Sonography of Posterior Tibialis Tendon Dislocation

Dislocation of the posterior tibial tendon (PTT) at the ankle joint is a rare posttraumatic entity. It can be difficult to diagnose in the acute clinical setting because of local swelling and pain, which can substantially limit an adequate physical examination. Consequently, the condition may be recognized later and treated surgically, resulting in secondary impairment of ankle function. We report a case of a 21-year-old soccer player who sustained an acute posttraumatic anterior dislocation of the posterior tibialis tendon diagnosed on the basis of sonography and confirmed by magnetic resonance imaging and surgery. At a 4-year follow-up, sonography confirmed the normal position of the tendon and integrity of the retinaculum as well as a local spur at the level of retinaculum reinsertion. We suggest sonography as a first-line, readily available, noninvasive, and low-cost imaging modality for diagnosing posterior tibialis tendon dislocation.