Calcifications simulating peroneus longus tendinitis

In two patients with sprains of the ankle joint calcification adjacent to the posterior tibial margin was evident in the lateral projection of a standard radiographic examination. Calcifying peroneus longus tendinitis was suggested. Further tangential views and computed tomography (CT) scan disclosed, however, that the calcifications in both patients were located in the tibial insertion of the posterior and inferior tibio-fibular ligament. In such cases, a correct diagnosis will avoid unnecessary treatment for a non-existent tendinitis.