The Ponseti method of treatment for congenital clubfoot: importance of maximal forefoot supination in initial casting.

The correction of cavus deformity requires further supination of the forefoot. In the Ponseti method, the initial cast is applied with the forefoot supinated such that the plane of the metatarsal heads is parallel to the long axis of the tibia. This study reviewed Pirani scores of 27 patients with 38 clubfeet treated over an 18-month period by the Ponseti method to evaluate changes in midfoot deformity after the initial cast. Initial average scores for severity of the lateral border deformity, medial crease, and talonavicular joint reducibility decreased from 0.92, 0.75, and 0.75, respectively, to 0.73, 0.25, and 0.5, respectively, after the first cast. The improvement in Pirani scores provides support for the efficacy of the initial cast to reduce the cavus and also increase the reducibility of the midfoot. Failure to address the cavus deformity with the initial cast as described by Ponseti may lead to persistent rigidity and incomplete correction.