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•	Surgery
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Osteoarthritis

Highlights

Overview:

Osteoarthritis, also known as degenerative joint disease, is the most common form of arthritis. It is a long-term disease of the joint cartilage and bone, commonly thought to result from "wear and tear" on a joint. There are also other causes, such as some birth defects, trauma, and metabolic disorders.

Risk Factors:

• In people younger than 45, osteoarthritis occurs more frequently in males. After age 45, it develops more often in females.
• Obesity places people (particularly women) at a higher risk for osteoarthritis.
• Some occupations with repeated stressful motions can contribute to the deterioration of cartilage.

Exercise: Three types of exercise are best for people with osteoarthritis:

• Strengthening exercises, which include isometric exercises (pushing or pulling against static resistance). For patients with arthritis in the hip or knees, exercises that strengthen the muscles of the upper leg are important.
• Range-of-motion exercises increase the amount of movement in a joint and muscle.
• Aerobic, or endurance, exercises help control weight and may reduce inflammation in some joints.

Complementary Medicine:

• Acupuncture appears to be a safe and may be a helpful addition to standard therapy for some patients, such as pregnant women, who cannot take most pain medications.

Surgery:

• A recent study found that elderly patients with poorly controlled osteoarthritis do very well after joint replacement surgery. However, physicians often neglect to suggest this option to older patients.
• A variation on the traditional hip replacement is the newer procedure known as minimally invasive hip replacement. This surgeion must be extremely experienced. The procedure uses special instruments and a shorter incision (3 - 6 inches vs. 10 - 12 inches in traditional hip replacement).

Introduction

Osteoarthritis, also known as degenerative joint disease, is the most common form of arthritis. Scientists now believe osteoarthritis results from a combination of genetic problems and joint injuries. In this disorder, a joint loses cartilage, the slippery material that cushions the ends of bones, over time.

Osteoarthritis is a chronic disease of the joint cartilage and bone, often thought to result from "wear and tear" on a joint. There are other causes, such as birth defects, trauma, and metabolic disorders. Joints appear larger, are stiff and painful, and usually feel worse with increased use throughout the day.

As a result, the bone beneath the cartilage changes and develops bony overgrowth. The tissue that lines the joint can become inflamed, the ligaments can loosen, and the muscles around the joint can weaken. The patient feels pain when using the joint. Nearly all vertebrates suffer from osteoarthritis, including porpoises and whales, as did dinosaurs.

Click the icon to see an animation about osteoarthritis.

Joints

Joints provide flexibility, support, stability, and protection. Specific parts of the joint: the synovium and cartilage, provide these functions.

Synovium. The synovium is the fluid-filled lining of a joint. Synovial fluid is a lubricating liquid that supplies nutrients and oxygen to cartilage.

Cartilage. The cartilage is a slippery tissue that coats the ends of the bones. Cartilage is one of the few tissues in the body that does not have its own blood supply. It has a number of essential parts, including:

Click the icon to see an image of the synovial membrane and cartilage in the knee joint.

• Chondrocytes. Chondrocytes, the basic cartilage cells, are critical for balance and function.
• Water. Cartilage contains a lot of water, which decreases with age. About 85% of cartilage is water in young people. Cartilage in older people is about 70% water.
• Proteoglycans. These large molecules help make up cartilage. They are important because they can bond to water, which keeps high amounts of water in cartilage.
• Collagen. This essential protein in cartilage forms a mesh to give the joint support and flexibility. Collagen is the main protein found in all connective tissues of the body, including the muscles, ligaments, and tendons.

The combination of collagen mesh and water forms a strong and slippery pad in the joint. This pad cushions the ends of the bones in the joint during muscle movement.

Osteoarthritis: The Disease Process

Deterioration of Cartilage. Osteoarthritis develops when cartilage in a joint deteriorates. The process is usually slow.

• In the early stages of disease, the surface of the cartilage, or the synovium (joint lining) in some people, becomes inflamed and swollen. The joint loses proteoglycan molecules and other tissues. This joint then begins to lose water. Fissures and pits appear in the cartilage.
• As the disease progresses and more tissue is lost, the cartilage starts to get hard. As a result, it becomes increasingly prone to damage from repetitive use and injury.
• Eventually, large amounts of cartilage are destroyed, leaving the ends of the bone within the joint unprotected.

Complicating the process are abnormalities in the bone around arthritic joints. As the body tries to repair damage to the cartilage, problems can develop:

• Clusters of damaged cells or fluid-filled cysts may form around the bony areas or near the fissures in the cartilage.
• Fluid pockets may also form within the bone marrow itself, causing swelling. The marrow, which runs up through the center of the bone, is rich in nerve fibers. As a result, these injuries may cause a lot of pain in many patients with osteoarthritis.
• Bone cells may respond to damage by multiplying, growing, and forming dense, misshapen plates around exposed areas.
• At the margins of the joint, the bone may produce outcroppings, on which new cartilage cells (chondrocytes) multiply and grow abnormally.

Location of Osteoarthritis

Unlike some other types of arthritis, such as rheumatoid arthritis, osteoarthritis does not spread through the entire body. Rather, it affects one or several joints. Osteoarthritis affects joints differently depending on their location in the body.

• It is common in joints of the fingers, feet, knees, hips, and spine.
• It sometimes occurs in the wrist, elbows, shoulders, and jaw, but it is not common in these locations.

Causes

The biological factors leading to the deterioration of cartilage in osteoarthritis are not entirely understood. Many experts believe that osteoarthritis results from a genetic susceptibility that causes some biological response to injuries to the joint, which in turn leads to progressive deterioration of cartilage. In addition, the body's ability to repair cartilage decreases with increasing age.

Aging Cells

Although osteoarthritis generally accompanies aging, osteoarthritic cartilage is chemically different from normal cartilage of the same age. As chondrocytes (the cells that make up cartilage) age, they lose their ability to make repairs and produce more cartilage. This process may play an important role in the development and progression of osteoarthritis.

Genetic Factors

Researchers report a high correlation of osteoarthritis between parents and children, and between siblings. Genetic factors may be involved in about half of osteoarthritis cases in the hands and hips, and in a somewhat lower percentage of cases in the knee. Several genes that might contribute to an inherited risk are under investigation. For example, mutations in the ank gene may be important in some cases. The ank gene regulates pyrophosphate, a chemical that inhibits the formation of mineral deposits, and may protect the cartilage in joints. About 60% of people with osteoarthritis have mineral deposits in their cartilage. Mutations in the ank gene may result in lower pyrophosphate levels in the joint, leading to accumulation of mineral deposits and arthritis.

Another gene, called the osteoprotegerin gene, is important in regulating bone and cartilage formation. Mutations in this gene may also play a role in osteoarthritis.

Inflammatory Response and Matrix Metalloproteinases

The inflammatory response is an overreaction of the immune system to an injury or other assault in the body, such as an infection. This response causes specific immune factors, called cytokines, to gather in injured areas and cause inflammation and damage to body tissue and cells. The inflammatory response plays an important role in rheumatoid arthritis and other muscle and joint problems associated with autoimmune diseases.

