Return to Performance After Ulnar Collateral Ligament Surgery in Major League Baseball Pitchers
Authors: Mastroianni Michael A. , Kunes Jennifer A. , El-Najjar Dany B. , Obana Kyle K. , Desai Sohil S. , Morrissette Cole R. , Alexander Frank J. , Rondon Alexander J. , Trofa David P. , Popkin Charles A. , Levine William N. , Ahmad Christopher S. 
Published: January 2025

Background: Even though return to play is important for Major League Baseball (MLB) pitchers and teams, return to performance after ulnar collateral ligament (UCL) surgery using several advanced analytic and pitch-tracking metrics has not been well studied. Purpose: To evaluate return to performance in MLB pitchers using modern advanced analytic and pitch-tracking metrics at 1, 2, and 3 seasons after UCL surgery. Study Design: Case series; Level of evidence, 4. Methods: A retrospective analysis was performed on 129 MLB pitchers who underwent primary UCL reconstruction or repair between November 2017 and November 2023 and reported return-to-play and return-to-performance rates at 1, 2, and 3 seasons postoperatively. Return-to-performance data were then collected for 58 MLB pitchers who had at least 2 seasons of postoperative data using public sources affiliated with MLB and used in previous studies. Return-to-performance analysis consisted of paired and unpaired t tests comparing preoperative and postoperative metrics. The percentage of pitchers who returned to their preinjury performance for each respective advanced analytic or pitch-tracking metric was also recorded for each season after surgery. Return to full performance, defined as a pitcher returning to form in each key metric including expected fielding independent pitching, FanGraphs wins above replacement (fWAR), velocity, fastball velocity, and spin rate, was also evaluated. Data on advanced analytics released in 2020 measuring the physical quality of pitches (Stuff+), command of the strike zone (Location+), and overall pitching ability (Pitching+) was also examined for the first time. Binary logistic regression was conducted to evaluate for any predictive factors of return to performance. Results: The mean age was 27.6 ± 3.0 years. 1.6% returned to play at 1 year, 71.9% at 2 years, and 82.0% at 3 years from reported date of surgery with a mean of 584 ± 194 days. At 3 seasons postoperatively, pitchers returned to performance in pitch count (55%), expected fielding independent pitching (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 3.9%, 11.8%, and 28.1% of pitchers returned to full performance by 1, 2, and 3 seasons postoperatively, respectively. Only an additional 19.3% of pitchers met 4 out of 5 full performance criteria. Binary logistic regression identified starting pitchers and preoperative faster velocity and older age as strong negative predictors of return to full performance. Conclusion: Pitchers provided only half of their value to teams at 3 years postoperatively, despite presumably being physically recovered. Even though most pitchers regained their previous form in various pitching metrics, the majority of pitchers did not return to full form. Overall, being a starting pitcher was the strongest negative predictor of returning to full performance, followed by faster preoperative velocity and older age. The return-to-performance rate for each pitching metric improved season to season after returning from an injury. Despite returning to play at high rates, pitchers still needed time to recover their performance.