The Cotton osteotomy: indications and techniques.

Stage II posterior tibial tendon dysfunction (PTTD) is characterized by an incompetent posterior tibial tendon that results in a flexible pes planovalgus deformity. As the hindfoot drifts into valgus, compensatory varus develops in the forefoot. Alternatively, in some cases medial column instability can result in primary forefoot varus that drives the hindfoot into valgus. Recently, there has been increasing awareness of the importance of forefoot varus in PTTD.