Health Library

Osteoarthritis

Osteoarthritis is the most common form of arthritis and is associated with the aging process.

Even from the outside, you can see that the knee of an older person looks considerably different than that of a younger person.

Let's take a look at the joint itself to see the differences.

Osteoarthritis is a chronic disease, a disease that persists for a long time. It causes the deterioration of the cartilage within a joint. For most people, the cause of osteoarthritis is unknown, but metabolic, genetic, chemical, and mechanical factors play a role in its development.

Symptoms of osteoarthritis include loss of flexibility, limited movement, and pain and swelling within the joint. The condition results from injury to the cartilage, which normally absorbs stress and covers the bones, so they can move smoothly. The cartilage of the affected joint is roughened and becomes worn down. As the disease progresses, the cartilage becomes completely worn down and the bone rubs on bone. Bony spurs usually develop around the margins of the joint.

Part of the pain results from these bone spurs, which can restrict the joint's movement as well.

Review Date: 4/9/2026  

Reviewed By: Frank D. Brodkey, MD, FCCM, Associate Professor, Section of Pulmonary and Critical Care Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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