Osteoarthritis (OA) is a chronic joint disease characterized by degeneration and destruction of joint cartilage and osteophytes. The disease is more prevalent after middle age. Studies have shown that the prevalence of osteoarthritis is 10-17% in people aged 40 years and 50% in people aged 60 years and older. In people over the age of 75, 80% of them have osteoarthritis. The ultimate disability rate of the disease is 53%. Clinically, swollen and painful joints, osteophytes and limited mobility are most common. There are no geographical or racial differences in the development of osteoarthritis. Age, obesity, inflammation, trauma and genetic factors may be associated with the development of this disease. Clinical manifestations 1. Symptoms and signs Osteoarthritis is mainly characterized by pain, swelling, morning stiffness, joint effusion and bony hypertrophy of the affected joints, which may be accompanied by bone rubbing sounds during activity, dysfunction or deformity. (1) Joint pain and pressure pain The most common manifestation of this disease is localized pain and pressure pain in the joints. The weight-bearing joints and hands are most likely to be involved. It is usually mild or moderate intermittent pain in the early stage, which improves with rest and worsens with activity. There may be localized pressure pain in the joints, which is especially obvious when there is joint swelling. (2) Swelling of the joint In the early stage, there is limited swelling around the joint, but as the disease progresses, there may be diffuse swelling of the joint, thickening of the bursa or joint effusion. In the later stage, bony swelling around the joint may be detected. (3) Morning stiffness Patients may experience joint stiffness and adhesion in the morning, which may be relieved after activity. The duration of morning stiffness is relatively short, usually a few minutes to ten minutes, and rarely exceeds half an hour. (4) Joint friction sounds are mainly seen in osteoarthritis of the knee joint. Due to the destruction of cartilage and roughness of the joint surface, there is a bone rubbing sound (sensation) and twisting sensation when the joint is moved, or accompanied by local pain in the joint. 2, different parts of the osteoarthritis (1) hand The distal interphalangeal joint is most commonly involved, manifesting as bony expansion on both sides of the extensor side of the joint, called Heberden’s node. The proximal interphalangeal joint is referred to as a Bouchard node when it is present on the extensor side. It may be associated with mild localized erythema, pain, and tenderness of the nodule. The involvement of the first carpometacarpal joint may result in a square hand deformity due to osteophytes at its base, and a snake-like deformity due to finger joint hyperplasia and lateral subluxation. (2) Knee Knee involvement is the most common in clinical practice. Risk factors include obesity, knee trauma, and meniscectomy. The main manifestation is knee pain, which is aggravated by activity and relieved by rest. Severe cases may present with inversion or valgus deformity of the knee. (3) Hip The involvement of the hip joint is mostly characterized by localized intermittent dull pain, which may become persistent with the development of the disease. In some patients, the pain can radiate to the groin, inner thighs and buttocks. The hip joint movement is mostly limited by internal rotation and external rotation, followed by internal retraction, external rotation and extension. (4) Spine Cervical spine involvement is more common. There may be hyperplasia and osteophytes of the vertebral body, intervertebral disc and posterior synovial joint, causing local pain and stiffness, and corresponding radiological pain and neurological symptoms when local blood vessels and nerves are compressed. Involvement of the cervical spine compresses the vertebrobasilar artery, causing symptoms of inadequate blood supply to the brain. Intermittent claudication and cauda equina syndrome may occur when lumbar spine osteophytes lead to spinal stenosis. (5) Foot The metatarsophalangeal joint is often involved, and in addition to local pain, pressure pain and bony hypertrophy, deformities such as bunions may occur.