Osteoarthritis Health Article

Definition

Osteoarthritis (OA) is a progressive disorder of the joints caused by gradual loss of cartilage that may result in the development of bony spurs and cysts at the margins of the joints. The name osteoarthritis comes from three Greek words meaning bone, joint, and inflammation.

Description

OA is one of the most common causes of disability due to limitations of joint movement, particularly in people over the age of 50. It is estimated that 2% of the United States population under the age of 45 also suffers from osteoarthritis; this figure rises to 30% in persons between the ages of 45 and 64, and 63–80% in those over age 70. Approximately 90% of the American population will have some features of OA in their weight-bearing joints by age 40. Men tend to develop OA at earlier ages than women.

OA typically develops gradually, over a period of years. Patients with OA may have joint pain on only one side of the body. It primarily affects the knees, hands, hips, feet, and spine.

Causes and symptoms

Osteoarthritis results from deterioration or destruction of the cartilage that normally acts as a protective cushion between bones, particularly in weight-bearing joints such as the knees and hips. As the cartilage is worn away, the bones may form spurs, areas of abnormal hardening, and fluid-filled pockets in the marrow. These are known as subchondral cysts. As the disorder progresses, pain results from deformation of the bones and fluid accumulation in the joints. Pain may be relieved by rest, but worsened by placing weight on, or moving, the joint. In the early stages of OA, the pain is minor and may take the form of mild stiffness in the morning. In the later stages of OA, inflammation develops; the patient may experience pain even when the joint is not being used; and he or she may suffer permanent loss of the normal range of motion in that joint.

Osteoarthritis typically has been considered by laypeople as an inevitable part of aging caused by simple wear and tear on the joints. This view has been replaced by recent research into cartilage formation and preservation. Osteoarthritis is now considered to be the end result of several different factors that can contribute to cartilage damage, and is classified as either primary or secondary.