[Failure of Dwyer's procedure in internal pes cavus in children. Physiopathological considerations and therapeutic deductions].

The authors have performed 34 Dwyer's calcaneal osteotomies in children with pes cavus confined to the medial arch in non-paralytic lesions (poliomyelitis and spina bifida were excluded). In 12 cases it was associated with osteotomy of the 1st metatarsal or with plantar release. No arthrodeses were performed in these 34 cases. After an average follow-up of five years the results were doubtful: in 24 instances the deformity was the same or worse. In 21 cases a secondary operation was necessary. The authors considered that the Dwyer's procedure corrects only the varus of the heel which is a secondary deformity. They believe that, in pes cavus, there is a dynamic clawing of the toes in the swing phase of gait. This produces secondary deformities. In the sagittal plane there is a synergic or paralytic imbalance at the metatarso-phalangeal level leading to vertical displacement of the 1st metatarsal and deepening of the medial arch. In the frontal plane, this vertical displacement leads to an irreducible pronation of the forefoot with secondary varus of the heel. In the horizontal plane a lateral rotation of the talus results in varus of the calcaneum.