Increased knee pain following motor vehicle accident last month, CT scan at outside hospital showed internal derangement. MENISCI: Abnormal signal intensity within the posterior horn of the lateral meniscus extending to the femoral surface as well as blunting of the posterior horn of the lateral meniscus is compatible with a complex tear. The medial meniscus appears intact.ARTICULAR CARTILAGE AND BONE: Signal abnormality compatible with bone marrow edema is present within the posterior aspect of the lateral femoral condyle as well as within the lateral aspect of the tibial plateau. No discrete fractures are identified. Osteoarthritic degenerative changes affect the knee including tricompartmental osteophyte formation and subchondral sclerosis. There is a full-thickness cartilage defect involving the lateral tibial condyle underlying the posterior horn of the lateral meniscus which measures approximately 12 x 12 mm (7/9). Full-thickness cartilage loss is also present along the posterior aspect of the lateral femoral condyle. There is an additional near full-thickness focus of cartilage thinning involving the weightbearing portion of the medial femoral condyle (4/21). There is near full-thickness cartilage loss involving the medial facet of the patella as well as the patellar apex with mild underlying reactive bone marrow edema. There is also near full-thickness cartilage thinning involving the femoral trochlea particularly the lateral aspect.LIGAMENTS: The cruciate ligaments appear intact. The collateral ligaments appear intact.EXTENSOR MECHANISM: The extensor mechanism appears intact.ADDITIONAL
1.Bone marrow edema within the lateral femoral condyle and tibial plateau compatible with contusions.2.Complex tear of the posterior horn of the lateral meniscus.3.Severe arthritic degenerative changes including foci of full-thickness cartilage loss.4.Large popliteal cyst.