Pitch Performance After Ulnar Collateral Ligament Surgery in Major League Baseball Pitchers

Return to performance after ulnar collateral ligament (UCL) surgery in Major League Baseball (MLB) pitchers has been investigated; however, pitch-specific return to performance using several advanced metrics has been minimally studied.

To evaluate pitch performance 1, 2, and 3 seasons after UCL surgery in MLB pitchers.

Case series; Level of evidence, 4.

We performed a retrospective analysis on 129 MLB pitchers who underwent primary UCL reconstruction or repair from November 2017 to November 2023. Pitch types analyzed included fastballs, sliders, curveballs, sinkers, cutters, changeups, and splitters. The exclusion criteria included pitchers without 1 preoperative and 2 postoperative qualifying seasons (ie, >100 pitches in a calendar year) of pitch-tracking data except for analysis of Stuff+ (measures physical qualities of a pitch), Location+ (measures strike-zone command), and Pitching+ (measures overall pitching ability), which were first released in 2020 and thus analysis is secondary to power limitations, resulting in 54 total MLB pitchers. Data were obtained from public web sources. Statistical analyses included paired and unpaired t tests, as well as binary logistic regression to identify predictors of returning to performance. Return to preinjury pitch performance was also evaluated.

The mean age was 26.8 + 3.6 years, 74.1% of the included pitchers were right-handed, and 42.6% were starting pitchers. All individual pitches had recovered to their preoperative velocity levels by their second season back from surgery. Multiple pitches showed alterations returned to full performance at a higher than 44% in the horizontal and vertical approach angles above the mean. All pitches had significantly longer release extensions and regained their velocity and spin rate nearly 70% of the time by their third season back. Horizontal and vertical movement also recovered well for each pitch type. Nearly all pitchers returned to performance in their fastballs and sliders' Stuff+, Location+, and Pitching+, while the remaining pitches analyzed trended to not return to performance as frequently. No single pitch returned to full performance at a higher than 44% rate. Binary logistic regression did not identify any significant predictors for returning to performance in any pitch.

Pitch-specific differences in return to performance exist after UCL surgery. No pitch returned to full performance at a higher than 44% rate 3 seasons after returning from injury, with changeups faring the best. All pitches had recovered to their preoperative mean velocity and movement levels by 2 seasons prior. Nearly all pitchers returned to performance in fastball and slider physical pitch qualities (Stuff+), strike-zone command (Location+), and overall ability (Pitching+) while sinkers, curveballs, changeups, cutters, and splitters struggled more frequently in these metrics. Altogether, we believe this study better informs MLB players and teams about expectations regarding return to performance of specific pitch types after UCL surgery.