Tarsal coalition and painful flatfoot.

The prevalence of tarsal coalition is probably 1% or less. The two sites most commonly affected are the calcaneonavicular joint and the middle facet of the talocalcaneal joint. Diagnosis should be suspected in the preteen or teenage patient with insidious or sudden onset of pain in the midfoot to hindfoot associated with a lack of motion in the subtalar joint. Initial treatment with immobilization or an orthosis may relieve symptoms, but most patients will have persistent symptoms that warrant surgical correction. Long-term results indicate that excision of the coalition is moderately successful in relieving symptoms in the calcaneonavicular bar. Long-term success with excision of subtalar bars is less clear, although early relief of symptoms is usually possible.