MR Classification of Tear Types and Popliteous Muscle Attachments in Lateral Disccid Menisci

ABSTRACT

PURPOSE: To determine the types of meniscal tears and type of popliteal muscle attachment in lateral disccid menisci. MATERIALS AND METHODS: MR images from 40 patients with arthroscopically proven disccid meniscal tears were reviewed. The type of capsular attachment of the popliteal muscle in these patients was compared with 100 normal controls. Fourteen men and 26 women were included in this study ranging in age from 8 to 52 yea rs. RESULTS: Disccid mensical tears were divided into five types. Arthroscopic cor- relation revealed that thirty-six cases(90%) of disccid meniscal tears were cor- rectly diagnosed using MR imaging. Peripheral tear wasthe commonest tear type occurring in 13 patients. In 9 of these the meniscal fragment was displaced. Hori- zontal tears occurred in 5, longitudinal tears in 4 and transverse tears in 2 patients. Multiple tears were present in 16 patients with the commonest combi- nation of peripheral and horizontal. Popliteal capsular attachments of disccid mensical tears were more prominent than in the normal control group. CONCLUSION: The types of tears in disccid menisci were different from normal meniscal tears. Peripheral detachment with displacement of torn segments was a very frequent finding in disccid mensical tears. Prominent capsular attachment of popliteal muscles is probably an associated finding in disccid menisci.