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About osteoarthritis (OA)
There are more than 100 different kinds of arthritis and osteoarthritis is the most common form in older people


The word "arthritis" means joint inflammation, which is a normal bodily reaction to injury or disease.  Arthritis is one of the most common diseases in this country. It affects half of all people age 65 and older and is a major cause of pain and disability in older adults.   

The three most common kinds of arthritis in older people are osteoarthritis, rheumatoid arthritis, and gout. Osteoarthritis is the most common form of arthritis in older people, however, although painful, it generally causes less inflammation than other types of arthritis, such as rheumatoid arthritis.

Osteoarthritis is a disease of the cartilage in joints. Cartilage is the slippery tissue that cushions the ends of bones in a joint and allows bones to glide smoothly over each other. Cartilage also helps absorb the shock of certain movement.

Osteoarthritis causes progressive breakdown of the top layer of cartilage. It breaks down and wears away and evetually allows bones under the cartilage to rub together. The rubbing causes pain, swelling, and loss of motion of the joint. Over time, the joint may lose its normal shape. Also, bone spurs may grow on the edges of the joint. Bits of bone or cartilage can break off and float inside the joint space, which can cause more damage and pain.

Osteoarthritis results from chemical changes in the cartilage that cause it to break down faster than it can be produced. In most cases, the cause of this cartilage breakdown is unknown. Hereditary factors most often influence this disease. Photo courtesy of

Osteoarthritis may also develop as a result of another condition (secondary osteoarthritis).
  • Unhealthy weight puts extra strain on the joints, particularly the large weight-bearing joints, such as the knees, hips, and balls of the feet.
  • A single major joint injury or minor, repetitive joint injuries may result in cartilage changes over time.
  • A previous infection of the joint may alter the chemical makeup of cartilage and lead to osteoarthritis.
  • Aging does not cause osteoarthritis but is a factor in developing symptoms. Almost all people over 65 years of age show X-ray evidence of osteoarthritis in the hands.
  • Vitamin D deficiency can also result in arthritis.
ArrowMore about Osteoarthritis:
Written by N Thompson, ARNP, MSN, reviewed by M Thompson, MD, Internal Medicine, last updated October 2006

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