This animation compares a normal adult knee joint and a knee joint affected by osteoarthritis.
Osteoarthritis is the most common form of arthritis and is associated with the aging process. Osteoarthritis is a chronic disease causing 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.
Reviewed last on: 10/6/2008
Thomas N. Joseph, MD, Private Practice specializing in Orthopaedics, subspecialty Foot and Ankle, Camden Bone & Joint, Camden, SC. Review provided by VeriMed Healthcare Network.