What is tarsal coalition, and where does it occur?
Tarsal coalition refers to abnormal congenital bridging between the tarsal bones of the foot. This bridging, or nonsegmentation, can be fibrous, cartilaginous, or osseous. The two most common types of tarsal coalition are the talocalcaneal coalition and the calcaneonavicular coalition. The talocalcaneal coalition occurs on the medial aspect of the joint, and involves the middle facet. MRI will show the bony fusion as well as associated abnormalities, such as edema within the involved bone. Coalition is often discovered during adolescence or young adulthood with symptoms of pain and stiffness in the hindfoot or midfoot. Tarsal coalition occurs bilaterally in 25% of cases. If symptoms are severe, it can be treated surgically.
