The knee joint is an important joint that has various functions such as walking, running, jumping, squatting, etc. It also carries the weight of your body. Once the knee joint is diseased, the cartilage of the joint is destroyed and the surface turns from a smooth mirror-like surface to a rough or even defective surface, which further deforms the femoral condyles. This results in pain, difficulty walking, limited mobility, limping, and sometimes difficulty performing even easy movements. When the above disease has progressed to a certain point and the joint has been destroyed, surgery is required. An artificial knee joint is used to replace the original damaged joint to restore functions such as walking. The greatest benefit of artificial joint surgery is that it can eliminate joint pain after surgery, greatly improve the function of the joint, and improve the patient’s quality of life so that he or she can work and live well during their lifetime. I. What conditions are suitable for knee replacement surgery? 1, various inflammatory arthritis of the knee joint, including rheumatoid arthritis, osteoarthritis, hemophilic arthritis, Charcot arthritis, etc.; 2, a few traumatic arthritis; 3, osteoarthritis after failed high tibial osteotomy; 4, patellofemoral arthritis in a few elderly people; 5, resting infectious arthritis (including tuberculosis); 6, a few primary or secondary osteochondral necrosis disease. After artificial knee replacement, you need to develop good habits of life and activities to maintain the stability of the joint, and learn some simple rehabilitation knowledge to carry out joint rehabilitation exercises. It is important to pay attention to the prevention and treatment of infections, such as tonsillitis, skin infections, ringworm, etc. After surgery, you can do cycling, walking, dancing, swimming and other sports, but do not encourage strenuous sports such as running, jumping, long-distance walking, climbing, etc. Third, the rehabilitation of knee arthroplasty Rehabilitation exercises are essential for the success of total knee replacement surgery. 1. Pre-operative instruction First of all, the static contraction exercises of the quadriceps muscle of the affected limb and the active movement of the ankle joint should be strengthened, requiring the quadriceps muscle to remain contracted for 10 seconds each time, and every 10 times for one group, completing 5 to 10 groups per day. The patient sits on the bed and performs straight leg raising exercises and ankle joint resistance flexion and extension exercises, the number of times can be determined according to the patient’s condition and repeated 2 to 3 times a day. In addition, patients should learn how to use crutches to prepare for walking with a cane after surgery. 2. Postoperative rehabilitation training (1) On the first day after surgery, apply ice continuously and perform static contraction of the quadriceps (contract for 2-3 seconds each time, relax for 3-5 seconds, 10 times/group, 3 groups/day) and active movement of the ankle joint. Pay attention to practicing passive knee extension by: elevating the ankle to suspend the knee in the air using your own limb weight and ice bag to straighten the leg (gentle manipulation if necessary). (2) Active and passive knee flexion with assistance (range of motion to the extent that the patient can follow the pain, 2 times/group, 3-4 groups/day) was started on the 2nd-3rd postoperative day. Muscle strength exercises were performed for straight leg raises and continued ice application.