Intrasheath Subluxation of the Peroneal Tendons

Abstract

The instability of the peroneal tendons involving lesions of the superior peroneal retinaculum and the fibular attachment has been historically well studied. Intrasheath subluxation of the peroneal tendons is a more recently described clinical entity defined by reversal of the anatomic relationship of the peroneal tendons or displacement of the peroneus longus into a longitudinal tear of the peroneus brevis. The presentation and history can mimic the more classically defined instability of the peroneal tendons from the fibular groove. Careful clinical examination of intrasheath subluxation will demonstrate that the peroneal tendons remain with their fibular groove, but during circumduction of the ankle, a painful mechanical snapping posterior to fibula can be elicited and palpated. The clinical suspicion is best confirmed with dynamic ultrasound wherein the reversal of anatomic peroneal tendon relationship can be visualized. A limited role for nonoperative management has been found. Surgical management with fibular groove deepening and addressing concomitant peroneal tendon tears has been demonstrated to result in a high rate of success.