A small amount of synovial fluid is already present in the knee joint in normal people. For patients with increased knee effusion, it is mainly caused by synovitis inside the knee joint. After the synovial membrane is stimulated by external or internal stimulation, it leads to edema and hyperplasia of the synovial membrane, which leads to an increase in exudate, thus destroying the balance of exudation and absorption, resulting in a small amount of effusion in the knee joint, causing soreness, swelling and pain in the knee joint. Therefore, after a small amount of knee joint effusion occurs: First, avoid repeated flexion and extension of the knee joint and excessive weight-bearing activities, which may lead to an increase in the amount of effusion, resulting in significant swelling and pain in the knee joint. Second, you can apply hot compresses to the knee joint, preferably with a warm water bag or hot towel, to promote blood circulation in the knee joint, which will facilitate the absorption of the effusion. Third, during the pain period, you can take oral non-steroidal anti-inflammatory drugs, such as ibuprofen, fenpropathrin, nimesulide and other drugs, after oral administration can fight the aseptic inflammation of the synovial membrane, relieve pain, for the absorption of the knee joint effusion, also has a very good effect.