General issues of rehabilitation of total knee arthroplasty 1. Rehabilitation objectives (1) To strengthen the muscle strength of the periprosthetic knee muscles through muscle strengthening training and to promote the recovery of general strength and condition. (2) To improve the muscle strength around the knee joint and its soft tissue balance and coordination to ensure joint stability through walking or other coordination training. (3) Through joint mobility training, the knee joint can meet the needs of daily life and some social activities. (4) Prevent postoperative joint adhesions, improve local or whole lower limb blood circulation, and avoid certain postoperative complications through active and passive knee joint activities. (5) To improve the patient’s mental and psychological outlook and to stimulate enthusiasm for life. 2. Rehabilitation principles (1) Individual treatment principle: Due to different patients’ physique, condition, psychological quality, subjective functional requirements and surgical procedures, etc. are different. Artificial knee arthroplasty rehabilitation does not exist a uniform routine, should be different from person to person. (2) Comprehensive training principle: the knee is only one of the weight-bearing joints, and rheumatoid arthritis involves multiple joints and organs, therefore, dealing with the knee alone is not enough to improve the patient’s function. (3) The principle of gradual progress: Patients who undergo knee arthroplasty have long-term pain, deformity and dysfunction, and the soft tissues and bones around the knee are invaded, so the patient’s functional level can only be gradually improved. 3. Indications and contraindications for rehabilitation Artificial knee replacement is an absolute indication for rehabilitation activities. Even without knee replacement, local knee pain, deformity, and dysfunction are absolute indications for rehabilitation. Contraindications to rehabilitation include: ① hyperthermia, ② heart rate greater than 100 beats/min at rest, ③ systolic blood pressure less than 13.33 KPA with symptoms of hypotension, ④ diastolic blood pressure greater than 16 KPA with symptoms of hypertension, ⑤ serious dysfunction of the heart, lungs, liver, kidneys, brain and other vital organs, and absolute silence is required from the perspective of medical treatment. The above contraindications are not absolute, but passive exercise and muscle immobilization training can still be performed appropriately, but Passive exercise and muscle immobilization training can still be performed, but they must be performed under supervision with full consideration of the systemic status. In addition, for patients with severe pain, rehabilitation training can be actively carried out under continuous analgesic pump or anesthesia; for patients who are not in serious condition but are obviously weak and have no desire to exercise, rehabilitation exercises should be carried out under psychological support. The patient’s degree of recovery and the possibility of recovery are expected. Based on the above evaluation, we design the desired goals based on our experience. The next step is to develop an individualized rehabilitation plan to achieve the desired goals based on the patient’s current physical and psychological status. According to this plan, the patient, family and medical staff will implement the rehabilitation plan, and then, according to the patient’s response and the degree of functional recovery, the rehabilitation plan will be repeatedly evaluated and revised periodically so that the patient’s functions can be gradually restored. The purpose of the pre-rehabilitation evaluation is to collect information about the patient’s condition and analyze its significance on a case-by-case basis, which can be used as the original information for designing rehabilitation goals and making rehabilitation plans. The information required for the evaluation includes factors related to the primary disease (including the course and duration of the disease, previous treatments and effects, diagnosis, etc.), local knee condition, systemic status and complications, mental and intellectual status, age, gender, economic ability and other social background information. 