58-year-old male with hemarthrosis. Evaluate for structural abnormality versus PVNS. MENISCI: The medial and lateral meniscus appear normal.ARTICULAR CARTILAGE AND BONE: There is generalized thinning of the articular cartilage along the medial femoral condyle. There are focal areas of intermediate signal intensity partial defects along the articular cartilage of the medial femoral condyle anteriorly with adjacent subchondral bone marrow edema. Similarly there are foci of intermediate signal intensity partial defects along the articular cartilage of the medial facet of the patella. There are focal areas of subchondral bone marrow edema within the medial and lateral facet of the patella.LIGAMENTS: The collateral and cruciate ligaments appear normal.EXTENSOR MECHANISM: The extensor mechanism appears normal.ADDITIONAL
1. Findings most compatible with pigmented villonodular synovitis.2. Articular cartilage degeneration and other findings as described above.