Poster 50: Return to Performance Following UCL Surgery in Major League Baseball Pitchers

Abstract

Objectives:

While return to play is important for Major League Baseball (MLB) pitchers and teams, return to performance following UCL surgery using modern advanced analytic and pitch-tracking metrics has not been well studied despite their wide-spread value throughout the league. Therefore, the primary objective of this study was to evaluate return to performance using more predictive advanced analytic and pitch-tracking outcomes in the seasons following UCL surgery. Our secondary objective was to evaluate return to play (RTP) rates from November 2017 to June 2023, providing an up-to-date analysis during a period focused on value and advanced analytics. Our hypothesis was that almost all MLB pitchers will return to play by three seasons post-operatively, however a fewer percentage will have ultimately returned to performance. Overall, this study better informs current MLB players and teams about expectation regarding return to play and performance following UCL surgery, using outcomes that help drive player evaluation throughout the league.

Methods:

We performed a retrospective analysis on 119 MLB pitchers who underwent primary UCL reconstruction or repair from November 2017 to June 2023, and reported return to play and performance rates at one, two, and three seasons post-operatively. Return to performance analysis was then collected for 54 total MLB pitchers who met inclusion criteria (two seasons of both pre- and post-operative data) using public sources affiliated with MLB and used in previous studies. Return to performance analysis consisted of paired t-tests comparing pre- to post-operative metrics. The percentage of pitchers who returned to their pre-injury performance for each respective advanced analytic or pitch-tracking metric was also recorded for each season after surgery. Return to full performance was also evaluated. Binary logistic regression evaluated for any predictive factors.

Results:

Mean age was 26.5 + 3.4 years, 70.6% of included pitchers were right-handed, and 43.1% were starting pitchers. Five pitchers underwent primary UCL repair (4.2%), 113 pitchers underwent primary UCLR (94.9%), and one pitcher underwent hybrid UCL reconstruction with internal brace augmentation (0.9%). 4% returned to play at 1-year post-operatively, 79% at 2-years, and 99% at 3-years with a mean of 558 + 159 days. On average, pitchers showed a mild but significant decrease in cumulative metrics, strike zone command (Location+), and overall pitching ability (Pitching+) post-operatively. At 3-seasons post-operatively, pitchers returned to performance in pitch count (55%), xFIP (68%), fWAR (48%), velocity (76%), fastball velocity (80%), horizontal movement (81%), vertical movement (66%), Stuff+ (78%), Location+ (89%), and Pitching+ (78%) at varying degrees. Only 4%, 12%, and 28% of pitchers returned to full performance by 1-, 2- and 3-seasons post-operatively, respectively. Binary logistic regression did not identify any pre-operative factors associated with return to fWAR and full performance at 3-seasons.

Conclusions:

4%, 12%, and 28% of pitchers returned to full performance by 1-, 2- and 3-seasons post-operatively. Only 48% of pitchers returned to their pre-injury fWAR 3-seasons after surgery, suggesting that only half of pitchers provide the same value to teams despite presumably being fully recovered. In addition, the return to performance of each pitching metric improved season to season after returning from injury, suggesting that despite returning to play pitchers still need time to fully recover performance. Over 75% of pitchers returned to their pre-injury performance in velocity (76%), fastball velocity (80%), Pitching+ (78%), and Location+ (89%) at 3-seasons. There were no pre-operative factors that predicted return to fWAR or full performance at 3-seasons. UCL surgery restored pitcher’s rate-based metrics, velocities, movement, spin, vertical approach angles, and horizontal release points. Several modern advanced analytic and pitch-tracking metrics were characterized following UCL surgery for the first time.