Inflammation probably plays at most a minor role in the formation of osteoarthritis and is more likely to be a result -- not a cause -- of the disease. However, inflammation may play an important role in the progression of osteoarthritis and in its chronic nature. The effects of the inflammatory response in osteoarthritis are likely to be different, and less severe, from those in rheumatoid arthritis.

Some theories on how the inflammatory response may contribute to osteoarthritis involve overproduction of enzymes called matrix metalloproteinases or MMPs (also called collagenases). Large amounts of MMPs break down collagen, the building blocks of cartilage. Some studies suggest that immune factors called vascular endothelial growth factor (VEGF) are overproduced during the inflammatory response and in turn increase production of MMPs.

Another theory suggests that the inflammatory response is triggered by the changes and injuries in the bone that occur during osteoarthritis. According to this theory, the cartilage absorbs the immune factors released in this process. Once in the cartilage, these immune factors suppress cartilage cell growth, and activate MMPs.

Abnormal stress or Injuries

Joint damage from injuries or recurrent stress to the joint is the starting point in the osteoarthritis disease process. Osteoarthritis sometimes develops years after a single traumatic injury to or near a joint. Patients with knee injuries may be up to five times more likely to have osteoarthritis in the injured knee than those without injuries, and patients with hip injuries may be more than three times more likely to develop arthritis in the injured hip. Proper treatment of injuries, such as surgical repair of ligament tears in the knee with a strong rehabilitation approach, may help prevent the development of osteoarthritis.

Other Medical Conditions that Can Cause Osteoarthritis

Other causes of osteoarthritis include:

• Bleeding disorders that cause bleeding in the joint, such as hemophilia
• Disorders that block the blood supply near a joint, such as avascular necrosis
• Complications of persistent, inflammatory arthritic conditions, particularly chronic gout, pseudogout, or rheumatoid arthritis
• Conditions that cause iron build-up in the joints, such as hemochromatosis

Symptoms

The pain of osteoarthritis typically begins gradually and progresses slowly over many years. People under age 40 may have the condition with no symptoms at all. Osteoarthritis is commonly identified by the following symptoms:

• Pain that worsens during activity and gets better during rest. This is the most common symptom of osteoarthritis. As the disease advances, the pain may occur even when the joint is at rest.
• Pain is generally described as aching, stiffness, and loss of mobility. The symptoms are often worse when resuming activities after periods of no activity.
• The pain may be intermittent, with bad spells followed by periods of relative relief.
• Pain seems to increase in humid weather.
• Some people have muscle spasm and contractions in the tendons.
• Osteoarthritis in the knee may cause a crackling-like noise (called crepitus) when moved.

Symptoms by Location

Hand. Osteoarthritis of the hand occurs most often in older women and may be inherited within families. The following joints are most frequently affected:

• Distal interphalangeal (DIP) joint. The first joint below the fingertips is the most common location of osteoarthritis of the hand. These joints can develop bony growths known as Heberden's nodes.
• Carpometacarpal (CMC) joint. The joint at the base of the thumb, where the thumb joint connects with the wrist, is the second most common location.
• Proximal interphalangeal (PIP) joint. The middle joints of the fingers can also develop osteoarthritis. These joints may develop small, solid lumps (nodules) known as Bouchard's nodes.

Click the icon to see an image of osteoarthritis.

Osteoarthritis of the hand may predict the later development of osteoarthritis in the hip or knee.

Knee. Osteoarthritis is particularly debilitating in the weight-bearing joints of the knees. The meniscus, the cartilage pad between the joint formed by the thighbone and the shinbone, plays an important role in protecting this joint. It acts as a shock absorber. The joint is usually stable until the disease reaches an advanced stage when the knee becomes enlarged and swollen. Although painful, the arthritic knee usually retains reasonable flexibility.

In a knee surgery called meniscectomy, the doctor removes damaged meniscus (cartilage) after an injury. However, preserving the meniscus, even if it is damaged, is believed to be better than removing it, since even a small amount of meniscus helps protect the joint and prevent osteoarthritis from worsening. Experts recommend that patients try lifestyle changes (exercise and weight loss), braces, and medication before having knee surgery.

Click the icon to see an image of the knee joint.

Hips. About 1 in 4 people will develop hip arthritis over the course of their lifetime. Being obese increases the risk. Osteoarthritis frequently strikes the weight-bearing joints in one or both hips. Pain develops slowly, usually in the groin and on the outside of the hips, or sometimes in the buttocks. The pain also may radiate to the knee, confusing the diagnosis. Those with osteoarthritis of the hip often have a restricted range of motion (particularly when trying to rotate the hip) and walk with a limp, because they slightly turn the affected leg to avoid pain.

Click the icon to see an image of the hip joint.

Spine. Osteoarthritis may affect the cartilage in the disks that form cushions between the bones of the spine, the moving joints of the spine itself, or both. Osteoarthritis in any of these locations can cause pain, muscle spasms, and diminished mobility. In some cases, the nerves may become pinched, which also produces pain. Advanced disease may result in numbness and muscle weakness. Osteoarthritis of the spine is most troublesome when it occurs in the lower back or in the neck, where it can cause difficulty in swallowing.

Click the icon to see an image of the spine.

Shoulder. Osteoarthritis is less common in the shoulder area than in other joints, but it may develop in the shoulder joint (the glenohumeral joint). In such cases, it is most often associated with a previous injury, and patients gradually develop pain and stiffness in the back of the shoulder. Osteoarthritis also can develop in the acromioclavicular (AC) joint, which is between the shoulder blade and the collarbone. However, it rarely causes symptoms in this location.

Conditions with Similar Symptoms

Numerous conditions cause symptoms of joint aches and pains. Something as simple as sleeping on a bad mattress or as serious as cancer can mirror symptoms of osteoarthritis. Other problems that can cause aches and pains in the joints include physical injuries, infections, tendinitis, and poor circulation. A number of rare genetic diseases attack the joints.

Osteoarthritis can generally be distinguished from other joint diseases by considering several factors together:

• Osteoarthritis usually occurs in older people and is located in only one or a few joints.
• The joints are less inflamed than in other arthritic conditions.
• Progression of pain is usually gradual.

Below are a few of the most common disorders that can be confused with, or may even accompany, osteoarthritis.

Rheumatoid Arthritis

Osteoarthritis may be confused with rheumatoid arthritis, particularly when osteoarthritis affects multiple joints in the body. Rheumatoid arthritis begins in the synovial membrane rather than the cartilage. It normally occurs earlier in life than osteoarthritis, often striking people in their 30s and 40s. Rheumatoid arthritis affects many joints, and often occurs symmetrically on both sides of the body. People with rheumatoid arthritis generally have morning stiffness that lasts for at least an hour. (Stiffness from osteoarthritis usually clears up within half an hour.) Although osteoarthritis can occasionally cause swollen, red joints, this appearance is much more typical of rheumatoid arthritis and other types of inflammatory arthritis.

