Adult-acquired flatfoot deformity.

Originally known as posterior tibial tendon dysfunction or insufficiency, adult-acquired flatfoot deformity encompasses a wide range of deformities. These deformities vary in location, severity, and rate of progression. Establishing a diagnosis as early as possible is one of the most important factors in treatment. Prompt early, aggressive nonsurgical management is important. A patient in whom such treatment fails should strongly consider surgical correction to avoid worsening of the deformity. In all four stages of deformity, the goal of surgery is to achieve proper alignment and maintain as much flexibility as possible in the foot and ankle complex. However, controversy remains as to how to manage flexible deformities, especially those that are severe.