Posterior tibial tendon dysfunction.

Posterior tibial tendon dysfunction, a common entity, frequently is unrecognized and inappropriately managed. Acutely, pain and swelling are present over the medial ankle and longitudinal arch. Long-standing inflammation can lead to tendon rupture, resulting in a progressive planovalgus or "flat foot" deformity. Plain radiographs illustrate the changes in bony anatomy associated with chronic posterior tibial deficiency, while magnetic resonance imaging scans can identify the three stages of posterior tibial tendon pathology. Most cases are amenable to conservative therapy, including rest and administration of nonsteroidal antiflammatory agents. Often a short period of immobilization in a cast or the use of an orthosis is beneficial. In cases with persistent tenosynovitis, complete tendon rupture, or progressive deformity, surgical intervention is indicated.