I. Functional exercise: Functional exercise after total knee surgery is mainly based on muscle strength, joint mobility and gait training, which is carried out in four stages. 1, the first stage 0 ~ 2 days after surgery, this period of the affected limb large cotton pad pressure bandage, rehabilitation training is mainly through the muscle isometric contraction, promote blood circulation, prevent muscle atrophy and the formation of deep vein thrombosis of the lower limb. Method: Strengthen the isometric contraction training of quadriceps and N cord muscles, contract hard for 10 seconds, relax for 10 seconds, 10 times/group, 2~3 groups/d; at the same time, do dorsiflexion and plantarflexion exercises of ankle joint, dorsiflexion for 10 seconds, plantarflexion for 10 seconds, 10 times/group, 2~3 groups/d. 2. Second stage 3~5 days after surgery, at this stage, the large cotton pad of the affected limb is removed and the wound drainage tube is removed, the main purpose of rehabilitation training is By increasing the muscle strength of the quadriceps and N cord muscles and the active and passive extension and flexion activities of the affected knee joint, it promotes wound healing, prevents muscle atrophy and improves joint mobility. Methods: (1) On the basis of continuing to exercise the quadriceps and N cord muscles, the affected limb should be instructed to perform straight leg raising exercises, keeping the limb raised in the air for as long as possible, with the number of times ranging from few to many, so as not to cause fatigue. (2) Continuous passive knee movement (CPM) was performed after the drainage tube was removed, the starting angle of CPM training was 0°, the ending angle was 30°, a flexion and extension activity was completed within 1~2 minutes, 1h/time, 2 times/d. According to the patient’s pain tolerance level, the daily increment was 5°~10°, and the knee flexion angle reached 90° or more within 1 week. (3) Active knee flexion and extension exercise Patients lying flat, remove the soft pillow under the knee, the health care worker hold one hand under the patient’s knee, one hand holding the heel to perform knee flexion activities, when feeling pain, ask the patient to heel along the bed surface slowly straighten the knee joint, so repeatedly from small to large amplitude, the amount of activity from small to large, gradually transition to active knee flexion and extension exercise. Phase 3: 6 days to 2 weeks after surgery, the wound pain of the affected limb has been relieved, so continue to strengthen the muscle strength and knee mobility of the affected limb while carrying out gait training. Method: Encourage the patient to get out of bed as soon as possible, start to hold the walker or practice standing at the end of the bed, at this time the center of gravity is on the healthy side of the lower limb, the affected limb is not weight-bearing or partially weight-bearing according to individual differences, later the center of gravity gradually transitions to the affected limb, start to hold the walker or crutches to walk, walk with the healthy limb in front first, the affected limb follows, and then move the walker forward. 4.The fourth stage After discharge, the purpose of functional exercise is to increase the knee mobility and weight-bearing capacity of the affected limb, further strengthen the balance function of the lower limb, proprioception, muscle strength training, and improve the self-care ability of daily life. (1) Continue the muscle strength training of the quadriceps and N cord muscles, such as leg extension and straight leg raise in sitting and supine position, and knee flexion training in prone position; at the same time, strengthen the active or resistance training of knee flexion and extension activities, such as handrail squatting, bicycle stepping and stair walking. (2) Further strengthen the weight-bearing training of the affected limb, gradually increasing the weight-bearing strength until it can be fully weight-bearing. (3) Strengthen the walking training, with head up, eyes level in front and hips not cocked. It is worth noting that the principle of gradual progress should be followed throughout the rehabilitation training process, and the amount of training should be small to large, so as not to cause significant pain in the affected knee; before daily training, patients should be asked about their self-perception and whether they have any uncomfortable reactions to judge the amount of exercise; after exercise, attention should be paid to whether there is swelling in the knee joint; during training and walking, safety protection should be done, especially for patients with knee instability; patients with more serious For patients with more severe knee flexion disorders, a plaster cast can be used to fix the knee in the extended position at night rest for 4-6 weeks. In order to reduce the wear and tear on the knee joint and to prevent falls, it is recommended that patients should use a cane for life, especially when going out, to maximize the life of the knee joint. 2. Diet Patients are instructed to strengthen nutrition, to eat more food rich in protein, vitamins, calcium and iron, to increase their resistance, and to control weight gain appropriately to reduce the weight bearing on the joint. 3.Review Within 6 months, review the patient once a month; come to the hospital for review on time, and promptly consult the doctor if the following conditions occur: swelling and pain in the affected limb, redness, swelling, heat and pain in the local incision. Systemic occult lesions such as respiratory tract infection, urinary tract infection, tonsillitis, toothache, etc. should be treated promptly to prevent distant infection of the knee joint.