Spontaneous Rupture of the Extensor Pollicis Longus with the Extensor Pollicis Brevis Deformity.

This paper examines three cases of spontaneous ruptures of the extensor pollicis longus (EPL) with the extensor pollicis brevis (EPB) deformity. The patients ranged from 39 to 71 years old. Non-dominant hands were involved in all three cases. There were no trauma nor pathological cause of EPL ruptures. A tendon transfer using the extensor indicis proprius was performed in each case. Intraoperative findings showed hypoplastic EPB in one case and EPB defects in two cases. A weak or defective EPB puts an excessive load on the EPL, which might be one of the causes of spontaneous EPL rupture.