Rehabilitation after knee arthroplasty and synovectomy requires three stages of training in a 2-week unit. 1. Early stage of rehabilitation: The goal of rehabilitation in this stage is to reduce swelling, relieve pain and promote tissue healing. After surgery, you can move the patella and ankle joint and perform isotonic contraction exercises for the quadriceps muscle. The focus of training at this stage is to be able to passively extend the knee fully and flex the knee to 90°. Active knee flexion should be avoided at this stage. Encourage the patient to do plantar flexion and dorsal extension activities, active stretching and passive stretching of the calf flexor muscles to prevent deep vein thrombosis of the lower limb. 2. Middle stage of rehabilitation: continue passive activities of the knee joint, and the angle of passive activities should be maintained at 120° for 4 weeks after surgery. Perform resistance exercises with the doctor’s consent. Exercise up and down the ladder, the height of the step is gradually transitioned from 10cm to 20cm. 3. Late stage of rehabilitation: active knee flexion, in this stage the knee flexion angle should be restored to the functional level. Both ends of the elastic band are fixed at the level of the calf, and resistance exercises are performed in all directions. The person stands inside the elastic band circle and squats with resistance in a shear gait. Appropriate low-intensity exercises such as swimming or badminton are performed. If you have any discomfort after knee arthroplasty and synovectomy, you should go to the hospital as soon as possible, and the doctor will formulate an individualized diagnosis and treatment plan according to your specific condition, so as to avoid delaying your condition.