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.
Healthy Joint |
Joint with OA |
Image source: NIAMS |
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.
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.