The Epidemiology of Acromioclavicular (AC) Joint Sprain in 25 National Collegiate Athletic Association Sports

Abstract

No previous studies have described the incidence of acromioclavicular (AC) joint injury in a large-sample of National Collegiate Athletic Association (NCAA) student-athletes. Such research is needed to understand the injury prevalence, injury mechanisms, and recovery patterns in NCAA student-athletes. PURPOSE: To describe the epidemiology of AC joint sprain injuries in 25 NCAA championship sports. METHODS: AC joint sprains from the NCAA Injury Surveillance Program were analyzed for the 2009/2010-2014/15 academic years. AC joint sprain injury rates, rate ratios (RR), and injury proportion ratios (IPR) were reported with 95% confidence intervals (CI). The RRs were also compared between sex-comparable sports (i.e., soccer, basketball, ice hockey, lacrosse, baseball/softball, indoor track, outdoor track, cross country, tennis, and swimming and diving). RESULTS: During the study period, a total of 844 AC joint sprains were reported, for a rate of 1.72/10000 athlete-exposures (AE). The highest rates of AC joint sprain occurred in Men’s Ice Hockey (6.40/10000AE) and Football (3.79/10000AE) and Women’s Ice Hockey (2.12/10000AE). The AC joint sprain rate was higher in competition than practice (6.15 vs. 0.72/10000AE; RR=8.58; 95%CI: 7.44, 9.89). Most AC joint sprains were due to player contact (54.7%, n=462), followed by surface contact (29.0%, n=245). Overall, 71.1% of AC joint sprains resulted in time loss of less than 1 week. In sex-comparable sports, the AC joint sprain rate was higher in men than women (1.85 vs. 0.40/10000AE; RR=4.67; 95%CI: 3.56, 6.14). In sex-comparable sports, males had a larger proportion of injuries due to player contact than females (54.1% vs. 36.1%; IPR=1.50; 95%CI: 1.06, 2.13); females had a larger proportion of injuries due to surface contact than males (31.1% vs. 20.1%; IPR=1.55; 95%CI: 1.01, 2.38). CONCLUSIONS: Overall, most AC joint sprains were due to contact, particularly with other players. Differences in mechanisms in sex-comparable sports highlight rule differences between men’s and women’s sports and is an area of future exploration. Further research into the specific activities and exposures at the time of injury may lend a better understanding of the causation of these injuries and lead to appropriate interventions to decrease their incidence and severity.