A multisport epidemiologic comparison of anterior cruciate ligament injuries in high school athletics

Abstract

Background: The knee joint is the second most commonly injured body site after the ankle and the leading cause of sportrelated surgeries. Knee injuries, especially of the anterior cruciate ligament (ACL), are among the most economically costly sport injuries, frequently requiring expensive surgery and rehabilitation. Objective: To investigate the epidemiology of ACL injuries among high school athletes by sport and sex. Design: Descriptive epidemiology study. Main Outcome Measure(s): Using an Internet-based datacollection tool, Reporting Information Online (RIO), certified athletic trainers from 100 nationally representative US high schools reported athlete-exposure and injury data for athletes from 9 sports during the 2007/08-2011/12 academic years. The outcome of interest in this study was ACL injuries. Results: During the study period, 617 ACL injuries were reported during 9 452 180 athlete exposures (AEs), for an injury rate of 6.5 per 100 000 AEs. Nationally, in the 9 sports studied, an estimated 215 628 ACL injuries occurred during the study period. The injury rate was higher in competition (17.6) than practice (2.4; rate ratio [RR]=7.3, 95% confidence interval [CI]= 6.08, 8.68). Girls' soccer had the highest injury rate (12.2) followed by boys' football (11.1), with boys' basketball (2.3) and boys' baseball (0.7) having the lowest rates. In sex-comparable sports, girls had a higher rate (8.9) than boys (2.6; RR = 3.4, 95% CI = 2.64, 4.47). Overall, 76.6% of ACL injuries resulted in surgery. The most common mechanisms of injury were playerto- player contact (42.8%) and no contact (37.9%). Conclusions: Anterior cruciate ligament injury rates vary by sport, sex, and type of exposure. Recognizing such differences is important when evaluating the effectiveness of evidencebased, targeted prevention efforts. © by the National Athletic Trainers' Association, Inc.