[Biomechanics of the upper ankle joint]

In most cases the ankle joint represents a simple hinge, the unimpaired function of which is dependent on normal play of the distal tibiofibular joint. During flexion and extension of the ankle joint, bending of the fibula is responsible for a substantial part of the mediolateral translational movement of the distal tibiofibular syndesmosis. In comparison with articular body forms under typical stress conditions, ligamentous restraints are of secondary importance. Tensile behaviour of fibular collateral ligaments seems to allow restricted, functional follow-up treatment. In the injury pattern of the ankle joint, the role of the interosseous membrane needs further evaluation. The clinical problems associated with tibiofibular subluxation and synostosis can be explained naturally by the impaired biomechanics of the ankle joint.