MR Findings of Flexor Hallucis Longus Dysfunction

ABSTRACT

PURPOSE: To find the MR findings and evaluate the usefulness of MR in flexor hallucis longus(FHL) dysfunction. MATERIALS AND METHODS: From 1992 to 2003, fourty patients were found to have surgically confirmed FHL dysfunction. 24 cases of 22 patients who had performed MR were included in this study. We analyzed the signal intensity of FHL tendon and muscle, tendon sheath, sheath effusion, and bone lesions, retrospectively. RESULTS: Non-specific, increased sheath effusion of FHL tendon was seen in 12 cases (50%). Large amount of sheath effusion(grade 3) was observed in 5 cases (21%). The signal intensity of FHL tendon was normal in all cases. High signal intensity at the FHL muscle, proximal to musculotendinous junction was seen in 1 case (4%). One case (4%) of marrow edema of the talus and another one case (4%) of osteochondritis dissecans of the talus was seen. CONCLUSION: Non-specific, increased sheath effusion of FHL tendon was observed on MR in FHL dysfunction patients. Therfore, MR has a limited role in diagnosis of FHL dysfunction and is useful to exclude other bone and tendon diseases causing medial ankle pain.