The Effect of Ulnar Collateral Ligament Reconstruction on Pitch Velocity in Major League Baseball Pitchers.

BACKGROUND The medial ulnar collateral ligament (UCL) is the primary restraint to valgus load, and injury is commonly encountered as a result of overuse in throwing athletes. Reconstruction of this ligament has allowed for a high rate of return to sport for elite pitchers. Public perception of this procedure has resulted in a commonly held belief of increased throwing velocity following UCL reconstruction. HYPOTHESIS Fastball velocity for Major League Baseball (MLB) pitchers is significantly decreased following UCL reconstruction. STUDY DESIGN Case series; Level of evidence, 4. METHODS A total of 129 pitchers were identified as undergoing UCL reconstruction from publicly available reports, and a final group of 80 MLB pitchers were included for analysis. Statistics were collected, including pitch velocity, pitch selection, and performance outcomes. Pre- and postoperative statistics were compared using paired t tests to allow for evaluation of each pitcher relative to his baseline velocity and performance. RESULTS Mean fastball velocity was significantly decreased following UCL reconstruction, with a presurgical mean velocity of 91.3 mph and postoperative velocity of 90.6 mph (P = .003). The greatest observed difference was in pitchers older than 35 years, with fastball velocity decreasing from 91.7 to 88.8 mph (P = .0048). Pitchers threw fewer fastballs after reconstruction. Pitch velocity for curveballs, changeups, and sliders did not change significantly after UCL reconstruction. Additionally, pitchers threw fewer innings and pitches following reconstruction and produced fewer wins above replacement relative to their preinjury state. CONCLUSION Contrary to popular opinion, fastball velocity for MLB pitchers is significantly decreased following UCL reconstruction, which should reinforce the importance of preventing overuse injuries.