MR-IMAGING OF MENISCAL SUBLUXATION IN THE KNEE

Purpose: The aim of this study was to establish diagnostic criteria fo r meniscal subluxation, and to determine whether there was any connect ion between meniscal subluxation and other common meniscal and knee-jo int abnormalities. Material and Methods: The normal position of the me niscal body was assessed in 10 asymptomatic volunteers. MR signs of me niscal subluxation were evaluated retrospectively in 60 symptomatic pa tients with pain in the knee, impaired mobility, and/or joint swelling who had no clear diagnosis after the evaluation of case history, clin ical examination, and radiography. The criterion for subluxation of th e meniscus was defined as a distance of greater than or equal to 3 mm between the peripheral border of the meniscus and the edge of the tibi al plateau. Results: In the volunteers, the mean distance from the med ial meniscus to the edge of the tibial plateau was 0.07 mm, and that f rom the lateral meniscus was 0 mm. In 55 symptomatic patients without meniscal subluxation, the mean distance from the meniscus to the edge of the tibial plateau was 0.27 mm. Five patients (8%) had evidence of meniscal subluxation, 4 in the medial meniscus and one in thr lateral meniscus. The most commonly associated knee abnormality was joint effu sion in 5 knees and osteoarthritis in 2 knees. Conclusion: Meniscal su bluxation was not a rare finding with MR imaging in patients with pain ful knees. Meniscal subluxation was associated with other knee abnorma lities such as joint effusion or osteoarthritis.