Inferomedial displacement of the meniscal free fragment: MR findings.

To define the accuracy of Magnetic Resonance (MR) in the diagnosis of inferomedial displacement of the meniscal fragment.The MR examinations of the knee performed between December 2002 and April 2004 on 676 patients (mean age 32 years) with knee trauma and subsequently subjected to arthroscopy were retrospectively reviewed to assess the presence of bucket-handle meniscal tear and inferomedial displacement of the meniscal free fragment. The MR examinations were performed using a superconductive 0.5 T MR unit with a transmitting/receiving coil dedicated for the extremities. The MR images were acquired with SE T1 and GE T2* sequences in the sagittal, coronal and axial planes with 3 mm thickness and 1 mm gap. The images were independently reviewed by two authors blinded to the arthroscopic findings. In case of disagreement, a third author, unaware of the arthroscopic findings, gave his judgment.On MR images a bucket-handle meniscal tear was identified in 54/676 patients. In 6 out of 54 patients, an inferomedial meniscal fragment displacement of the medial meniscus with associated inflammatory synovial reaction around the fragment was detected. In one case an associated inflammatory bursal reaction with effusion around the distal insertion of the medial homolateral collateral ligament was detected. All cases were confirmed by arthroscopy and no statistical differences between the two authors were observed.MR allows the detection of the inferomedial meniscal fragment displacement and a more correct planning of arthroscopy with a strong reduction of repeat interventions.