Congenital diastasis of the inferior tibiofibular joint: case report and treatment analysis.

Congenital diastasis of the inferior tibiofibular joint is a rare anomaly, seen at birth. It is commonly associated with a variety of conditions: talipes equinovarus deformity of the foot, an unduly prominent and distally placed medial malleolus, accentuated tibia vara and tibial intorsion, widened inferior tibiofibular joint and tibial shortening. The condition was first reported in 1972 by Tuli and Varma1 (2 cases), followed by Bose2 (1976, 1 case), Jones and associates3 (1978, 4 cases) and Onimus and colleagues4 (1990, 4 cases). To date, in the English orthopedic literature, 17 children have been reported with congenital tibiofibular diastasis.1,2,3,4,5,6,7,8,9 All children presented clinically with associated talipes equinovarus deformity of the foot of varying severity. Often noted later were the associated aspects of the congenital diastasis, widening of the ankle mortise, tibial intorsion and a short tibia. All had tibial hypoplasia of varying severity, with evident hypoplasia of the lateral distal plafond. The talus was often wedged and elevated between the tibia and fibula. The fibula was frequently hypertrophic and on lateral radiographs was seen crossing the tibia anteriorly. We report here our experience with 1 child with this unusual anomaly. We also developed and present a treatment algorithm for congenital tibial diastasis based on an analysis of the English literature.