Major Review Reveals That Osteoarthritis is a Complex
Disease with New Solutions
A multidisciplinary group of scientists has declared that osteoarthritis
(OA), the most common form of arthritis, is "surprisingly complex," but has
outlined a number of new approaches to its understanding, prevention and treatment. Their
report, a review by 28 researchers at 17 academic and government institutions, cites over
250 published articles and is presented in two parts in the Annals of Internal Medicine.
The effort was led by David T. Felson, M.D., M.P.H., of Boston University,
and Reva C. Lawrence, M.P.H., of the National Institute of Arthritis and Musculoskeletal
and Skin Diseases (NIAMS), a part of the National Institutes of Health (NIH).
The disease, says the review, can result from an inherited predisposition
to OA combined with a joint injury. Regular runners have almost no additional risk of OA,
but football and soccer players and baseball pitchers are at increased risk. A healthy
lifestyle helps — exercise can lessen disability if OA has developed. Strengthening
the thigh muscles reduces risk of OA of the knee, as can losing weight. For people who
have the disease, a combination of treatment approaches, including new medications and
patient education, is effective.
"I am delighted that we have been able to publish this comprehensive,
two-part review arising from our 1999 conference 'Stepping Away from OA,' " says
Stephen I. Katz, M.D., Ph.D., director of the NIAMS. "OA is a major public health
problem, affecting some 20 million people in this country."
The review points out that in the United States about 6 percent of adults
over 30 have OA of the knee and about 3 percent have OA of the hip. The disease is
responsible for more trouble walking and stair climbing than any other disease, and it is
the most common indication for total joint replacement of the hip and knee. Before age 50
the prevalence of OA in most joints is higher in men than women. After this age, more
women are affected by OA of the hand, foot and knee. The occurrence of the disease
increases with age, rising 2- to 10-fold in people from 30 to 65 years of age.
In osteoarthritis, there is focused, progressive loss of cartilage, the
slippery material that cushions the ends of bones, along with changes in the bone below
the cartilage leading to bony overgrowth. The tissue lining of the joint can become
inflamed, the ligaments looser, and associated muscles weak, with resulting pain when the
joint is used.
The review covers risk factors, such as being overweight and joint injury
from specific sports, and treatments ranging from established and new medications,
exercise, and patient education to surgery when other treatments do not work. It also
discusses new areas of research, such as easily measured disease indicators known as
biomarkers, as well as engineering of new cartilage. Specific findings are given on the
attached backgrounder.
"This review shows that arthritis research is a vibrant area,
yielding new means of preventing the disease and slowing its progression, as well as new
and effective combinations of drug and behavioral treatments," says Dr. Katz, NIAMS
director. "People with osteoarthritis and those at risk for the disease should be
encouraged that there is much that they and their doctors can do about it."
The mission of the NIAMS is to support research into the causes,
treatment and prevention of arthritis and musculoskeletal and skin diseases, the training
of basic and clinical scientists to carry out this research and the dissemination of
information on research progress in these diseases. For more information about NIAMS, call
our information clearinghouse at 1-877-22-NIAMS or visit the NIAMS Web site at http://www.niams.nih.gov.
References:
The two-part review appears as:
- Felson DT, Lawrence RC, Dieppe PA, et al. Osteoarthritis: New Insights. Part 1:
The Disease and Its Risk Factors. Ann Internal Med 2000;133(8):635-646
- Felson DT, Lawrence RC, Hochberg MC, et al. Osteoarthritis: New Insights. Part 2:
Treatment Approaches. Ann Internal Med 2000;133(9):726-737
The development of the review was coordinated and funded by the NIAMS and
was based on a July 1999 conference at NIH initiated, organized and funded by the
Institute. Conference cosponsors were the NIH Office of Disease Prevention, NIH National
Center for Complementary and Alternative Medicine, NIH Office of Research on Women's
Health, NIH Office of Behavioral and Social Sciences Research, NIH National Center for
Medical Rehabilitation Research, National Institute of Child Health and Human Development,
Centers for Disease Control and Prevention, Arthritis Foundation and American Academy of
Orthopaedic Surgeons.
To interview Dr. Felson, contact Rebecca Sullivan, Boston University, at
(617) 638-8491. For Ms. Lawrence, contact Connie Raab, NIAMS, at (301) 496-8190 or RaabC@mail.nih.gov.
Backgrounder
Findings from the two-part NIAMS Annals of Internal
Medicine article: "Osteoarthritis: New Insights"
Risk factors and disease prevention:
Serious joint injury can lead to osteoarthritis (OA), but more often the
disease results from a combination of systemic and joint-related factors. OA is strongly
genetically determined, with genetic factors accounting for about half of OA in the hands
and hips and a smaller percentage of OA of the knees. However, several steps can be taken
to prevent or delay onset of OA.
