Female, 61 years old. Pain. MENISCI: There is abnormal signal intensity throughout the expected location of the anterior horn of the lateral meniscus as well as the anterior half of the body of the lateral meniscus indicating extensive tearing. Furthermore, there is slight lateral extrusion of the body of the lateral meniscus with deformity suggesting the possibility of a displaced meniscal fragment along the mid body. The posterior horn of the lateral meniscus appears relatively intact. The medial meniscus is intact.ARTICULAR CARTILAGE AND BONE: There is severe degeneration of the articular cartilage of the lateral tibiofemoral compartment with areas along the weightbearing surface of the lateral femoral condyle and lateral tibial plateau essentially devoid of cartilage. As seen on recent radiographs, there is a focal depression of the surface of the lateral femoral condyle above the torn anterior horn of the lateral meniscus with what appears to be disruption of the subchondral bone plate posteriorly. There are parallel curvilinear bands of high and low signal intensity deep to the depression as well as extensive edema throughout the lateral femoral condyle and extending into the distal femoral metaphysis. These findings suggest osteonecrosis with subchondral collapse perhaps in association with a prior subchondral stress fracture. There are also subchondral cysts and mild edema type signal within the lateral tibial plateau, likely degenerative in etiology. The articular cartilage of the medial and patellofemoral compartments is relatively spared.LIGAMENTS: The cruciate and collateral ligaments are intact. EXTENSOR MECHANISM: The extensor mechanism is intact.ADDITIONAL
1.Severe cartilage degeneration and meniscal tearing affecting the lateral compartment with focal depression of the articular surface of the lateral femoral condyle suggesting osteonecrosis with extensive adjacent marrow edema.2.Joint effusion and Baker's cyst.