Incidence, Anatomic Distribution, and Return to Training After Stress Fractures in Okinawan Athletes

Background: Stress fractures are common in young athletes and a major cause of time lost from training. While epidemiological data exist from Western countries, reports from Asian regions, particularly in subtropical settings, are limited, as year-round training may influence injury risk. Purpose: To assess stress fracture characteristics among adolescent and recreational athletes in Okinawa. Study Design: Descriptive epidemiology study. Methods: A retrospective review of medical records from orthopaedic clinics and sports medicine centers across Okinawa Prefecture, Japan, between 2018 and 2019 was conducted. Athletes aged <50 years who were diagnosed with imaging-confirmed stress fractures were included. Data on age, sex, sport, fracture site, and return to training (RTT) (defined as symptom-free resumption of sport-specific practice) were collected. Results: A total of 309 stress fractures were identified in 303 athletes (mean age, 15.6 ± 5.9 years; 47% women). The tibia (31%), metatarsals (28%), and tarsal bones (18%) were the most frequently affected sites. Soccer (21%), basketball (21%), and track and field (14%) accounted for the majority of cases. The median RTT time was 7 weeks (interquartile range [IQR], 4-8 weeks). High-risk fracture sites, such as the fifth metatarsal bone and patella, required significantly longer recovery (median, 8 weeks [IQR 4-12 weeks]; P < 0.01). Conclusion: This is the first epidemiological study on stress fractures in a subtropical region of Japan. The findings highlight sport- and site-specific patterns and demonstrate that high-risk anatomic sites require prolonged recovery before a safe return. These results provide important evidence for the development of region-specific prevention and rehabilitation strategies for adolescents and recreational athletes.