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Definition

Osteoarthritis (OA) is a progressive disorder of the joints caused by gradual loss of cartilage that may result in the development of bony spurs and cysts at the margins of the joints. The name osteoarthritis comes from three Greek words meaning bone, joint, and inflammation.

Description

OA is one of the most common causes of disability due to limitations of joint movement, particularly in people over the age of 50. It is estimated that 2% of the United States population under the age of 45 also suffers from osteoarthritis; this figure rises to 30% in persons between the ages of 45 and 64, and 63–80% in those over age 70. Approximately 90% of the American population will have some features of OA in their weight-bearing joints by age 40. Men tend to develop OA at earlier ages than women.

OA typically develops gradually, over a period of years. Patients with OA may have joint pain on only one side of the body. It primarily affects the knees, hands, hips, feet, and spine.

Causes and symptoms

Osteoarthritis results from deterioration or destruction of the cartilage that normally acts as a protective cushion between bones, particularly in weight-bearing joints such as the knees and hips. As the cartilage is worn away, the bones may form spurs, areas of abnormal hardening, and fluid-filled pockets in the marrow. These are known as subchondral cysts. As the disorder progresses, pain results from deformation of the bones and fluid accumulation in the joints. Pain may be relieved by rest, but worsened by placing weight on, or moving, the joint. In the early stages of OA, the pain is minor and may take the form of mild stiffness in the morning. In the later stages of OA, inflammation develops; the patient may experience pain even when the joint is not being used; and he or she may suffer permanent loss of the normal range of motion in that joint.

Osteoarthritis typically has been considered by laypeople as an inevitable part of aging caused by simple wear and tear on the joints. This view has been replaced by recent research into cartilage formation and preservation. Osteoarthritis is now considered to be the end result of several different factors that can contribute to cartilage damage, and is classified as either primary or secondary.

Primary osteoarthritis

Primary OA results from abnormal stress on weight-bearing joints, or normal stress affecting weakened joints. Primary OA most frequently affects the finger joints, the hips and knees, the cervical and lumbar spine, and the big toe. Some gene mutations appear to be associated with OA. Obesity also increases the pressure on the weight-bearing joints of the body. Finally, as the body ages, there is a reduction in the ability of cartilage to repair itself. In addition to these factors, some researchers have theorized that primary OA may be triggered by enzyme disturbances, bone disease, or liver dysfunction.

Secondary osteoarthritis

Secondary OA results from chronic or sudden injury to a joint. It can occur in any joint. Secondary OA is associated with the following factors:

• trauma to the body, including sports injuries
• repetitive stress injuries associated with certain occupations (i.e., the performing arts, construction or assembly line work, computer keyboard operation, etc.)
• repeated episodes of gout or septic arthritis
• poor posture or bone alignment caused by developmental abnormalities
• metabolic disorders

Diagnosis

The two most important diagnostic clues in the patient's history are the pattern of joint involvement and the presence or absence of fever, rash, or other symptoms outside the joints.

History and physical examination

When taking vital signs (i.e., blood pressure, weight, temperature), the patient's gait and arm and hand movement should be observed by the nursing staff or physician assistants; if pain is the chief complaint, the affected joint should be examined. After a brief examination, the nurse, nurse practitioner, or physician assistant should ask the length of time the pain has affected the patient and if there have been any limitations in his or her work or home life. The practitioner should record abnormal symptoms on the intake sheet for review by the physician. As part of the physical examination, the physician will evaluate swelling, limitations on the range of motion, pain on movement, and crepitus (i.e., cracking or grinding sound heard during joint movement). Osteoarthritis is often similar in presentation to rheumatoid arthritis, but lacks the presence of inflammation (until its very late stages) found in rheumatoid arthritis.

Diagnostic imaging

There is no laboratory test specific to the diagnosis of OA. Laboratory tests are important, however, in ruling out other diseases that may be responsible for the symptoms the patient is presenting. Treatment is usually based on the results of diagnostic imaging, which is conducted by a radiologic technician or radiologist. The features of the disease are a loss of joint space, the presence of subchondral cysts, and evidence of new bone formation (i.e., bone spurs). The patient's symptoms, however, do not always correlate with x-ray findings. Magnetic resonance imaging (MRI) and computed tomography (CT), or computed axial tomography (CAT) scans can be used to more precisely determine the location and extent of cartilage damage.

Prognosis

Osteoarthritis is a progressive disorder without a permanent cure. In some patients, the rate of progression can be slowed by weight loss, appropriate exercise, surgical treatment, and the use of alternative therapies.

Health care team roles

Early detection and diagnosis are key factors that affect the outcome of the progression of OA. Patients may present with vague symptoms of joint pain and stiffness, which should be noted when taking the patient history. The patient should be asked when these symptoms began. Co-morbid conditions such as heart disease, hypertension, or other disease should be considered. After ongoing observation and consultation with the patient, a more complete diagnosis can be made.

As with other painful conditions, understanding of the patient's lifestyle changes and physical condition is of the highest priority. Patient education and follow-up

support can assist with the mental health treatment, if necessary. Health care staff should counsel the patient on the basic facts of OA, make themselves available for follow-up phone consultation, and track the patient's visits to other health care providers. If the patient seems especially distressed about the condition, staff may recommend to the physician that the patient seek mental health support.

Should a rheumatologist or other subspecialist be consulted by the patient, members of the health care team should coordinate and monitor the treatment prescribed outside of the team's environment.

