1, the day of surgery: after the disappearance of anesthesia, the ankle joint plantarflexion and dorsiflexion training will begin, which can prevent the occurrence of venous thrombosis of the lower limbs. Method: both ankles relax naturally, maximize dorsal extension, then maximize plantarflexion by dorsal extension, and so on repeatedly. Ankle plantarflexion and dorsiflexion exercises are greater than 15 times/hour, the number of times is not limited. Quadriceps isometric contraction exercises: both thighs naturally straight, repeated contraction of the thigh muscles for 5 seconds, and then relaxation of the activity for 2 seconds. The number of contractions and relaxations per day totaled 3 groups, each group 50 times, a total of 150 times. 2.Post-operative day 2: Continue the first day of practice. Start walking with crutches, the time is not longer than 20 minutes every day. When resting, the support is adjusted at 0-30 degrees, and when going down to the ground, the support is adjusted to the straight position. 3.Postoperative day 3-3 weeks: Continue the practice on the second day, gradually increase the time of walking on the ground, according to the reaction after walking, the time will be increased to 1-2 hours. 4.Postoperative week 4-5: Strengthen the number of straight leg raising, muscle contraction and relaxation should be more than 1000 times/day. The brace is adjusted to 0-60 degrees. 5. Postoperative week 6: go to the brace every day to practice increasing the angle of knee flexion gradually to 90 degrees, the time is less than 30 minutes, the brace is adjusted to 0-90 degrees. The brace was adjusted to 0-90 degrees. The brace could be removed during sleep. 6. Postoperative week 8: Require knee flexion greater than 120 degrees. Remove the brace and start daily life. If the pain is heavy and the reaction is big during the exercise, ice packs can be applied after the exercise. 7.3 months after surgery: start walking fast, jogging, and go to the outpatient clinic for recheck every month.