Pediatric Lateral Ankle Avulsion Fractures: Age-Specific Patterns and Diagnostic Clues

Lateral ankle injuries are common in pediatric populations. Avulsion fractures are a distinct injury involving bony disruption and may be underrecognized given their radiographically occult nature in skeletally immature patients. This study aims to compare the frequency, clinical presentation, and patient-reported outcomes (PROs) of lateral ankle avulsion fractures versus non-avulsion injuries in pediatric patients, with a focus on age-related differences.

Prospective cohort observational study conducted at a tertiary pediatric orthopedic/sports medicine practice. Patients aged 5 to 12 with a first lifetime lateral ankle injury within 30 days of the injury were consecutively enrolled, receiving clinical radiographs and research-based lateral ankle ultrasounds. Patients were classified into avulsion and non-avulsion groups based upon ultrasound findings, and additional comparisons were done between younger (age 5 to 10) and older (age 11 to 12) groups.

Among 132 patients (mean age 9.95 (95% CI: 9.54-10.36), 56% younger group, 65% female), 44 avulsion fractures (33%) were identified. Avulsion fractures were significantly more common in the younger group (47%) than in the older group (16%) ( P <0.001). Swelling and bruising were more frequent in avulsion fractures ( P <0.001). Despite differences in injury type, initial presentation PROs did not differ.

Avulsion fractures account for one-third of pediatric lateral ankle injuries and are more frequent in younger children than older children, likely due to greater skeletal immaturity. Swelling and bruising may aid in accurate diagnosis. Longitudinal studies are needed to determine if these fractures lead to subfibular ossicles, which are associated with chronic pain and instability.

Level II.