The Highly Variable Typologies of Posterior Malleolus Fractures of the Ankle

Objectives: Although historical studies frequently classify posterior malleolus fractures (PMFs) according to fragment size, our hypothesis is that PMFs have more complex patterns than is widely recognized. None of the studies so far have provided a comprehensive picture of the complexity of PMFs or guidelines for surgical decision making. The optimal management of PMFs is still unclear. This study aims to look at the typology of PMFs using a combination of initial injury radiographs, preoperative computed tomographic (CT) scans, and intra-operative image intensifier (II) screening, as well as fixation technique and a surgery fixation approach, in order to gain insight into PMFs. Methods: Between 2013 and 2015, 56 consecutive patients, all with bi- or tri-malleolar fracture or dislocation of ankle joints, with one or more posterior fragments, who were treated at our institute, were identified. We retrospectively analysed the patients' preoperative initial injury radiographs, CT scans, and II data to see the stability of the ankle joints in coronal and sagittal planes, and look at the typology in relation to fracture fixation technique and surgery fixation approach. Conclusions: Bi- or tri-malleolar fractures of the ankle with associated posterior malleolar fractures appear to be highly variable. We identified certain types of PMFs which we can categorise. Ankle stability in the coronal and sagittal planes on initial injury radiographs, intra-operative II and preoperative CT scans are critical in order to identify different PMFs patterns. PMFs have highly variable typology regardless of fragment size and this must take into consideration when deciding treatment plans.