[Experimental study of the classification of intra-articular calcaneus fractures]

Improvement of the diagnostic techniques applied in calcaneus fractures, particularly the increased use of computed tomography, calls for a detailed fracture classification. Thirty lower leg cadaver specimens were submitted to axial loading. Fracture lines could be divided into a relatively constant primary fracture, running from the posterior subtalar joint surface to the tuber calcanei, and highly variable secondary fractures. In order to classify the fracture specimens, the calcaneus was divided into four segments: the sustentacular segment, the posterior subtalar joint segment, the segment of the anterior process, and the tuberosity segment. In addition, the following joints were identified at the calcaneus: the posterior subtalar joint, the anterior subtalar joint, and the calcaneo-cuboid joint. Each specimen was classified by the number of segments (x) and the number of joints (y) affected, and accordingly labelled as x-segment, y-joint fracture. The addition of both numbers was used to grade the severity of the fracture. This classification was easily applicable to all 25 experimental fracture specimens, and also to 33 clinical cases.