Peripheral Tears of Complete Discoid Lateral Meniscus Follow a Staged Progression.

Background: Peripheral tears of complete discoid lateral meniscus (DLM) display a wide spectrum of clinical manifestations. However, a staging system for such tears has not yet been established. Purpose: To determine whether there is a progression in the pattern of peripheral tears in complete DLM and establish a comprehensive staging system that categorizes these tears into distinct stages. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A consecutive series of 298 knees diagnosed with complete DLM between July 2006 and December 2022 were retrospectively reviewed. A staging system based on clinical symptoms, presence of tears on magnetic resonance imaging (MRI), and stability during arthroscopic examination was used to classify patients into seven stages (stage 0-6). Patient demographic data and International Cartilage Regeneration & Joint Preservation Society (ICRS) grade on MRI were assessed. Results: A total of 18 knees were classified as stage 0, 27 as stage 1, 46 as stage 2, 51 as stage 3, 22 as stage 4, 122 as stage 5, and 12 as stage 6. Each stage was defined by characteristic clinical features. A higher ICRS cartilage grade in both the lateral femoral condyle (Spearman coefficient, Conclusion: Progressive stages characterize the development of peripheral tears in a complete DLM. Higher stages are associated with more severe displacement of tears and increased cartilage degeneration.