X-rays of joints affected with rheumatoid arthritis show changes in the bones that differ from those occurring in osteoarthritis. In rheumatoid arthritis, blood tests often show a specific antibody, known as rheumatoid factor, which is not present with osteoarthritis. In another blood test, levels of a factor called erythrocyte sedimentation rate (ESR) are often elevated in rheumatoid arthritis, but they are generally normal in osteoarthritis. Rheumatoid arthritis also does not usually show up in the fingertips where osteoarthritis is common.

Rheumatoid arthritis is a body-wide (systemic) autoimmune disease that initially attacks the synovium, a connective tissue membrane that lines the cavity between joints and secretes a lubricating fluid.

Click the icon to see an image of osteoarthritis vs. rheumatoid arthritis.

Chondrocalcinosis

Chondrocalcinosis is a disease in which calcium crystals known as CPPD (calcium pyrophosphate dihydrate) accumulate in the joints. This condition affects about 25% of the population and can accompany and even worsen osteoarthritis. Chondrocalcinosis has been called pseudogout or pseudo-osteoarthritis, the latter particularly when it affects the knees. A doctor can usually differentiate between the two disorders, however, because chondrocalcinosis usually damages other joints (such as wrists, elbows, and shoulders) that are not normally affected by osteoarthritis. The condition may explain why some patients with osteoarthritis benefit from colchicine, a drug used for gout and other crystal-induced joint diseases.

Charcot's Joint

Charcot's joint occurs when an underlying disease, usually diabetes, causes nerve damage in the joint, which leads to swelling, bleeding, increased temperature, and changes in bone. There may be a loss of sensation that leads to an increased risk of injury from overuse.

Risk Factors

In the U.S., osteoarthritis affects about 12.1% of adults over 25 (21 million people). The prevalence of osteoarthritis increases with age. Older adults are at higher risk for osteoarthritis.

Gender

In people younger than 45, osteoarthritis occurs more frequently in males (although it is not common in younger adults). After age 45, it develops more often in females. Some research suggests that women may also experience greater muscle and joint pain, in general, than men.

Education

The incidence of osteoarthritis is highest in people with lower educational levels. In a 2000 study, 41% of adults with less than a high school education had arthritis, compared to 21% of college graduates.

Geography

Although the average rate of osteoarthritis among older adults in the U.S. is 60%, it can vary widely among geographical regions. The rates in older adults are lowest (34%) in Hawaii and highest (70%) in Alabama. In general, the highest prevalence of arthritis in the United States occurs in the central and northwestern states.

Ethnicity and Inheritance

The rate of osteoarthritis varies among ethnic groups. In the U.S., Caucasians and African-Americans have higher rates of arthritis than Hispanics or other ethnic groups. Osteoarthritis also tends to favor specific joints over others in certain ethnic groups. The following are some examples:

• Older African-American men are about 33% more likely than Caucasian men to have hip osteoarthritis. In one study, although men in both groups had equal risks for arthritic knees, African-American men were more likely to have arthritis in both knees and to have more severe cases. Although comparable disparities in knee arthritis were observed between African-American and Caucasian women, they might be explained by greater average weight among African-American women. The study could not account for the differences among men, however.
• Asians appear to have a higher incidence of osteoarthritis in the knee, an equal risk for osteoarthritis in the spine, and a lower risk for osteoarthritis in the hips compared to Caucasians.

Genes that determine the angles, amount of force, and other structural factors in the hip joints, or genes that regulate the chemistry in the joints, may account for ethnic differences.

Physical and Anatomical Factors

Some researchers suggest that a number of people have anatomical abnormalities, such as mismatched surfaces on the joints, which could be damaged over time. Legs of unequal length or skewed feet can cause jerky movement and may cause osteoarthritis. One study reported that people whose knees bent inward ("knock-kneed") or outward ("bow-legged"), for example, were more likely to have progressive osteoarthritis of the knee.

Obesity

Obesity, defined as being 20% over one's healthy weight, places people (particularly women) at increased risk for osteoarthritis. It also worsens osteoarthritis once deterioration begins. This higher risk is due to increased weight on the joints. However, being obese also increases the risk for osteoarthritis in the fingers as well as the knees and hips, suggesting that being overweight may contribute to osteoarthritis in other ways. Some research indicates that obesity may produce an inflammatory response, which is now a major suspect in age-related diseases -- not only osteoarthritis but also heart disease. [For more information, see In-Depth Report #53: Weight control and diet.]

Work and Leisure Factors

Because injuries can trigger the disease process, people whose work or leisure activities place them at risk for muscle and joint injuries may face a higher risk for osteoarthritis later on.

Workers at Higher Risk. Certain occupations with repeated stressful motions (such as squatting or kneeling with heavy lifting) can contribute to the deterioration of cartilage. People with jobs that require kneeling or squatting for more than an hour a day are at high risk for knee osteoarthritis. Jobs that involve lifting, climbing stairs, or walking also pose some risk.

Exercise. There has been some question about the role of strenuous exercise in osteoarthritis. Sports that definitely pose a higher risk for osteoarthritis have repetitive or direct joint impact (such as football), joint twisting, or both (baseball pitching, soccer). The increase in exercise intensity by young girls, including increased incidence of significant injuries, has raised concerns that we may see an increase in the incidence of future osteoarthritis.

Regular and moderate exercise, however, is important for everyone and does not increase the risk for osteoarthritis. Recreational weight-bearing exercise (walking, jogging), done by middle-aged and elderly people, neither prevents osteoarthritis nor increases risk. Furthermore, many factors associated with a sedentary life (muscle weakness, obesity) are associated with a higher risk for osteoarthritis.

Diagnosis

Osteoarthritis is often visible in x-rays. Cartilage loss is suggested by certain characteristics of the images:

• The normal space between the bones in a joint is narrowed.
• There is an abnormal increase in bone density.
• Bony projections, cysts, or erosions are visible.

If the doctor suspects other conditions, or if the diagnosis is uncertain, additional tests are necessary.

It is important to note that a negative x-ray does not rule out osteoarthritis. Likewise, some people may have minimal symptoms even though an x-ray clearly shows they have arthritis.

An MRI exam of an arthritic joint is generally not needed, unless the doctor suspects other causes of pain.

X-rays are a form of ionizing radiation that can penetrate the body to form an image on film. Structures that are dense (such as bone) will appear white, air will be black, and other structures will be shades of gray depending on density. X-rays can provide information about obstructions, tumors, and other diseases, especially when coupled with the use of barium and air contrast within the bowel.

Physical Exam

The affected joint in patients with osteoarthritis will generally be tender to pressure right along the joint line. Joint movement may cause a crackling sound. The bones around the joints may feel larger than normal. The joint's range of motion is often reduced, and normal movement is often painful.

Blood Tests

Blood test results may help identify other causes of arthritis (if present) besides osteoarthritis. Some examples include:

• Elevated levels of rheumatoid factor (specific antibodies in the synovium) are usually found in patients with rheumatoid arthritis
• The erythrocyte sedimentation rates (ESR, or "sed rate") indicates inflammatory arthritis or related conditions, such as rheumatoid arthritis or systemic lupus erythematosus.
• Elevated uric acid levels in the blood may indicate gout.

A number of other blood tests may help identify other rheumatological illnesses.

