Joint fluid leakage

After synovial injury of the knee joint, the synovium showed congestion, edema, and neutrophil infiltration. Synovial blood vessels dilate, and extravasation of plasma and cells produces a large amount of exudate, while synovial cells are active, producing a large amount of mucin. Exudate contains red blood cells, white blood cells, bilirubin, fat, mucin and cellulose. Severe joint fluid is bloody. Joint swelling and restricted movement.