Effect of Ulnar Collateral Ligament Reconstruction on Performance in Major League Baseball Pitchers: A 2-Year Analysis of Advanced Pitching Statistics, Velocity, and Spin Rate

Background: Ulnar collateral ligament reconstruction (UCLR) is a common procedure for Major League Baseball (MLB) pitchers, with a rising incidence and significant financial and performance implications. However, the effect of UCLR on postinjury pitching performance remains controversial, particularly regarding advanced metrics such as spin rate and velocity. Purpose: To evaluate changes in pitching performance after UCLR and the association between pitch velocity, spin rate, and performance. Study Design: Case-control study; Level of evidence, 4. Methods: A total of 43 MLB pitchers who underwent UCLR between 2017 and 2021 were compared with 86 uninjured age-matched controls. Pitching metrics, including fielding independent pitching, skill-interactive earned run average, and walks plus hits per inning pitched, as well as pitch-specific velocity and spin rate were analyzed for 2 seasons before and at least 1 season after UCLR. Principal component analysis was used to assess overall performance. Results: Pitchers showed a significant decline in overall performance during the first season after UCLR ( P = .032) but returned to preinjury levels by the second season ( P = .287). There was a significant decrease in the off-speed pitch spin rate observed in the first season ( P = .041), but all other pitches demonstrated no significant change throughout the study period. Increases in fastball velocity ( P = .046), fastball spin rate ( P = .019), and off-speed pitch velocity ( P = .016) were associated with superior overall performance. Conclusion: The current study demonstrated that while pitchers experienced a significant decline in performance during the first season after UCLR, most of those who returned for a second season returned to their baseline preinjury performance. Additionally, increased velocity and spin rate were associated with improved performance in both injured and healthy pitchers, highlighting the value of these metrics in evaluating overall pitching performance.