Tests of the Synovial Fluid

If the diagnosis is uncertain or infection is suspected, a doctor may attempt to withdraw synovial fluid from the joint using a needle. There will not be enough fluid to withdraw if the joint is normal. If the doctor can withdraw fluid, problems are likely, and the fluid will be tested for factors that might confirm or rule out osteoarthritis:

• Cartilage cells in the fluid are signs of osteoarthritis.
• A high white blood cell count is a sign of infection.
• High uric acid in the fluid is an indication of gout.

Click the icon to see an animation on gout.

• Other factors may be present that suggest different arthritic conditions, including Lyme disease and rheumatoid arthritis.
• In people with known osteoarthritis, researchers may look for certain factors in synovial fluid (sulfated glycosaminoglycan, keratin sulfate, and link protein) that can suggest a more or less severe condition.

Prognosis

Osteoarthritis itself is not life threatening, but a person's quality of life can significantly deteriorate as a result of pain and lost mobility. The negative effects of osteoarthritis on activities and physical and mental health are significant regardless of age, educational level, or gender. Only heart disease has a greater impact on work. Five percent of people who leave the work force do so because of osteoarthritis. Unless alleviated by medication or corrected by surgery, a patien with advanced osteoarthritis may avoid even relatively low-impact activities, such as walking. No treatment can cure osteoarthritis, and none can alter its progression with certainty, but many available treatments can relieve symptoms and significantly improve the quality of life.

Lifestyle Changes

Many doctors suggest first trying lifestyle changes to reduce stress on affected joints. Physical therapy and supportive devices can be helpful. Intensive education on how to protect and care for an osteoarthritic joint may help patients avoid multiple visits to their doctor.

Occupational Changes

Once they have been diagnosed with osteoarthritis, patients should reduce shock to the affected joint. Hammering away at deteriorating cartilage is likely to speed up the degeneration. People in occupations with repetitive and stressful movement should find ways to reduce trauma. Adjusting the work area or substituting tasks that produce less stress on joints helps reduce shock.

Exercise

Joints need motion to stay healthy. Long periods of inactivity cause the arthritic joint to stiffen and the adjoining tissue to atrophy (waste away). A moderate exercise program that includes low-impact aerobics and power and strength training has benefits for osteoarthritic patients, even if exercise does not slow down the disease progression. Exercise helps:

• Reduce stiffness and increase flexibility. It may also help improve the strength and elasticity of knee cartilage.
• Promote weight loss.
• Improve strength, which in turn improves balance and endurance.
• Reduce stress and improve feelings of well being, which helps patients cope with the emotional burden of pain.

Exercise especially helps patients with mild-to-moderate osteoarthritis in the hip or in the knee. Many patients who begin an aerobic or resistance exercise program report less disability and pain. They are better able to perform daily chores and remain more independent than their inactive peers. Older patients and those with medical problems should always check with their doctor before starting an exercise program.

Three types of exercise are best for people with osteoarthritis:

• Strengthening exercise
• Range-of-motion exercise
• Aerobic, or endurance, exercise

Strengthening Exercise. Strengthening exercises include isometric exercises (pushing or pulling against static resistance). Isometric training builds muscle strength while burning fat, helps maintain bone density, and improves digestion. For patients with arthritis in the hip or knees, exercises that strengthen the muscles of the upper leg are important.

Some experts encourage patients to emphasize strengthening leg muscles as a first treatment step, before using pain relievers. Patients who rely on painkilling drugs may overuse knees, which do not have muscle tissue sufficiently strong enough to protect the joints from further damage. However, some studies suggest that building up thigh muscles may worsen osteoarthritis in people whose knees are misaligned (for instance those who are "bow-legged" or "knock-kneed"). Such individuals should check with a physical therapist for the best options. Strengthening the thigh muscles is certainly protective for people who have not yet developed osteoarthritis.

Exercise, such as weightlifting, helps build muscle that is usually lost with age and puts stress on bones, helping keep them strong and healthy.

Range-of-Motion Exercise. These exercises increase the amount of movement in a joint and muscle. In general, they are stretching exercises. The best examples are yoga and tai chi, which focus on flexibility, balance, and proper breathing. In one study, older adults who practiced the gentle movement, breathing, and meditation exercises of tai chi for 10 weeks reported less pain than their peers who did not learn the technique.

Click the icon to see an image of cholesterol.

Aerobic (Endurance) Exercise. These exercises help control weight and may reduce inflammation in some joints. Low-impact workouts also help stabilize and support the joint. Cycling and walking are beneficial, and swimming or exercising in water is highly recommended, for people with arthritis. (Patients with osteoarthritis should avoid high-impact sports, such as jogging, tennis, and racquetball.)

Click the icon to see an image of exercise.

Physical Therapy

In addition to exercise, manipulation of muscles and joints by a trained therapist may be helpful. If patients fail to improve on a home program, a referral to a physical therapist may be beneficial.

Weight Reduction

Overweight patients with osteoarthritis can lessen the shock on their joints by losing weight. Knees, for example, sustain an impact three to five times the body weight when descending stairs. Losing 5 pounds of weight can eliminate 20 pounds of stress on the knee. The greater the weight loss, the greater the benefit. [For more information, see In-Depth Report #53: Weight loss and diet.]

Vitamins and Other Dietary Factors

Calcium and Vitamin D. Calcium and vitamin D are important for strong bones. Although osteoarthritis is primarily a disease of joints, bone strength is also important, particularly in older people.

Click the icon to see an image of osteoporosis.

Heat and Ice

Ice. When a joint is inflamed (particularly in the knee) applying ice for 20 - 30 minutes can be effective. If an ice pack is not available, a package of frozen vegetables works just as well.

Heat Treatments. Patients afflicted with osteoarthritis of the hands can relieve pain with hot soaks and warm paraffin application. Osteoarthritis of the hip can be treated with heating pads.

Interestingly, moving to a warm climate does not seem to make much difference. According to one study, people who live in warmer places are actually more sensitive to small shifts in temperature than people who live in cold damp climates, and they feel pain as readily as their northern peers do in response to larger temperature shifts.

Mechanical Aids

A wide variety of devices are available to help support and protect joints:

• Splints or braces, worn while the joint is at rest or in use, help align joints and properly distribute weight. They are used most frequently to treat arthritic hands, wrists, knees, ankles, and feet. Many of these devices allow some movement within the affected joint and do not restrict nearby joints. They are usually made from lightweight metal, leather, elastic, foam, and moldable plastic with easy-to-use Velcro straps. Any brace, splint, or other device for joint protection should be custom-fitted by a physical or occupational therapist, or an orthotist. Poorly fitting or improperly used braces or splints can cause more harm than good.
• A commonly used brace for knee osteoarthritis that involves only one side of the knee joint is called an offloading brace.
• Using elastic supports on affected joints may benefit some people. For example, in one study, wearing insoles plus elastic straps supporting the ankle joint helped overweight women with osteoarthritis in the knee. It is important to consult with a doctor about how to use elastic supports.
• Wrapping the knee with special therapeutic tape that provides support to specific parts of the joint may be effective. In one clinical trial, patients experienced a 40% reduction in pain within a few days. They wore the tape for 3 weeks, and pain relief continued for 3 more weeks following treatment. Physical therapists or other trained health professionals should apply the tape. Longer-term studies are needed to determine if these benefits are continuous.
• Wearing orthopedic shoes or shock-absorbing soles in shoes can help during daily activities and gentle exercise. Heel wedges in the shoes can sometimes help patients avoid knee replacement surgery.
• A firm mattress also often proves beneficial.
• Canes, crutches, or walkers offer benefits to patients with advanced arthritis.
• Specially designed hip protectors, worn under the clothes, can also protect against hip fractures in elderly patients with impaired mobility who are apt to fall.

