Researchers suspect that osteoarthritis is caused by a combination of factors in the body and the environment. The chance of developing osteoarthritis increases with age. By age 65, half of the population has x-ray evidence of osteoarthritis in at least one joint, most often in the hips, knees, or fingers.

Osteoarthritis often results from years of wear and tear on joints. This wear and tear mostly affects the cartilage, the tissue that cushions the ends of bones within the joint. Osteoarthritis occurs when the cartilage begins to fray, wear away, and decay.

Putting too much stress on a joint that has been previously injured, improper alignment of joints, and excess weight all may contribute to the development of osteoarthritis.

Different types of arthritis have different symptoms. In general, people with most forms of arthritis have pain and stiffness in their joints.

Osteoarthritis usually develops slowly and can occur in any joint, but often occurs in weight bearing joints. Early in the disease, joints may ache after physical work or exercise. Most often, osteoarthritis occurs in the hands, hips, knees, neck, or low back.

Common signs of osteoarthritis include joint pain, swelling, and tenderness; stiffness after getting out of bed; and a crunching feeling or sound of bone rubbing on bone. Not everyone with osteoarthritis feels pain, however. In fact, only a third of people with x-ray evidence of osteoarthritis report pain or other symptoms.

To make a diagnosis of osteoarthritis, most doctors use a combination of methods and tests including a medical history, a physical examination, x-rays, and laboratory tests. However, x-rays are limited in their capacity to reveal how much joint damage may have occurred in osteoarthritis. X-rays usually don’t show osteoarthritis damage until there has been a significant loss of cartilage.

It is important for people with joint pain to give the doctor a complete medical history. Answering these questions will help your doctor make an accurate diagnosis:

• Is the pain in one or more joints?
• When does the pain occur and how long does it last?

• When did you first notice the pain?
• Does activity make the pain better or worse?

• Have you had any illnesses or accidents that may account for the pain?
• Is there a family history of any arthritis or rheumatic diseases?
• What medicines are you taking?

• A medical history is the patient’s description of symptoms and when and how they began. The description covers pain, stiffness, and joint function, and how these have changed over time.

• A physical examination includes the doctor’s examination of the joints, skin, reflexes, and muscle strength. The doctor observes the patient’s ability to walk, bend, and carry out activities of daily living.

The doctor will use a combination of tests to try to find out if osteoarthritis is causing the symptoms. A patient’s attitudes, daily activities, and levels of anxiety or depression have a lot to do with how severe the symptoms of osteoarthritis may be.

Osteoarthritis treatment plans often include ways to manage pain and improve function. Such plans can include exercise, rest and joint care, pain relief, weight control, medicines, surgery, and non-traditional treatment approaches.

Current treatments for osteoarthritis can relieve symptoms such as pain and disability, but right now there are no treatments that can cure osteoarthritis.

Exercise is one of the best treatments for osteoarthritis. It can improve mood and outlook, decrease pain, increase flexibility, and help you maintain a healthy weight.

The amount and form of exercise will depend on which joints are involved, how stable the joints are, whether or not the joint is swollen, and whether a joint replacement has already been done. Ask your doctor or physical therapist what exercises are best for you

For temporary relief of pain from osteoarthritis, you can use warm towels, hot packs, or a warm bath or shower. In some cases, cold packs such as a bag of ice or frozen vegetables wrapped in a towel can relieve pain or numb the sore area.

A doctor or physical therapist can recommend if heat or cold is the best treatment. For osteoarthritis in the knee, wearing insoles or cushioned shoes may reduce joint stress.

Doctors consider a number of factors when choosing medicines for their patients. In particular, they look at the type of pain the patient may be having and any possible side effects from the drugs.

For pain relief, doctors usually start with acetaminophen because the side effects are minimal. If acetaminophen does not relieve pain, then non-steroidal anti-inflammatory drugs such as ibuprofen and naproxen may be used. Some NSAIDs are available over the counter, while more than a dozen others, including a subclass called COX-2 inhibitors, are available only with a prescription.

Corticosteroids, hyaluronic acid, and topical creams are also used. Most medicines used to treat osteoarthritis have side effects, so it is important for people to learn about the medicines they take. For example, people over age 65 and those with any history of ulcers or stomach bleeding should use non-steroidal anti-inflammatory drugs, or NSAIDs, with caution.

Protecting and supporting the affected joint or joints is important. Some people use canes and splints to protect and to take pressure off the joints. Splints or braces are used to provide extra support for weakened joints.

For some people, surgery helps relieve the pain and disability of osteoarthritis. A doctor may perform surgery to smooth out, fuse, or reposition bones, or to replace joints.

The decision to have an operation depends on several factors. Both surgeon and patient should consider the patient’s level of disability, intensity of pain, lifestyle, age, and occupation. Today, more than 80 percent of surgeries for osteoarthritis involve replacing the hip or knee joint.

Researchers suspect that heredity plays a role in some osteoarthritis cases. Scientists have identified a mutation, or gene defect, affecting collagen — an important part of cartilage — in patients with an inherited kind of osteoarthritis that starts at an early age.

In the future, a test to determine who carries a genetic defect or defects could help people reduce their risk for osteoarthritis with lifestyle adjustments

Tissue engineering is an exciting area of research in osteoarthritis. This approach involves removing cells from a healthy part of the body and placing them in an area of diseased or damaged tissue. In some cases, this improves joint movement.

Researchers also are studying whether exercise can treat or prevent osteoarthritis. Studies on knee osteoarthritis and exercise found that strengthening the thigh muscle, also known as the quadriceps, can relieve symptoms of knee osteoarthritis and prevent more damage.

Studies also show that people with knee osteoarthritis who exercise appropriately feel less pain and function better.

The U.S. National Institutes of Health, through its National Library of Medicine and other Institutes, maintains a database of clinical trials, including those funded by the NIH, at ClinicalTrials.gov.

Early research suggests that acupuncture, which is the use of fine needles inserted at specific points in the skin, may provide pain relief for some patients. Some people claim that the dietary supplements glucosamine and chondroitin sulfate can relieve the symptoms of osteoarthritis.

The NIH is currently funding the Glucosamine and Chondroitin Arthritis Intervention Trial, or GAIT, to test whether or not glucosamine and/or chondroitin have a beneficial effect for people with knee osteoarthritis. The results of the first phase of the study indicate that these supplements did not provide significant relief from osteoarthritis pain among all participants.