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Osteoarthritis (OA)

(Degenerative Arthritis; Degenerative Joint Disease; Osteoarthrosis)


Kinanah Yaseen

, MD, Cleveland Clinic

Reviewed/Revised Dec 2022 | Modified Jun 2023
Topic Resources

Osteoarthritis is a chronic disorder that causes damage to the cartilage and surrounding tissues and is characterized by pain, stiffness, and loss of function.

  • 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, medications that reduce pain and improve function, and, for very severe cases, 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.

Osteoarthritis is classified as

  • Primary

  • Secondary

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 thumb, or it may affect many joints.

In secondary osteoarthritis, the cause is another disease or condition, such as

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.

Causes of Osteoarthritis

Normally, cartilage reduces the friction level in joints and protects them from wearing out, even after years of typical use, overuse, or injury. Osteoarthritis is caused most often by tissue damage. In an attempt to repair a damaged joint, chemicals accumulate in the joint and increase the production of the components of cartilage, such as collagen (a tough, fibrous protein in connective tissue) and proteoglycans (substances that provide resilience). Next, the cartilage may swell because of water retention, become soft, start to breakdown, and then develop cracks on the surface. Tiny cavities form in the bone beneath the cartilage, weakening the bone.

The attempt of the tissues to repair the damage may lead to new growth of bone and other tissue. Bone can overgrow at the edges of the joint, causing bumps (osteophytes) that can be seen and felt. Ultimately, the smooth, slippery surface of the cartilage becomes rough and pitted, so that the joint can no longer move smoothly and absorb impact. All the components of the joint—bone, joint capsule (tissues that enclose most joints), synovial tissue (tissue lining the joint cavity), tendons, ligaments, and cartilage—fail in various ways, thus altering the function of the joint.

Symptoms of Osteoarthritis

Usually, osteoarthritis symptoms develop gradually and affect only one or a few joints at first. Joints of the fingers, base of the thumbs, neck, lower back, big toes, hips, and knees are commonly affected.

Pain, often described as a deep ache, is the first symptom and, when in the weight-bearing joints, is usually made worse by activities that involve weight bearing (such as standing). In some people, the joint may be stiff after sleep or some other inactivity, but the stiffness usually subsides within 30 minutes, particularly if the joint is moved.

As the condition causes more symptoms, the joint may become less movable and may not be able to fully straighten or bend. New growth of bone and other tissue can enlarge the joints. The irregular cartilage surfaces cause joints to grind, grate, or crackle when they are moved, and tenderness develops.

Bony growths commonly develop in the joints closest to the fingertips (called Heberden nodes) or middle of the fingers (called Bouchard nodes).

In some joints (such as the knee), the ligaments, which surround and support the joint, stretch so that the joint becomes unstable and the muscles moving that joint may weaken. Alternatively, the hip or knee may become stiff, losing its range of motion. Moving the joint (particularly when standing, climbing stairs, or walking) can be very painful.

Osteoarthritis often affects the spine. Back pain is the most common symptom. Usually, damaged disks or joints in the spine cause only mild pain and stiffness. However, osteoarthritis in the neck or lower back can cause numbness, pain, and weakness in an arm or leg if the overgrowth of bone presses on nerves. The overgrowth of bone may be within the spinal canal in the lower back (lumbar spinal stenosis), pressing on nerves before they exit the canal to go to the legs. This pressure may cause leg pain with walking, suggesting incorrectly that the person has a reduced blood supply to the legs (intermittent claudication Symptoms Symptoms ). Rarely, bony growths in the neck compress the esophagus, making swallowing difficult.

Osteoarthritis may be stable for many years or may progress very rapidly, but most often it progresses slowly after symptoms develop. Many people develop some degree of disability.

People who develop a red, hot, and swollen joint should be evaluated by a doctor because these episodes are not usually caused by osteoarthritis and could result from an infection or gout.


Diagnosis of Osteoarthritis

  • X-rays

The doctor makes the diagnosis of osteoarthritis based on the characteristic symptoms, physical examination, and the appearance of joints on x-rays X-Rays X-rays are a type of medical imaging that use very low-dose radiation waves to take pictures of bones and soft tissues. X-rays may be used alone (conventional x-ray imaging) or combined with... read more (such as bone enlargement and narrowing of the joint space). However, x-rays are not very useful for detecting osteoarthritis early because they do not show changes in cartilage, which is where the earliest abnormalities occur. Also, changes on the x-ray often do not closely correspond with a person's symptoms. For example, an x-ray may show only a minor change in a person who has severe symptoms, or an x-ray may show numerous changes in a person who has very few if any symptoms.

Magnetic resonance imaging (MRI) can reveal early changes in cartilage, but it is rarely needed for the diagnosis.

