[Subtalar arthrodesis with calcaneal osteotomy].

The amount of postraumatic deformities of the calcaneus after fracture is classified in 5 types (Type I-V). The bony situation includes in the simple group A malunions, in group B the more demanding nonunions and in Group C the worst cases with additional aseptic or septic necrosis of parts of the calcaneus. For type I with posttraumatic arthritis of the subtalar joint and without malalignement, an in situ-arthrodesis is suitable. Type II, with an additional varus- or valgus hind foot deformity, but especially in type III with additional loss of height and dorsal tilting of the talus a bone block distraction arthrodesis is required. Type IV includes, additionally to the pathology of type I to type III, a lateral translation of the calcaneus. This indirectly causes a severe hind foot valgus and an abutment of the posterior facet towards the lateral malleolus. This type needs osteotomy of the calcaneus through the old fracture surfaces, performed using a bilateral approach. Type V is very rare but the most difficult one for reconstructive surgery because the talus is additionally tilted out of the ankle joint. Therefore, in addition to the bilateral approach and calcaneal osteotomy, an anteromedian approach to the ankle joint is necessary. The surgical procedure in group A (malunion) is more or less the same like in group B (nonunion). Group C (aseptic / septic osteonecrosis) needs a preliminary radical necrectomy in a two stage reconstructive procedure.