1. Evaluation of factors related to the primary disease This evaluation includes the course and duration of the primary disease, previous treatments and effects, diagnosis, etc. In the case of rheumatoid arthritis, for example, items of particular significance to rehabilitation include: current clinical symptoms, clinical and X-ray staging of rheumatoid arthritis, function of related joints and muscle groups, laboratory tests (e.g. ESR, CRP), history of previous hormone application, years of bed rest or significantly reduced activity, etc. For the evaluation of rheumatoid arthritis, refer to the “Rheumatoid Arthritis Patient Questionnaire” and the “Activities of Daily Living (ADL) Questionnaire”. The evaluation of the local knee joint includes five aspects, namely the joint mobility (ROM) of the affected knee joint, the muscle strength of the quadriceps and the N cord, the knee joint score, the knee joint X-ray performance and the intraoperative situation (1) ROM: the patient is in principle in the prone position, if the hip joint has flexion contracture and cannot be prone, it is also measured in the supine position, and the two arms of the goniometer are tied to the line between the greater trochanter and the femoral epicondyle and the line between the fibula and the epicondyle. The flexion and extension of the knee were measured by tying the two arms of the goniometer to the line between the greater trochanter and the femoral epicondyle and the line from the lesser head to the epicondyle. (2) Quadriceps and N cord muscle strength: The common methods of muscle strength examination include ①Lovett’s method: It is characterized by reliable, valid and recognized results without the use of instruments. However, there are some limitations on muscle endurance and coordination. ②Muscle strength test method: In order to further quantitative assessment when muscle strength reaches grade III, special equipment can be used to determine. There are quantitative indicators for the determination of the apparatus, but it can only be used for certain parts, and can only measure muscle groups, but not individual muscles respectively. (3) The HSS knee function score and exercise score should be performed on the knee under the guidance of an experienced physician prior to surgery for postoperative evaluation and as a basis for revision of the rehabilitation plan and comparison of long-term outcomes. (4) Knee radiographs: The pre- and post-operative radiographs should focus on the local bone condition and the position of the prosthesis, the latter including the tilt of the planar prosthesis, patellofemoral and tibiofemoral joint alignment, etc. (5) Intraoperative situation: focus on the knee joint access selection, bone resection, soft tissue balance, prosthesis position, prosthesis selection, whether to use bone cement, joint alignment, intraoperative ROM of the knee joint, joint stability, etc. 3. Systemic status and complications Rheumatoid arthritis can be caused by the original disease or treatment response, such as heart, lung, liver, kidney and other organ diseases. Patients with osteoarthritis are mostly elderly and may be accompanied by systemic diseases such as diabetes and hypertension. Patients with hemophilia are associated with bleeding tendencies. In addition, these patients are weak due to long-term chronic illnesses and reduced activity, thus many systemic complications may occur under surgical strikes. Therefore, a rigorous evaluation of the systemic condition and treatment before and after the surgery can help the rehabilitation exercise, and these factors can determine the start time of the rehabilitation exercise, the intensity of the exercise, and the adjustment of the rehabilitation program. Complications of artificial knee arthroplasty include thrombosis and embolism, poor wound healing, infection, joint instability, fracture, patellar tendon rupture, common peroneal nerve injury, patellar dislocation and subluxation, prosthesis loosening, prosthesis wear, prosthesis deformation and fracture. During the rehabilitation process, care must be taken to avoid some of these complications. Once they occur, the rehabilitation plan must be modified in time. 4. Spiritual, psychological and Chilean status According to this examination, it is possible to understand whether the patient can tolerate the rehabilitation exercise psychologically or spiritually and whether he/she can help to understand the instructions of the medical staff. This investigation does not necessarily require direct consultation with a psychiatrist, but can be judged by the medical staff through simple conversation and interaction with the patient, and if necessary, IQ and CMI tests can be used to check the patient’s intelligence level and personality characteristics. It is more common to see a group of patients who are physically able to tolerate rehabilitation exercises and have no mental or intellectual impairment, but lack the desire and demand for rehabilitation due to long-term illness. 