Prevalence and Sport-Specific Comparison of Lateral Ankle Sprain and Chronic Ankle Instability in 2200 Collegiate Athletes

BackgroundThis study aimed to evaluate the prevalence and potential associations among lateral ankle sprains (LAS), recurrent LAS, chronic ankle instability (CAI), and CAI by criteria for clinical practice (CAI-C). Chronic ankle instability by criteria for clinical practice is a condition that meets CAI inclusion criteria but also falls under the exclusion criteria defined by the International Ankle Consortium (IAC). Chronic ankle instability by criteria for clinical practice represents a broader clinical definition of CAI.MethodsThis study was a descriptive epidemiological study of the prevalence of LAS, recurrent LAS, CAI, and CAI-C in sports disciplines. A total of 2,175 athletes (1,522 males and 653 females) from 12 sports were surveyed using a structured questionnaire incorporating the Japanese version of the Identification of Functional Ankle Instability. Classification was based on criteria from the IAC.ResultsThe results showed that 52.9% of the participants experienced LAS, and 36.2% had a recurrence. Among those with LAS history, 68.5% had recurrent episodes. Chronic ankle instability was observed in 17.9% of athletes, and CAI-C was present in 32.6%, nearly 1.8 times more prevalent than typical CAI. In particular, the prevalence of CAI-C was more than twice that of CAI in rugby football, cheerleading, and soccer. Furthermore, 90.0% of recurrent LAS cases progressed to CAI-C. Chronic ankle instability was most prevalent in basketball and handball, whereas CAI-C was prevalent not only in these sports but also in soccer and judo, based on adjusted residuals ≥1.96.ConclusionsWe found that the number of participants with CAI-C differed from that of participants with CAI. This finding suggests that CAI may not reflect the entire clinical population with CAI conditions. Therefore, it has been suggested that it is also necessary to identify CAI-C in clinical practice. These findings underscore and support the need to consider tailored prevention programs and clinical attention to at-risk sports to reduce the long-term impact of ankle instability in athletes.Levels of Evidence:Prognostic, Level IV: case series.