I. Etiology The synovium is the inner tissue of the joint capsule and is called the synovial layer. It has the functions of removing foreign bodies from the joint, synthesizing, secreting and reabsorbing synovial fluid, and participating in intra-articular immunity. The synovial layer can be divided into the inner synovial layer (near the joint) and the subsynovial layer (near the periosteum). The synovial layer of the knee joint is widely distributed throughout the inner surface of the knee joint and is the largest synovial cavity in the body. However, the presence of structures such as the cruciate ligament makes the subsynovial layer very complex and makes it susceptible to injury. The synovial membrane of the knee joint is damaged or ruptured due to chronic strain, trauma or surgical stimulation, resulting in congestion, exudation and a large amount of fluid accumulation, and fibrous and mechanized fibrous deposits over time, resulting in adhesions between the synovial membranes of the joint and affecting joint activities, which is called traumatic synovitis of the knee joint. Clinical manifestations The main clinical manifestations of traumatic synovitis of the knee joint are pain, swelling, peri-articular pressure, twisting sound in the joint, and increased local temperature. When the joint fluid reaches 50ml, the knee joint flexion is limited and the floating patella test may be positive. X-ray examination shows no abnormalities in the knee bone. The diagnosis of the disease is not difficult, but attention should be paid to exclude joint tuberculosis, tumors, fractures, etc. Treatment 1. General treatment Rest and hot compresses play an important role in relieving acute joint pain and promoting the absorption of joint effusion. 2, joint puncture For patients with joint cavity effusion in the acute stage, this treatment should be preferred. At this time, the joint cavity effusion is more and the tension is high, under local anesthesia and strict aseptic technique, joint puncture is performed at the outer edge of the patella to completely remove the effusion and blood, and inject 1% lidocaine 3-5ml and prednisolone 12.5-25mg, then cover the puncture hole with sterile gauze and compression with elastic bandage. Wrap. 3, drug treatment can be oral or topical drugs, such as aspirin 50 ~ 150mg, 1 ~ 2 times / d, or local application of safflower oil, etc.. In the chronic stage, it is advisable to take Chinese medicines mainly to dispel wind and dry dampness and strengthen the muscles and bones, such as Lulodan, and can be combined with external Chinese medicine.