60-year-old male with pain over the left knee. MENISCI: There is a horizontal tear of the anterior horn of the lateral meniscus extending to the femoral articular surface. The tear is noted on multiple images extending from the attachment of the transverse meniscal ligament into the body of the meniscus. The posterior horn appears intact. There is intermediate signal abnormality consistent with intrasubstance degeneration of the medial meniscus, which otherwise appears intact.ARTICULAR CARTILAGE AND BONE: There is mild to moderate degeneration of the articular cartilage of the lateral facet of the patella with underlying degenerative subchondral foci of signal abnormality. There is focal signal abnormality within the inferior aspect of the femoral trochlea likely reflecting full-thickness degeneration. The trochlear groove is flattened suggesting dysplasia. There is focal near full-thickness degeneration of the articular cartilage of the medial femoral condyle above the posterior horn of the medial meniscus. There is a lobulated lesion of increased signal intensity in the distal femoral metaphysis compatible with a benign enchondroma. LIGAMENTS: There is thickening of and increased signal intensity of the proximal fibers of the lateral collateral ligament proper suggesting degeneration or sequela of an old injury. The ACL, PCL, and MCL appear intact.EXTENSOR MECHANISM: There is mild increased signal intensity within the undersurface fibers of the proximal patellar tendon suggesting tendinosis. The extensor mechanism appears intact.ADDITIONAL
1. Horizontal tear of the lateral meniscus.2. Osteoarthritis with cartilage degeneration as described above.3. Thickening and increased signal intensity of the lateral collateral ligament proper may reflect degeneration or the sequela of prior injury.4. Mild proximal patellar tendinosis.5. Baker's cyst.6. Femoral trochlear dysplasia.