5. Social background information such as age, gender, and economic ability These are factors that are not related to the disease and that the patient already has, and can be used to determine the favorable and unfavorable factors for the patient’s recovery. Generally speaking, from 13 to 50 years of age, exercise is rarely affected by age. Over 50 years of age, their physical strength and desire for rehabilitation are significantly reduced, and the failure rate of rehabilitation exercise increases, especially if the preoperative disease is more severe and older, and they are easily satisfied with a poorer postoperative function. Women are generally less motivated to rehabilitate than men, and this tendency is especially pronounced in older women. Through conversation, the rehabilitation worker should investigate the patient’s social background in detail, including life history, education history, work experience, family members and family relationships, housing situation, economic situation, personal preferences, personality traits, and approach to the world. Especially important is the patient’s attitude toward the disease and life, which will directly affect the patient’s willingness to recover and the collaborative attitude of the medical staff. Based on this information, it is only when the patient is discharged from the hospital that realistic and acceptable work and life instructions can be provided to the patient. Since the function of the knee joint is mainly reflected in the joint mobility and muscle strength of the quadriceps and the N-flexor, the main content of rehabilitation is ROM exercises and muscle strength enhancement exercises of the quadriceps and the N-flexor. In addition, in order to cooperate with walking and recovery of physical strength, physical recovery exercises can be carried out. 1, ROM exercise and quadriceps, N rope muscle strength strengthening exercise general issues (1) exercise volume: exercise volume in terms of exercise intensity x time to express. When deciding on the amount of exercise, a variety of factors must be considered. First, the initial amount is limited to a minimum, rather than excessive, it is better to increase the amount in small increments; second, the amount of exercise is increased or decreased according to the reaction after exercise and the next day (general state, fatigue, local swelling, pain, etc.). Instead of making the patient very fatigued and affecting the next day’s exercise and rehabilitation confidence, it is better to gradually increase the amount, which also allows the patient to see the functional progress after daily exercise and helps to enhance rehabilitation confidence. Again, evenly distribute the amount of exercise and give the patient short breaks. In addition, short periods of daily exercise are more effective than long periods of exercise on alternate days. Finally, adjust the intensity, time and manner of exercise according to the needs of different rehabilitation periods and functional recovery. (2) Treatment before and after rehabilitation: Rehabilitation exercises usually do not need to be prepared beforehand, but if possible, it is better to start formally after a light full-body recovery exercise. In addition, when the knee joint is swollen and painful, infrared light, ultra-short wave, hot compress and other warm therapy, or cold therapy can be applied to relieve local muscle spasm caused by pain, massage and other similar effects. When stretching the knee joint with flexion contracture or limitation of flexion, warm therapy in hydrotherapy can be applied to relieve pain, soften the tissue and relax the muscles. For patients with severe pain or those who are more sensitive to pain, small amounts of analgesics, such as morphine, cocaine, and nonsteroidal antipyretic analgesics, can be added to the exercise. For 2 weeks after surgery, knee ROM still cannot reach 90° (or 9°~10° days after surgery, knee flexion cannot reach 75°~90° and knee extension cannot reach -5°~-10°), the knee should be moved passively under epidural anesthesia or general anesthesia. (3) Place of rehabilitation exercise: There are no special requirements for the place of exercise itself, almost any place can be exercised, but to facilitate the patient’s concentration, the place should be quiet, and the exercise should preferably be supervised, especially for those who are not strongly willing to rehabilitate (4) Preparation before rehabilitation exercise: Loose clothing is appropriate, but do not interfere with the activity, and wear shoes with non-slip soles to avoid falls. Before exercise, especially for the elderly, you must urinate and defecate, and avoid exercising within 30-60 MIN after waking up or immediately after getting up. (5) Auditory stimulation: In the exercise, use sound to stimulate the patient, can give the patient to encourage, so that the patient maximum force, especially for low muscle strength and limited mobility, exercise family members or health care workers say “hold on”, “in a “, “and “harder”, etc. is very effective, especially when there is fatigue. Experience has shown that this method can sometimes multiply the ability to exercise. (6) The cooperation of different forms of exercise; knee pain can cause restricted