Risk Stratification for Ulnar Collateral Ligament Injury in Major League Baseball Players: A Retrospective Study From 2007 to 2014

Background: Ulnar collateral ligament (UCL) injury has become increasingly common in Major League Baseball (MLB) players in recent years. Hypothesis: There is a significant difference in preinjury fastball velocity between MLB pitchers with tears and matched controls without UCL injury. Pitchers with injuries are throwing harder and getting injured earlier in their MLB careers. Study Design: Cohort study; Level of evidence, 3. Methods: From 2007 to 2014, a total of 170 documented UCL injuries (156 pitchers, 14 position players) occurred in MLB. Inclusion criteria for this study consisted of any player who tore his UCL in MLB during this time frame. There were 130 regular-season tears (April-September). From this group, 118 players who pitched more than 100 innings prior to tear were matched to subjects with no tear and were compared using a logistic regression analysis. A subgroup of early tear players who threw less than 100 career innings (n = 37) was also identified and compared with the larger tear group using a logistic regression analysis. Results: Of the 130 tears that occurred during the regular season, a significantly larger number (62%) occurred in the first 3 months (P = .011). The rate of UCL tears per MLB player (P = .001) was statistically significant. In the group of 118 matched tears, the mean fastball velocity was greater in the tear group (91.7 mph) compared with the control group (91.0 mph; P = .014). Furthermore, relief pitchers made up a greater percentage of the early tear group (<100 innings) compared with the later tear group (P = .011). Sixteen of the 170 UCL tears (9.4%) were recurrent tears, with 5 of 16 experiencing both tear and retear within the past 4 years. Conclusion: There is a statistically significant difference in the mean fastball velocity of pitchers who injure their UCL. Small increases in pitcher fastball velocity are a main contribution to the increased rate of tear in MLB. In addition, there has been an increased incidence of injury in the first 3 months of the season. Finally, early tears are more likely to occur in relief pitchers than starters.