MR imaging of the peroneal tunnel

Fifteen ankles of five male volunteers, five female volunteers, three cadavers, and two patients suspected of injury were imaged. Sagittal localizer scans were obtained through mid- to lateral ankle followed by T1-weighted (echo time 20 ms, repetition time 600 ms) oblique axial sections paralleling the plane of the superior peroneal retinaculum. The anatomical structures seen on magnetic resonance images correlated closely with subsequently frozen and cut cadaver sections. The position of the peroneal tendons could be determined with absolute certainty, the posterior fibular anatomy could be defined, and the retinaculum could be identified in all cases. Though demonstrating considerable variability with respect to thickness, the retinaculum could be seen with sufficient confidence to establish its integrity or lack thereof in most instances. Magnetic resonance should therefore be considered as an aid in the diagnosis of acute peroneal ligament rupture when the clinical picture is not definitive.