The first stage is 2 weeks after surgery: 1. On the day of surgery, elevate the affected limb and provide local cold therapy to help reduce swelling and pain. 2. 1 day after surgery, start to do isometric contraction training of the quadriceps muscle for 5 seconds each time, and repeat to prevent muscle atrophy and enhance muscle strength. 3.Strengthen ankle pump exercise to promote blood circulation, reduce swelling and prevent deep vein thrombosis. 4. You can walk on crutches on the day of surgery or around the next week. Phase II 2 to 4 weeks: 1.Stitches were removed in two weeks, and knee flexion exercises were started in 2 to 3 weeks. 2. Under the pain-free condition of the affected limb, maintain the length of the muscle at rest, stimulate the flexion and extension reflexes, increase the proprioception, and prepare for active movement. 3. Perform knee extension exercises in conjunction with progressive resistance training. Do knee extension exercises against gravity within a range of less than 30 degrees of knee flexion. Place a soft pillow under the knee, keep the knee flexed at 30 degrees, and then lift it off the bed until the affected knee is straight, and so on and so forth. The intensity of the exercise is 10 to 15 minutes twice a day, and according to the functional status of the affected knee, the treatment is individualized, measured, safe and progressive. 4. Support the weight with a tucked cane or walker to increase stability and meet the requirements for partial weight bearing of the affected limb. Phase 3, 4 to 6 weeks: 1. Increase joint range of motion, prevent joint adhesions, and continue passive joint movement, requiring passive knee flexion at or near 90 degrees at 4 weeks. 2. Enhance muscle strength and increase joint stability. In the quadriceps training chair and net frame training quadriceps and N rope muscle strength, gradually increase the resistance. 3.Walking and stair training: gradually increase the walking time and distance, adjust the gait and posture in the process of walking, and complete the transition of the center of gravity from the lower limb on the healthy side to the lower limb on the affected side, should be maintained when walking up and down the stairs, pay attention to safety, and walk according to your ability. 4. Six weeks of knee flexion of more than 100 degrees. The fourth stage after 6 weeks to six months after surgery: 1. 6 to 8 weeks after surgery, if the walking speed reaches normal, the crutches can be gradually removed. 2.Continue quadriceps isometric contraction exercises. 3. After six months, you can resume sports if you recover well after the doctor’s examination.