Physeal Bar Formation After Pediatric Medial Malleolus Fractures

Pediatric medial malleolus fractures are commonly Salter-Harris (SH) type III or IV fractures of the distal tibia and are associated with a risk of physeal bar formation and subsequent growth disturbance. The purpose of this study was to determine the incidence of physeal bar formation following pediatric medial malleolus fracture and evaluate for patient and fracture characteristics predictive of physeal bar formation. Seventy-eight consecutive pediatric patients during a 6-year period who had either an isolated medial malleolar or a bimalleolar ankle fracture were retrospectively reviewed. Forty-one of 78 patients had greater than 3 months of radiographic follow-up and comprised the study population. Medical records were reviewed for demographic information, mechanism of injury, treatment, and need for further surgery. Radiographs were reviewed to assess for initial fracture displacement, adequacy of fracture reduction, SH type, percentage of the physeal disruption from the fracture, and physeal bar formation. Twenty-two of 41 patients (53.7%) developed a physeal bar. The mean time to diagnosis of physeal bar was 4.9 months (range, 1.6-11.8 months). Twenty-seven percent (6 of 22) of bars were diagnosed at greater than 6 months from injury. Adequacy of reduction was predictive of physeal bar formation, although all patients were reduced to within 2 mm. The mean residual displacement of patients with a bar was 1.2 mm compared with 0.8 mm for those without a bar (P=.03). Because the bar formation rate is greater than 50% on radiographs, routine radiographic assessment of all pediatric medial malleolar fractures should continue for at least 12 months after injury. [Orthopedics. 2024;47(1):e33-e37.].