is experienced in elbow surgery. As such, the results may not be translatable to a large majority of surgeons. While tears were classified as distal or proximal, in many professional athletes there was some degree of degeneration throughout the entire course of the native UCL given the stress placed on the medial elbow by these athletes over a prolonged period of time. The number of patients included in this study was small and more large-scale studies are needed to confirm these results; the number of cases included may have limited the power of this study. There was a trend for those who had proximal tears to play fewer games (10 vs 26), which may be clinically relevant, but further research is needed in this area to determine if this remains true. This study is meant to further discussion regarding UCL tear location and surgical intervention.
Conclusion
Professional baseball players who sustain a distal UCL tear and undergo UCLR may be more likely to RTS than those who sustain a proximal UCL tear and undergo UCLR. Players with distal UCL who underwent UCLR saw higher utilization postoperatively than those with proximal UCL tears. Further work is needed in this area to confirm this result.
Footnotes
Submitted March 2, 2020; accepted May 28, 2020.
One or more of the authors has declared the following potential conflict of interest or source of funding: B.J.E. has received hospitality and education payments from Arthrex, Smith & Nephew, and DePuy Synthes; and hospitality payments from Linvatec and Stryker. P.N.C. has received royalties from DePuy, consulting fees from Arthrex and Mitek, and hospitality payments from Tornier. D.W.A. has received consulting fees from Stryker Corp and education payments from Arthrex and Stryker. J.C. has received education payments from Supreme Orthopedic Systems. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.