Posttraumatic Tibiofibular Synostosis After Treatment of Distal Tibiofibular Fractures in Children

Introduction:Posttraumatic pediatric distal tibiofibular synostosis is a rare complication following fracture. This is a retrospective, multicenter case series of synostosis of distal tibiofibular fractures in children. The purpose was to evaluate the incidence and pattern of posttraumatic distal tibiofibular synostosis in children.Methods:Of the 604 pediatric distal tibiofibular fractures, 20 patients (3.3%) with synostosis after treatment of distal tibiofibular fractures were identified at 3 tertiary referral centers. There were 12 boys and 8 girls, with a mean age of 8.42.0 years (range, 3.7 to 11.5 y) at the time of injury. Medical records were reviewed, and serial radiographs were analyzed to determine fracture configuration, pattern of synostosis, and changes in the relative positions of the proximal and distal tibial and fibular physes and in the alignment of the ankle.Results:The time from the occurrence of fracture until the recognition of the synostosis ranged from 2 to 6 months (mean, 2.8 mo). The most common fracture configuration was oblique tibial fracture combined with comminuted fibular fracture. There were 12 focal types and 8 extensive types. The proximal tibiofibular distance was decreased in 13 patients. Proximal migration of the distal fibular physis developed in all cases. Five patients exhibited ankle valgus of 10 degrees or greater with moderate or severe distal fibular shortening. Eight patients were symptomatic after synostosis and 12 patients were asymptomatic.Conclusions:We identified 2 patterns of synostosis after the treatment of pediatric distal tibiofibular fracture: focal and extensive. The focal type was more prevalent than the extensive type, which was more likely to occur due to high-energy injury. When a tibiofibular cross-union develops, it creates growth abnormalities that warrant observation and potential treatment, as it may lead to progressive deformity or ankle pain.Level of Evidence:Level IV.