There are no blood tests for the diagnosis of osteoarthritis, but certain blood tests may help rule out other disorders.

If a joint is swollen, doctors may inject an anesthetic to numb the area and then insert a needle into the joint to draw a sample of the joint fluid. The fluid is examined to differentiate osteoarthritis from other joint disorders such as infection and gout.

Treatment of Osteoarthritis

  • Physical measures, including physical and occupational therapy, joint protection, and appropriate weight loss

  • Medications

  • Surgery

The main goals of osteoarthritis treatment are to

  • Relieve pain

  • Maintain joint flexibility

  • Optimize joint and overall function

Physical measures

Appropriate exercises—including stretching, strengthening, and postural exercises—help maintain healthy cartilage, increase a joint’s range of motion, and most importantly strengthen surrounding muscles so that they can absorb stress better. Exercise can sometimes slow down the worsening of osteoarthritis of the hip and knee. Doctors often recommended people exercise in water (such as in a pool) because water spares the joints from stress.

Stretching exercises should be done daily.

Exercise must be balanced with a few minutes of rest of painful joints (every 4 to 6 hours during the day), but immobilizing a joint is more likely to worsen the disease than relieve it.

Using excessively soft chairs, recliners, mattresses, and car seats may worsen symptoms.

People should not put pillows under their knees when reclining because doing so can cause the hip and knee muscles to become tight. (This recommendation contrasts with the recommendation that people with low back pain and sciatica put a pillow between their knees. For such people, using a pillow relieves the stress on the lower back and hip [see Sciatica Sciatica Sciatica is pain along the sciatic nerves. These nerves run from the lower back, through the buttocks, and down the legs, ending just below the knee. A herniated disk, complications of osteoarthritis... read more Sciatica ].)

Moving car seats forward, using straight-backed chairs with relatively high seats (such as kitchen or dining room chairs), firm mattresses, and bed boards (available at many lumber yards), and wearing orthotics, supportive shoes, or athletic shoes are often recommended.

Toilet seat risers can make standing up easier and less uncomfortable for people who have painful osteoarthritis of the knees or hips, particularly if their muscles are weak.

For osteoarthritis of the spine, specific exercises sometimes help, and back supports may be needed when pain is severe. Exercises should include both muscle-strengthening as well as low-impact aerobic exercises (such as walking, swimming, elliptical machine use, and stationary bicycle riding). If possible, people should maintain ordinary daily activities and continue to perform their normal activities, such as a hobby or job. However, physical activities may have to be adjusted to limit lifting and bending in ways that can aggravate the pain of osteoarthritis.

Other additional measures can help relieve pain and help people live with osteoarthritis. They include


Medications are used to supplement exercise and physical therapy. Medications, which may be used in combination or individually, do not directly alter the course of osteoarthritis. They are used to reduce symptoms and thus allow more normal daily activities.

A pain reliever (analgesic), such as acetaminophen, used before activities that cause discomfort or used regularly to relieve more constant joint discomfort, may be all that is needed for mild to moderate pain. Although side effects are not common, people should not take acetaminophen in higher than recommended doses, particularly if they have liver disease or drink considerable alcohol. When taking acetaminophen, people should also make sure not to simultaneously take one of the numerous over-the-counter drug products that contain acetaminophen.

Sometimes, however, people may need a more potent analgesic, such as tramadol.

Alternatively, a nonsteroidal anti-inflammatory drug (NSAID) Nonsteroidal Anti-Inflammatory Drugs Pain relievers (analgesics) are the main drugs used to treat pain. Doctors choose a pain reliever based on the type and duration of pain and on the drug's likely benefits and risks. Most pain... read more may be taken to lessen pain and swelling. NSAIDs reduce pain and inflammation in joints and can be used in combination with other analgesics. NSAIDs also come in gel and cream forms that can be rubbed into the skin (such as diclofenac gel 1%) over the joints of the hands and knees and may help relieve symptoms. However, NSAIDs have a higher risk of serious side effects than acetaminophen when used long term. People who take NSAIDs by mouth often also take a medication to protect the stomach lining and also may have their kidney function and blood pressure monitored.

Sometimes other types of pain medicine may be needed. For example, a cream made from cayenne pepper—the active ingredient is capsaicin—can be applied directly to the skin over the joint. Doctors may also recommend lidocaine patches for pain relief, but there is no evidence these patches are effective. Duloxetine, a type of antidepressant taken by mouth, may reduce the pain caused by osteoarthritis.

Muscle relaxants (usually in low doses) occasionally relieve pain caused by muscles straining to support joints affected by osteoarthritis. In older people, however, they may cause more side effects than relief.