joint mobility and in severe cases lead to a decrease in muscle strength. On the contrary, ROM and muscle strength should be exercised at the same time when exercising, and should not be neglected. It has been proven that even if the passive knee ROM has been achieved, if the patient has low muscle strength, then the gained ROM will be partially lost. (7) Maintenance rehabilitation exercises; after a period of rehabilitation exercises after artificial knee arthroplasty, the patient’s muscle strength and ROM are almost normal, but it is necessary to maintain rehabilitation exercises for a long time or even for life, otherwise the acquired function may be reduced, especially in patients with rheumatoid arthritis. This is especially true for patients with rheumatoid arthritis, because exercise may improve disuse muscle atrophy, but myositis-induced muscle atrophy still exists, and exercise must be continued in order to maintain or enhance the function that has been obtained. (8) Explanation to patients: The purpose and method of exercise should be explained to patients and their families before exercise, and they should work together with the effort to exercise. Often the patient is made aware of the results of the exercise to increase his or her confidence in recovery. (9) Exercise of related joint functions; the knee is only one of the weight-bearing walking joints, and exercise of other joints and muscle groups is also very important. Especially hip ROM and muscle strength exercises. (10) Protection of the wound during postoperative exercise: in the process of postoperative exercise, if the wound has not healed exactly, special attention must be paid to avoid contaminating the wound, and once the wound is exposed, it should be disinfected and the dressing changed immediately. 2. ROM exercise Postoperatively, through ROM exercise, the contracted soft tissues are pulled to avoid adhesions, so that the surrounding tissues can maintain appropriate stress stimulation, avoid degeneration, promote blood circulation in the lower limbs, and prevent deep vein thrombosis and embolism. formation and embolism. Preoperative ROM exercises for artificial knee arthroplasty are also very beneficial, and ROM exercises are particularly important in the 2 weeks after surgery. According to Kettelkamp, the range of knee flexion and extension required for daily activities is approximately 67 degrees for walking, 83 degrees for stepping up, 90 degrees for stepping down, and 93 degrees for standing up from a chair. The range of knee flexion required when walking up and down steps is also related to height and step height. (1) Methods 1) Continuous passive motion (CPM): CPM is generally used after 2-3 days of knee extension after artificial knee replacement. 2-3 days of immobilization allows the soft tissues that were loosened during surgery to be stretched, which is especially important for those with severe preoperative flexion contractures. In addition 2 to 3 days of braking reduces postoperative bleeding. Postoperative use of CPM allows for easier joint movement, prevents fibrous contracture and avoids adhesions, shortens recovery time, and increases confidence in recovery. However, CPM may cause a lack of knee extension and limitation of flexion, which can be avoided by adjusting the length of the patient’s thigh and calf to each arm of the CPM and securing it firmly. In addition, at 6-12 months postoperatively, satisfactory ROM can be obtained through active activities even without CPM. 2) Active knee flexion and extension activities: Used when the quadriceps and over-N cord muscles have recovered to some extent and postoperative pain is mild, and performed at the same time as CPM exercises. Patients should be asked to exercise ROM and muscle strength simultaneously to the extent that CPM activities allow as much as possible. Specific methods include assisted active knee flexion and extension activities, random active knee flexion and extension activities, and resistance active knee flexion and extension activities. Assisted active knee extension exercises quadriceps muscle strength, assisted active knee flexion and extension exercises rouge muscle strength, resistance active knee flexion requires rouge muscle contraction and resistance active knee extension requires quadriceps muscle contraction. (3) ROM exercises for extension lag and flexion limitation: for 2 weeks after surgery when the knee cannot be fully straightened or flexed up to 90. the purpose is to peel off newer adhesions, elongate contracted soft tissues, and increase ROM. for better results, the knee extension lag is generally more than 5°~10° and flexion is less than 75°~90° at 9~10 days after surgery, that is, when the correction is started by manipulation, otherwise the longer it takes, the worse the results. The longer the time, the worse the result. Under anesthesia and supervision in the ward, the knee is passively straightened and flexed to 90° or more. After the anesthesia wears off, oral NSAIDs are administered and the original exercise is continued. (2) Notes on ROM exercise: 1) Adopt a relaxed position that is comfortable for the patient according to different situations and eliminate the patient’s mental tension. (2) Consider carefully the fixed support points and force points during the manual correction to prevent injury. 