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Osteoarthritis, which is also called degenerative arthritis or degenerative joint disease, is primarily a disease that results from the breakdown and loss of cartilage in joints (e.g., knees, hips, wrists). Cartilage, a connective tissue that covers the surfaces of articular joints, is essential for proper joint function because it allows the ends of bones to slide over one another smoothly. Osteoarthritis results from both mechanical (e.g., trauma to joints) and biological (metabolic) events that interfere with the maintenance of healthy cartilage. Eventually, cartilage may be lost, causing the bones in the joint to rub together, and bony spurs may form.

SIGNS, SYMPTOMS, AND DIAGNOSIS

Osteoarthritis is characterized by joint pain, tenderness, swelling, and limitation in joint movement. The joints most often affected are the joints of the fingers, the base of the thumb, the hips, the knees, the neck (cervical spine), and the lower back (lumbar spine). Unlike some types of arthritis that affect multiple organ systems, any inflammation associated with osteoarthritis is limited to the joints. Pain after joint use that subsides with resting the joint is a classical sign of osteoarthritis. As osteoarthritis worsens, pain may occur at rest or at night. Health care providers diagnose osteoarthritis based on a history of joint symptoms, physical examination, and radiographic (X-ray) changes. X-ray changes may include joint-space narrowing, changes in the bones, and the presence of bony spurs.

In addition to the physical symptoms, osteoarthritis also impacts psychological, social, and economic well-being. Psychological effects include stress, depression, anger, feelings of helplessness, and anxiety. The social impacts may include decreased community involvement and lack of understanding by family, friends, and coworkers. The economic status of people with arthritis and their families is also affected. The financial burden of health care and days lost from work may seriously impact the financial well-being of persons with arthritis and their families.

Age is a major demographic risk factor for the development of osteoarthritis. Although aging does not cause osteoarthritis, the prevalence of osteoarthritis increases with age. Almost half of people over the age of sixty-five have arthritis—mostly osteoarthritis. Osteoarthritis is also more common among women than among men. In addition to age, risk factors for osteoarthritis include joint injury and being overweight (especially for knee and hip osteoarthritis). Reduction of weight has been shown to reduce the risk of symptomatic osteoarthritis in overweight people.

THE BURDEN OF OSTEOARTHRITIS

Osteoarthritis is the most common form of the more than one hundred conditions that are considered arthritis and other rheumatic conditions. In 1998, these conditions affected 43 million Americans, and they are among the most common chronic diseases. Arthritis is also a leading cause of disability—it limits activities for 7 million Americans. The costs of arthritis are enormous. In 1992, the costs of medical treatment and lost wages were estimated at $65 billion. The cost of osteoarthritis alone may currently exceed $15.5 billion.

Osteoarthritis affects as many people as all of the other types of arthritis combined. Almost 22 million Americans have osteoarthritis—almost one of every twelve people in the United States. Prevalence estimates of osteoarthritis will differ by how the data are collected or how the diagnosis is made. For example, people who have pain due to osteoarthritis may not show X-ray changes, and those with X-ray changes consistent with osteoarthritis may not have symptoms. The prevalence of osteoarthritis is high and will get even higher as the number of older Americans increases. In 2020, an estimated 60 million Americans will have arthritis—osteoarthritis alone is likely to affect over 30 million people. Osteoarthritis is a major cause of disability. Sixty to 80 percent of people with osteoarthritis are limited in their activities because of the disease.

OSTEOARTHRITIS TREATMENT AND CONTROL

There is no known cure for osteoarthritis, yet there are effective treatment and control strategies. Management of osteoarthritis is directed toward reducing pain, minimizing or preventing disability, and improving quality of life. Achieving these goals not only requires good clinical care, but also depends on the active involvement of the person with osteoarthritis in self-management strategies and proactive efforts by the public health system.

Clinical Care. The American College of Rheumatology (ACR) has published guidelines on the medical management of osteoarthritis of the hip and knee that outline the key components of appropriate management. The guidelines list therapeutic strategies, including medications, rehabilitation therapies, and surgery. Medical management of osteoarthritis primarily focuses on prescribing appropriate medications and recommending self-management strategies or making referrals to rehabilitation, self-management, or surgical services.

Medication recommendations for osteoarthritis are evolving. Nonsteroidal anti-inflammatory drugs (NSAID) were, until recently, the primary medication treatment for osteoarthritis. However, due to concerns about the gastrointestinal toxicity of NSAIDs, the 1995 ACR medical-management guidelines concluded that the first-line medication for symptomatic osteoarthritis should be acetaminophen. NSAIDs were recommended for those individuals who do not get sufficient pain relief from acetaminophen. In 1998, a new form of NSAID, called COX-2 Inhibitors, was released. COX-2 medications are similar to other NSAIDs in their effect on pain and joint inflammation, but they have significantly fewer gastrointestinal side effects. Physicians now vary in whether they initiate treatment for osteoarthritis with acetaminophen, another NSAID, or a COX-2 medication.

