Osteoarthritis (AH-stee-oh-ar-THREYE-tis) is the most common type of arthritis, especially among older people. Sometimes it is called degenerative joint disease or osteoarthrosis.
Osteoarthritis is a joint disease that mostly affects the cartilage (KAR-til-uj). Cartilage is the slippery tissue that covers the ends of bones in a joint. Healthy cartilage allows bones to glide over one another. It also absorbs energy from the shock of physical movement. In osteoarthritis, the surface layer of cartilage breaks down and wears away. This allows bones under the cartilage to rub together, causing pain, swelling, and loss of motion of the joint. Over time, the joint may lose its normal shape. Also, bone spurs--small growths called osteophytes--may grow on the edges of the joint. Bits of bone or cartilage can break off and float inside the joint space. This causes more pain and damage.
People with osteoarthritis usually have joint pain and limited movement. Unlike some other forms of arthritis, osteoarthritis affects only joints and not internal organs. For example, rheumatoid arthritis--the second most common form of arthritis--affects other parts of the body besides the joints. It begins at a younger age than osteoarthritis, causes swelling and redness in joints, and may make people feel sick, tired, and (uncommonly) feverish.
Who Has Osteoarthritis?
Osteoarthritis is one of the most frequent causes of physical disability among adults. More than 20 million people in the United States have the disease. By 2030, 20 percent of Americans--about 70 million people--will have passed their 65th birthday and will be at risk for osteoarthritis. Some younger people get osteoarthritis from joint injuries, but osteoarthritis most often occurs in older people. In fact, more than half of the population age 65 or older would show x-ray evidence of osteoarthritis in at least one joint. Both men and women have the disease. Before age 45, more men than women have osteoarthritis, whereas after age 45, it is more common in women.
How Does Osteoarthritis Affect People?
Osteoarthritis affects each person differently. In some people, it progresses quickly; in others, the symptoms are more serious. Scientists do not know yet what causes the disease, but they suspect a combination of factors, including being overweight, the aging process, joint injury, and stresses on the joints from certain jobs and sports activities.
What Areas Does Osteoarthritis Affect?
Osteoarthritis most often occurs at the ends of the fingers, thumbs, neck, lower back, knees, and hips. Osteoarthritis hurts people in more than their joints: their finances and lifestyles also are affected.
Financial effects include
- The cost of treatment
- Wages lost because of disability.
Lifestyle effects include
- Feelings of helplessness
- Limitations on daily activities
- Job limitations
- Trouble participating in everyday personal and family joys and responsibilities.
Despite these challenges, most people with osteoarthritis can lead active and productive lives. They succeed by using osteoarthritis treatment strategies, such as the following:
- Pain relief medications
- Rest and exercise
- Patient education and support programs
- Learning self-care and having a "good-health attitude."
Osteoarthritis Basics: The Joint and Its Parts
Most joints--the place where two moving bones come together--are designed to allow smooth movement between the bones and to absorb shock from movements like walking or repetitive movements. The joint is made up of:
- Cartilage: a hard but slippery coating on the end of each bone. Cartilage, which breaks down and wears away in osteoarthritis, is described in more detail below.
- Joint capsule: a tough membrane sac that holds all the bones and other joint parts together.
- Synovium (sin-O-vee-um): a thin membrane inside the joint capsule.
- Synovial fluid: a fluid that lubricates the joint and keeps the cartilage smooth and healthy.
- Ligaments, tendons, and muscles: tissues that keep the bones stable and allow the joint to bend and move. Ligaments are tough, cord-like tissues that connect one bone to another. Tendons are tough, fibrous cords that connect muscles to bones. Muscles are bundles of specialized cells that contract to produce movement when stimulated by nerves.
How Do You Know if You Have Osteoarthritis?
Usually, osteoarthritis comes on slowly. Early in the disease, joints may ache after physical work or exercise. Osteoarthritis can occur in any joint. Most often it occurs at the hands, knees, hips, or spine.
