1, age With increasing age, articular cartilage will also gradually degenerate, chondrocyte function decreases, the cartilage repair compensatory capacity decreases. 2, chronic strain Long-term poor posture, weight-bearing force, excessive weight, resulting in soft tissue damage to the knee joint. 3, obesity The increase in weight and the onset of knee osteoarthritis is directly proportional. Obesity is also a factor that aggravates the disease. Obese people’s weight loss can reduce the onset of osteoarthritis of the knee. 4, bone density When the subchondral bone trabeculae become thin and stiff, their tolerance to pressure is reduced, so the chances of osteoarthritis in osteoporotic patients will increase. 5, trauma and force bearing Frequent knee injuries, such as fractures, cartilage, ligament damage. Abnormal state of the joint, such as in the post-patellar resection link in an unstable state, when the joint withstand muscle force imbalance and coupled with local pressure, degenerative changes in cartilage will occur. Normal joints and activities or even after strenuous exercise is not osteoarthritis. 6, genetic factors The involvement of joints varies from race to race, such as hip, carpometacarpal joint osteoarthritis in Caucasians, but people of color and the country is rare, gender also has an impact, the disease is more common in women. Data show that the incidence of osteoarthritis in women with Heberden’s nodes is two to three times higher in their mothers and sisters than in their families without the disease.