If a joint suddenly becomes inflamed, swollen, and painful, most of the fluid inside the joint may need to be removed and a special form of cortisone may be injected directly into the joint. This treatment may provide temporary pain relief and increased joint flexibility in some people.

A series of 1 to 5 weekly injections of hyaluronate (a substance similar to normal joint fluid) into the knee joint may provide some pain relief in some people for prolonged periods of time. These injections should not be given more often than every 6 months. Hyaluronate injections are less effective in people with severe osteoarthritis and do not slow the progression of the arthritis.

Several nutritional supplements (such as glucosamine sulfate and chondroitin sulfate) have been tested for potential benefit in treating osteoarthritis. So far, results are mixed, and the potential benefit of glucosamine sulfate and chondroitin sulfate in treating pain is unclear, and they do not seem to change the progression of joint damage. There is no good evidence that any other nutritional supplements work.


Surgical treatment may help when other treatments fail to reduce pain or improve function. Some joints, most commonly the hip and knee, can be replaced with an artificial joint. Replacement, particularly of the hip, is usually very successful, almost always improving motion and function and dramatically decreasing pain. Therefore, joint replacement should be considered when pain is unmanageable and function becomes limited. Because an artificial joint does not last forever, the procedure is often delayed in very young people so the need for repeated replacements can be minimized. If other treatments are ineffective, surgical procedures can be done to help relieve symptoms of back or neck osteoarthritis, particularly nerve compression. The benefit of limited, arthroscopic surgical procedures for osteoarthritis of the knee, such as repair of the meniscus or reconstruction of knee ligaments, is uncertain.

A variety of methods that restore cells inside cartilage have been used in younger people with osteoarthritis (often caused by an injury) to help heal small defects in cartilage. However, such methods have not yet proved valuable when cartilage defects are extensive, as commonly occurs in older people.

Replacing All of a Hip (Total Hip Replacement)

Sometimes the whole hip joint must be replaced. The whole hip joint is the top (head) of the thighbone (femur) and the surface of the socket into which the head of the thighbone fits. This procedure is called total hip replacement or total hip arthroplasty. The head of the thighbone is replaced with a ball-shaped part (prosthesis), made of metal. The prosthesis has a strong stem that fits within the center of the thighbone. The socket is replaced with a metal shell lined with durable plastic.

Replacing All of a Hip (Total Hip Replacement)

Replacing a Knee

A knee joint damaged by osteoarthritis may be replaced with an artificial joint. After a general anesthetic is given, the surgeon makes an incision over the damaged knee. The knee cap (patella) may be removed, and the ends of the thigh bone (femur) and shinbone (tibia) are smoothed so that the parts of the artificial joint (prosthesis) can be attached more easily. One part of the artificial joint is inserted into the thigh bone, the other part is inserted into the shinbone, and then the parts are cemented in place.

Replacing a Knee

Spotlight on Aging: Osteoarthritis

Many myths about osteoarthritis remain. For example, people think that it is an inevitable part of aging, like gray hair and skin changes, that it results in little disability, and that treatment is not effective.

Osteoarthritis does become more common with aging. For instance, as people age, the following occur:

  • The cartilage that lines the joints tends to thin.

  • The surfaces of a joint may not slide over each other as well as they used to.

  • The joint may be slightly more susceptible to injury.

However, osteoarthritis is not an inevitable part of aging. It is not caused simply by the wear and tear that occurs with years of joint use. Other factors may include single or repeated injury, abnormal motion, metabolic disorders, joint infection, or another joint disorder.

Effective treatment, such as pain medications (analgesics), exercises and physical therapy, and, in some cases, surgery, is available.

Ligament damage is also common with aging. Ligaments, which bind joints together, tend to become less elastic as people age, making joints feel tight or stiff. This change results from chemical changes in the proteins that make up the ligaments. Consequently, most people become less flexible as they age. Ligaments tend to tear more easily, and when they tear, they heal more slowly. Older people should have their exercise regimen reviewed by a trainer or doctor so that exercises likely to tear ligaments can be avoided.

Sometimes the pain caused by osteoarthritis cannot be relieved by a simple analgesic, such as acetaminophen. More potent analgesics, such as tramadol, may be required, but doctors prescribe them only when necessary, to avoid problems with side effects and possible addiction. However, these medications can cause confusion in older people. Nonsteroidal anti-inflammatory drugs (NSAIDs) that are rubbed into the skin over the affected joint may be a better option for older people. Less of the NSAID is absorbed than if it is taken by mouth, which minimizes the risk of side effects.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  • Arthritis Foundation: Information about osteoarthritis and other types of arthritis and available treatments, lifestyle tips, and other resources

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