There is no clinically effective topical formula for treating knee joint effusion. However, it can be treated through a combination of exercise therapy, medication, physical therapy, surgery and other treatments. 1. Exercise therapy: fluid in the knee joint will lead to pain, swelling and other manifestations, in order to alleviate the swelling of the limb, you can under the guidance of a professional doctor to carry out a certain degree of intensity of swimming, muscle stretching and other sports, in order to reduce the fluid on the surrounding tissue stimulation. 2. Medication: A large amount of fluid in the knee joint will cause obvious pain and activity limitation. At this time, you can follow the doctor’s instructions to take ibuprofen, diclofenac sodium and other non-steroidal anti-inflammatory drugs to relieve the local inflammatory reaction and pain. 3. Physiotherapy: In the early stage of swelling caused by knee joint effusion, the affected limb should be elevated to promote blood circulation in the limb, and the physiotherapy treatment of ice packs can be used to improve the local inflammation and relieve pain. 4. Surgery: If the amount of fluid in the knee joint is large and the degree of pain and swelling is heavy, arthrocentesis will be performed under the operation of a specialized doctor. The fluid in the joint will be extracted to improve the swelling and pain. When there is fluid in the knee joint, it is recommended to go to the orthopedic department of the hospital to clarify the disease situation, and then carry out professional treatment for the cause.