- Weight loss can reduce the risk of OA. In one major study cited by the review, people
who lost 11 pounds cut their risk in half.
- Weakness of the quadriceps muscle (in front of the thigh) is common in patients with OA.
It is clear that strengthening the quadriceps can help: a relatively small increase in
strength (20 percent for men and 25 percent for women) can lead to a 20-30 percent
decrease in risk of OA.
- There is low or no additional risk of OA from regular, moderate running. However, sports
that involve high-intensity, acute, direct joint impact from contact with other players,
playing surfaces or equipment do have an increased risk of OA; football is an example.
Sports that involve both repetitive joint impact and twisting also have an increase risk
of OA; examples are soccer and baseball pitching. The authors suggest that individual
counseling, rule changes, changes in equipment and playing surfaces, and training can help
reduce injuries. Early diagnosis and treatment of and complete rehabilitation from joint
injuries can decrease risk of subsequent OA.
- High intakes of vitamin C are associated with lower rates of OA on X-ray and less knee
pain from OA. High levels of vitamin D protect against new and progressive OA.
- Much of the OA in men is attributable to occupational activities, particularly jobs
requiring kneeling or squatting, along with heavy lifting.
- In the future, research may enable doctors to use biomarkers to help identify people at
risk for OA and people with OA at risk for disease progression. These biomarkers could
also help doctors assess the effectiveness of treatments. OA biomarkers are substances in
joint fluid, blood or urine that indicate changes in bone or cartilage.
Treatment:
Once OA develops, certain factors put a patient at risk for disability.
These include pain, depression, muscle weakness and poor aerobic capacity. Although the
expert group said that OA cannot be cured, there are new medications available, and recent
studies have shown the potential of treatments that range from new medications to
complementary medicine, patient education approaches, exercise and surgery. These
approaches are often combined.
Medications
- Acetaminophen can help mild or moderate joint pain in OA.
- The next drugs of choice are tramadol and nonsteroidal anti-inflammatory drugs (NSAIDs).
- The use of NSAIDs is often associated with problems in the gastrointestinal (GI) tract
and kidney problems. For people who experience these problems, the review suggests use of
either a combination of an NSAID and a drug that protects the GI system or newer agents
known as COX-2 inhibitors. These new agents act against inflammation but with much less
effect on the GI system. The federal Food and Drug Administration recently approved two
such drugs, celecoxib and rofecoxib.
- Opioid painkillers can also be used in patients with OA, as can creams containing
painkillers applied to the skin (for example, capsaicin cream).
Nondrug approaches, including exercise and patient education
- Glucosamine and chondroitin sulfate have received tremendous popular attention, and a
recent meta-analysis of 15 studies cited by the review shows they may have some positive
effects on OA. However, the review authors call for high-quality independent studies to
evaluate the efficacy of these compounds. They cite an NIH study underway that is expected
to yield results in 2004.
- Exercise is important in people with OA. The review says that deconditioned muscle,
inadequate motion, and joint stiffness make the signs and symptoms of OA worse. It
recommends well-designed exercise programs that include training for strength and
endurance. Exercise can help patients regain or maintain motion and flexibility through
low-intensity, controlled movements that don't increase pain.
- Shock-absorbing footwear and other devices can help OA of the knee. Two papers cited
suggest that heel wedges in the shoes are an alternative to knee replacements in certain
cases of OA of the knee.
- Research on the efficacy of acupuncture in OA thus far is inconclusive but promising. A
large NIH study of this approach is underway that should be completed in June 2001.
- Behavioral interventions are safe and effective in the treatment of OA. Interventions
include telephone, mail-delivered and group self-management programs, which are more
effective than just providing information. In fact, the review called patient education
"the cornerstone" of osteoarthritis treatment. One group patient education
program developed with NIAMS support at Stanford University and now taught nationwide by
the Arthritis Foundation as the Arthritis Self-Management Program has been shown to reduce
pain, doctor's visits, and depression in patients with arthritis as long as 4 years later.
Surgery (after nonsurgical treatments fail)
- Removal of bone or joint tissue can relieve symptoms.
- Joint fusion can also relieve pain, and is most often done in the spine and in the small
joints of the hands and feet.
- Total joint replacement, according to the review, is the greatest advance in OA
treatment in the past century. It can reduce pain and disability and restore patients to
near-normal function. To help replacements last longer, intense research is focusing on
more wear- and corrosion-resistant materials as well as how the tissue around the
replacements responds.
- Replacement of damaged cartilage shows promise, with three types available:
use of one's own cartilage, use of donor cartilage, and tissue engineering of cartilage
progenitor cells. Development of the latter is still in its infancy.
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