3) Do not rush and use violence, but proceed slowly, evenly and in stages. 4) It is best to maintain a fixed device for a period of time after exercise to maintain the therapeutic effect. Generally, mild knee flexion deformity occurs in knees with long-term flexion contracture even after artificial knee replacement due to contracture of the N cord muscle, and normal people also tend to have mild knee flexion in the resting position, so fixation in the extended knee position helps to maintain ROM during sleep, which generally must be continued for 6-8 weeks after surgery to prevent (5) ROM exercise is related to the prosthesis, as there are many artificial knee prostheses, each of which has its own flexion limit, which is determined at the time of prosthesis design, such as 100° to 120° for the full condylar prosthesis, 105° for the PCA type, and 140° for the YS type prosthesis, so the postoperative ROM exercise should not exceed this limit, otherwise it will change the biomechanics of the prosthetic knee joint or cause tissue damage. In addition, the tibial plateau should be tilted back 3° to 7°, if it is horizontal or tilted forward, it will inevitably affect the knee flexion, so the tilt of the tibial plane prosthesis must be understood by X-ray before ROM exercise. 6) Related joint functions also affect the knee ROM exercise, especially the ipsilateral hip function. Since the rectus femoris and suture muscles start at the anterior inferior iliac spine and the anterior superior iliac spine, respectively, and end at the tibial tuberosity and the upper tibia, they span the hip and knee joints, and can both flex the hip and extend the knee when contracted, so it is easier to flex the knee in the hip flexion position and extend the knee in the hip extension position. Therefore, when exercising the knee ROM, the hip joint should be placed in the appropriate position. In addition, since the hip and knee are both weight-bearing joints, the failure of one will inevitably affect the function of the other, so while exercising the knee ROM, the hip ROM and muscle strength should be exercised at the same time. For patients with indications for joint replacement of both hip and knee, in order to facilitate the post-operative exercise of artificial knee replacement, it is currently advocated that artificial hip replacement should be performed first. 7) Knee ROM exercise should take into account the surgical situation and complications. If an inverted U-shaped approach is used, care must be taken to avoid excessive stretching of the quadriceps muscle during postoperative ROM exercises to prevent the patellar tendon from tearing off at its stop. If severe osteoporosis is confirmed preoperatively or intraoperatively, care should be taken during exercise to avoid fractures, especially when manipulating to correct extension lag and flexion limitation. In severe flexion deformity, tibial rotation is relatively large, making it difficult to accurately place the prosthesis during surgery. Postoperative exercises should be performed with care to maintain good joint alignment throughout the knee ROM. The intraoperative ROM of artificial knee arthroplasty is the ROM when the soft tissue is relaxed under anesthesia. If postoperative strain on the common peroneal nerve is found, care should be taken to avoid further strain on the common peroneal nerve as much as possible during postoperative exercise to extend the knee so as not to affect future rehabilitation. If postoperative infection occurs, regardless of whether there is a second surgery, the knee should be temporarily braked and ROM exercises should be stopped until the infection is controlled. 