What is osteoarthritis?

What is osteoarthritis?

Osteoarthritis (OA) is an age-related disease involving the breakdown of the joint cartilage - a tissue in the joint that helps it move normally. The loss of joint cartilage causes pain, stiffness and decreased mobility in the affected joints. In most people with OA, joint cartilage becomes damaged through mechanical "wear and tear" - a lifetime of walking or running on hard surfaces, for example.

Other possible causes of osteoarthritis include previous joint injury or heredity. The disease most often affects the knees, fingers, hips, neck and lower back. It is not found as often in the wrists, elbows, shoulders, ankles or jaw unless these joints have been injured or put under heavy stress.

Osteoarthritis occurs in men and women and is most often diagnosed in middle-aged and older people. It can occur in people who have other forms of arthritis as well. According to the Arthritis Foundation, almost 21 million people in the United States have osteoarthritis.

How osteoarthritis affects the joints

A joint is the place where two bones meet. Cartilage normally covers and cushions the ends of the two bones. This prevents the hard surfaces of the bones from rubbing together and causing damage.

After "wear and tear" or a joint injury damages the cartilage, it becomes torn and frayed, loses its elasticity and eventually wears away altogether. The bones begin to rub together as the joint is moved. Bony growths, or "spurs," begin to form on the ends of the bone. The joint becomes painful, is stiff after periods of inactivity and its movement ultimately may be limited.

Symptoms

If you have osteoarthritis, your joints will probably hurt most after you've used them too much or after a long period of not using them much at all. In the morning, you may get up feeling stiff, but the stiffness goes away as you go about your daily movements. Pain in your joints may cause you to limp, and you may find it difficult to go up or down stairs.

The knuckles of your hands may swell and feel painful. You may feel pain and even a "grating" sensation as you move your knee. Other joints, such as your hip or the large joint at the base of the big toe, may also feel stiff and tender.

Diagnosis and treatment

Doctors commonly diagnose osteoarthritis by listening to a patient's history and doing a physical exam. The doctor may also order X-rays to evaluate the condition of the joints, and in some cases may do joint aspiration (a procedure in which fluid is drained from a painful joint and examined).

OA may be treated with medications to control pain and reduce inflammation, if any. These medications include:

Non-narcotic pain relievers (acetaminophen).

Narcotics, for short-term pain relief (propoxyphene, codeine and oxycodone).

Nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin, ibuprofen, naproxen and prescription NSAIDs.

Corticosteroids may be injected into an arthritic joint after joint aspiration.

Topical pain relievers (creams, rubs or sprays applied directly to the skin).

Other treatment strategies for osteoarthritis include physical therapy, aerobic exercise that does not put undue stress on the joints, and maintaining a normal weight or losing weight. Ultimately, in some cases, surgery may be needed to remove bone spurs within a joint, reposition the bones or otherwise repair bony damage. Some patients may need to have their damaged joints surgically replaced with artificial ones.

Is osteoarthritis the same as osteoporosis?

No, although the two conditions may sound similar. Osteoarthritis is a type of arthritis involving damage to joints. Osteoporosis is an unrelated disease in which bones gradually lose their mass and become weak and brittle. Eventually, people with osteoporosis may suffer vertebral fractures as the bone fails to support the weight of the spinal column or hip fractures after minor falls.

Osteoporosis is best prevented by building strong bone over the years by consuming enough calcium from food or supplements, not smoking and doing weight-bearing exercise. In contrast, your calcium intake does not directly affect your risk for osteoarthritis.

What is the difference between osteoarthritis and rheumatoid arthritis?

Osteoarthritis is usually found in middle-aged to older people, developing slowly over many years. Inflammation of the joints is not very common, although pain, stiffness and limitation of motion may be present. If one joint is affected, the corresponding joint on the other side of the body may not be. In addition, pain is usually limited to the affected joint. Weight-bearing joints like the knees and hips are most often involved. Patients may get up in the morning with joint stiffness, but it usually goes away gradually as the joint is used.

Rheumatoid arthritis is usually first manifested in people between ages 25 and 50 but can occur in young children and even small babies. The disorder may develop quickly after the first symptoms appear, over several weeks or months. It typically causes inflammation of the joints and usually involves the joints on both sides of the body. Many joints may be affected. Patients may have a sense of overall sickness and fatigue, and may have fever and lose weight. Morning joint stiffness may be prolonged.

Points to remember

Osteoarthritis is the "wear and tear" form of arthritis, typically affecting middle-aged and older people.

Osteoarthritis is often caused by mechanical joint stress over years, although it may also be triggered by joint injury or caused by heredity.

The symptoms of osteoarthritis are typically pain and stiffness, with inflammation less common. Morning stiffness is usually brief. The affected joint may have limited movement with loss of function.

Treatments for osteoarthritis include medications to reduce pain and (when needed) relieve inflammation, physical therapy and exercise, maintaining a normal weight or losing weight, and surgery when needed.

Osteoarthritis and osteoporosis are two different disorders. They both involve bone, which is why both words contain osteo.

Osteoarthritis and rheumatoid arthritis affect people in different ways. Someone with osteoarthritis may experience pain and stiffness in an isolated joint or joints. A person with rheumatoid arthritis may experience an overall feeling of sickness and fatigue, as well as joint pain, stiffness and inflammation.

For help in managing your arthritis, see your doctor. You may find helpful information on Web sites of organizations that offer support, such as the Arthritis Foundation.