Tarsal coalition is defined as an abnormal bony, cartilaginous, or fibrous union of two or more tarsal bones. The incidence of tarsal coalition is approximately 2% in the general population. Talocalcaneal and calcaneonavicular coalitions are the most common. The talonavicular coalition is a rare entity with an incidence of approximately 1.3% among patients with tarsal coalitions. We present a case of a 12-year-old girl who had talonavicular and talocalcaneal coalitions associated with a recurrent ankle sprain. The talonavicular coalition was asymptomatic, and the talocalcaneal coalition was the cause of ankle pain and recurrent sprain. Surgical resection of the talocalcaneal coalition led to successful clinical and functional outcomes. In conclusion, the possibility of multiple tarsal coalitions should be considered in tarsal coalition patients, and the talocalcaneal coalition should be considered as a differential diagnosis in an adolescent patient with a recurrent ankle sprain.
Keywords: adolescent; ankle instability; tarsal coalition.