Osteoarthritis (OA) is the most common form of arthritis. Some people call it degenerative joint disease or “wear and tear” arthritis. It occurs most frequently in the hands, hips, and knees.
- Arthritis due to damage of joint cartilage and surrounding tissues becomes very common with aging.
- Pain, swelling, and bony overgrowth are common, as well as stiffness that follows awakening or inactivity and disappears within 30 minutes, particularly if the joint is moved.
- The diagnosis is based on symptoms and x-rays.
- Treatment includes exercises and other physical measures, drugs that reduce pain and improve function, and, for very severe changes, joint replacement or other surgery.
Osteoarthritis, the most common joint disorder, often begins in the 40s and 50s and affects almost all people to some degree by age 80. Before the age of 40, men develop osteoarthritis more often than do women, often because of injury or deformities. Many people have some evidence of osteoarthritis on x-rays (often by age 40), but only half of these people have symptoms. From age 40 to 70, women develop the disorder more often than do men. After age 70, the disorder develops in both sexes equally.
With OA, the cartilage within a joint begins to break down and the underlying bone begins to change. These changes usually develop slowly and get worse over time. OA can cause pain, stiffness, and swelling. In some cases it also causes reduced function and disability; some people are no longer able to do daily tasks or work.
In primary (or idiopathic) osteoarthritis, the cause is not known (as in the large majority of cases).
Primary osteoarthritis may affect only certain joints, such as the knee, or many joints.
In secondary osteoarthritis, the cause is another disease or condition, such as
- An infection
- A joint abnormality that appeared at birth
- An injury
- A metabolic disorder—for example, excess iron in the body (hemochromatosis) or excess copper in the liver (Wilson disease)
- A disorder that has damaged joint cartilage—for example, rheumatoid arthritis or gout
Some people who repetitively stress one joint or a group of joints, such as foundry workers, farmers, coal miners, and bus drivers, are particularly at risk. The major risk factor for osteoarthritis of the knee comes from having an occupation that involves bending the joint. Curiously, long-distance running does not increase the risk of developing the disorder. However, once osteoarthritis develops, this type of exercise often makes the disorder worse. Obesity may be a major factor in the development of osteoarthritis, particularly of the knee and especially in women.
Symptoms of Osteoarthritis
Symptoms range from stiffness and mild pain that comes and goes to severe joint pain. Common signs include joint pain, swelling, and tenderness; stiffness after getting out of bed; and a crunching feeling or sound of bone rubbing on bone. Not everyone with osteoarthritis feels pain.
Osteoarthritis most commonly affects the hands, lower back, neck, and weight-bearing joints such as knees, hips, and feet. Osteoarthritis affects just joints, not internal organs.
Osteoarthritis of the hands seems to run in families. If your mother or grandmother has or had osteoarthritis in their hands, you’re at greater-than-average risk of having it, too. Women are more likely than men to have osteoarthritis in the hands. For most women, it develops after menopause.
When osteoarthritis involves the hands, small, bony knobs may appear on the end joints (those closest to the nails) of the fingers. They are called Heberden’s (HEBerr-denz) nodes. Similar knobs, called Bouchard’s (boo-SHARDZ) nodes, can appear on the middle joints of the fingers. Fingers can become enlarged and gnarled, and they may ache or be stiff and numb. The base of the thumb joint also is commonly affected by osteoarthritis.
The knees are among the joints most commonly affected by osteoarthritis. Symptoms of knee osteoarthritis include stiffness, swelling, and pain, which make it hard to walk, climb, and get in and out of chairs and bathtubs. Osteoarthritis in the knees can lead to disability.
The hips are also common sites of osteoarthritis. As with knee osteoarthritis, symptoms of hip osteoarthritis include pain and stiffness of the joint itself. But sometimes pain is felt in the groin, inner thigh, buttocks, or even the knees. Osteoarthritis of the hip may limit moving and bending, making daily activities such as dressing and putting on shoes a challenge.
Osteoarthritis of the spine may show up as stiffness and pain in the neck or lower back. In some cases, arthritis-related changes in the spine can cause pressure on the nerves where they exit the spinal column, resulting in weakness, tingling, or numbness of the arms and legs. In severe cases, this can even affect bladder and bowel function.
How many people have OA?
OA affects over 32.5 million US adults.
What causes OA?
OA is caused by damage or breakdown of joint cartilage between bones.
What are the risk factors for OA?
- Joint injury or overuse—Injury or overuse, such as knee bending and repetitive stress on a joint, can damage a joint and increase the risk of OA in that joint.
- Age—The risk of developing OA increases with age.
- Gender—Women are more likely to develop OA than men, especially after age 50.
- Obesity—Extra weight puts more stress on joints, particularly weight-bearing joints like the hips and knees. This stress increases the risk of OA in that joint. Obesity may also have metabolic effects that increase the risk of OA.
- Genetics—People who have family members with OA are more likely to develop OA. People who have hand OA are more likely to develop knee OA.
- Race— Some Asian populations have lower risk for OA.
How is OA diagnosed?
A doctor diagnoses OA through a review of symptoms, physical examination, X-rays, and lab tests.
A rheumatologist, a doctor who specializes in arthritis and other related conditions, can help if there are any questions about the diagnosis.
How is OA treated?
There is no cure for OA, so doctors usually treat OA symptoms with a combination of therapies, which may include the following:
- Increasing physical activity
- Physical therapy with muscle strengthening exercises
- Weight loss
- Medications, including over-the-counter pain relievers and prescription drugs
- Supportive devices such as crutches or canes
- Surgery (if other treatment options have not been effective)
In addition to these treatments, people can gain confidence in managing their OA with self-management strategies.
How is osteoarthritis treated?
The goals of your treatment for osteoarthritis include:
- Reducing pain and other symptoms.
- Improving joint function.
- Stopping the disease from getting worse.
- Maintaining your quality of life.
Treating osteoarthritis usually includes:
- Exercising, which can lower joint pain and stiffness and increase flexibility and muscle strength. Speak to your doctor or physical therapist about a safe, well-rounded exercise program. Remember to start any exercise program slowly and take the time to adjust to the new level of activity.
- Managing your weight to help lower the stress on joints. In addition, if you are overweight or obese, losing weight can help to lower pain, prevent more injury, and improve movement in your joints. This can be especially helpful for your knees or hips.
- Using braces or orthotics that your doctor prescribes and that are fitted by a health care professional.
Some people may need medications to help manage the symptoms of osteoarthritis. Your doctor may recommend surgery if all other treatments tried have not helped your osteoarthritis. However, surgery is not right for everyone, and your doctor will decide if it’s best for you.