Osteoarthritis is a chronic joint disease in which the main changes are degeneration of the cartilage surfaces of the joints and secondary osteophytes. The main manifestations are joint pain and inflexibility. X-rays show narrowing of the joint space, dense subchondral bone, broken trabeculae, sclerosis and cystic changes. There is lip-like hyperplasia at the edge of the joint. In the later stage, the bone ends are deformed and the joint surface is uneven. The cartilage in the joint peels off and the bone fragments into the joint, forming an intra-articular free body. Osteoarthritis, also known as degenerative arthritis, is not actually an inflammatory condition, but is primarily a degenerative condition that involves premature aging of the joints, particularly the articular cartilage. Osteoarthritis represents the aging of the joints, so it is called age-related arthritis. [Differential diagnosis] 1, rheumatoid arthritis Age of onset is mostly 30 to 50 years old, with multiple symmetrical involvement of large and small joints of the extremities, while osteoarthritis is more common in the distal interphalangeal joints. Rheumatoid arthritis is often accompanied by systemic symptoms, while RF tests are often positive, one of the most important points of differentiation from osteoarthritis. 2, ankylosing spondylitis Ankylosing spondylitis is prevalent in men, and mainly in young people, with lower back pain as the main symptom in the early stages, and in the X-ray lesions are mainly sacral arthritis, and in the late stages can appear “bamboo joint” spine, 90% of patients are HLA-B27 positive, can be distinguished from osteoarthritis. 3, other types of arthritis can be distinguished from other types of osteoarthritis, such as psoriatic arthritis, can also be accompanied by distal interphalangeal joint damage, but with the original skin damage, can be distinguished. Hemophilic arthritis, mostly with recurrent bleeding tendency and family history, can be differentiated from osteoarthritis.