MR imaging of meniscal cysts: evaluation of location and extension using athree-layer approach

Purpose: To analyze the extension of medial and lateral meniscal cysts rela tive to the capuloligamentous planes of the knee. Materials and methods: Th e MR images of 32 patients with meniscal cysts were reviewed. The location and extension of the meniscal cysts with reference to the capsule and ligam ents were recorded. Results: Most medial meniscal cysts were located poster omedially. Posteromedial meniscal cysts usually penetrated the capsule and were located between layer I and the fused layers II + III. From this site some extended anteriorly and then became located superficial to the superfi cial MCL. The location of lateral meniscal cysts was more varied. Anteriorl y the cysts were located deep to the iliotibial band, whereas posterolatera l cysts were located deep to the lateral collateral ligament. Conclusion: A lthough the site of capsular penetration of meniscal cysts is determined by the location of meniscal tears, the possible pathways of extension appear to be determined by the capsuloligamentous planes of the knee. (C) 2001 Els evier Science Ireland Ltd. All rights reserved.