Joint-preserving surgery of asymmetric ankle osteoarthritis with peritalar instability.

A varus or valgus talar tilt that increases under weight-bearing is commonly seen in osteoarthritic ankles. Loss of peritalar stability may be the underlying cause for the talus shifting and rotating on the calcaneonavicular surfaces, as given by applied forces. The instability pattern and the resulting deformity can be assessed and classified using weight-bearing conventional radiographs. Appropriate osseous balancing may be the most appropriate treatment to restore a regular position of talus within the ankle mortise. In cases with severe peritalar instability, subtalar fusion may be advised. Soft tissue reconstruction may be needed to achieve physiologic balance of the hindfoot complex.