(I) Initial stage (0-1 week after surgery) 1. On the day of surgery: After anesthesia subsides, start to move the toes and ankle joint. (1) Ankle pump – forceful, slow, full-range flexion and extension of the ankle joint, 5 minutes/group, 1 group/hour; (2) Quadriceps isometric exercises – i.e., tensing and relaxing of the thigh muscles. It should be done as much as possible without increasing the pain; (3) N cord muscle isometric exercises – the affected leg is pressed down hard on the pillow, so that the posterior thigh muscles are tensed and relaxed. The requirements are the same as above. All exercises should be done as much as possible without increasing the pain; (4) 24 hours after surgery, you can walk on the ground with the help of crutches, but only to go to the toilet and other necessary activities. (2) Postoperative day 1: (1) continue the above exercises; (2) change the ankle pump to anti-gravity exercises; (3) start straight leg raising – extend the knee and then raise the leg straight up to the heel of the foot away from the bed at 15M, hold for 5 seconds. 30 times/group, 3-4 groups/day; (4) start side leg raising exercises. Requirements and number of times as above; (5) start the back leg raising exercise, prone, straight leg raising after knee extension until the toe of the foot is 5M from the bed, hold for 5 seconds. Requirements and number of times as above; (6) Weight bearing and balance: Separate the feet under protection and move the center of gravity alternately from side to side within the range of micro-pain. 5 minutes/times, 2 times/day; Separate the feet anteriorly and posteriorly and move the center of gravity. If the pain and swelling are not obvious, you can go down to the ground with or without crutches, but do not encourage more walking. 3. Postoperative day 3 (1) Continue the above exercises; (2) Start flexion exercises, see notes for methods. (1) Continue the above exercises; (2) Start single-leg standing balance exercises. 5 minutes/times, 2-3 times/day; (3) Start prone position “leg hooking exercises”, 30 times/group, 2-4 groups/day; (4) active (4) Active knee flexion up to 90 degrees. 5.Post-operation day 5: (1) Continue and strengthen the above exercises; (2) Start the active extension and flexion exercises within 0-45 degrees of body weight in the standing position. 30 times/group, 2-3 groups/day, and apply ice packs for swelling and pain after the exercises. 6, the first week after surgery: (1) active flexion greater than 90 °; (2) can stand on one foot, can not use the crutches to walk short distances; (3) began to squat against the wall static squatting exercises. Static squatting exercises: back against the wall, feet shoulder width apart, toes and knee joints are forward, not “inside and outside eights”, with the increase in strength gradually increase the angle of squatting (less than 90 °), 2 minutes / times, interval of 5 seconds, 5-10 consecutive / group. 2-3 groups / day; (4) begin to stand “hook legs (4) Begin standing “hook leg” exercise resisted flexion to pain-free maximum angle held for 10-15 seconds. 30 repetitions/set, 4 sets/day. (ii) Early stage: (2 weeks-1 month after surgery) Objective: to strengthen mobility and muscle strength exercises: to improve joint control and stability; to start resuming daily activities. As the level of muscle strength increases, exercises to improve absolute strength are the main focus in this period. Choose a medium load (the load of fatigue when completing 20 movements), 20 times/group, 2-4 consecutive sets of exercises, rest 60 seconds between sets, until fatigue. Attention should be paid to control the amount of exercise to avoid joint swelling and fluid accumulation. If there is swelling and warmth in the joints after the exercise, ice packs should be applied in time. 1.Postoperative week 2: (1) Active flexion to 120-130°; (2) Strengthening muscle strength exercises. (a straight leg lift up to 6 minutes); (3) joints without obvious swelling, pain, should be as far as possible to walk in a normal gait; (4) began to guide the knee straight position thigh band resistance muscle exercise exercises load, angle, number and time, according to their own conditions. Generally 30 times/group, 2-4 groups/day; 2, postoperative week 3: (1) passive flexion to 140 °; (2) strengthening muscle exercises; (3) the beginning of the front and back, lateral stride exercises gradually transition and gradually increase the load. 30 times/group, 4 groups/day; (4) start to guide the knee extension position thigh band resistance muscle exercises exercise load, angle, frequency and time according to their own conditions. 30 times/group, 4 groups/day; (3) Mid-term: (1 month-2 months after surgery) Purpose: Strengthen the joint mobility training to the same as the healthy side; strengthen the muscle training to improve joint stability; restore the ability of daily life activities, and light exercise. 1.Postoperative week 5: (1) Active flexion up to 150° (full range, the same as the healthy leg), and basically painless; (2) Beginning of the affected side of the single leg 45 degrees position half squatting exercise. 5 minutes / times, 4 times / day; (3) Beginning of stationary bicycle exercise. 30 minutes / times, 2 times / day. (2) Postoperative weeks 6-8: (1) active flexion and extension angle to the same as the healthy side, and no pain; (2) can complete daily activities, such as going up and down the stairs, riding a bicycle, walking more than 5,000 meters without swelling and pain in the joints; (3) begin to kneeling exercises; (4) began to pedal exercises; (5) began to swim, jumping rope and jogging. (D) Post-operative period: (2-3 months after surgery) Purpose: To fully resume daily life activities. Strengthen muscle strength and joint stabilization. Gradually resume exercise. Increase the maximum strength, use a large load of 70% 1RM (the amount of fatigue load to complete 12 movements), 8-12 times / group, 2-4 groups of continuous exercises, rest 90 seconds between groups, until fatigue. 1, start the knee loop exercise; 2, start the jumping up and down exercise; 3, start the lateral jumping exercise; 4, mobilize to start the exercise of basic movements in special sports. Wear knee pads for protection if necessary. (E) Recovery exercise period: (3 months after surgery) Purpose: to fully resume exercise or strenuous activities. (1) Gradually resume strenuous activities or special training; (2) Strengthen the muscle strength and the stability of the joints in running and jumping; (3) Muscle strength test, the muscle strength of the affected side reaches more than 85% of the healthy side, and there is no pain in the exercise and no obvious swelling, then the exercise can be resumed completely.