Pitch-Specific Advanced Analytic and Pitch-Tracking Risk Factors for Ulnar Collateral Ligament Injuries in Major League Baseball Pitchers

Background: The utilization of new pitch-tracking metrics has driven player development and provides more predictive pitch-specific data on physical characteristics and performance. Given the differences in each pitcher's arsenal, these pitch-specific metrics provide new potential variables to investigate ulnar collateral ligament (UCL) injury risk. Purpose: To evaluate the association of several pitch-specific advanced analytic and pitch-tracking metrics on UCL surgery rates in Major League Baseball (MLB) pitchers. Study Design: Case-control study; Level of evidence, 3. Methods: We performed a retrospective case-control study on all MLB pitchers who underwent primary UCL reconstruction or repair from April 2018 to November 2023. Exclusion criteria included pitchers without 2 qualifying seasons of preoperative pitch-tracking data or who previously underwent UCL surgery. Matched controls were identified in a 2:1 manner by using season, age, position, handedness, and pitch count as covariates. Pitch-specific advanced analytic and pitch-tracking metrics used commonly in the evaluation of MLB players were collected from public web sources sponsored by MLB. Statistical analysis consisted of unpaired t tests comparing preinjury metrics between the case and control groups, along with binary logistic regression. Results: A total of 115 MLB pitchers who underwent UCL reconstruction or repair were compared with 230 matched controls. Increased velocity for fastballs, changeups, and sinkers were all associated with UCL surgery. A decreased horizontal release point for fastballs, curveballs, and sinkers were also associated with UCL surgery, along with an increased horizontal approach angle above average for fastballs and sinkers. An increased spin rate for sliders and an increased release extension for cutters were also associated with surgery. Large statistically significant differences in Pitching+ and Location+ for fastballs, changeups, and sinkers, and in Stuff+ for changeups, were associated with surgery. There were no differences in pitch-specific pitch count, active spin, spin axis, vertical release point or approach angle, or overall pitch movement between cases and controls. Binary logistic regression showed that higher velocity fastballs, sliders, and changeups were all associated with UCL surgery, along with sliders with a higher spin rate and cutters with a longer release extension. Conclusion: This study demonstrated that pitch-specific associations with UCL surgery exist compared with matched controls. Specifically, higher velocity fastballs, sliders, and changeups were all associated with UCL surgery, along with sliders with a higher spin rate and cutters with a longer release extension. Fastballs, changeups, and sinkers with superior ability (Pitching+) and command (Location+) were also associated with UCL surgery. While fastball velocity appears to play a role in the rise of UCL injuries, recent trends in decreased fastball usage and improved secondary pitches suggest that an increased focus on entire pitching arsenals is warranted. This study investigated a number of pitch-specific advanced analytic and pitch-tracking metrics as potentially new variables to assess UCL injury risk.