Surgical treatment of concomitant chronic ankle instability and longitudinal rupture of the peroneus brevis tendon.

Chronic lateral ankle instability can be associated with a longitudinal rupture of the peroneus brevis tendon. Patients with these problems have atypical posterolateral or retromalleolar pain, as well as clinical signs of ligamentous instability. This injury is frequently concomitant with lateral ligament injuries and the injury mechanism is similar; however, the tendon rupture is often missed. Laxity or insufficiency of the superior peroneal retinaculum allows the anterior part of the peroneus brevis tendon to ride upon the sharp posterior fibular edge, resulting in a longitudinal rupture of the tendon. We report on the results after surgical treatment in nine patients (10 ankles) with combined instability of the lateral ankle ligaments and longitudinal rupture of the peroneus brevis tendon. All these patients underwent surgical repair of the peroneus tendon, reconstruction of the superior peroneal retinaculum, removal of the sharp posterior edge of the fibula and correction of the ligamentous instability of the anterior talofibular and calcaneofibular ligaments. One constant finding at surgery was a longitudinal intratendineal rupture of the peroneus brevis tendon combined with insufficiency of the superior peroneal retinaculum and insufficiency of the lateral ligaments. At follow-up 3 (2-5) years post-operatively, the functional results were excellent or good in nine ankles and fair in one. All the patients with excellent or good results had resumed their preinjury activity level. We conclude that this lesion should be suspected in patients with lateral ligamentous instability, combined with retromalleolar pain. In these cases, it is important to address both the tendon rupture and the ligamentous insufficiency.