Stable ankle joint fractures. Indications for operative or conservative treatment?

Abstract

In German literature, ankle joint fractures are mostly classified in three groups according to Weber. In cases of the type A, the fracture line runs below, in cases of type B at height of the syndesmotic ligaments. C-type fractures are typically seen above this region. However, this practical and simple classification allows no inferences at accompanying injuries which in turn influence the functional outcome. We observed isolated fractures of the lateral malleolus in more than 60 % of all type B-fractures, as soon as in the majority the type A-fractures. Since isolated medial ankle fractures occur very rarely, careful exclusion of further injuries is advisable here. In order to differentiate stable ones from unstable type B ankle injuries, we carry out a manual stress test, if there is less than 2 mm fracture dislocation and a congruent ankle mortise. In this manner we could find that stable lateral ankle fractures are characterized with a combination of an intact dorsal syndesmotic and medial ligament. Stable type B and undisplaced type A fractures were treated conservatively with an ankle brace (Aircast?). Unstable ankle injuries were treated by ORIF. Conservative treatment for undisplaced medial malleolar fractures is recommended, if x-rays showed less than 2 mm dislocation which allows a tibio-talare impingement. Biomechanical investigations could prove a significant increase in ankle joint stability, when an axial load of 300 N was applied to various horizontal loads. The talus does not follow automatically a displaced fibular fracture. The dorsal syndesmotic and the medial deltoid ligaments control ankle joint stability.