I. Early exercise (from the day of surgery to the third day after surgery): Apply ice pack for 24 hours, take oral analgesic drugs, and start muscle function exercise immediately after surgery. Quadriceps contraction training: 1, the patient lying down, lower limbs straight, the affected limbs do quadriceps static contraction to maintain 5 seconds and then relax, ten groups a day. 2, straight leg raising exercises: patients lying down or sitting position, toes up tense leg muscles, slowly straight leg raising, the height of the heel from the bed 20 centimeters appropriate, keep suspended for 10 seconds, and then put down, 4 times a day. 3, ankle pump exercises: patients lie flat on the bed, muscle relaxation, keep the knee straight, ankle dorsiflexion at an even pace, keep 8-10 groups per minute, do 3-5 minutes each time, three times a day. Continuous passive motion (CPM) exercise was started on the 2nd-7th postoperative day, with a starting angle of 0 degrees and a termination angle of 20 degrees, and one dorsiflexion and extension in one minute at a slow speed, twice a day for 30 minutes each time. The angle was gradually increased and so was the speed. The drainage tube was removed on the 2nd-3rd postoperative day. On the third day, partially weight-bearing walking on crutches. Second, medium-term exercise (8-14 days after surgery) At this time, gradually increase the weight of the affected knee, but should still be partially weight-bearing crutches, mainly to increase the joint flexion and extension angle exercises. Straighten the leg as much as possible, maintain the movement, count to 5. Then try to flex the knee, maintain the movement, count to 5, and repeat. Third, late exercise (15-21 days after surgery) The focus is to gradually restore the weight-bearing capacity of the affected limb, start walking and gait training, and strengthen the patient’s balance training. Further strengthen the quadriceps and N cord muscle strength training, using isotonic, isometric and isotonic muscle strength training methods. The patient was trained to walk up and down the stairs, and in the early stage, the patient mainly relied on crutches and the healthy lower limb to support walking up and down the stairs. The affected limb gradually transitioned from non-weight-bearing to partial weight-bearing. The healthy side goes up first, and the affected side goes down first; after the patient adapts to the training, the dependence on crutches will be gradually reduced, and the patient will eventually be able to get rid of the crutches and walk independently.