Treatment of isolated talonavicular coalition: Case report and literature review.

Tarsal coalition refers to an abnormal fibrous, cartilaginous, or bony connection that develops between two or more tarsal bones. Talocalcaneal coalition and calcaneonavicular coalition account for more than 90% of all cases of tarsal coalition. Coalition exists early at birth, but bony connection usually develops during the patient's late growth period. Isolated cases of talonavicular coalition have rarely been reported. We herein report a case involving an 11-year-old patient with an isolated talonavicular coalition from a soft tissue to bony connection who was treated with arthroscopy for ankle arthritis. To our knowledge, this is the first case in which the whole formation of the talonavicular coalition was observed with a series of radiographic and magnetic resonance imaging examinations. The pain caused by the talonavicular coalition was managed by nonoperative treatment, while the ankle pain caused by the arthritis was relieved after ankle arthroscopy. At 6 years postoperatively, the patient remained pain-free while walking for 30 minutes and was satisfied with the operative outcome. Continuous follow-up confirmed that after the formation of talonavicular coalition, the coalition can continue to progress, forming bony talocalcaneal coalition and calcaneocuboid coalition.