The knee joint is the most complex and weight-bearing joint in the human body, just like the most wearable spindle in a car. Therefore, of all the joints in the human body, the knee joint is the most prone to degeneration, and the medical term for the disease that develops when the knee joint degenerates is osteoarthritis of the knee joint. According to statistics, 60% of people over the age of 50 suffer from osteoarthritis, and 90% of women and 80% of men over the age of 65 suffer from this disease. These diseases seriously affect the quality of life of the elderly, and elderly patients not only suffer from the pain of the disease, but also bring many burdens to the family and society. There will be 300,000 to 500,000 artificial joint replacements in the United States each year, and if we project the proportion of the population, there will be about 1 million to 1.5 million bone and joint patients in China who need artificial joint replacement surgery. Thirty years of experience in China has proven that artificial joint replacement is the most reliable and effective method for severely diseased joints. Etiology: ① Trauma to the knee joint. ②Ageing. ③Endocrine disorders. ④Neurotrophic disorders. (5) Local wear and tear of the joint. (6) Congenital or developmental osteoarthritic disorders, etc. Clinical manifestations: 1. Joint pain is the most common symptom of the disease, early pain is mild, mostly occurs during activity, relieved after rest, later it is also painful at rest, and often occurs at night. Overexertion can make the pain suddenly aggravated. 2. Morning stiffness is limited and relieved after activity. The duration will not exceed 30 minutes. 3. Difficulty in movement It is slowly progressive. In the early stage, it is mild, only in the morning or after sitting for a long time, and can recover after activity. As the disease progresses, the symptoms gradually worsen to the extent that the range of motion of the joint is significantly reduced. Treatment: 1.Conservative treatment: including medication, intra-articular injection, functional exercise, physical therapy, etc. Surgery: (1) Arthroscopic surgery Arthroscopic surgery is suitable for osteoarthritis with obvious meniscus damage, free body and other diseases. For this kind of disease, the arthroscopic knee joint clean-up operation carried out by the Department of Orthopedics and Joint Surgery of Oriental Hospital can effectively relieve the symptoms. (2) Osteotomy Osteotomy is suitable for joint weight-bearing line misalignment, uneven load distribution, overload on one side while the other side is intact, or knee inversion or knee valgus deformity. (3) Joint fusion This procedure is performed by removing the joint surface and fusing the bone with the bone, which can relieve pain and restore stable weight-bearing capacity, but at the expense of joint movement. Therefore, it is generally not recommended. (4) Artificial joint replacement The ultimate solution for osteoarthritis of the knee is to replace the joint surface with an artificial knee joint. In severely degenerated knees, artificial joint replacement has the combined advantages of relieving joint pain, maintaining joint mobility, maintaining joint stability and not affecting limb length.