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Osteoarthritis

What is osteoarthritis?

Called the "wear and tear" arthritis, osteoarthritis is the most common form of arthritis. Nearly all vertebrates suffer from osteoarthritis, including porpoises and whales, and those long-extinct giants, the dinosaurs. It is a chronic disease in which the cartilage breaks down. Cartilage is a slippery tissue that covers the ends of bones in a joint, allowing the bones to glide over one another. It also absorbs energy from the shock of physical movement. When cartilage in a joint deteriorates osteoarthritis occurs.

There are two categories of osteoarthritis, primary and secondary. Primary osteoarthritis appears without any apparent cause, usually as a result of aging. Secondary osteoarthritis occurs in joints that have sustained injuries, experienced infections or fractures. Obesity can also cause secondary osteoarthritis due to the added pressure on weight bearing joints. Secondary osteoarthritis can also occur as the result of another type of arthritis, such as rheumatoid.

What are the symptoms?

As the cartilage in a joint deteriorates the bones begin to rub together, causing pain, swelling, and loss of motion of the joint. The joint may begin to lose shape. Small bone spurs called osteophytes may grow on the edges of the joint. Inflammation may or may not be present. The pain may act like a roller coaster, with pain spells followed by periods of relief. These symptoms almost always begin gradually, taking years until the pain is severe enough to be reported to a doctor. Osteoarthritis is commonly found in the joints of the fingers, feet, knees, hips, and spine, and is rarely found in joints of the wrist, elbows, shoulders, and jaw.

How is it diagnosed?

Although it is usually not difficult to diagnose OA, no single test can pinpoint the disease. Most doctors use a combination of patient history and exam, and x-rays to diagnose the disease and rule out other causes for the symptoms.

How is it treated?

Treatment of osteoarthritis focuses on decreasing pain and improving joint function. This can be done in a number of different ways.

Occupational changes:
People in occupations requiring repetitive and stressful movement should find ways to reduce joint trauma. Adjusting the work area or substituting tasks that produce less stress on joints can help reduce shock.

Exercise:
Research shows that one of the best treatments for osteoarthritis is exercise. It can improve mood and outlook, decrease pain, increase joint flexibility, improve the heart and blood flow, maintain or decrease weight, and promote general well being. The amount and form of exercise will depend on which joints are involved, how stable the joints are, and whether a joint replacement has already been done.

Weight loss:
Overweight people can lessen the shock on their joints by losing weight. Knees, for example, sustain an impact three to five times the body weight when descending stairs. So a loss of five pounds can eliminate at least 15 pounds of stressful impact on the joint. The greater the weight loss, the greater the benefit.

Rest and joint care:
Treatment plans include regularly scheduled rest. People with OA must learn to recognize the body's signals, and know when to stop or slow down. Splints or braces provide extra support for weakened joints. They also keep the joint in proper position during sleep or activity. An occupational therapist or a doctor can help get a properly fitting splint.

Acupuncture:
Some people have found pain relief using acupuncture. Preliminary research shows that acupuncture may be a useful part of an osteoarthritis treatment plan.

Medications:
NSAIDS (Nonsteroidal anti-inflammatory drugs) are commonly used to treat osteoarthritis. Available over the counter or by prescription, they fight inflammation or swelling and relieve pain.

Acetaminophen such as Tylenol can also be very effective in treating the pain of OA. Research has shown that in many patients with osteoarthritis, acetaminophen relieves pain as effectively as NSAID's.

Topical pain-relieving creams, rubs, and sprays can be applied directly to the skin. There are many brands available over the counter.

Narcotic pain relievers may be needed in cases of severe pain.

Corticosteroids are typically injected into affected joints rather than taken orally to relieve the pain.

Hyaluronic acid is a newer medication for joint injection, used to treat osteoarthritis of the knee. This substance is a normal component of the joint, involved in joint lubrication and nutrition.

Glucosamine and chondroitin sulfate are found in the synovial fluid of the knee. Several studies have reported some pain relief and improved function from taking either one or a combination of the two natural substances. It is available over the counter.

Statistics

• Osteoarthritis affects an estimated 20.7 million Americans.
• Almost everyone over the age of 75 is affected in at least one joint.
• Before age 45, more men have it, while after age 45 osteoarthritis is more common in women.
• OA is responsible for more than 7 million physician visits per year.

Surgery:
For some people, surgery helps relieve the pain and disability of osteoarthritis. Surgery may be performed to resurface bones, smooth the rough edges. They may also remove loose pieces of bone or cartilage to improve joint function. Currently about 80% of osteoarthritis surgeries are joint replacements. After surgery and rehabilitation, the patient usually feels less pain and swelling, and can move more easily.

What research is being done?

Researchers suspect that genetics play a part in about 25% of osteoarthritis cases. Scientists have identified a gene defect that affects collagen, an important part of cartilage in patients with an inherited kind of osteoarthritis that starts at an early age. They are looking for other genetic mutations. In the future, a test to determine who carries the genetic defect (or defects) could help people reduce their risk for osteoarthritis with lifestyle adjustments.

There is currently no treatment that has been proven to reverse or stop the disease process once it begins. Researchers are looking for something to prevent, slow down, or reverse joint damage. One experimental antibiotic drug, doxycycline, may stop certain enzymes from damaging cartilage. The drug has responded well in clinical studies, but more studies are needed. Researchers are also studying growth factors or other natural chemical messengers. These potential medicines may be able to stimulate cartilage growth or repair.

The National Center for Complementary and Alternative Medicine at the National Institute of Health is supporting a clinical trial to see if either glucosamine or chondroitin sulfate alone, or in combination with each other, really do reduce pain and improve function.

In studies of older women, they found a lower risk of osteoarthritis in women who had used oral estrogens for hormone replacement therapy. The researchers suspect that low estrogen levels could increase risk for the disease, but further studies are needed.

There are currently several different tissue engineering studies going on. Certain body chemicals called enzymes may help cartilage to break down. Scientists are working to genetically engineer cells that would inhibit these enzymes and prevent the damage they cause. They are also looking into cartilage cell replacement. Researchers remove cartilage cells from the patient's own joint, clone or grow new cells using tissue culture and other laboratory techniques, and inject the newly grown cells into the patient's joint. Stem cell transplants may be a big help in the future. Researchers hope to insert stem cells, taken from bone marrow, into cartilage where they will make new cartilage. If successful, this process could be used to repair damaged cartilage and avoid the need for surgical joint replacements with metal or plastics.

Some of the related information found on Arthritis Insight:

For support visit our Chat Room and Message Boards.
For medication information see our Medication Index.
For information about tests and blood work go to Tests & Labs.
To find out about surgeries and joint replacements see Surgeries.
For more sites about Osteoarthritis check out our Web Links.

For more information:

Osteoarthritis: by drdoc online
Cush's Osteoarthritis & G/CS Page
The Arthritis Foundation
Mayo Clinic: Osteoarthritis, A Self Help Guide

Tina J. Underwood
Page last updated on June 18, 2000