[Joint-preserving surgical correction of advanced flexible planovalgus deformity of the adult foot].

BACKGROUND: Adult acquired flatfoot deformity is characterized by a progressive functional deficit of the foot that leads to an eversion of the subtalar joint complex with heel valgus, abduction of the forefoot and collapse of the medial arch. In the case of a flexible deformity, a joint-preserving operative reconstruction is advisable, which should correct all elements of the deformity. A calcaneal lengthening osteotomy can correct excessive abduction of the forefoot, which can be measured by the amount of talar head uncoverage visible on AP weight-bearing x‑rays of the foot. THERAPY: Any calcaneal lengthening osteotomy leads to an incongruence between talar and calcaneal joint surfaces of the subtalar joint, which is a risk factor for secondary degenerative changes. It is, therefore, advisable to limit the amount of lengthening to the necessary minimum. A residual heel valgus can be corrected by an additional medial displacement osteotomy as adjunct to the calcaneal lengthening. Calcaneal osteotomies are usually part of a complex reconstruction of advanced but still flexible adult flatfoot deformities. In addition to the correction of the hindfoot deformity, persistent forefoot supination needs to be corrected. In cases of midfoot instability, which is frequently located in the naviculo-cuneiforme joint line, a corrective arthrodesis is recommended. Without midfoot instability forefoot a Cotton osteotomy is able to reduce forefoot supination and add to reconstruction of the medial arch of the foot. All bony corrections should be combined with soft tissue reconstruction, i.e. spring ligament repair, Flexor tendon transfer and, in cases of gastrocnemius shortening, a gastroc recession.