ostearthritis

a noninflammatory degenerative joint disease marked by degeneration of the articular cartilage, hypertrophy of bone at the margins, and changes in the synovial membrane. Primary osteoarthritis, as part of the normal aging process, is most likely to strike the joints that receive the most use or stress over the years. These include the knees, the joints of the big toes, and those of the lower part of the spine. Another common form of osteoarthritis affects the distal joints of the fingers; this form usually occurs in women. Called also degenerative joint disease.

Symptoms vary from mild to severe, depending on the amount of degeneration that has taken place. Osteoarthritis is caused by disintegration of the cartilage that covers the ends of the bones. As the cartilage wears away, the roughened surface of the bone is exposed, and pain and stiffness result. In severe cases the center of the bone wears away and a bony ridge is left around the edges. This ridge may restrict movement of the joint. Osteoarthritis is less crippling than rheumatoid arthritis, in which two bone surfaces may fuse, completely immobilizing the joint.

Treatment is aimed at preventing crippling deformities, relieving pain, and maintaining motion of the joint; see also treatment of arthritis.