Female 40 years old Reason: right knee medial meniscus tear History: right knee pain. MENISCI: There is mild attenuation and blunting of the posterior horn and body of the medial meniscus that may reflect prior partial meniscectomy or alternatively chronic attritional tearing but we see no discrete tear involving the medial meniscus. The anterior horn of the medial meniscus and the lateral meniscus appear normal. ARTICULAR CARTILAGE AND BONE: There is edema within the medial femoral condyle particularly along its weight-bearing aspect and extending laterally. Within the edema is a curvilinear focus of low signal intensity in the subchondral bone, the etiology of which is uncertain and could be degenerative, represent a small focus of osteonecrosis or perhaps a subchondral fracture. It appears to be associated with at least one small cyst. There is mild heterogeneity of the signal of the overlying cartilage which may represent degeneration although the possibility of neo-cartilage related to prior microfracture is also considered. There is a small full-thickness cartilage defect just above the free edge of the anterior horn of the medial meniscus.Moderate osteoarthritis affects the patellofemoral joint with multi-focal cartilage defects of varying thickness.There is also a focus of abnormal subchondral signal in the anterior aspect of the lateral femoral condyle with mild heterogeneity and thinning of the overlying cartilage suggesting degeneration. There is minimal subchondral edema-like signal more posteriorly in the lateral femoral condyle just above the free edge of the posterior horn of the lateral meniscus with the overlying articular cartilage appearing intact. Tricompartmental osteophytes are noted.LIGAMENTS: The cruciate and collateral ligaments are intact. EXTENSOR MECHANISM: The extensor mechanism is intact.ADDITIONAL
1. Slight attenuation of the posterior horn and body of the medial meniscus may reflect prior partial meniscectomy or perhaps chronic attritional tearing but we see no discrete meniscal tear.2. Osteoarthritic changes as described above, most severely affecting the patellofemoral joint.3. Subchondral focus of curvilinear low signal intensity in the weight-bearing portion of the medial femoral condyle associated with marrow edema which may be degenerative in etiology or reflect focal osteonecrosis or perhaps a subchondral fracture. The possibility of prior microfracture at this site is also considered.4. Small joint effusion and mild synovitis.