Current concepts review: Tarsal coalition

The two most common types of tarsal coalitions are talocalcaneal and calcaneonavicular. Painful tarsal coalitions have an incidence of approximately 1%. However, because most coalitions are presumed asymptomatic, the true prevalence is unknown. Tarsal coalition is inherited in an autosomal dominant fashion with variable penetrance. The etiology is believed to be a failure of mesenchymal differentiation. The onset of pain at a coalition corresponds to the ossification of the coalition. Microfracture at the ossifying coalition-bone interface is a proposed source of pain. Advances in imaging capabilities with CT and MRI allow clinicians to characterize the size, character, and location of the coalition. In choosing between resection and arthrodesis, CT and MRI more accurately show the presence of arthrosis in surrounding joints. The initial treatment for a tarsal coalition is conservative. A medial heel wedge, arch support, UCBL, or cast is first-line treatment. Isolated talar beaking is not characteristic of degeneration of the joints of the hindfoot and, therefore, is not a contraindication to coalition resection. True degenerative change is an absolute indication for arthrodesis. Calcaneonavicular coalitions unresponsive to conservative treatment are best managed by coalition resection. Some form of interposition is recommended at the site of the resection; interpostion of EDB muscle belly is most commonly used. Talocalcaneal coalitions unresponsive to conservative treatment are best managed by coalition excision, although outcomes are not as good as those after excision of calcaneonavicular coalitions. Older age at presentation, larger extent of coalition, and increased hindfoot valgus may be predictive of poorer outcomes. Triple arthrodesis is the accepted form of salvage after failed excision of a tarsal coalition. Copyright © 2006 by the American Orthopaedic Foot & Ankle Society, Inc.