Epidemiology of Elbow Ulnar Collateral Ligament Injuries Among Baseball Players National Collegiate Athletic Association Injury Surveillance Program, 2009-2010 Through 2013-2014

Background: Injuries to the ulnar collateral ligament (UCL) of the elbow are of major concern in baseball; however, the epidemiology of these injuries among National Collegiate Athletic Association (NCAA) athletes is poorly described. Purpose: To determine the incidence of UCL injuries in NCAA baseball and investigate the risk factors involved. Study Design: Descriptive epidemiology study. Methods: All UCL injuries for academic years 2009-2010 through 2013-2014 were extracted from the NCAA Injury Surveillance Program database. The incidence was calculated for different positions, activity, time in game, competition status, and injury characteristics and compared via injury risk ratios to determine risk factors for injury occurrence. The NCAA provides sampling weights based on division and year. For all other injury characteristic analysis, unweighted data were used. Results: Over the course of the 2009-2010 to 2013-2014, 20 UCL injuries were reported in the NCAA Injury Surveillance Program over 177,992 athletic exposures (AEs) for an overall incidence of 1.12 per 10,000 AEs (95% CI, 0.63-1.62). Eighty-five percent occurred during throwing, and 100% were new injuries. Of the injuries sustained during games, 28.6% occurred early (warm-up through third inning) and 71.4% late (fourth inning or later), with a risk ratio of 1.3 for late-game injuries (95% CI, 0.24-6.44). Of those injured, 45.0% were able to return to play by the next season, while the remainder were out for at least 7 days. Injury was season ending for 15% of athletes (0.17 per 10,000 AEs), and 15% of athletes required surgery. Conclusion: UCL injury is a potentially season-ending, even career-ending, injury among NCAA baseball players. Additionally, while more injuries occurred later in games, the current study revealed no significant difference in injury rates with respect to time in game. Last, the authors found a higher reported rate of extensive time away from sport after UCL injury than previously published studies on this patient population.