Acute grade 4 traumatic cartilage defect of lateral femoral condyle

Large full thickness (grade 4) cartilage defect within the central weightbearing lateral femoral condyle with the detached cartilage located within the joint paralleling the cartilage of the posterior non-weightbearing lateral femoral condyle. There is minimal subchnodral marrow reaction at the site of chondral defect.  No meniscal tear in association. Chronic horizontal oblique tear of the medial meniscal posterior horn extending to the tibial surface with associated lobulated parameniscal cyst posterior to the posterior root attachment. The fibular collateral ligament appears to have a longitudinal split its mid-portion but is not completely torn and there is partial tearing of a tibial limb of the biceps femoris tendon insertion. Cruciate ligaments and medial collateral ligament are intact.  There is a large knee joint effusion.