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Performance and Return to Sport After Ulnar Nerve Decompression/Transposition Among Professional Baseball Players

Background: Isolated ulnar nerve decompression/transposition is an uncommon surgical procedure among professional baseball players. Purpose/Hypothesis: To determine performance and rate of return to sport (RTS) among professional baseball players after isolated ulnar nerve decompression/transposition, including those who required decompression/transposition after ulnar collateral ligament reconstruction (UCLR), and to compare outcomes between cases and matched controls. The authors hypothesized a high rate of RTS among professional baseball players undergoing isolated ulnar nerve decompression/transposition with no difference in RTS rate or performance between cases and controls as related to earned run average, WHIP ([walks + hits]/innings pitched), wins above replacement, and on base + slugging percentage. Study Design: Cohort study; Level of evidence, 3. Methods: Utilizing the injury database of Major League Baseball, we identified all professional baseball players who underwent isolated ulnar nerve decompression/transposition between 2010 and 2016. De-identified demographic and performance data (before and after surgery) for each player were recorded from Major League Baseball records. Performance metrics were then compared between cases and matched controls. Results: The study included 52 players; 83% were pitchers; and 14 underwent prior UCLR. Most surgical procedures (92%) were anterior subcutaneous transpositions. Overall, 62% of players were able to successfully RTS, and 56% returned to the same or higher level. There was no significant difference between cases and controls in the majority of pre- and postoperative performance metrics—specifically, earned run average, WHIP, wins above replacement, and on base + slugging percentage. When players who had UCLR before ulnar nerve decompression/transposition were compared with controls with a history of UCLR but no subsequent ulnar nerve decompression/transposition, the only performance difference of all the recorded metrics was that cases allowed more walks per 9 innings (4.4 vs 2.8, P = .011). Conclusion: Anterior subcutaneous transposition is the most common surgical procedure among professional baseball players to address ulnar neuropathy at the elbow. Players have a 62% rate of RTS, which is lower than expected for this nonreconstruction or repair procedure. For players who successfully RTS, performance metrics versus matched controls remained the same except for allowing significantly more walks per 9 innings. Postoperatively, pitchers with UCLR before ulnar nerve decompression/transposition who had a successful RTS performed the same as matched controls with prior UCLR without subsequent ulnar nerve decompression/transposition.