Talocalcaneal coalition: computed tomography and magnetic resonance imaging diagnosis.

A correct evaluation of site and extension of the talocalcaneal coalition inducing biomechanical ankle alterations is very important for planning therapy. Four male patients were submitted to computed tomography (CT) and three of them were also examined by means of magnetic resonance imaging (MRI). In one patient, studied by CT only, a bilateral talocalcaneal coalition was present, while the other three patients, controlled with CT and MRI, were affected by monolateral talocalcaneal coalition which was of osseous type in one case and fibrocartilaginous in two cases. CT and MRI provided detailed information on type and extension of the coalition and both helped in distinguishing between osseous and fibrocartilaginous forms. Only MRI showed an area of subchondral ischemic disease of the posterior subtalar joint in one patient with monolateral fibrocartilaginous talocalcaneal coalition. Compared with CT, MRI proved to be more accurate in evaluation of the talocalcaneal coalition, due to its wider display capability.