We sit, stand and walk all depend on the flexion and extension of the knee joint. This hinged movement of the knee depends on the smooth cartilage on the surface of the joint bones and the surrounding well-developed muscles. In age-related arthritis, this cartilage is broken down, making movement difficult and painful, and giving rise to inversion or valgus deformities of the knee, which appear on X-rays as joint space narrowing, marked osteophytes, and altered force lines in the lower extremities. The incidence of age-related knee osteoarthritis is high in people over 50. In China, the elderly population is about 100 million or more, and about 80 million people will have X-ray manifestations of osteoarthritis, and about 40 million people will have symptoms. Countermeasures] For senile osteoarthritis, if the knee pain significantly affects the patient’s life, there is an indication for surgery as long as the physical condition allows. The surgery is to remove the bone that has become diseased and add a cap on the surface of each thigh bone and calf bone to form an artificial joint, which is called artificial knee replacement surgery. This is a very mature surgery in orthopedics and the results are very precise. 【Tips】 Life is movement, movement reflects life. For elderly patients in good health, it is not worthwhile to suffer from pain and quality of life for nothing just because of age-related knee osteoarthritis. Artificial joint replacement surgery should be actively performed so that the elderly can enjoy their old age in peace.