Osteoarthritis associated with a ball-and-socket ankle joint. A case report.

A ball-and-socket joint is an unusual disturbance of normal ankle development. Previous reports have noted good function and the absence of osteoarthritic change in ankles with this configuration. A 50-year-old man with no history of injury developed an osteoarthritic ball-and-socket deformity of the ankle joint. Associated musculoskeletal anomalies included toe syndactylization, genu valgum deformity, and tarsal coalition, a condition that may predispose to the development of this ankle anomaly. Associated valgus deformity of the ankle contributed to the osteoarthritic changes. The conspicuous absence of osteoarthritis in other joints of patients previously reported with this abnormality may be explained by the lack of long-term follow-up examinations.