3. Muscle strengthening training Patients with prolonged knee disuse and reduced activity have decreased quadriceps and carpus muscle strength to varying degrees. Generally, different training methods are used for O to 5 levels of muscle strength. (1) Muscle function retraining: It is used for muscle strength enhancement training of the anterior tibial muscle group in artificial knee replacement combined with common peroneal nerve palsy, when the anterior tibial muscle group cannot contract at all (O level) or has muscle contraction but cannot make the ankle joint dorsiflexion. This method is similar to passive ROM exercises, but emphasizes the sensation of muscle movement transmitted subconsciously into the center. The method is as follows: The physician touches the lateral anterior tibial muscle group with his finger and says to the patient: From now on exercise the anterior tibial muscle group, which serves to bring the foot up. This will focus the patient’s attention on the anterior tibial muscle group, then passively make the ankle dorsiflexion, let the patient experience the feeling of muscle movement, you can let the patient do ankle dorsiflexion on the healthy side, let the patient experience the feeling of muscle contraction and ankle dorsiflexion, ask the patient to concentrate on the anterior tibial muscle group, regardless of the muscle contraction ability to try hard, the doctor through words to encourage “lift up The physician encourages the patient to “lift the top of the foot, lift it again”, while dorsiflexing the ankle for the patient with his hand, so that the patient can make efforts to achieve this movement. The doctor fixes the ankle joint with his hand and does 1~2 sets of several sessions each time, with 1-2 minutes rest between each session. When muscle contraction starts to occur, i.e. when muscle strength reaches level 1, as many passive ankle dorsiflexion exercises as possible should be performed to maintain motor memory. (2) Auxiliary active exercise: when the muscle strength of quadriceps and carpus reaches grade II, that is, you should try to reduce the resistance caused by the limb’s own weight and perform auxiliary exercises. From low muscle strength, always need auxiliary movement, until you can overcome slight resistance to full joint flexion and extension activities, this recovery process should be with the degree of muscle strength recovery constantly change auxiliary methods. The lateral recumbent position actively flexes and extends the knee joint on the slippery surface, and the part that cannot be reached is assisted by hand force, and the inclination of the movement surface is gradually increased as muscle strength increases. The side lying position in the bath uses buoyancy to assist active knee flexion and extension, because the bath can also be used for warm therapy, so it is especially suitable for patients with pain, and the buoyancy of the water can be used as both resistance and assistance, if used with the water sports resistance plate, it can be suitable for patients with various muscle strength levels for muscle strength enhancement training. When the muscle strength is weak in the horizontal plane movement. Muscle strength can slightly overcome resistance after the hook will be moved back, so that the movement surface tilt, movement on the inclined plane, or hand resistance. The quadriceps muscle is slightly stronger to move on the vertical plane, and the part that cannot be reached is assisted by the hand; the supine position mainly exercises the rectus femoris, and the sitting position mainly trains the middle femoral muscle and the medial and lateral muscles. (3) Active exercise: muscle strength recovery to level III can overcome their own gravity that should start active exercise, including straight leg raising exercises, sit-up exercises, etc.. When muscle strength level III (mainly quadriceps), getting down to the ground to bear weight and walking can help improve quadriceps and N cord muscle strength, improve muscle coordination, improve physical condition, avoid complications caused by bed rest, and enhance rehabilitation confidence, but accidents such as falls and shear movements must be avoided. If the knee joint is unstable, a knee brace can be brought. With the affected limb standing upright alone and bearing the full weight, the quadriceps and N cord muscles are both contracted isometrically through the longitudinal pressure of the weight, thereby improving muscle strength. Patients with bone cement can go down early after surgery, while patients without bone cement should delay for 5-6 weeks to avoid affecting the growth of bone tissue and failing to achieve the purpose of biological fixation of the prosthesis. Due to the lack of quadriceps muscle strength, the patient’s walking posture may be characterized by swinging the pelvis after flexing the hip, making the hip externally rotated and swinging the lower limb to the front in the flexed knee position, while bending forward and exploring the body with the arm back. Such a posture does not play the effect of muscle strength enhancement, is a kind of false compensatory exercise. The correct posture is head up, chest up, abdomen, standing position knee flexion hip, through the first step, after standing stable body slightly forward, and then take the other leg. (4) Resistance active exercise: This muscle strength strengthening training is suitable for patients whose muscle strength has reached grade IV to V and can overcome the