Process and tubercle fractures of the hindfoot.

Process and tubercle fractures of the talus and calcaneus can be a source of significant pain and dysfunction. Successful management requires extensive knowledge of the complex osseoligamentous anatomy of the hindfoot. The large posterior process of the talus is composed of a medial and a lateral tubercle; an os trigonum may exist posterior to the lateral tubercle. The talus has a lateral process that articulates with the fibula and subtalar joint; the calcaneus possesses a frequently injured anterior process that articulates with the cuboid. Injury to these hindfoot structures is caused by inversion and eversion of the ankle, which can occur during athletic activity. These injuries often are misdiagnosed as ankle sprains. A high degree of clinical suspicion is warranted, and specialized radiographs or other imaging modalities may be required for accurate diagnosis. Nonsurgical management with cast immobilization is frequently successful when the fracture is correctly diagnosed acutely. Large fragments may be amenable to open reduction and internal fixation. Untreated, chronic injuries can cause significant pain and functional impairment that may be improved substantially with late surgical intervention.