Left knee pain, instability, crepitus with flexion. Joint effusion. Question of prior ACL injury. MENISCI: The medial and lateral menisci are intact.ARTICULAR CARTILAGE AND BONE: There is near full thickness to full thickness loss of cartilage of the median eminence of the patellar articular cartilage with underlying subchondral edema. There is thinning of the articular cartilage of the lateral femoral condyle above the anterior meniscal horn with minimal subchondral edema. The articular cartilage of the medial femoral condyle is intact.LIGAMENTS: The collateral and cruciate ligaments are intact. EXTENSOR MECHANISM: The extensor mechanism is intact.ADDITIONAL
1. Lesion anterior to the ACL may represent arthrofibrosis or focal PVNS.2. Additional focal areas of signal abnormality may also represent focal PVNS.3. Chondromalacia as described above. 