[X-ray computed tomography in the study of fractures of the calcaneus]

In a series of 28 calcaneal fractures, computed tomography scanning has shown axial deformities in the coronal and horizontal (plantar) planes not previously recognized. Two-thirds of the fractures investigated showed a deformity in at least two planes. A combination of dorsiflexion, valgus and adduction was present in one-third of the cases. This examination allowed a precise measure to be made of the enlargement of the calcaneus which very frequently occurs and was greater than 25 per cent in two-thirds of the cases. It makes it possible to visualize subtalar and calcaneocuboid incongruence with great precision and, in particular, to determine the size of the incongruous surface and its severity. Computed tomography scanning showed the existence of subtalar incongruity without depression of the thalamus, which is a concept which is not well recognized. It shows incongruity which is not evident on normal radiographs or, conversely, which may be falsely interpreted from deceptive pictures. The results of this study indicate that the usual classifications based on radiological examination are inadequate and need to be revised. The accuracy of this examination leads to the hope of more precise indications for treatment in the future.