Medications

Many medications are available for relieving the symptoms of osteoarthritis. A major analysis indicated that drug therapy is generally more effective than non-drug treatments (surgery, acupuncture). However, a 2006 review of knee osteoarthritis studies found that pain-relief medications generally help only for the first 2 - 3 weeks of treatment. The following are some of the medications used in mild-to-severe cases:

• Acetaminophen
• Nonsteroidal anti-inflammatory drugs (NSAIDs) or COX-2 inhibitors
• Capsaicin
• Tramadol
• Narcotic pain relievers (oxycodone, oxymorphone, or morphine)
• Glucosamine and chondroitin (see Alternative and Complementary Medicine section)

Acetaminophen

Acetaminophen (Tylenol, Anacin-3, Panadol, Phenaphen, Valadol, and others) is currently the first choice for treating osteoarthritis. Acetaminophen may be less effective than NSAIDs in reducing moderate-to-severe pain. Because acetaminophen has fewer side effects, most experts suggest trying this drug first, then switching to an NSAID if acetaminophen does not provide sufficient pain relief.

Side Effects. Acetaminophen is inexpensive and generally safe. It poses far less of a risk for gastrointestinal problems than NSAIDs and does not appear to increase the risk for miscarriage (as NSAIDs do), even when used regularly.

It does have some adverse effects, however, and the daily dose should not exceed 4 grams (4,000 mg). Patients who take high doses of this drug for long periods are at risk for liver damage, particularly if they drink alcohol and do not eat regularly.

The kidneys are responsible for removing wastes from the body, regulating electrolyte balance and blood pressure, and the stimulation of red blood cell production.

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

Nonsteroidal anti-inflammatory drugs (NSAIDs) block prostaglandins, the substances that dilate blood vessels and cause inflammation and pain. There are dozens of NSAIDs available:

• Over-the-counter NSAIDs include aspirin, ibuprofen (such as Advil, Nuprin, Motrin IB, and Rufen), naproxen (such as Aleve and Naprosyn), ketoprofen (such as Actron and Orudis KT).
• Prescription NSAIDs include ibuprofen (Motrin), naproxen (Naprosyn, Anaprox), flurbiprofen (Ansaid), diclofenac (Voltaren, Cataflam), tolmetin (Tolectin), ketoprofen (Orudis, Oruvail), nabumetone (Relafen), dexibuprofen (Seractil), indomethacin (Indocin), meloxicam (Mobic, generic).
• Topical NSAIDs delivered in gels, creams, or patches do not appear to provide any long-term benefits in reducing arthritic pain. A review of clinical trial data, published in 2004, suggested that guidelines that recommend topical NSAIDs for treatment of osteoarthritis should be revised.

Many experts now recommend that patients use oral NSAIDs for only a short period of time. Long-term use of NSAIDs does not actually delay the progression of osteoarthritis and may increase patients' risk of side effects. High dosages of NSAIDs can cause heart problems (such as increased blood pressure), kidney problems, and stomach bleeding.

Drug manufacturers of prescription and over-the-counter NSAIDs must now include with their products the same boxed warning used for the COX-2 inhibitor celecoxib (Celebrex). This boxed warning emphasizes an increased risk for cardiovascular events and gastrointestinal bleeding in people taking these drugs. Due to its proven heart benefits, aspirin was excluded from these labeling revisions.

Both NSAIDs and COX-2 inhibitors are equally effective for pain relief and pose similar risks for heart attacks.

NSAID-Induced Ulcers and Gastrointestinal Bleeding

Long-term use of NSAIDs is the second most common cause of ulcers, and the rate of NSAID-caused ulcers is increasing. Such ulcers are also more likely to bleed than those caused by the bacteria H. pylori. NSAID-related bleeding and stomach problems may be responsible for 107,000 hospital admissions and 16,500 deaths each year. Because there are usually no gastrointestinal symptoms from NSAIDs until bleeding begins, doctors cannot predict which patients taking these drugs will develop bleeding.

Among the groups at high risk for bleeding are elderly people, anyone with a history of ulcers or digestive tract bleeding, patients with serious heart conditions, alcohol abusers, and those on certain medications, such anticoagulants ("blood thinners"), corticosteroids, or bisphosphonates (drugs used for osteoporosis).

Click the icon to see an image of a gastric ulcer.

Drugs for Prevention NSAID-Induced Ulcers. If you have NSAID-induced ulcers, follow these steps:

• Switch to alternative pain relievers. This is the first step in preventing or healing ulcers caused by NSAIDs. If people cannot change drugs, they should use the lowest NSAID dose possible.
• Try proton-pump inhibitors (PPIs). These drugs help reduce NSAID-induced ulcer rates by as much as 80% compared with no treatment. Brands include omeprazole (Prilosec), esomeprazole (Nexium), lansoprazole (Prevacid), rabeprazole (AcipHex), and pantoprazole (Protonix).
• Try misoprostol or diclofenac sodium/misoprostol (Arthrotec). If other drugs are inappropriate, misoprostol protects against the major intestinal toxicity of NSAIDs. It was the first drug approved for preventing NSAID-induced ulcers. It is equally or even more, effective than some of the PPIs, but it does not heal existing ulcers and has more side effects than PPIs. Patients tend to stop using it. Arthrotec is a combination of misoprostol and the NSAID diclofenac. One study found that patients taking Arthrotec had 65 - 80% fewer ulcers than those who took NSAIDs alone.

Healing Existing Ulcers. A number of drugs are available to heal NSAID-induced ulcers. Treatment takes about 2 - 6 weeks. Proton-pump inhibitors are the most effective drugs. Others that may be beneficial include sucralfate (or H2 blockers), such as famotidine (Pepcid AC), cimetidine (Tagamet), ranitidine (Zantac).

COX-2 Inhibitors (Coxibs)

Coxibs inhibit an inflammation-promoting enzyme called COX-2. This drug class was initially thought to provide benefits equal to NSAIDs but cause less gastrointestinal distress. However, following numerous reports of cardiovascular events, as well as skin rashes and other adverse effects, the FDA has been re-evaluating the relative risks and benefits of this drug class. Rofecoxib (Vioxx) and valdecoxib (Bextra) have been withdrawn from the United States market. Celecoxib (Celebrex) is still available, but patients should discuss with their doctors whether this drug is appropriate and safe for them.