applied resistance. The specific practice is similar to the auxiliary active exercise and active exercise. Exercise using freehand, skids and weights, friction, buoyancy fluid resistance, etc. For example, after bending the knee 90° sitting position to lift the straight leg exercise, after being able to lift 50 times, you can add weight to the ankle, starting from 1kg, increasing lkg each time until 4.5kg; after bending the knee 50 times in a standing position with the hip extended, you can add weight to the ankle, starting from o.5kg until 2.25kg; in addition, there are bending the knee to sit up, squatting position, up and down stairs, static bicycle and other exercise The isometric exercise is suitable for muscle strength II. Isometric exercise is suitable for muscle strength II to V. The quadriceps isometric exercise method is to try to dorsiflex the ankle joint, try to extend the knee, quadriceps contraction, so that the kneecap to the proximal pull, and then count 5, relax, that is, once. You can do this 50 times per hour, or you can add resistance to prevent active knee flexion and extension without joint activity, so as to make the quadriceps or carpus muscle isometric contraction. In addition, standing on one leg with the knee extended is also an isometric exercise, which can make the quadriceps and rouge muscles contract in equal length at the same time. Isokinetic exercise is used for those with muscle strength of grade III to V. On the isokinetic device, the patient does work at a selected speed, and the isokinetic converts any movement force above this speed into a resistance against the movement, i.e. the greater the overspeed, the greater the resistance generated. This resistance is called adaptive resistance, which is automatically adjusted at any point in the entire range of motion with the amount of force the patient exerts, and this exercise requires the patient to do his best. (5) Considerations for muscle strengthening exercise: including the following. (1) Method selection: In order to select the most appropriate training method for the patient, a variety of factors should be considered. For example, the purpose of training (whether to maintain or improve muscle strength, instantaneous explosive force or muscle endurance), posture and position, general status, physical strength, location, existing muscle strength, rehabilitation period (preoperative, early postoperative, mid-term, late postoperative), etc. The main function of the lower limb and trunk muscles is to maintain muscle tension for a long period of time, so isometric exercise can exercise ROM while exercising muscle strength. Therefore, the selection of exercise methods should be applied in a comprehensive manner. In addition, because there are many exercise methods, they should be selected or modified according to the existing conditions. 2) Resistance adjustment: According to the existing muscle strength and ROM of the patient, the resistance must be increased or decreased appropriately, and the posture and position should be adjusted appropriately. 3) Fixation: When exercising the quadriceps and N cord muscles, the thighs should be fixed; if the fixation is not stable, it is difficult to use the muscle strength. 4) exercise posture and position; posture position to facilitate exercise, but also to prevent pseudo-compensatory exercise, so as not to overwork or fail to achieve the purpose of exercise. The compensatory muscles of quadriceps include internal and external rotators (compensatory movement is to extend the knee while rotating the hip internally and externally), gluteus maximus and gastrocnemius (compensatory movement is to extend the knee in the sagittal plane in the standing position). Therefore, the correct exercise to enhance the strength of the N rope muscles should be “sagittal knee flexion”. 4.Strength recovery training In order to cooperate with the knee function exercise, so that the patient’s walking weight-bearing function can be improved, must carry on the strength recovery training, especially the long-term bedridden, have the history of hormone use, combined with other systemic complications. These patients are physically weak and have poor muscle strength. This training is not aimed at damage such as low muscle strength or limited joint mobility, but rather to train all muscles, joints, heart and lung functions, etc. It is a training to improve the whole body strength. In addition, in order to adapt to the use of walking frames and crutches after artificial knee replacement, it is necessary to exercise the muscles of the upper limbs, back and abdomen. There are a series of exercises for physical recovery, which can be found in other rehabilitation books. For artificial knee replacement, the exercises are simplified to “biceps, triceps, quadriceps, back, and abdominal”. Simple