Osteoarthritis refers to a joint disease caused by a variety of factors that lead to fibrosis, cracking, ulceration, and loss of joint cartilage. Its occurrence is related to age, obesity, inflammation, trauma, and genetic factors. Its pathology is characterized by degenerative destruction of articular cartilage, subchondral bone sclerosis or cystic changes, osteophytes at the joint edges, synovial hyperplasia, joint capsule contracture, ligament relaxation or contracture, and muscle atrophy and weakness. Symptoms and signs: 1. Joint pain and pressure pain: Initially, mild or moderate intermittent occult pain, which improves at rest and worsens after activity, and the pain is often related to weather changes. In the late stage, there may be persistent pain or nocturnal pain. There is localized pressure pain in the joints, which is especially obvious when accompanied by joint swelling. 2. Joint stiffness: stiffness and tightness of the joints when waking up in the morning, also known as morning stiffness, can be relieved after activity. Joint stiffness is aggravated when air pressure decreases or air humidity increases, and the duration is usually short, often a few minutes to ten minutes, rarely more than 30 minutes. 3.Joint enlargement: hand joint enlargement and deformation is obvious, and some knee joints may also cause joint enlargement due to the formation of bone redundancy or joint effusion. 4. Bone rubbing sound/sensation: due to destruction of articular cartilage, uneven joint surface and out of joint movement, mostly seen in the knee joint. X-ray: asymmetric joint space narrowing, subchondral bone sclerosis and/or cystic changes, joint edge hyperplasia and bone redundancy formation or with varying degrees of joint effusion, free bodies visible in some joints or joint deformation. MRI: articular cartilage thinning, defect and meniscal degeneration, which can directly show the injury; MRI can show the long-term evolution process, secondary to mucous-like changes and tumor-like changes; in addition, the recurrence of intra-articular bleeding caused by proliferating synovium and bone marrow exposure leading to easy bleeding, and its attention to the differentiation of synovial diseases such as pigmented villous nodular synovitis and arthritis.