Changes in pitching mechanics after ulnar collateral ligament reconstruction in major league baseball pitchers.
BACKGROUND
Medial ulnar collateral ligament (UCL) reconstruction is a common procedure performed on Major League Baseball pitchers. Variations in pitching mechanics before and after UCL reconstructive surgery are not well understood.


METHODS
Publicly available pitch tracking data (PITCHf/x) were compared for all Major League Baseball pitchers who underwent UCL reconstruction between 2008 and 2013. Specific parameters analyzed were fastball percentage, release location, velocity, and movement of each pitch type. These data were compared before and after UCL reconstructive surgery and compared with a randomly selected control cohort.


RESULTS
There were no statistically significant changes in pitch selection or pitch accuracy after UCL reconstruction, nor was there a decrease in pitch velocity. The average pitch release location for 4-seam and 2-seam fastballs, curveballs, and changeups is more medial after UCL reconstruction (P < .01). Four-seam fastballs and sliders showed decreased horizontal breaking movement after surgery (P < .05), whereas curveballs showed increased downward breaking movement after surgery (P < .05).


CONCLUSIONS
Pitch selection, pitch velocity, and pitch accuracy do not significantly change after UCL reconstruction, nor do players who require UCL reconstruction have significantly different pitch selection, velocity, or accuracy than a randomly selected control cohort. Pitch release location is more medial after UCL reconstruction for all pitch types except sliders. Breaking movement of fastballs, sliders, and curveballs changes after UCL reconstruction.
['Portney|Daniel A|DA|', 'Lazaroff|Jake M|JM|', 'Buchler|Lucas T|LT|', 'Gryzlo|Stephen M|SM|', 'Saltzman|Matthew D|MD|']
D000328:Adult D054874:Athletic Performance D001484:Baseball D001696:Biomechanical Phenomena D016022:Case-Control Studies D004551:Elbow Joint D006801:Humans D008297:Male D009068:Movement D012189:Retrospective Studies D000070638:Ulnar Collateral Ligament Reconstruction D055815:Young Adult
Pitch Baseball UCL PITCHf/x release location MLB Tommy John Valgus instability