[Calcaneal fractures: guidelines for the diagnosis with computerized tomography].

We report on 31 cases of calcaneal fractures studied with CT according to the latest classification by the Italian Surgical Society of the Foot. Of the utmost importance is the radiologic assessment of the posterior facet and of the underlying bone, which make up the so-called talamus which bears most of the body weight. In our series, talamus fractures were the most frequent ones (26/31 cases): they are characterized by a main sagittal line, running obliquely and dividing the posterior surface and the bone into an anteromedial, or substentacular, fragment and a posterolateral, or tuberosity, fragment. According to fracture severity, the first differential criterion is the presence/absence of displacement and depression (type I fractures the latter, 6 cases in our series, and (types II and III the former, 20/26 cases in our series). Based on the degree of displacement and depression, fractures as classified as type II (10/26 cases) when only the lateral portion of the talamus is displaced and depressed, or as type III (10/26 cases) when the whole talamus is fragmented, displaced and depressed. Moreover, other worsening factors must be considered and B subgroups differentiated in types II and III fractures; these factors are: calcaneus-cuboid facet involvement, lateral wall fragmentation, posterior facet comminution, a small sustentacular fragment and a secondary frontal fracture interrupting the plantar cortex. Extra-talamic fractures, defined as such when isolated, rarely occur. Relative to the anterior apophysis, radiologic attention must be focused on fractures of the dorsal prominence, or beak, which are very often misdiagnosed. As regards the posterior tuberosity, its lateral dislocation must be studied because it may account for calcaneofibular impingement. CT exhibits excellent potentials, provided that slices are thin, acquired on the axial and coronal planes and that, as far as possible, sagittal reconstructions are used, the latter being very useful to depict talamic surface.