The calcaneus is the most commonly fractured tarsal bone and accounts for about 2% of all fractures. Advances in cross-sectional imaging, particularly in computed tomography (CT), have given this modality an important role in identifying and characterizing calcaneal fractures. Fracture characterization is essential to guide the management of these injuries. Calcaneal fractures have characteristic appearances based on the mechanism of injury and are divided into two major groups, intraarticular and extraarticular. Most calcaneal fractures (70%-75%) are intraarticular and result from axial loading that produces shear and compression fracture lines. Of the two major systems for classifying intraarticular fractures-Hannover and Sanders-the latter is used most often and is helpful in treatment planning and determining prognosis. Extraarticular fractures account for about 25%-30% of calcaneal fractures and include all fractures that do not involve the posterior facet. The article describes in detail calcaneal anatomy, mechanism of calcaneal injuries and their associated fracture patterns, CT features of intra- and extraarticular fractures, and management implications. Familiarity with calcaneal anatomy and fracture patterns is essential for radiologists to guide the treating physicians.
(c) RSNA, 2005.