Osseous and non-osseous coalition of the middle facet of the talocalcaneal joint.

Sixteen patients (eighteen feet) who had a coalition of the middle facet of the talocalcaneal joint had operative resection of the coalition because nonoperative treatment, such as casts, failed to relieve the symptoms. The patients were symptomatic for an average of one and a half years (range, four months to two years) before they were seen by us. The average age at the time of the operation was fourteen years (range, seven to nineteen years). Three feet had resection with no material interposed, six had resection with interposition of fat, and nine had resection with interposition of half of the tendon of the flexor hallucis longus muscle. The average length of follow-up was four years (range, two to eight years). The result was excellent for eight feet, good for eight feet, and fair for one foot; for one foot, the result was poor because the coalition recurred. Three types of coalition were identified on preoperative computed-tomography scans that correlated with the operative findings. Type I was an osseous bridging of the middle facet joint (five feet). Type II (cartilaginous coalition) was marked narrowing of the middle facet joint with cortical irregularity (three feet). In Type III (fibrous coalition), there was only slight narrowing of the middle facet joint (ten feet). The type of coalition did not influence the result. Fibrous coalitions were the most difficult to detect; bone scintigraphy was used to confirm the diagnosis when other tests were equivocal. We believe that symptomatic coalition of the middle facet of the talocalcaneal joint should be treated with resection when non-operative methods fail to relieve symptoms.