Capsaicin

Capsaicin is a component of hot red peppers and may bring pain relief when used as a skin cream (Zostrix). This is the only skin preparation that does more than just mask pain or reduce it temporarily. Capsaicin seems to reduce a substance in the body, known as substance P, which contributes both to inflammation and the delivery of pain impulses from the central nervous system. A small amount of capsaicin must be applied to the area of inflammation about four times a day. During the first few days of use, the patient will experience a warm, stinging sensation when the cream is applied. This sensation goes away, and pain relief usually begins within 1 - 2 weeks.

Tramadol

Tramadol (Ultram) is a pain reliever that has been used as an alternative to opioids. It has opioid-like properties but is not as addictive. (Dependence and abuse have been reported, however.) It can cause nausea but does not cause severe gastrointestinal problems, as NSAIDs can. Some patients experience severe itching. A combination of tramadol and acetaminophen (Ultracet) is now available and provides more rapid pain relief than tramadol alone, with more long-lasting benefits than acetaminophen. Side effects are the same as for each of these drugs.

Narcotics

Narcotics, pain-relieving and sleep-inducing drugs that act on the central nervous system, are the most powerful medications available for the management of moderate-to-severe pain. There are two types of narcotics:

• Opiates, which are derived from natural opium (morphine and codeine)
• Opioids, which are synthetic drugs. They include oxycodone (such as Percodan, Percocet, Roxicodone, and OxyContin), hydrocodone (Vicodin), oxymorphone (Numorphan), and fentanyl (Duragesic)

Although the use of narcotics for arthritic pain is controversial, many studies have suggested that they are rarely addictive for pain sufferers except among patients with a history of substance abuse. Opioids may have a place in osteoarthritis treatment when milder drugs are not effective or appropriate.

The use of such drugs may be beneficial when included as part of a comprehensive pain management program. Such a program involves screening prospective patients for possible drug abuse and then regularly monitoring those who are taking it, adjusting the dose as necessary to achieve an acceptable balance between pain relief and side effects. Common side effects include anxiety, constipation, nausea and vomiting, dizziness, drowsiness, paranoia, urinary retention, restlessness, and labored or slow breathing. Unfortunately, opioid abuse among young people is a major concern.

Corticosteroids

When pain becomes a major problem and less potent pain relievers are ineffective, doctors may try corticosteroid (steroid) injections, usually by giving the patient a shot in their joint every 3 months. Corticosteroid shots are useful only if inflammation is present in the joint. Relief from pain and inflammation is of short duration, and this treatment is rarely used for chronic osteoarthritis. These drugs may not be as effective for women as they are for men.

Patients are usually advised not to have more than two or three injections a year, since there is some concern that repeated injections over the long term may be harmful. A reassuring study found no greater disease progression in people who had injections every 3 months for 2 years compared to those who were given sham injections on the same schedule. Because long-term use of corticosteroids has many potentially serious side effects, steroid medications are never given by mouth or systemically for the treatment of osteoarthritis.

Hyaluronic Acid Injections (Viscosupplementation)

Shots of hyaluronic acid (such as Hyalgan, Synvisc, Artzal, and Nuflexxa) into the joint -- a procedure called viscosupplementation -- are one of the recommended treatments for osteoarthritis. Hyaluronic acid is a naturally occurring substance in joints, which acts as a lubricant for slow movements and a shock absorber for fast motions. In high amounts, it also may have anti-inflammatory effects.

• Patients receive a series of three to five shots spread a week apart.
• The doctor will first use a local anesthetic because these viscous (sticky) shots need a large needle.
• The drug is injected into the joint.
• Patients need to avoid weight-bearing activities for about 48 hours after each shot.

Hyaluronic injections appear to be about as effective as NSAIDs and corticosteroid shots for relieving pain, at least in men, and they have no adverse effects in the stomach or intestines. While several studies have shown a benefit for this treatment, a number of studies on viscosupplementation have shown little or no benefits, particularly in women, and more research is needed to determine if they are useful. The shots are also expensive. Accurate placement of the needle directly into the knee joint space is important and may be difficult, even for experienced doctors, if there is no fluid build-up in the joint. Best success rates are with a specific approach into the kneecap called the lateral midpatellar.

Side Effects. Serious adverse reactions are rare. The most common side effects, pain at the injection site and knee pain and swelling, are usually mild and temporary. More research is needed to confirm benefits and long-term risks.

Investigational Therapies

Researchers are studying various drugs that may provide pain relief or stop the disease process itself: The treatments below are still experimental, and may not be available to patients in the United States.

• Bisphosphonates such as alendronate (Fosamax) and risedronate (Actonel) help prevent bone loss in people with osteoporosis. They are currently being investigated for osteoarthritis as well.
• Tetracycline antibiotics, such as doxycycline, may have a role to play in treating osteoarthritis. Initial results from clinical trials suggest that doxycycline may help delay joint space narrowing. Its effects on osteoarthritis pain are less clear, and side effects of long-term treatment with tetracycline are unknown.
• Licofelone is a drug that inhibits both the COX enzyme plus an inflammatory substance called lipoxygenase 5. Early trials indicate it may be as effective, and safer, than either NSAIDs or COX-2 inhibitors. In addition to pain relief, licofelone may actually slow down the progression of osteoarthritis.
• Botulinum toxin type A (Botox) injections are being investigated for patients with knee osteoarthritis. However, no strong evidence to date supports its use.
• Clinical trials of gene therapies that either fight joint degradation or strengthen cartilage are in very early stages.

Alternative and Complementary Medicine

Glucosamine hydrochloride and chondroitin sulfate are natural substances that are part of the building blocks found in and around cartilage. Extracts of these substances have been used in Europe for more than a decade to reduce pain and improve mobility in patients with osteoarthritis. For many years, researchers in the U.S. have been studying whether these dietary supplements really work for relieving osteoarthritis pain.

Earlier studies indicated a potential benefit from these agents. However, several high-quality studies involving large numbers of patients have indicated that, in general, glucosamine and chondroitin do not seem to provide any more help than a placebo for the symptoms of osteoarthritis.

Dosage. There are no current recommended dosages. Patients in the National Institute of Health's GAIT trial took 1,500 mg of glucosamine and 1,200 mg of chondroitin.

Side Effects. The safety records of both substances appear excellent. Long-term effects are still unknown, but studies of up to 3 years have reported no significant side effects. However, there are some concerns that glucosamine may affect insulin and blood sugar (glucose) metabolism. Patients with diabetes should not take glucosamine without first talking to their doctors.

Other Herbs and Supplements

Ginger (Zingiberaceae). No good evidence indicates that Ginger provides a benefit for osteoarthritis.

S-adenosylmethionine (SAMe). S-adenosylmethionine (SAMe, pronounced "Sammy") is a synthetic form of a natural byproduct of the amino acid methionine. It has been marketed as a remedy for both depression and arthritis, but scientific evidence supporting these claims is scant. Cost can run $60 - 120 per month.

Herbs and Supplements

Generally, manufacturers of herbal remedies and dietary supplements do not need FDA approval to sell their products. Just like a drug, herbs and supplements can affect the body's chemistry, and therefore have the potential to produce side effects that may be harmful. There have been several reported cases of serious and even lethal side effects from herbal products. Always check with your doctor before using any herbal remedies or dietary supplements.