Osteoarthritis of the fingers is one type of osteoarthritis that seems to have some hereditary characteristics; that is, it runs in families. More women than men have it, and they develop it especially after menopause. In osteoarthritis, small, bony knobs appear on the end joints of the fingers. They are called Heberden's (HEB-err-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. Osteoarthritis of the hands can be helped by medications, splints, or heat treatment.
Cartilage: The Key to Healthy Joints
Cartilage is 65 to 80 percent water. Three other components make up the rest of cartilage tissue: collagen, proteoglycans, and chondrocytes.
- Collagen (KAHL-uh-jen): a fibrous protein. Collagen is also the building block of skin, tendon, bone, and other connective tissues.
- Proteoglycans (PRO-tee-uh-GLY-kanz): a combination of proteins and sugars. Strands of proteoglycans and collagen weave together and form a mesh-like tissue. This allows cartilage to flex and absorb physical shock.
- Chondrocytes (KAHN-druh-sytz): cells that are found all through the cartilage. They mainly help cartilage stay healthy and grow. Sometimes, however, they release substances called enzymes that destroy collagen and other proteins. Researchers are trying to learn more about chondrocytes.
The knees are the body's primary weight-bearing joints. For this reason, they are among the joints most commonly affected by osteoarthritis. They may be stiff, swollen, and painful, making it hard to walk, climb, and get in and out of chairs and bathtubs. If not treated, osteoarthritis in the knees can lead to disability. Medications, weight loss, exercise, and walking aids can reduce pain and disability. In severe cases, knee replacement surgery may be helpful.
Osteoarthritis in the hip can cause pain, stiffness, and severe disability. People may feel the pain in their hips, or in their groin, inner thigh, buttocks, or knees. Walking aids, such as canes or walkers, can reduce stress on the hip. Osteoarthritis in the hip may limit moving and bending. This can make daily activities such as dressing and foot care a challenge. Walking aids, medication, and exercise can help relieve pain and improve motion. The doctor may recommend hip replacement if the pain is severe and not relieved by other methods.
Stiffness and pain in the neck or in the lower back can result from osteoarthritis of the spine. Weakness or numbness of the arms or legs also can result. Some people feel better when they sleep on a firm mattress or sit using back support pillows. Others find it helps to use heat treatments or to follow an exercise program that strengthens the back and abdominal muscles. In severe cases, the doctor may suggest surgery to reduce pain and help restore function.
The Warning Signs of Osteoarthritis
- Steady or intermittent pain in a joint
- Stiffness in a joint after getting out of bed or sitting for a long time
- Swelling or tenderness in one or more joints
- A crunching feeling or the sound of bone rubbing on bone
- Hot, red, or tender? Probably not osteoarthritis. Check with your doctor about other causes, such as rheumatoid arthritis.
*Pain? Not always. In fact, only a third of people whose x-rays show evidence of osteoarthritis report pain or other symptoms.
No single test can diagnose osteoarthritis. Most doctors use a combination of the following methods to diagnose the disease and rule out other conditions:
The doctor begins by asking the patient to describe the symptoms, and when and how the condition started. Good doctor-patient communication is important. The doctor can give a better assessment if the patient gives a good description of pain, stiffness, and joint function, and how they have changed over time. It also is important for the doctor to know how the condition affects the patient's work and daily life. Finally, the doctor also needs to know about other medical conditions and whether the patient is taking any medicines.
The doctor will check the patient's general health, including checking reflexes and muscle strength. Joints bothering the patient will be examined. The doctor will also observe the patient's ability to walk, bend, and carry out activities of daily living.
Doctors take x-rays to see how much joint damage has been done. X-rays of the affected joint can show such things as cartilage loss, bone damage, and bone spurs. But there often is a big difference between the severity of osteoarthritis as shown by the x ray and the degree of pain and disability felt by the patient. Also, x-rays may not show early osteoarthritis damage, before much cartilage loss has taken place.
The doctor may order blood tests to rule out other causes of symptoms. Another common test is called joint aspiration, which involves drawing fluid from the joint for examination.
