Objective: Our objective is to describe the characteristic MR imaging features of longitudinal tears of the peroneus brevis tendon and to describe pathologic conditions and normal variants that are associated with these tears which may require surgical intervention at the time of primary tendon repair.
Materials and methods: We retrospectively reviewed 10 MR images of asymptomatic volunteers and 31 MR images of 27 patients with evidence of longitudinal splits of the peroneus brevis tendon. Seven of these cases were surgically proven. In addition, we assessed five pathologic conditions and normal variants: lateral collateral ligamentous tears; injuries to the superior peroneal retinaculum; low-lying muscle belly of the peroneus brevis tendon; peroneus quartus muscle; and convex, flat, or irregular retromalleolar groove.
Results: In the patient's group, we saw longitudinal splits as clefts and an irregularity of the contour of the peroneus brevis tendon with (71%) and without (29%) signal changes on proton density-weighted and T2-weighted MR imaging sequences. Divisions of the split tendon assumed a characteristic C-shaped configuration that partly enveloped the peroneus longus tendon. Fifteen cases revealed other pathologic conditions and normal variants known to be associated with or to predispose to tears of the peroneus brevis tendon. These include ankle ligamentous tears (n = 3); abnormal superior peroneal retinaculum (n = 4); low-lying muscle belly of the peroneus brevis tendon (n = 1); peroneus quartus muscle (n = 2); and convex, flat, or irregular retromalleolar groove (n = 15). MR imaging revealed tears in all patients with surgical proof (n = 7).
Conclusion: MR imaging is a useful technique for revealing longitudinal tears of the peroneus brevis tendon as well as showing anatomic and pathologic factors associated with or predisposed to tears.