[Bucket-handle meniscal tears of the knee. Magnetic resonance findings]

Magnetic Resonance Imaging (MRI) is a valuable technique to study knee meniscal tears. A series of 330 patients with knee traumas was retrospectively reviewed to systematize the semiologic features of a particular kind of meniscal tear, the "bucket-handle" one. MR investigations were performed with an 0.5-T superconductive magnet, surface coil and spin-echo T1-weighted and gradient-echo (FFE) T2*-weighted sequences on the coronal and the sagittal planes. Twenty-nine patients exhibited bucket-handle tears, 25 of the medial and 4 of the lateral meniscus. In all 29 patients joint effusion was observed; in 18 patients capsulo-ligamentous lesions were associated. MR findings were confirmed by arthroscopy and/or surgery. Semiologic features characterizing the bucket-handle tear on the coronal plane are: truncated triangular shape of the peripheral meniscus and low-intensity band between the posterior cruciate ligament and the tibial plateau, corresponding to the central fragment displaced in the intercondylar notch. In the lateral meniscus, the fragment is found beneath the anterior cruciate ligament. On the sagittal plane this band parallels the posterior or anterior cruciate ligaments, depending on the involved meniscus, with a typical "second cruciate posterior or anterior ligament" or "third cruciate ligament" pattern. The semiology of such findings of bucket-handle meniscal tears is useful in the differential diagnosis with other kinds of meniscal tears.