It usually is not difficult to tell if a patient has osteoarthritis. It is more difficult to tell if the disease is causing the patient's symptoms. Osteoarthritis is so common--especially in older people--that symptoms seemingly caused by the disease actually may be due to other medical conditions. The doctor will try to find out what is causing the symptoms by ruling out other disorders and identifying conditions that may make the symptoms worse. The severity of symptoms in osteoarthritis is influenced greatly by the patient's attitude, anxiety, depression, and daily activity level.
Most successful treatment programs involve a combination of treatments tailored to the patient's needs, lifestyle, and health. Osteoarthritis treatment has four general goals:
- Improve joint care through rest and exercise.
- Maintain an acceptable body weight.
- Control pain with medicine and other measures.
- Achieve a healthy lifestyle.
Treatment Approaches to Osteoarthritis
- Weight control
- Rest and joint care
- Pain relief techniques
- Alternative therapies
Osteoarthritis treatment plans often include ways to manage pain and improve function. Such plans can involve exercise, rest and joint care, pain relief, weight control, medicines, surgery, and nontraditional treatment approaches.
Research shows that exercise is one of the best treatments for osteoarthritis. Exercise can improve mood and outlook, decrease pain, increase flexibility, improve the heart and blood flow, maintain weight, and promote general physical fitness. Exercise is also inexpensive and, if done correctly, has few negative side effects. The amount and form of exercise will depend on which joints are involved, how stable the joints are, and whether a joint replacement has already been done.
On the Move: Fighting Osteoarthritis With Exercise
You can use exercises to keep strong and limber, extend your range of movement, and reduce your weight.
Some different types of exercise include the following:
These can be performed with exercise bands, inexpensive devices that add resistance.
These keep your lungs and circulation systems in shape.
Range of motion activities:
These keep your joints limber.
These can help you maintain daily living skills.
Neck and back strength exercises:
These can help you keep your spine strong and limber.
Ask your doctor or physical therapist what exercises are best for you. Ask for guidelines on exercising when a joint is sore or if swelling is present. Also, check if you should (1) use pain-relieving drugs, such as analgesics or anti-inflammatories (also called NSAIDs), to make exercising easier, or (2) use ice afterwards.
Rest and joint care:
Treatment plans include regularly scheduled rest. Patients must learn to recognize the body's signals, and know when to stop or slow down, which prevents pain caused by overexertion. Some patients find that relaxation techniques, stress reduction, and biofeedback help. Some use canes and splints to protect joints and take pressure off them. Splints or braces provide extra support for weakened joints. They also keep the joint in proper position during sleep or activity. Splints should be used only for limited periods because joints and muscles need to be exercised to prevent stiffness and weakness. An occupational therapist or a doctor can help the patient get a properly fitting splint.
Nondrug pain relief:
People with osteoarthritis may find nondrug ways to relieve pain. Warm towels, hot packs, or a warm bath or shower to apply moist heat to the joint can relieve pain and stiffness. In some cases, cold packs (a bag of ice or frozen vegetables wrapped in a towel can relieve pain or numb the sore area. (Check with a doctor or physical therapist to find out if heat or cold is the best treatment.) Water therapy in a heated pool or whirlpool also may relieve pain and stiffness. For osteoarthritis in the knee, patients may wear insoles or cushioned shoes to redistribute weight and reduce joint stress.
Osteoarthritis patients who are overweight or obese need to lose weight. Weight loss can reduce stress on weight-bearing joints and limit further injury. A dietitian can help patients develop healthy eating habits. A healthy diet and regular exercise help reduce weight.
Doctors prescribe medicines to eliminate or reduce pain and to improve functioning. Doctors consider a number of factors when choosing medicines for their patients with osteoarthritis. Two important factors are the intensity of the pain and the potential side effects of the medicine. Patients must use medicines carefully and tell their doctors about any changes that occur.
