Performance and Return to Sport Following Ulnar Nerve Transposition/Decompression in Professional Baseball Players

BACKGROUND: Isolated ulnar nerve decompression/transposition is an uncommon surgery amongst professional baseball players. PURPOSE: To determine the rate of return to sport (RTS) and performance upon RTS in professional baseball players following isolated ulnar nerve decompression/transposition, including those who required an ulnar nerve transposition/decompression following ulnar collateral ligament reconstruction (UCLR), and to determine if outcomes differ between players with isolated ulnar nerve decompression/transposition and matched controls. HYPOTHESIS: There is a high rate of RTS in professional baseball players undergoing isolated ulnar nerve decompression/transposition with no significant difference in RTS rate or performance (specifically related to the primary outcome performance variables of earned run average (ERA), WHIP ((walks +hits)/innings pitched), wins above replacement (WAR), and on base + slugging percentage (OPS)) between cases and controls. METHODS: All professional baseball players who underwent isolated ulnar nerve decompression/transposition between 2010-2016 were included. Demographic and performance data (pre and post surgery) for each player was recorded. Performance metrics were then compared between cases and a group of matched controls. RESULTS: Overall 52 players, 83% pitchers (14 who underwent prior UCLR) were included. Most surgeries (92%) were anterior subcutaneous transpositions. Overall, 62% of players were able to successfully RTS and 56% returned to the same or a higher level. There was no significant difference between cases and controls in the majority of performance metrics pre-operative or post-operatively, specifically ERA, WHIP, WAR, and OPS. When players who had a UCLR prior to their ulnar nerve transposition/decompression were compared to controls with a history of a UCLR but who did not go on to have an ulnar nerve transposition/decompression, the only performance difference of all the recorded metrics was cases allowed more walks per 9 innings (4.4 vs. 2.8; p=0.011). CONCLUSION: Anterior subcutaneous transposition is the most common surgery in professional baseball players to address ulnar nerve compression. Players have a 62% rate of RTS. Upon RTS, players performance compared to matched controls remains the same in the majority of performance metrics including ERA, WHIP, WAR, and OPS. Post-operatively, pitchers with a UCLR prior to ulnar nerve transposition/decompression performed the same as matched controls with prior UCLR.