Osteoarthritis (OA) refers to a joint disease caused by a variety of factors that lead to fibrosis, cracking, ulceration, and loss of articular cartilage. The etiology is unclear, and its occurrence is related to age, obesity, inflammation, trauma, and genetic factors. The pathology is characterized by degeneration and destruction of articular cartilage, subchondral bone sclerosis or cystic changes, osteophytes at the joint edges, synovial hyperplasia, contracture of the joint capsule, ligament relaxation or contracture, muscle atrophy and weakness, etc. OA is more common in middle-aged and elderly patients, more women than men, with a prevalence of up to 50% in people over 60 years of age, and up to 80% in people aged 75 years. The disability rate of the disease can be as high as 53%. OA is more likely to occur in joints with high load, more activities, such as the knee, spine (cervical and lumbar spine), hip, ankle, hand and other joints. Classification OA can be divided into two categories: primary and secondary. Primary OA occurs mostly in the middle-aged and elderly, no clear systemic or local causes, and genetic and physical factors have a certain relationship. Secondary OA can occur in young adults and can be secondary to trauma, inflammation, joint instability, chronic and repeated cumulative strain or congenital diseases. Clinical manifestations Symptoms and signs 1, joint pain and pressure pain at the beginning for mild or moderate intermittent hidden pain, better at rest, increased after activity, 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 is a stiffness and tightness in the morning when waking up, also known as morning stiffness, which 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. Enlarged joints The joints of the hands are obviously enlarged and deformed, and Heberden’s nodes and Bouchard’s nodes may appear. Some of the knee joints may also become enlarged due to the formation of osteoid or joint effusion. 4. Bone rubbing sound (sensation) occurs when the joint moves due to destruction of articular cartilage and unevenness of the joint surface, mostly in the knee joint. 5. Joint weakness and impaired movement Joint pain, decreased mobility, muscle atrophy, and soft tissue contracture can cause joint weakness, soft legs or joint locking when walking, inability to fully straighten or impaired movement. Laboratory tests Routine blood, protein electrophoresis, immune complexes and serum complement are generally within normal limits. Patients with concomitant synovitis may have mildly elevated C-reactive protein (CRP) and hematocrit (ESR). Patients with secondary OA may present with abnormal laboratory tests of the primary disease. X-rays Asymmetrical joint space narrowing, subchondral bone sclerosis and/or cystic changes, joint edge hyperplasia and osteophyte formation or with varying degrees of joint effusion, some intra-articular free bodies or joint deformation are seen. Diagnostic points According to the patient’s symptoms, signs, x-ray performance and laboratory tests, it is generally not difficult to diagnose OA, and the diagnosis can be made by referring to the diagnosis and assessment process of OA.