Acupuncture

Acupuncture is being increasingly used to reduce osteoarthritis pain. The technique is painless and involves the insertion of small fine needles at select points in the body. The studies of thousands of patients with chronic osteoarthritis pain compared acupuncture to conventional treatment (such as physical therapy and anti-inflammatory drugs). These studies showed positive results lasting for up to 6 months after treatment. However, when acupuncture treatment was compared to sham acupuncture, any benefit was minimal. In any case, acupuncture appears to be a safe and beneficial addition to standard therapy for certain patients, such as pregnant women, who cannot take most pain medications.

Acupuncture, hypnosis, and biofeedback are all alternative ways to control pain. Acupuncture involves the insertion of tiny sterile needles, slightly thicker than a human hair, at specific points on the body.

Transcutaneous Electric Nerve Stimulation

Transcutaneous electric nerve stimulation (TENS) uses low-level electrical pulses to suppress pain. Patients are barely aware of the sensation. According to one study, the optimal treatment length is 40 minutes. A variant (sometimes called percutaneous electrical nerve stimulation, or PENS) applies these pulses through a small needle to acupuncture points. A review of trials reported that both methods were better than placebo (sham treatments) in treating osteoarthritis of the knee, although additional well-designed studies are needed.

Low-Level Laser Therapy

Low-level laser therapy (LLLT) generates extremely pure light in a single wavelength. It does not produce heat and is painless. Some researchers are combining LLLT with transcutaneous electric nerve stimulation (TENS). Studies report widely varying results, with some showing significant reductions in pain and others reporting no effect. The differences may be due to different approaches, and standardized methods are needed before any benefits can be shown.

Hydrotherapy

Hydrotherapy, also called spa therapy or balneotherapy, is an ancient therapy that uses bathing in mineral baths for soothing pain. Although many studies report positive results, including improved quality of life, very few of them have been rigorously conducted. A major analysis reported weak evidence on any real effect of hydrotherapy on pain or quality of life, but some patients may find comfort in this pleasant therapy.

Surgery

Different surgical procedures are available as a final measure to relieve pain and increase function in patients with osteoarthritis. Certain surgical procedures can help relieve pain if medications fail. Even with these procedures, however, joint replacement may still be needed later on.

Arthroscopy

Arthroscopy is performed to clean out bone and cartilage fragments that, in theory at least, may cause pain and inflammation. More than 650,000 of these procedures are done on arthritic knees each year in the U.S., and about half of patients report less pain after the procedure.

A rigorous 2002 trial, however, found that arthroscopic knee surgery was no more effective than sham surgery (in which surgeons only pretended to operate on the knee) for relief of osteoarthritic pain or stiffness. The study, which followed patients at a Veterans Affairs hospital for 2 years, has called into serious question whether the popular procedure has any real benefits for osteoarthritis beyond what might be achieved by a placebo response. Research and debate continues on whether arthroscopy provides true benefits for those with osteoarthritis and, if so, which patients may benefit the most from it. Arthroscopy is most likely to benefit people with evidence of bone and cartilage fragments in the joint, or patients whose joints lock or catch with movement.

Click the icon to see an illustrated series detailing knee arthroscopy surgery.

Joint Replacement (Arthroplasty)

When osteoarthritis becomes so severe that pain and immobility make normal functioning impossible, many people become candidates for artificial (prosthetic) joint implants using a procedure called arthroplasty. Hip replacement is the most established and successful replacement procedure, followed by knee replacement. Knee replacement, in fact, has a slightly better long-term success rate than hip replacement. Other joint surgeries (such as shoulders, elbows, wrists, and fingers) are less common, and some arthritic joints (in the spine, for instance) cannot yet be treated in this manner. When two joints, such as both knees, need to be replaced, having the operations done sequentially rather than at the same time may result in fewer complications.

Click the icon to see an illustrated series detailing knee joint replacement surgery.

Candidates. The primary indications for surgery are pain and significant limitations of movement, including walking, that cannot be treated by less invasive therapies. Some experts suggest, however, that joint replacement should be considered earlier rather than as a last resort. They argue that patients who wait until they are severely disabled do not recover as completely as those who have the procedure earlier.

Patients who may not be good candidates are those with the following conditions:

• Severe neurologic, emotional, or mental disorders
• Severe osteoporosis
• Other chronic medical conditions
• Obesity

Surgeons often prefer to delay prosthetic implantation in younger patients, because implants wear out and the patient will need at least one revision procedure later on. Newer, longer-lasting materials, however, may help reduce the rate of revision operations.

Elderly patients with poorly controlled osteoarthritis often do very well after joint replacement surgery. While full recovery may take older patients longer than younger people, the long-term outcome of the surgery is excellent, and leads to significant improvements in pain and quality of life. Depending on the number of other medical problems present, older patients should also be assessed for hip replacement procedures.

Although the following is mostly a description of hip replacement surgery, the principles are similar for other arthroplasty surgeries.

The surgeon removes the ball and socket joint that joins the pelvis and thigh bone (femur) and replaces it with an artificial joint (a prosthesis). It is composed of two pieces:

• A cup-like device fits in the hip socket (called the acetabula), which has been hollowed out. This ball-and-socket cup is positioned to form the new joint.
• A metal shaft, or stem, with a polished metal ball at the top, is inserted into the narrow center of the femur.

The prosthesis is usually made of a metal alloy and plastic. A ceramic implant may prove to last longer than other materials and be a safe option for younger patients.

There are different options available for attaching it to the adjoining bones:

• A cement made of polymethylmethacrylate (usually preferred for older patients who generally have thinner bones).
• So-called cementless implants, in which the prosthesis is coated with a porous material that allows bone to grow into and eventually adhere to the device. These implants are usually used for patients younger than age 65, who are likely to need repeat surgery in their lifetime.

Minimally invasive hip replacement surgery. A variation on the traditional hip replacement is the newer procedure known as minimally invasive hip replacement. This procedure, which requires an extremely experienced surgeon, uses special instruments and a shorter incision (3 - 6 inches vs. 10 - 12 inches in traditional hip replacement). The patients report less pain and are usually able to go home within 48 hours after surgery. Minimally invasive hip replacement can be done with 1 or 2 incisions. The 2 incision technique is more complicated and time consuming, and at the moment seems to have a higher rate of complications.

Click the icon to see an illustrated series detailing hip joint replacement surgery.

Complications. Complications can occur, and, although uncommon, some can be life threatening. There is a 1% chance of death within 3 months of an initial procedure and a 2.6% risk after a repeat procedure. The risks are highest in the first 3 months. Those at highest risks for complications are elderly adults, men (compared to women), African-Americans, and those with serious medical conditions.

