1, is the high incidence of the elderly: the incidence of the disease is closely related to age. 2, is more female patients: especially after menopause; in the 45 to 55 years of age, the frequency of men and women is equal, and after 55 years of age, there is a clear predominance of female patients, on the whole, women are twice as likely to suffer from osteoarthritis as men. 3, is obese people prone to osteoarthritis: epidemiological studies have found that obesity has a certain impact on the occurrence of osteoarthritis of the knee. In addition to the mechanical factors caused by obesity, but also with the obese systemic metabolic factors. The stress and direction of the knee joint depends on the force line of the limb, body shape, muscle strength and their interactions. The incidence of knee osteoarthritis in obese women is four times higher than that in normal weight women. In addition, obesity when the distribution of fat and the occurrence of osteoarthritis correlation, that is, waist fat patients are prone to hip and knee osteoarthritis, while the hip, thigh fat but rarely cause osteoarthritis. 4, is a number of special occupational personnel susceptible to osteoarthritis: such as miners, cotton pickers, heavy laborers, teachers, salespeople, professional athletes or dancers, etc., mainly due to long-term wear and tear of joint cartilage by high-intensity stress or injury caused. 5, is that patients who have had joint injuries that were not treated in a timely manner are also an important factor in causing osteoarthritis: such as ligament damage around the joint causing joint instability, meniscal injury or intra-articular fracture. 6, is artificially changing the biomechanical environment of the joint can cause osteoarthritis: such as wearing high-heeled shoes, walking increases the stress normally experienced by the knee joint, and changes the stress point of the knee joint, also easy to cause osteoarthritis.