[Congenital synostoses of the tarsus. Concept, classification, diagnosis and therapeutic approach].

The incidence of congenital tarsal coalition is about 1%. It is recognized as the main etiology of painful, rigid flatfoot in the pediatric population. Talonavicular (50%) and talocalcaneal (40%) coalition are the most common presentation. We must suspect a tarsal coalition in a child with mechanical pain and shoes deformity. Rigid and painful planovalgus deformity are found in physical exam which led to describe in the pass this entity as peroneal spastic flatfoot. Lateral and oblique (35 degrees-45 degrees) radiographs must be practice to observe the coalition. The presence of a beak in the head of the talus or a half moon condensation image as the result of the superposition of the talus over the calcaneus are commonly described. CT-scan is also useful to delineate the size of the coalition and its location. Resection of the bar is the surgical treatment of choice. Excision of the coalition and interposition of fat or a graft must be tried in young patients in order to preserve foot biomechanical properties and to avoid long term problems associated with arthrodesis. Triple arthrodesis or subtalar arthrodesis must be used in older patients with degenerative signs in radiographs or in those cases of multiple coalition or if resection has failed.