Patient contact has been shown to be a valuable aspect of the management of OA. Optimal follow-up consists of staff members (i.e., nurses, nurse practitioners, physicians assistants) making phone calls to patients and recording changes in symptoms, compliance with treatment regimen, and any decline of condition. Nursing parameters can include pain control, assessment of medication efficacy, exercise, diet, means of joint protection, and awareness of psychosocial factors of depression/anxiety.

Knowledge of over-the-counter medications for OA can assist the patient in avoiding drug interactions or undue financial burden. Patients with limited range of motion may require special accommodations in waiting and treatment rooms; they may need an entrance to the building or a bathroom that is specially made to accommodate the handicapped, or a modified examination table.

Treatment

Treatment of patients with OA is tailored to the needs of each individual. Patient's symptoms vary widely due to the location of the joints involved, the rate of progression, the severity of symptoms, the degree of disability, and individual response to specific forms of treatment. Most treatment programs include several forms of therapy and include the participation of the entire health care team.

Patient education and psychotherapy

Patient education is an important part of OA treatment because of the highly individual nature of the disorder and its potential impact on the patient's life. Patients who are depressed because of changes in employment or recreation usually benefit from participation in self-help groups, or counseling. The patient's family or friends should be involved in discussions of coping, household reorganization, and other aspects of the patient's disease and treatment regimen.

Medications

Patients with mild OA may be treated only with pain relievers such as acetaminophen (i.e., Tylenol). Most patients with OA, however, are given nonsteroidal anti-inflammatory drugs (NSAIDs). These include compounds such as ibuprofen (e.g., Motrin, Advil), ketoprofen (e.g., Orudis), and naproxen (e.g. Naprosyn). NSAIDs have the advantage of relieving slight inflammation as well as pain. Patients taking NSAIDS, however, may experience side effects, including stomach ulcers, sensitivity to sun exposure, kidney disturbances, and nervousness/anxiety or depression. Topical capsaicin cream (e.g., AthriCare) may provide relief when applied to affected areas.

Some OA patients are treated with corticosteroids, which are injected directly into the joints to reduce inflammation. As of 2001, studies were being conducted regarding the use of hyaluronic acid, which is more commonly injected into the knee. Because the joint naturally contains some hyaluronic acid (for joint lubrication), the addition of extra hyaluronic acid can protect the joint, in some cases, for six months to one year.

Physical therapy

Patients with OA are encouraged to exercise as a way of keeping joint cartilage lubricated and mobile. Consultation with a physical therapist is highly recommended, as it can ensure patient compliance and safety while exercising. Low-impact exercises to increase balance, flexibility, and range of motion are also recommended. These exercises may include walking, swimming or other water activities, yoga, and other stretching exercises, or isometric exercises (i.e., a program of exercises in which a muscle group is tensed against another muscle group or an immovable object so that the muscles may contract without shortening).

Physical therapy may also include massage, the application of moist hot packs, or soaks in a hot tub. Prescriptions may be written for protective devices. Instructions for their use would be given to patients by physical therapy staff.

Surgery

Surgical treatment of OA may include the replacement of a damaged joint with an artificial part or appliance, surgical fusion of spinal bones, scraping or removal of damaged bone from the joint, or the removal of a piece of bone in order to realign the bone.

Protective measures

Support staff will be required to educate the patient on the correct use of any protective measure, the length of time it will be needed, and counsel on the correct way to bend, lift or move the affected joint. The consequences of not using protective measures should be outlined (i.e., exacerbation of symptoms, additional muscle strain, undue pain from noncompliance). Depending on the location of the affected joint, patients with OA may be advised to use neck braces or collars, crutches, canes, hip braces, knee supports, bed boards, or elevating chairs and toilet seats. Patients would also be advised to avoid unnecessary bending, stair climbing, or lifting of heavy objects.

Potential treatments

Several methods of treatment for OA are being investigated. They include:

• Disease-modifying drugs. These compounds may be useful in assisting the body to form new cartilage or improve its repair of existing cartilage.
• Hyaluronic acid. This treatment is well supported in theory.
• Electromagnetic therapy. This treatment is viewed with skepticism by mainstream medicine.
• Gene therapy. This is a promising area of treatment, although it may not be available for several years.

Alternative treatment

DIET. Food intolerance can be a contributing factor to OA, although this is more significant in rheumatoid arthritis. Dietary suggestions that may be helpful for people with OA include emphasizing high-fiber, complex-carbohydrate foods, while minimizing fats.

NUTRITIONAL SUPPLEMENTS In recent years, a combination of glucosamine and chondroitin sulfate has been studied as a dietary supplement to help the body maintain and repair cartilage. These substances are nontoxic and do not require prescriptions, but studies continue to be conducted to evaluate their effectiveness. Other supplements that may be helpful in the treatment of OA include the antioxidant vitamins A, C, and E, and minerals selenium and zinc.

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KEY TERMS

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Bouchard's nodes—Swelling of the middle joint of the finger.

Cartilage—Elastic connective tissue that covers and protects the ends of bones.

Primary osteoarthritis—OA that results from hereditary factors or stresses on weight-bearing joints.

Secondary osteoarthritis—OA that develops following joint surgery, trauma, or repetitive joint injury.

Subchondral cysts—Fluid-filled sacs that form inside the marrow at the ends of bones as part of the development of OA.

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Michele R. Webb