Arthritis due to damage of joint cartilage and surrounding tissues becomes very common with aging.
Pain, swelling, and bony overgrowth are common, as well as stiffness that follows awakening or inactivity and disappears within 30 minutes, particularly if the joint is moved.
The diagnosis is based on symptoms and x-rays.
Treatment includes exercises and other physical measures, drugs that reduce pain and improve function, and, for very severe changes, joint replacement or other surgery.
Osteoarthritis, the most common joint disorder, often begins in the 40s and 50s and affects almost all people to some degree by age 80. Before the age of 40, men develop osteoarthritis more often than do women, often because of injury. Many people have some evidence of osteoarthritis on x-rays (often by age 40), but only half of these people have symptoms. From age 40 to 70, women develop the disorder more often than do men. After age 70, the disorder develops in both sexes equally.
Osteoarthritis is classified as
In primary (or idiopathic) osteoarthritis, the cause is not known (as in the large majority of cases). Primary osteoarthritis may affect only certain joints, such as the knee, or many joints.
In secondary osteoarthritis, the cause is another disease or condition, such as
A joint abnormality that appeared at birth
A metabolic disorder—for example, excess iron in the body (hemochromatosis) or excess copper in the liver (Wilson disease)
A disorder that has damaged joint cartilage—for example, rheumatoid arthritis or gout
Some people who repetitively stress one joint or a group of joints, such as foundry workers, farmers, coal miners, and bus drivers, are particularly at risk. The major risk factor for osteoarthritis of the knee comes from having an occupation that involves bending the joint. Curiously, long-distance running does not increase the risk of developing the disorder. However, once osteoarthritis develops, this type of exercise often makes the disorder worse. Obesity may be a major factor in the development of osteoarthritis, particularly of the knee and especially in women.