Osteoarthritis of the knee, also known as age-related arthritis and degenerative arthritis, occurs after middle age and is more common in women than men. The pathology is based on progressive degeneration, destruction and loss of articular cartilage caused by various pathogenic factors, and the formation of bone redundancy at the edges of the articular cartilage and subchondral bone, resulting in a series of joint symptoms and signs. up to 70.4% of patients over 50 years of age. The causes are age, injury and overuse, obesity, genetics, estrogen, etc. Pain: The most common symptom is pain, swelling and discomfort after early joint activity, which can be reduced or disappeared after rest. Restriction of movement: In the early stage, it is mild and only feels inflexible in the morning or after sitting for a long time, and can recover after activity. As the disease progresses, the range of motion of the affected joint decreases, resulting in fixation in a certain position. Signs: joint pain, joint swelling, joint stiffness, deformity, and friction sensation or friction sounds when moving. Bony enlargement is common and may cause tenderness in the joint space, at the attachment of the joint capsule and at the pars interarticularis tendons. Radiographs: 1) asymmetrical narrowing of the joint space; 2) osteosclerosis and deformation of the subchondral bone; 3) bony bulge at the joint edges; 4) joint rats; 5) subarticular cystic changes with well-defined sclerotic walls at the edges; 6) bone deformation or joint subluxation. radiographic grading: grade 0, no changes; grade 1, slight bony bulge; grade 2, significant bony bulge but no involvement of the joint space; grade 3, moderate narrowing of the joint Grade 3, moderate narrowing of the joint space; Grade 4, significant narrowing of the joint space with subchondral bone sclerosis. Treatment: The goals of knee osteoarthritis treatment are: to control pain, to stop and delay the progression of the disease, and to improve joint function and quality of life. 1. Health education: Maintain an optimistic and positive mood and avoid falling into depression. Patients should establish a reasonable lifestyle, adjust labor intensity, reduce climbing, keep warm, and protect the affected joints. Obese people should reduce weight and avoid wearing high heels. Appropriate exercises and muscle exercises can be performed to increase the stability of joints, and the increase of muscle strength can buffer the external impulse and reduce the possible damage. 2.Physical therapy: physiotherapy in the acute stage to relieve pain, reduce swelling and improve function; in the chronic stage to enhance local blood circulation and improve joint function. 3.Medication: Non-steroidal anti-inflammatory and analgesic drugs: such as loxoprofen sodium, fotarine, fenbid, meloxicam, etc.; chondroprotective agents: glucosamine hydrochloride (sulfate) capsule, 500mg, 3 times daily; topical drugs: ointment, fotarine emulsion and Yunnan Baiyao aerosol, etc. 4. Intra-articular injection: medical glucose 2ml, intra-articular injection, once every 2 weeks, 3 times; the advantages are: avoiding the adverse reactions of oral drugs, the drug acts directly on the lesion site, and the effect is fast. Chitosan is a natural polymer compound that can participate in the metabolism of cartilage, and can form a viscoelastic protective film on the surface of articular cartilage and gradually restore the damaged cartilage under the film. Joint injection can not only provide exogenous aminosaccharide and play its role in cartilage metabolism, but also its viscosity is similar to synovial fluid, which has good biocompatibility and slows down the process of cartilage degeneration. It is currently applied in many large hospitals in China with good results. Our hospital is also taking this method, the total efficiency is more than 90%. 5, knee replacement: persistent pain with obvious joint destruction, significant joint space narrowing and severe functional limitations can be considered.