LAUSR

CONTEXT Continued monitoring of ankle sprain rates and distributions is needed to assess temporal patterns and gauge how changes in incidence may be associated with prevention efforts. OBJECTIVE Describe the epidemiology of ankle sprains in 15 high school sports during the 2011/12-2018/19 school years. STUDY DESIGN Descriptive epidemiology study. SETTING Online injury surveillance from high school sports. PATIENTS High school athletes who participated in practices and competitions during the 2011/12-2018/19 school years. METHODS A convenience sample of high school athletic trainers (ATs) provided injury and athlete-exposure (AE) data to the National High School Sports-Related Injury Surveillance Study (HS RIOTM). Ankle sprain rates per 10,000AE with 95% confidence intervals (CI) and distributions were calculated. Yearly rates were examined overall, by event type, injury mechanism, and recurrence. RESULTS Overall, 9,320 ankle sprains were reported (overall rate=2.95/10,000AE; 95%CI: 2.89-3.01). The highest sport-specific rates were reported in girls' basketball (5.32/10,000AE), boys' basketball (5.13/10,000AE), girls' soccer (4.96/10,000AE), and boys' football (4.55/10,000AE). Most ankle sprains occurred during competition (54.3%) and were due to contact with another person (39.5%) and non-contact (35.0%). Also, 14.5% of injuries were noted as recurrent. Across the included academic years, ankle sprain rates generally increased. Compared to the 2011/12 academic year, rates in the 2018/19 academic year overall were 22% higher; non-contact-related and recurrent ankle sprain rates also generally increased, with 91% and 29% increases, respectively. CONCLUSIONS Time trends suggest ankle sprain rates have increased across the past decade, particularly among those with non-contact-related mechanisms; this contrasts previous research suggesting decreases in incidence. Findings may pinpoint specific etiological factors that should direct prevention efforts. This includes considering both person-contact and non-contact mechanisms through mitigating illegal contact through rule changes and enforcement, alongside bracing and proprioceptive and balance training programs.