Developmental Patterns and Clinical Relevance of Os Trigonum, Os Subfibulare, and Os Subtibiale in Young Athletes: A Cross-Sectional Study of 1,167 Athletes

OBJECTIVE: To clarify prevalence patterns, symptomatic rates, and sport-specific risk factors associated with os trigonum, os subfibulare, and os subtibiale in young athletes presenting with ankle pain. DESIGN: Retrospective cross-sectional study. SETTING: Single-center sports medicine clinic. PARTICIPANTS: A total of 1167 young athletes (≤22 years) with ankle pain who underwent standardized weight-bearing radiographs. INDEPENDENT VARIABLES: Accessory ossicle type, age, physeal status, sport category, and sex. MAIN OUTCOME MEASURES: Prevalence, symptomatic presentation, and surgical excision. RESULTS: Accessory ossicles were identified in 361 athletes (30.9%), comprising 406 total ossicles. Os trigonum was most prevalent (21.8%), followed by os subfibulare (9.9%) and os subtibiale (3.2%). Os trigonum was more frequent in athletes with closed physes, whereas os subfibulare and os subtibiale were more frequent in athletes with open physes (all P < 0.05). Among athletes with accessory ossicles, 37 (10.2%) were symptomatic, 73.0% were trauma-related, and 83.8% occurred in cutting/pivoting sports. Cutting/pivoting sports independently predicted symptomatic presentation (Odds ratio 2.41, 95% confidence interval 1.07-5.45; P = 0.034), whereas age, physeal status, and sex were not independently associated. CONCLUSIONS: Accessory ossicles showed distinct prevalence patterns across skeletal maturity groups, but symptomatic presentation was independently associated with cutting/pivoting sports rather than age or skeletal maturity. These findings may help clinicians assess the potential clinical relevance of accessory ossicles identified in young athletes with ankle pain.