Osteoarthritis develops in a joint when cartilage begins to break down. Cartilage is tough, protective tissue. It cushions the places where bones come together to form a joint. Cartilage can break down for several reasons, including:
- "Wear-and-tear" as people grow older
- Joint-related injuries
- Damage to the joint from infections and diseases
|Cartilage normally protects the joint, allowing for smooth movement. Cartilage also absorbs shock when pressure is placed on the joint, like when walking. Arthritis involves the breakdown of cartilage. Without the usual amount of cartilage, the bones of the joint rub together, causing pain, swelling and stiffness.
In most cases, the exact cause cannot be identified. Unfortunately, damaged cartilage cannot heal and become normal again.
Watch an animation about osteoarthritis.
Osteoarthritis often involves several joints. However, it does not "spread" from joint to joint throughout the body. It typically strikes the:
- Weight-bearing joints (knees, hips, back, feet)
The knees, hips, and lower back (spine) are most commonly affected.
Osteoarthritis is a "non-inflammatory" type of arthritis, which means that inflammation is not the key component. It is completely different from the less common rheumatoid arthritis -- in which the body's immune system attacks its own tissues, causing inflammation.
While osteoarthritis sometimes may be painful, it is not always disabling, and unlike rheumatoid arthritis, is unlikely to produce severe deformity of the joints.
Review Date: 12/24/2012
Reviewed By: Ariel D. Teitel, MD, MBA, Clinical Associate Professor of Medicine, Division of Rheumatology, NYU Langone Medical Center. Review provided by VeriMed Healthcare Network.
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