Specific complications include the following:

• Deep blood clots in the legs (known as deep vein thrombosis) and pulmonary embolism. Deep blood clots can develop in the legs after this surgery. This poses a very small risk (0.9%) for pulmonary embolism -- a dangerous condition in which the clot travels to the lungs. Anticoagulants (blood thinners) are important for preventing blood clots. These drugs include warfarin and low-molecular weight heparin. Anticoagulant therapy is given during the hospital stay and continued for several weeks at home. The patient also wears specially fitted elastic stockings to help prevent clots. Patients who are overweight are at higher than average risk for post-operative blood clots
• Infection. Wound infection occurs in about 0.2% of joint replacements and requires prompt removal of the implant to treat the infection. A new prosthesis must be re-implanted at a later time. Any pre-existing infection must be treated and cured before surgery is performed. (Older women should be aware of urinary tract infections, which may require postponing surgery.) After surgery, patients should take certain precautions. For example, they should take antibiotics before invasive dental procedures or other surgery because bacteria can be introduced into the bloodstream and infect the areas around the artificial joints.
• Hip dislocation. Occurs in about 3.1% of first hip procedures. The rate is much higher (14.4%) in revision operations.

Click the icon to see an image of a dislocated hip.

• Pain. Thigh pain can occur after hip replacement. Porous hip prostheses are more likely to produce thigh pain than cement implants, although advanced techniques using a tapered shaft are reducing this complication.
• Failure. The primary reason for implant failure is osteolysis (bone destruction) caused by long-term wear. The main source of wear is from tiny particles released from the prosthesis.
• Other complications. These include uneven leg lengths, nerve damage that can cause numbness or weakness, urinary tract infections, delayed healing, and allergic reactions to the metal. Long-term, there have been rare reports of a possible autoimmune response, in which loose particles released from the prosthetic device trick certain immune system factors into attacking healthy cells. Any incidence of unexplained weight loss and fatigue may be symptoms of this uncommon event.

Rehabilitation. Aside from the surgeon's skill and the patient's underlying condition, the success rate depends on the kind and degree of activity the joint receives following replacement surgery.

The patient is urged and aided into getting out of bed and walking the day after surgery. Most hip replacement patients leave the hospital within a week and can walk with crutches within 2 - 4 weeks, recovering fully in about 3 months.

Physical therapy takes about 6 weeks to rebuild adjoining muscle and strengthen surrounding ligaments. Studies suggest that an exercise program started before surgery and resumed afterward can improve recovery. Continuous passive motion (CPM) is an effective regimen for knee replacement patients. It uses a mechanical device that slowly moves the joint through an arc of motion for an extended period of time. It is used to prevent scar tissue from developing. In one review, a combination of physical therapy and CPM were more beneficial than physical therapy alone.

Limitations After Surgery. While many patients find that joint replacement provides remarkable pain relief and restores some mobility, they need time to adjust to the artificial joint.

Limitations after hip surgery include:

• Usually patients with new hips are able to walk several miles a day and climb stairs, but they cannot run.
• Prosthetic hips should not be flexed beyond 90 degrees, so patients must learn new ways to perform activities requiring bending down (like tying a shoe).

Limitations after knee surgery include:

• Walking distance improves in 80% of patients after knee replacement surgery, but patients still cannot run.
• Only slightly more than half of patients report improvement in stair climbing. (Artificial knee joints generally have a range of motion of just 110 degrees.)

Failure Rates. Infection is a major cause of early failure and always requires revision. Improper balancing of the ligaments and other tissues surrounding the joint and resulting poor joint stability is also a common reason for failure of arthroplasty. Surgical expertise is important for avoiding this complication.

Older cement prostheses have a particularly high rate of bone loss and loosening due to cement deterioration. In general, studies report reoperation rates of over 30% after 10 years. Fortunately, advances in cement and prosthetic implants are improving the implant survival rates and reducing the need for revision procedures.

Uncemented arthroplasty using porous material has shown good results for the hip, although it may be less successful for knee replacement. In spite of short-term success, longer experience with this method suggests it may not be superior to cement prostheses. Failure of bone to grow into the porous material is a relatively common event, a problem that does not occur with cement prostheses. Some experts recommend cement implants over cementless ones for total knee arthroplasty.

Revision Arthroplasty

A repair procedure called arthroplasty revision may be used in cases where the original transplant fails. The specific procedure depends on whether the bone defects that occurred are contained or uncontained.

• Contained defects can be repaired with small bone grafts, the use of cement, or oversized cementless implants as required.
• Uncontained defects are more severe and may require a large bone graft or specially constructed implants to restore bone.

If a second arthroplasty is required, the potential for complications is magnified: more bone is cut, more blood is lost, and the operation takes longer. Patients are also generally older and more vulnerable to complications.

Other Joint Procedures

Resection Arthroplasty. In resection arthroplasty, a false joint of scar tissue is created. This procedure is used most often in treating arthritis of the foot.

Osteotomy. If only a certain section (the medial compartment) of the knee is damaged and deformed by osteoarthritis, the surgeon may choose to perform an osteotomy:

• The surgeon opens the knee.
• The surgeon performs a debridement (removal of damaged tissue) in the joint to eliminate the loose or torn fragments that are causing pain and inflammation.
• The bone is then reshaped to remove the deformity.
• The procedure may ease symptoms and slow disease progression. It is best used in heavier adults who are under 60 years old.

Hemicallotasis. Hemicallotasis is a procedure for the knee that may be a less invasive alternative to osteotomy. The surgeon attaches the knee with pins to an external frame-like device that lengthens the deformed part of the knee over several weeks. The patient is mobile during this period. Infections at the pin site are the most common complications.

Arthrodesis. If the affected joint cannot be replaced, surgeons can perform a procedure called arthrodesis that eliminates pain by fusing the bones together. The patient must understand, however, that fusing the bones makes movement of the joint impossible. Bone fusion is most often done in the spine and in the small joints of the hands and feet.

Unicompartmental Knee Arthroplasty. Unicompartmental knee arthroplasty (also called unicondylar knee arthroplasty) may be a useful procedure in cases of limited knee damage. It is recommended for relatively sedentary patients who are 60 years or older and not obese. It may relieve pain and delay the need for a total knee replacement. The procedure involves a small incision and insertion of small implants. It retains important knee ligaments, which preserve more movement than a total knee replacement.

Cartilage Transplants. Autologous chondrocyte implantation, also called chondroplasty or the Carticel approach, is used for knees damaged by injuries. In this procedure, arthroscopy is used to first remove cartilage in eroded areas. The results have been good to excellent, although long-term benefits are questionable. Whether it has any benefit for older patients with osteoarthritis is not yet known. Other cartilage transplant procedures are also under study.

Hip Resurfacing. Hip resurfacing is a surgical alternative to total hip replacement. It involves scraping the surfaces of the hip joint and femur and placing a metal cap over the bone. The procedure preserves much of the bone, so that a standard hip replacement can be done years later if needed. It may provide more stability, a faster recovery, and greater range of motion, making it a potentially good option for young, physically active patients.

Resources

• www.rheumatology.org -- American College of Rheumatology
• www.arthritis.org -- Arthritis Foundation
• www.niams.nih.gov -- National Institute of Arthritis and Musculoskeletal and Skin Diseases
• www.aaos.org -- American Academy of Orthopaedic Surgeons
• www.fda.gov/cder/drug/infopage/cox2 -- FDA NSAID and COX-2 Inhibitor Information

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