70-year-old female with progressive knee pain and known Baker's cyst. Evaluate for meniscus tear or ligament tears and degree of degenerative changes of the joint. MENISCI: There is a branching linear increased signal abnormality within the posterior horn of the lateral meniscus which extends to the tibial and femoral articular surfaces with associated deformity and blunting of the meniscus consistent with complex tearing that extends to the body of the meniscus. There is lateral extrusion of the body of the meniscus. The anterior horn appears intact.There is globular signal abnormality within the posterior horn and body medial meniscus consistent with intrasubstance degeneration. Some of this signal abnormality extends to the tibial articular surface within the body of the meniscus, indicating undersurface tearing. The posterior and anterior horns appear intact.ARTICULAR CARTILAGE AND BONE: There is near full-thickness to full-thickness articular cartilage degeneration along the weightbearing surface of the lateral femoral condyle, posteriorly, above the posterior horn of the meniscus and lateral aspect of the lateral tibial plateau with associated degenerative subchondral signal abnormality. There is full-thickness articular cartilage degeneration along the lateral facet of the patella with underlying degenerative subchondral signal abnormality. There are foci of full-thickness articular cartilage degeneration along the medial facet of the patella with associated degenerative underlying subchondral signal abnormality. There is also full-thickness articular cartilage degeneration along the lateral facet of the femoral trochlea with underlying subchondral signal abnormality. The medial facet of the femoral trochlea appears relatively spared. There is tricompartmental osteophyte formation.LIGAMENTS: The cruciate and collateral ligaments appear intact. EXTENSOR MECHANISM: The extensor mechanism appears intact.ADDITIONAL
1. Complex tear of the lateral meniscus.2. Undersurface tearing/fraying of the medial meniscus.3. Tricompartmental osteoarthritic changes with full-thickness articular cartilage degeneration as described above.4. Moderate size joint effusion and Baker's cyst.