Extensive cortical thickening of the distal diaphysis of the femur, extending into the metaphyseal region, particularly medially. There is a mild degree of oedema within the bone with associated enhancement. The adjacent soft tissues show a mild degree of enhancement. There is enhancement of the synovium consistent with synovitis. The marrow signal remains intact. Moderate to large sized joint effusion is present. Mild loss of cartilage over the medial femoral condyle anteriorly and an area of defect seen within the medial femoral condyle anteriorly and posteriorly.