I. What is osteoarthritis? To understand what osteoarthritis is, we must first talk about the basic structure of joints. Take the knee joint as an example, the femur, tibia and patella constitute the bony structure of the knee joint, and within the joint, the surfaces of the femur, tibia and patella are covered with a layer of smooth articular cartilage, and there is a meniscus between the femur and tibia, and there is joint fluid similar to lubricant in the joint cavity. The articular cartilage, meniscus and joint fluid all play a role in cushioning and lubricating the joints during movement and activity, thus protecting the joints. As we age, or due to trauma and other factors, primary or secondary degeneration and structural disorders occur in the articular cartilage, followed by cartilage damage and exfoliation, and because there are fewer nutrient vessels in the articular cartilage and meniscus, it is extremely difficult to repair them on their own. When the articular cartilage is severely worn, the joint loses its proper cushion protection, the bone under the cartilage will be worn and destroyed, and the repair process of the subchondral bone and cartilage will lead to the hardening of the subchondral bone and osteophytes, thus gradually destroying and deforming the joint, resulting in joint enlargement, inversion deformity, inability to flex, squat, and even inability to walk and other joint dysfunction. It is a common, frequent and difficult to treat osteoarthrosis in the elderly. As our population gradually enters the ageing era, the incidence of osteoarthritis is expected to increase. The pain and disability caused by osteoarthritis severely reduces the quality of life of patients and has become one of the serious socioeconomic burdens of current society. The cause of osteoarthritis is still not completely clear. The team of osteoarthritis surgery in the First Hospital of Jinan University, led by Professor Zengang Cha, has conducted an in-depth investigation into the causes and mechanisms of osteoarthritis. Autoimmunity also plays an important role in the pathogenesis of osteoarthritis. It was shown that osteoarthritis is a pathological change caused by the interaction of multibiological factors and mechanical injury. In addition, our study also shows that osteoarthritis is closely related to common diseases such as diabetes and osteoporosis. Third, who are vulnerable to osteoarthritis 1, age: In general, people over 50 years old, especially women, that need to be alert to osteoarthritis, some studies have shown that the incidence of osteoarthritis in people over 60 years old has been as high as 80%. 2. History of joint trauma: A history of localized trauma to the knee has been proven in many studies to be a high risk factor for osteoarthritis of the knee. A history of knee trauma can lead to a younger age of onset of osteoarthritis, especially in patients who have had a combination of meniscal injury or meniscectomy at the time of trauma, who are at significantly increased risk of knee osteoarthritis. In addition, patients with previous intra-articular fractures or peri-articular fractures, such as tibial plateau fractures, intercondylar fractures of the femur, elbow fractures, etc., have a significantly increased risk of developing secondary traumatic arthritis. 3, obesity: in many studies have found that obesity can lead to increased risk of osteoarthritis of the knee. A survey conducted in Finland, for 823 cases of non-osteoarthritic subjects, after excluding age, gender and other factors, body mass index and osteoarthritis of the knee strong correlation. This may be interpreted as an increase in weight, which increases the burden on the joints, thus causing premature wear and tear of the joint surfaces, and also suggests that weight loss will help prevent and slow down the process of osteoarthritis of the knee. 4. Exercise habits: Various studies on the correlation between exercise habits and hip or knee osteoarthritis are conflicting. In general, long-term strenuous, weight-bearing exercise, such as long-distance running athletes, is associated with a significantly increased risk of osteoarthritis compared to the general population in the same age group, while non-weight-bearing exercise, such as swimming, instead reduces this risk. While general sports, such as recreational running, jogging, walking and other activities, this effect has not been found. Also, activities such as prolonged squatting and half-squatting (tai chi) have been found to increase the risk of developing osteoarthritis. 5. Presence of joint deformities: If there are congenital or acquired joint deformities, such as O-leg or X-leg, joint retroflexion, lameness, joint laxity, etc., they should be treated as early as possible, otherwise they are highly susceptible to osteoarthritis.