Rigid painful flatfoot secondary to tarsal coalition.

Rigid flatfoot secondary to tarsal coalition requires proper clinical and roentgenographic evaluation. In patients with limited subtalar motion and pain in the tarsal area, a coalition should be suspected. Proper roentgenographic evaluation with standard anteroposterior, lateral, and oblique views is essential. Calcaneonavicular coalition, as visible on an oblique film, may be a solid bony fusion or, more often, a cartilaginous coalition, which is characterized by flattening of the calcaneus and navicular at their junction. Axial (Harris) views demonstrate coalition in the middle and posterior facets, which may be cartilaginous or osseous. Lateral tomography is used to demonstrate irregularities of the anterior facet or the undersurface of the talar head. When symptomatic, a calcaneonavicular coalition with no degenerative changes of the tarsal joints is treated by resecting the bar and inserting the extensor digitorum brevis into the area from which the coalition is excised. An osseous bar is resected, or, if degenerative changes are noted, a triple arthrodesis is performed. Talocalcaneal coalition is first treated conservatively by a regimen of Plastizote shoe inserts, short-leg casts, or an ankle-foot orthosis. If conservative treatment fails to alleviate pain, a triple arthrodesis is indicated.