Osteoarthritis: Arthritis

Content provided by the Faculty of the Harvard Medical School

Osteoarthritis

Osteoarthritis is a form of joint disease that develops when cartilage deteriorates. Over time, the space between bones narrows and the surfaces of the bones change shape, leading eventually to friction and joint damage (see Figure 5). Osteoarthritis often affects more than one joint, and while it can affect any joint in the body, some joints are affected much more often than others. For example, osteoarthritis is quite common in the hip, knee, lower back, neck, and certain finger joints, but it is rare in the elbow.

Figure 5: Joint changes in osteoarthritis

Osteoarthritis is the most common of all joint diseases, accounting for about half of arthritis diagnoses in the United States. It affects approximately 21 million Americans. But these numbers only hint at the impact of osteoarthritis, which can send people to pain clinics and doctors' offices, make them reach for medications, keep them home from work, and curtail leisure and everyday activities. Because the risk of developing osteoarthritis increases with age, this form of arthritis is expected to become even more prevalent as the population of the United States grows older.

About equal numbers of men and women have osteoarthritis, but it tends to affect them differently. Men typically develop symptoms before age 45, while women usually don't have symptoms until after age 55. Women more often have osteoarthritis in the hands and knees. Men are more likely to have it in the hips, knees, and spine. Women are 10 times more likely to develop Heberden's nodes, a type of osteoarthritis in which hard, bony growths form on the joint nearest the fingertip.

Last updated:	September 05, 2008