The following types of medicines are commonly used in treating osteoarthritis:
- Acetaminophen: Acetaminophen is a pain reliever (for example, Tylenol*) that does not reduce swelling. Acetaminophen does not irritate the stomach and is less likely than nonsteroidal anti-inflammatory drugs (NSAIDs) to cause long-term side effects. Research has shown that acetaminophen relieves pain as effectively as NSAIDs for many patients with osteoarthritis.
Warning: People with liver disease, people who drink alcohol heavily, and those taking blood- thinning medicines or NSAIDs should use acetaminophen with caution.
*Note: Brand names included in this booklet are provided as examples only. Their inclusion does not mean they are endorsed by the National Institutes of Health or any other Government agency. Also, if a certain brand name is not mentioned, this does not mean or imply that the product is unsatisfactory.
- NSAIDs (nonsteroidal anti-inflammatory drugs): Many NSAIDs are used to treat osteoarthritis. Patients can buy some over the counter (for example, aspirin, Advil, Motrin IB, Aleve, ketoprofen). Others require a prescription. All NSAIDs work similarly: they fight inflammation and relieve pain. However, each NSAID is a different chemical, and each has a slightly different effect on the body.
NSAIDs can cause stomach irritation or, less often, they can affect kidney function. The longer a person uses NSAIDs, the more likely he or she is to have side effects, ranging from mild to serious. Many other drugs cannot be taken when a patient is being treated with NSAIDs because NSAIDs alter the way the body uses or eliminates these other drugs. Check with your health care provider or pharmacist before you take NSAIDs in addition to another medication. Also, NSAIDs sometimes are associated with serious gastrointestinal problems, including ulcers, bleeding, and perforation of the stomach or intestine. People over age 65 and those with any history of ulcers or gastrointestinal bleeding should use NSAIDs with caution.
Several new NSAIDs--valdecoxib (Bextra), celecoxib (Celebrex), and rofecoxib (Vioxx)--from a class of drugs known as COX-2 inhibitors are now being used to treat osteoarthritis. These medicines reduce inflammation similarly to traditional NSAIDs, but they cause fewer gastrointestinal side effects. However, these medications occasionally are associated with harmful reactions ranging from mild to severe. (See Current Research.)
- Other medications: Doctors may prescribe several other medicines for osteoarthritis, including the following:Topical pain-relieving creams, rubs, and sprays (for example, capsaicin cream), which are applied directly to the skin.
Mild narcotic painkillers, which--although very effective--may be addictive and are not commonly used.
Corticosteroids, powerful anti-inflammatory hormones made naturally in the body or manmade for use as medicine. Corticosteroids may be injected into the affected joints to temporarily relieve pain. This is a short-term measure, generally not recommended for more than two or three treatments per year. Oral corticosteroids should not be used to treat osteoarthritis.
Hyaluronic acid, a medicine for joint injection, used to treat osteoarthritis of the knee. This substance is a normal component of the joint, involved in joint lubrication and nutrition.
For many people, surgery helps relieve the pain and disability of osteoarthritis. Surgery may be performed to
- Remove loose pieces of bone and cartilage from the joint if they are causing mechanical symptoms of buckling or locking
- Resurface (smooth out) bones
- Reposition bones
- Replace joints.
Surgeons may replace affected joints with artificial joints called prostheses. These joints can be made from metal alloys, high-density plastic, and ceramic material. They can be joined to bone surfaces by special cements. Artificial joints can last 10 to 15 years or longer. About 10 percent of artificial joints may need revision. Surgeons choose the design and components of prostheses according to their patient's weight, sex, age, activity level, and other medical conditions.
The decision to use surgery depends on several things. Both the surgeon and the patient consider the patient's level of disability, the intensity of pain, the interference with the patient's lifestyle, the patient's age, and occupation. Currently, more than 80 percent of osteoarthritis surgery cases involve replacing the hip or knee joint. After surgery and rehabilitation, the patient usually feels less pain and swelling, and can move more easily.
Source: National Institute of Arthritis and Musculoskeletal and Skin Diseases
Last Reviewed: July 2001
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