Knee replacement surgery is a surgical procedure to replace an autologous joint that has lost its normal function with a knee joint made of artificial material to re-establish the function of the knee joint. The surgical methods are total knee replacement and unicondylar knee replacement (minimally invasive). The procedure is technically mature and effective, and the entire operation takes about 60-90 minutes. Patients can start functional knee exercises in bed on the day after surgery, and can get out of bed the day after surgery for proper functional exercises. Indications for knee replacement surgery: 1. elderly patients with severe knee pain, instability, deformity, and serious impairment of activities of daily living, who have been ineffective after conservative treatment or whose results are not significant; 2. various aseptic knee arthritis, such as rheumatoid arthritis, osteoarthritis of the knee, and a few traumatic arthritis; 3. osteoarthritis after failed tibial high osteotomy; 4. primary or secondary osteochondral Necrotizing diseases. Contraindications: 1. muscle paralysis around the knee joint; 2. knee joint has been fused in a functional position for a long time without pain and deformity. Relative contraindications: including young age, postoperative activity, obesity, poor surgical tolerance and patients with severe diabetes mellitus, cardiopulmonary insufficiency and cured knee tuberculosis.