Abstract: Adult acquired flatfoot deformity, causing by posterior tibial tendon dysfunction or insufficiency, mainly expresses midfoot abduction and hindfoot valgus as well as medial longitudinal arch collapse, and usually relates to progressive posterior tibial tendon weakening. There are many kinds of treatment methods, the purpose of the treatment is rebuilding arches with accurate forefoot and hindfoot alignment and maintain the flexibility of the foot and ankle as much as possible. In clinical, the people's understanding for adult acquired flatfoot is not sufficient, its diagnosis is mainly based on symptoms, medical history and image examination. Symptoms mainly expresses change of foot shape and later pain. Imaging examination, besides weight bearing lateral and oblique X-ray of foot, hindfoot axis X-ray, by measuring distance between the tibia axis and calcaneal axis, can be used to provide evidence for the selection of treatment.

Key words: Adult acquired flatfoot, Deformity, Image examination