Computed tomography in suspected tarsal coalition. Examination of 26 cases.

Coronal plane computed tomography (CT) was performed in 26 consecutive patients with clinical suspicion of tarsal coalition. Twenty patients had plain CT and 6 had CT talocalcaneonavicular arthrography. Fifteen patients were found to have coalition. Of these 15 patients, 12 had talocalcaneal coalition (9 bilateral, 3 unilateral), 2 patients had combined talocalcaneal and calcaneonavicular coalitions, and the remaining patient had bilateral calcaneonavicular coalitions. Surgical findings corroborated the CT diagnosis in 9 patients with talocalcaneal coalition and in 2 patients with calcaneonavicular coalition. Ossified talocalcaneal coalitions were found in children aged 6 and 10 years, i.e., well below the conventionally stated age range of 12 to 16 years. CT is the investigation of choice in suspected tarsal coalition if plain radiography is not diagnostic. CT arthrography did not generally provide further information, but may be useful if plain CT is equivocal.