From Carol & Richard Eustice,
Your Guide to Osteoarthritis.
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About.com Health's Disease and Condition content is reviewed by Kate Grossman, MD

Knee osteoarthritis is the most common type of osteoarthritis. More than 10 million Americans have knee osteoarthritis. It is also the most common cause of disability in the United States. Early diagnosis and treatment help manage knee osteoarthritis symptoms. An overview of knee osteoarthritis will help you understand symptoms, diagnosis, and treatment options.

Causes of Knee Osteoarthritis

Deterioration of articular cartilage is the main problem associated with knee osteoarthritis. The condition can be caused by:

• previous knee injury
• repetitive strain on the knee
• fractures, ligament tear, and meniscal injury which can affect alignment and promote wear and tear
• genetics which make some people more likely to develop knee osteoarthritis
• obesity
• problems with subchondral bone (the bone layer underneath cartilage)

Diagnosis of Knee Osteoarthritis

Medical history, physical examination, and x-rays are used to diagnose knee osteoarthritis. X-rays are very helpful, allowing the doctor to see evidence of joint space narrowing and rule out other causes of knee pain. If more detailed imaging is needed, an MRI may be ordered. Arthroscopic knee surgery is another way to view the condition of the knee.

Symptoms of Knee Osteoarthritis

Knee osteoarthritis typically develops gradually over a period of years. The primary symptoms associated with knee osteoarthritis include:

• pain (mild, moderate, or severe)
• stiffness
• limited range of motion in the knee
• localized swelling

Knee osteoarthritis pain is usually worse following activity, especially overuse of the affected knee. Stiffness can worsen after sitting for prolonged periods of time. As knee osteoarthritis progresses, symptoms generally become more severe. Pain can become continuous rather than only when weight-bearing.

Treatment of Knee Osteoarthritis

Knee osteoarthritis cannot be cured but there are treatments available to help manage the symptoms. Medications, starting with acetaminophen, can help manage and relieve pain. Some patients obtain better pain relief when using NSAIDs (nonsteroidal anti-inflammatory drugs) or Celebrex, the one remaining COX-2 selective inhibitor. There are opioid analgesic medications available for patients who need stronger pain relief.

Aside from medications, other treatments include:

• local intraarticular injections of steroids or viscosupplements
• exercise / physical therapy
• weight loss if overweight
• topical creams
• knee brace or support
• joint protection techniques
• heat and cold
• glucosamine and chondroitin sulfate
• surgery as a last resort

Getting diagnosed and treated while knee osteoarthritis is still in the early stages is most beneficial. If treated early, many people can effectively manage mild to moderate knee osteoarthritis.

Test Your Knowledge - Knee Osteoarthritis

_{Sources:
Osteoarthritis of the Knee. JAMA. February 26, 2003 - Vol. 289. No.8.
A Patient's Guide to Osteoarthritis of the Knee. Center for Orthopaedics and Hip and Knee Surgery. 7/29/2007. <http://www.eorthopod.com/public/patient_education/6516/osteoarthritis_of_the_knee.html>.}