The rehabilitation phase of the protection period (2-12 weeks after surgery) 1. Rehabilitation of joint mobility of the operated limb: determine the range of joint extension and flexion that should be achieved according to the time after surgery. Apply progressive extension training programs to counteract joint contractures and adhesions caused by braking. 2. Rehabilitation training for walking load of the operated limb: adopt the stage load method, i.e., gradually increase the weight by 25%, 50%, 75% and 100% of body weight. Up and down step training. Progressive rehabilitation phase (3-6 months postoperatively) Muscle strengthening training: using elastic bands, sandbag resistance manic pump exercise and straight leg raise exercise, using integrated rehabilitation trainer or resistance muscle training on Cybex machine. Recovery exercise training phase (>6 months postoperatively) Flexibility, full squatting and running activities were started after 6 months. Swimming, cycling, walker and ski machine training are effective ways to improve endurance.