Most of the time, the cause of OA is unknown. It is mainly related to aging, but metabolic, genetic, chemical, and mechanical factors can also lead to OA.

The symptoms of osteoarthritis usually appear in middle age and almost everyone has them by age 70. Before age 55, the condition occurs equally in both sexes. However, after 55 it is more common in women.

The disease causes the cushioning (cartilage) between the bone joints to wear away. As the disease gets worse, the cartilage disappears and the bone rubs on bone. Bony spurs usually form around the joint.

OA can be primary or secondary.

Primary OA occurs without any type of injury or obvious cause.

Secondary OA is osteoarthritis due to another disease or condition. The most common causes of secondary OA are:

• Inflammatory disorders such as septic arthritis
• Injury
• Metabolic conditions, such as acromegaly
• Problems with anatomy (for example, being bow-legged)

The symptoms of osteoarthritis include:

• Deep aching joint pain that gets worse after exercise or putting weight on it and is relieved by rest
• Grating of the joint with motion
• Joint pain in rainy weather
• Joint swelling
• Limited movement
• Morning stiffness

Some people might not have symptoms.

A physical exam can show:

• Grating of a joint with motion
• Joint swelling
• Limited range of motion
• Tenderness

An x-ray of affected joints will show loss of the joint space, and in advanced cases, wearing down of the ends of the bone and bone spurs.

The goals of treatment are to:

• Increase the strength of the joints
• Maintain or improve joint movement
• Reduce the disabling affects of the disease
• Relieve pain

The treatment depends on which joints are involved.

MEDICATIONS

The most common medications used to treat osteoarthritis are nonsteroidal anti-inflammatory drugs (NSAIDs). They are pain relievers that reduce pain and swelling. Types include aspirin, ibuprofen, and naproxen.

Although NSAIDs work well, long-term use of these drugs can cause stomach problems, such as ulcers and bleeding. Manufacturers of NSAIDs include a warning label on their products that alerts users to an increased risk for cardiovascular events (heart attacks and strokes) and gastrointestinal bleeding.

Other medications used to treat OA include:

• COX-2 inhibitors (coxibs). Coxibs block a substance called COX-2 that causes swelling. This class of drugs was first thought to work as well as other NSAIDs, but with fewer stomach problems. However, reports of heart attacks and stroke have led the FDA to re-evaluate the risks and benefits of the COX-2s. Celecoxib (Celebrex) is still available at the time of this report, but labeled with strong warnings and a recommendation that it be prescribed at the lowest possible dose for the shortest possible period of time. Ask your doctor whether the drug is right and safe for you.
• Steroids. These medications are injected right into the joint. They can also be used to reduce inflammation and pain.
• Supplements. Many people are helped by over-the-counter remedies such as glucosamine and chondroitin sulfate. There is some evidence that these supplements can help control pain, although they do not seem to grow new cartilage.
• Artificial joint fluid (Synvisc, Hyalgan). These medications can be injected into the knee. They may relieve pain for up to 6 months.

LIFESTYLE CHANGES

Exercise helps maintain joint and overall movement. Ask your health care provider to recommend an appropriate home exercise routine. Water exercises, such as swimming, are especially helpful.

Other lifestyle recommendations include:

• Applying heat and cold
• Eating a healthy balanced diet
• Getting rest
• Losing weight if you are overweight
• Protecting the joints

PHYSICAL THERAPY

Physical therapy can help improve muscle strength and the motion at stiff joints. Therapists have many techniques for treating osteoarthritis. If therapy does not make you feel better after 3-6 weeks, then it likely will not work at all.

BRACES

Splints and braces can sometimes support weakened joints. Some prevent the joint from moving; others allow some movement. You should use a brace only when your doctor or therapist recommends one. Using a brace the wrong way can cause joint damage, stiffness, and pain.

SURGERY

Severe cases of osteoarthritis might need surgery to replace or repair damaged joints. Surgical options include:

• Arthroscopic surgery to trim torn and damaged cartilage and wash out the joint
• Cartilage restoration to replace the damaged or missing cartilage in some younger patents with arthritis
• Change the alignment of a bone to relieve stress on the bone or joint (osteotomy)
• Surgical fusion of bones, usually in the spine (arthrodesis )
• Total or partial replacement of the damaged joint with an artificial joint (knee arthroplasty , hip arthroplasty )

For more information and support, see arthritis resources .

Your movement may become very limited. Treatment generally improves function.

• Adverse reactions to drugs used for treatment
• Decreased ability to perform everyday activities, such as personal hygiene, household chores, or cooking
• Decreased ability to walk
• Surgical complications

Call your health care provider if you have symptoms of osteoarthritis.

Weight loss can reduce the risk of knee osteoarthritis in overweight women.

Gregory PJ, Sperry M, Wilson AF. Dietary supplements for osteoarthritis. Am Fam Physician. 2008;77:177-184.

Glass GG. Osteoarthritis. Dis Mon. 2006;52:343-362.