Peroneus longus tendon rupture as a cause of chronic lateral ankle pain.

Rupture of the peroneus longus tendon with an associated fracture of the os peroneum is an uncommon injury, which may present as chronic lateral ankle instability. There have been only seven cases documented in the literature since 1966. A case of chronic peroneus longus tendon rupture with os peroneum fracture is presented. The authors review their clinical, radiographic, and operative treatment of this patient and review the literature of this unusual injury.