It usually takes a month to return to sports after knee joint lubricant injection. Joint lubricant clinically called sodium vitrate, is a biological agent, can lubricate the joints, reduce the friction between the tissues, significantly improve the inflammatory reaction of the synovial tissue, the viscosity and lubrication function of the joint fluid, which can protect the articular cartilage, promote the healing and regeneration of the articular cartilage, and alleviate pain. The general course of treatment is one injection per week, a course of treatment is five injections. Knee joint injection lubricating fluid has a certain therapeutic effect on patients with certain cartilage injuries. However, if the patient already has severe osteoarthritis in the joint, the cartilage has been severely worn down and all of the cartilage has been exposed, sodium vitrate shots are less effective. Rest for at least one month after the knee joint lubricant injection and do not exert yourself. Usually do not do strenuous exercise, such as playing ball, if necessary, you can wear knee pads. Eat more fresh fruits, vegetables, high protein food, soy products and so on.