methods are pull-ups, sit-ups, swallow dots, five-point supports, sit-ups, etc. You can also choose the appropriate method according to the principle of muscle strengthening training. In addition to the above, postoperative rehabilitation also includes occupational therapy, ADL training, comprehensive basic movement training, physical therapy, etc. Since these methods are not the main focus of artificial knee arthroplasty, they are not described in detail, so please refer to the relevant books. The general rehabilitation steps of artificial knee arthroplasty 1, preoperative period The purpose of this exercise period is to let the patient understand the general procedures of postoperative rehabilitation, to restore physical strength, to strengthen the quadriceps and rouge muscles as much as possible, and to increase ROM. Therefore, it is not necessary to ask for too much, so as not to affect the confidence of postoperative rehabilitation. The methods are active knee flexion and extension (resistance or non-resistance), mild muscle electrical stimulation, etc. 2.Early postoperative period That is, from the day of surgery to the 3rd postoperative day. The pain is heavier during this period and the knee is fixed in extension. Patients must be closely observed after knee replacement, especially if they have abnormal cardiopulmonary function, shock, excessive bleeding, etc. In elderly patients with severe comorbidities, the patient can be observed in the intensive care unit for several hours after surgery and returned to the ward after stabilization Elevate the affected limb, active or passive ankle joint movement (10 times per hour in flexion and extension), and use an intravenous pump to promote blood circulation in the lower limb. If common peroneal nerve paralysis is found, the cause should be clarified. If the paralysis is due to compression by dressing, the dressing should be loosened, if the paralysis is due to pulling during correction of deformity, nerve nourishing drugs should be given. Such as vitamin B1, vitamin B12, etc. The joint is fixed in neutral position or passive ankle movement to prevent foot drop On the 3rd postoperative day, the drainage tube is removed, the top of the drainage tube and its intra-tubular clot for bacterial culture and sensitive drug test, and the front and lateral knee and 45° flexed knee patella axial radiographs are taken 3. Middle postoperative period From the 3rd postoperative day to the 2nd postoperative week, the primary purpose of exercise in this period is ROM, at least 90°~0°, followed by muscle strength recovery training. Knee function is mainly reflected in joint mobility and quadriceps and N cord muscles, so the main content of postoperative rehabilitation after total knee replacement is joint mobility exercise and quadriceps and N cord muscle strength enhancement exercise. CPM is the main means of early knee function exercise, in addition to restoring knee function, pulling contracted tissues, avoiding adhesions, promoting blood circulation in the lower extremities, and preventing deep vein thrombosis and embolism. CPM is generally considered to be started immediately after surgery, but for those with severe preoperative flexion contracture, the authors advocate that the knee be fixed in the straight position with a cast for 2 to 3 days after surgery to reduce flexion contracture and postoperative bleeding, and that CPM be started on the third postoperative day with an initial range of motion of 0° to 45°, followed by 2 h of continuous activity per day, and an increase in the range of motion of 10° per day to at least 90° before discharge. CPM makes it easier to move the joint, prevents postoperative adhesions, shortens postoperative recovery time, and increases the patient’s confidence in recovery. By 6 to 12 months postoperatively, the same knee mobility can still be achieved through active knee flexion and extension, even without CPM. For those with bone cement fixation, walking on the ground can usually be practiced on the fourth postoperative day with the help of medical staff or family members, and if the joint is unstable, a knee brace can be brought. For patients with more severe preoperative flexion deformity, the knee should still be fixed in the extended knee position with a plaster brace at night during this period, which should generally last for 4-6 weeks. 4. Late postoperative period That is, from 14 days to within 6 weeks after surgery, the purpose of this period is to strengthen the muscle strength and maintain the ROM that has been obtained. If the ROM fails to achieve more than 90°~0° of flexion and extension in the middle postoperative period, it should be corrected by manipulation in this period. In addition, there are other rehabilitation exercises, such as ADL training, occupational therapy, and physical therapy.