Distal tibiofibular synostosis after malleolar fractures treated using absorbable implants.

Three patients (3.8%) of 80 with displaced malleolar fractures treated by open reduction and internal fixation using absorbable polyglycolide rods were found to have developed distal tibiofibular synostosis. To assess the general incidence of this complication, the serial radiographs of 150 patients with an identical distribution of the initial fracture severity treated with AO-ASIF implants were examined for comparison. Among these, no cases of tibiofibular synostosis were found. The difference (P = .04) in incidence was postulated to be due to an osteogenic potential of the absorbable polymeric material, suggested previously in experimental studies. This study included fractures of the lateral malleolus and bimalleolar fractures, but patients with a disruption of the inferior tibiofibular syndesmosis causing tibiofibular diastasis on admission were excluded. The synostoses occurred in middle-aged, sedentary people, and no active measures were necessary because of the mild subjective symptoms of these patients. Previously, posttraumatic distal tibiofibular synostosis has been recorded as an uncommon late complication of severe ankle fractures with tibiofibular diastasis requiring transsyndesmotic fixation, but it has not been reported to occur after malleolar fractures of the kind surveyed in this study.