Other treatments are also used. For example, symptomatic knee osteoarthritis may benefit from an injection of cortisone into the joint. The role of other treatments, such as glucosamine, chondroitin, and injections of hyaluronan are under investigation.

Rehabilitation services, such as physical and occupational therapy, are also important in the management of osteoarthritis. Therapists may prescribe therapeutic exercise to increase joint range of motion, muscle strength, and aerobic conditioning; they make teach strategies to reduce fatigue and stress on joints; and they may recommend environmental or task modification and assistive devices to make it easier to perform daily activities. Rehabilitation services may also be used after joint surgery.

Persons with severe symptomatic osteoarthritis, marked by pain and declining function, may benefit from total joint replacement. Both total hip and knee replacement have substantially reduced pain and improved function in the vast majority of individuals who have received them.

Self-Management Strategies. The ACR guidelines for medical management of osteoarthritis recommend specific self-management strategies as well as clinical interventions. The guidelines specify self-management education, exercise and aerobic conditioning, and weight control as integral to optimal health outcomes in osteoarthritis.

Because of its demonstrated efficacy and cost-effectiveness, the premiere self-management education intervention for osteoarthritis is the Arthritis Self-Help Course (ASHC). ASHC, developed in the early 1980s by Kate Lorig and colleagues, was adopted in the United States by the Arthritis Foundation and has been disseminated nationwide. A 20 percent reduction in pain and a 43 percent reduction in physician visits was demonstrated in four-year follow-up studies of ASHC. Early research demonstrated that each individual's belief that there was "something they could do," which Lorig labeled "self-efficacy," was more strongly correlated with positive health outcomes from ASHC than were specific health behaviors. Cost-effectiveness calculations indicated an annual savings of $189 per osteoarthritis participant due to the decreased need for physician visits.

Physical activity and weight control are important self-management strategies in osteoarthritis. Physical Activity and Health: A Report of the Surgeon General (1996) specifically addressed osteoarthritis and stated that regular moderate exercise programs, either aerobic or resistance training, relieve symptoms and improve physical function and psychosocial status among people with osteoarthritis. Low-impact forms of exercise, such as walking, swimming, and stationary or on-the-road bicycling, are recommended to minimize the stress on affected joints. The Arthritis Foundation disseminates structured physical activity programs. Preliminary studies have shown positive health outcomes among participants in these programs. Obesity is a well-documented risk factor for the development of symptomatic osteoarthritis. A randomized controlled study showed that the amount of weight lost was strongly correlated with improvements in signs and symptoms of knee osteoarthritis.

Some persons with osteoarthritis choose to manage their condition by using various forms of complementary and alternative medicine (CAM) modalities, either along with, or in place of, medically prescribed therapies. Symptoms associated with chronic musculoskeletal conditions, including osteoarthritis, are among the most common reasons for using CAM. More information is needed, however, about the safety and efficacy of CAM modalities.

THE ROLE OF PUBLIC HEALTH IN ARTHRITIS TREATMENT AND CONTROL

Because of its large and increasing prevalence, and the large personal and societal costs, arthritis is recognized as a significant public health problem. In addition, effective management strategies are available yet underused. The National Arthritis Action Plan: A Public Health Strategy (NAAP) was developed under the leadership of the Centers for Disease Control and Prevention, the Arthritis Foundation, and the Association of State and Territorial Health Officials, and with the combined efforts of over ninety organizations. NAAP, released in 1999, outlines a comprehensive, systematic public health approach to decreasing the burden of arthritis for all Americans and improving the quality of life of those affected by arthritis. NAAP focuses on a population-based approach that can complement traditional medical care. Public health agencies and their partners play a role in promoting the importance of early diagnosis and appropriate management of osteoarthritis; and in assuring that persons with osteoarthritis are aware of the importance of, and have access to, effective self-management programs. Policy and system changes are needed to heighten awareness and improve access. Public health professionals are also responsible for monitoring the burden of osteoarthritis and identifying factors that influence the development or progression of osteoarthritis or disability from osteoarthritis.

JOSEPH E. SNIEZEK

TERESA J. BRADY

JAMES S. MARKS

(SEE ALSO: Chronic Illness; Noncommunicable Disease Control; Predisposing Factors; Rheumatoid Arthritis; Self-Care Behavior; Self-Help Groups)