550 MEP011 – ACL injury patterns in major league baseball (MLB): a systematic video analysis of injuries over 6 consecutive seasons (2017 – 2022)

AbstractBackground The knee is the most commonly injured lower body part in baseball and the most devastating of these injuries involves the anterior cruciate ligament (ACL). ACL injuries are associated with considerable and persistent personal, social, and economic impacts. Descriptions of ACL injury situational patterns in baseball are necessary to inform targeted injury countermeasures.Objective To describe the situational patterns of ACL injuries in professional baseball players playing in Major League Baseball (MLB).Design Retrospective systematic video analysis of ACL injuries Setting Professional baseball; MLBParticipants Professional baseball athletes participating in the regular MLB seasons from 2017 to 2022.Main Outcome Measurements Inning where injury occurred, injury mechanism, phase of play (offense, defense), action (running, fielding, hitting, catching), biomechanics, and situational pattern.Results Seventeen ACL injuries occurred over the 6 seasons (1 injury per 1535 games). Seventy-six percent (n=13) of these injuries occurred on defense. Outfielders accounted for the most injuries (n=7), followed by infielders (n=5), and pitchers (n=5). Analysis of knee joint kinematics was possible in 12 cases and knee valgus loading was the dominant kinematic pattern (83%). In terms of injury mechanisms, 12 (70%) injuries were non-contact, three (18%) were indirect-contact, and two (12%) were contact injuries. Of the 14 indirect- and non-contact injuries, nine (64%) involved players trying to avoid colliding with another player, or with the outfield walls. Of these nine injuries, two main situational patterns were observed: five (56%) involved unanticipated change-of-direction movements (e.g. to avoid a tag), and three (33%) involved landing from jump. Conclusions Most ACL injuries in baseball are from non-contact mechanism with a valgus loading pattern. Most ACL injuries involved unanticipated change-of-direction and jumping and landing situational patterns. Avoidance of collision is a common