Supination deformity of the forefoot.

Supination deformity of the forefoot is rare. Observations of eleven cases and the production of the deformity in rabbits suggest that loss of function of the peroneus longus muscle in combination with the effect of a strong tibialis anterior muscle is decisive for the appearance of the deformity. Primary conditions causing deformity were: spina bifida, talipes equinovarus, poliomyelitis, trauma and muscular dystrophy. Treatment by wedge resection of the first cuneiform and the first metatarsal bones and transfer of the tibialis anterior tendon was successful. Operations for supination deformity were carried out in nine cases.