MR IMAGING OF DISPLACED BUCKET-HANDLE TEAR OF THE MEDIAL MENISCUS

A bucket-handle tear of the meniscus is a vertical or oblique tear with longitudinal extension toward the anterior horn in which the inner fragment is frequently displaced toward the intercondylar notch with resultant mechanical locking of the knee joint. A precise MR diagnosis requires identification of the centrally displaced fragment because the peripheral nondisplaced component may have only a subtle truncated or foreshortened appearance that may escape detection. Eighteen consecutive cases of displaced bucket-handle tears of the medial meniscus diagnosed by MR had a characteristic low-signal band extending across the joint and projecting over the medial tibial eminence. The posterior portion was parallel and beneath the posterior cruciate ligament on both sagittal and coronal images. Arthroscopy confirmed the presence and location of the displaced fragment in all 18 cases. Awareness of this characteristic MR finding may increase the sensitivity of MR imaging in the diagnosis of bucket-handle tears of the medial meniscus.