There are many causes of fluid inside the knee, such as osteoarthritis, rheumatoid rheumatoid arthritis, sexual arthritis, gouty arthritis, etc. In addition to the treatment of the cause of the disease, you can also promote the absorption of fluid through physical therapy, commonly used methods are to reduce the activity, hot compresses and traditional Chinese medicine fumigation and so on. 1. Reduce activities: after the knee joint effusion, the affected limb should reduce the strenuous exercise, avoid running and jumping, climbing, and frequently going up and down the stairs. Reduce the excessive activity of the knee joint, which is conducive to the absorption of fluid in the joint cavity. 2. Hot compresses: promote the absorption of fluid in the joint cavity through hot compresses, microwave therapy, ion implantation and other physical therapy methods. 3. Traditional Chinese medicine fumigation: knee joint fluid can also be combined with the method of traditional Chinese medicine fumigation to promote the absorption of fluid. If the amount of fluid is relatively large, it can also be treated by puncture of the joint cavity. If there is no effect after more than three months of treatment, synovial cleaning can be performed through arthroscopy. If you have knee joint effusion, you must go to a regular hospital for consultation and treatment, do not treat it by yourself to avoid delaying the condition.