The operative treatment of hypermobile flatfeet in the young child.

Osteotomy of the anterolateral aspect of the calcaneus in 81 hypermobile flatfeet produced a good or excellent clinical result in 95 per cent of the feet. Roentgenographically, 72.8 per cent of the feet have normal alignment and normal joint spaces, 5 per cent have narrow subtalar joints, and 22.2 percent have narrowing of the talonavicular joint. Arthrosis of the talonavicular joint can be demonstrated preoperatively by routine roentgenograms and probably develops as a result of excessive load on this joint by the flatfoot position. It is frequently associated with loss of foot motion postoperatively but is usually not accompanied by foot pain. There is no relationship between preoperative pain in the foot and arthrosis of the talonavicular joint.