Morphologic Variations of the Fibular Malleolar Groove with Recurrent Dislocation of the Peroneal Tendons

Background: The shallow malleolar groove of the fibula is believed to be one of the important causes of dislocation of the peroneal tendons. However, no studies have investigated the morphological differences between patients with and without dislocation of the peroneal tendons. Materials and Methods: We investigated the morphological variations (concave, flat, or convex) of the malleolar groove of the fibula using magnetic resonance imaging (MRI) in 39 ankles from 36 patients with recurrent dislocation of the peroneal tendons, comparing them with 39 ankles in 39 patients without dislocation. We also evaluated the presence of the false pouch on the fibula surface and fibrocartilaginous ridge injury of the malleolar groove on MRI. Chi-square test was used for statistical analysis between the two groups. Results: MRI at 1 cm proximal from the tip of the fibula demonstrated that the malleolar grooves in patients with dislocation of the peroneal tendon were classified as concave in 4 patients, flat in 23, and convex in 12, whereas they were classified as concave in 6, flat in 22 and convex in 11 in the patients without dislocation of the peroneal tendons. No significant difference could be detected between the two groups. Conclusion: This study demonstrated that no significant difference could be detected in the morphological shape of the fibular malleolar groove between patients with and without dislocation of the peroneal tendons.