Computerized tomography of talocalcaneal tarsal coalition: a clinical and anatomic study.

Consistently accurate radiographic diagnosis of talocalcaneal tarsal coalitions is difficult because of the complex anatomy of the subtalar articulations. Standard techniques that include special radiographic views and plain tomography are useful but often inconclusive. In this study, computerized tomography (CT) was used to evaluate suspected talocalcaneal coalitions in patients with the clinical diagnosis of peroneal spastic flatfoot. CT demonstrated bony and nonbony coalitions in 14 of 22 patients studied. In the remaining eight patients, CT effectively ruled out the diagnosis of subtalar coalitions. If the coalition is obvious, CT will confirm it; if the clinical syndrome exists but standard radiographic procedures do not document the lesion, CT scan will be helpful in establishing a diagnosis. Anatomic studies of fresh cadaver feet compared CT, plain tomography, and plain radiographs for efficacy in visualizing the three subtalar facet joints. CT was superior to the other modalities for clearly identifying all aspects of the subtalar joint and talocalcaneal coalitions in patients and cadavers.