Fractures of the calcaneal apophysis.

Eleven patients with 12 open or closed fractures of the calcaneal apophysis were reviewed. The patterns of fracture varied, although all could be classified by a scheme similar to that used for physeal injuries in the long bones. Open injuries involved young children and were associated with subsequent maldevelopment of the posterior (nonarticular) portion of the calcaneus due to growth mechanism damage. The other susceptible age group, adolescence, had two patients with slipped calcaneal apophysis (type 1 injury), similar to slipped capital femoral epiphysis, and three patients with a splitting fracture through the apophysis and physis into the main part of the calcaneus (type 4 injury). Microscopic physeal injury was also observed in the calcaneus of a fatally injured boy.