Congenital Variations of the Peroneal Tendons

Abstract

Stenosing tenosynovitis, subluxation of the peroneal tendons, and peroneus brevis split tears can occur in association with an encroachment of an anomalous peroneus quartus tendon or low-lying peroneus brevis muscle belly. The presence of extra tissue within the fibular groove can contribute to stenosis or subluxation of the peroneus brevis tendon causing laxity of the superior peroneal retinaculum and eventually subluxation or dislocation of the peroneus brevis over the sharp posterior ridge of the distal fibula. This dynamic mechanism can eventually result in splitting or tearing of the peroneus brevis tendon. A convex or shallow fibular groove can further contribute to this dynamic phenomenon in Zone A. Also, an irregular retromalleolar groove predisposes to peroneal tendon disease. Hypertrophy of the peroneal tubercle along the lateral wall of the calcaneus can also contribute to stenosing tenosynovitis and impingement of the peroneal tendons in Zone B. The presence of an enlarged os peroneum can contribute to stenosing tenosynovitis or rupture of the peroneus longus tendon in the cuboid tunnel Zone C. Fracture of an enlarged or bipartite os peroneum with proximal migration of the proximal pole of the os peroneum can lead to peroneus longus tendon rupture.