Updated December 20, 2014.

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Arthritis of the knee joint is one of the most common causes of knee pain. There are different types of arthritis that can affect the knee joint, and the treatments may vary depending on the condition that is causing the symptoms.

Osteoarthritis is the most common type of knee arthritis. Also called wear-and-tear arthritis or degenerative joint disease, osteoarthritis is characterized by progressive wearing away of the cartilage in the joint.

As the protective cartilage is worn away, bone is exposed, the knee becomes swollen and painful, and activities become increasingly painful.

Knee arthritis typically affects patients as they get older. Symptoms are more common in patients who are overweight, and weight loss tends to reduce the severity of pain associated with knee arthritis. There is also a genetic component, meaning knee arthritis can be passed down within a family. Other factors that can contribute to developing knee arthritis include injuries to the knee, torn cartilage, and fractures to the bone around the joint.

Symptoms of Knee Arthritis

Knee arthritis symptoms tend to gradually progress as the condition worsens, however, symptoms may suddenly worsen with minor injury or overuse. Some patients report long episodes of mild symptoms, with sudden changes that increase the severity of their symptoms. Often patients report good months and bad months, or symptoms that fluctuate with the weather. This is important to understand because comparing the symptoms of arthritis on one particular day may not accurately represent the overall progression of the condition.

Since there is not a cure for arthritis, learning ways to slow the progression of arthritis is also important.

The most common symptoms of knee arthritis include:

• Pain with activities
• Limited range of motion
• Stiffness of the joint
• Swelling of the joint
• Tenderness of the knee
• A feeling the knee may "give out"
• Deformity of the joint (knock-knees or bow-legs)

Treatment of Knee Arthritis

Treatment should begin with the most basic steps and progress to the more invasive, possibly including surgery. Not all treatments are appropriate for every patient, and you should have a discussion with your doctor to determine which treatments are appropriate for your particular situation. The range of options includes:

• Weight Loss
  Probably one of the most important, yet least commonly performed treatments. The less weight the joint has to carry, the less painful activities will be.
• Activity Modification
  Limiting certain activities may be necessary, and learning new exercise methods may be helpful.
• Walking Aids
  Use of a cane or a single crutch is the hand opposite the affected knee will help decrease the demand placed on the arthritic joint.
• Physical Therapy
  Strengthening of the muscles around the knee joint may help decrease the burden on the knee. Preventing atrophy of the muscles is an important part of maintaining functional use of the knee.
• Anti-Inflammatory Medications
  Anti-inflammatory pain medications (NSAIDs) are prescription and nonprescription drugs that help treat pain and inflammation.
• Cortisone Injections
  Cortisone injections may help decrease inflammation and reduce pain within a joint.
• Synvisc
  Synvisc may be effective against pain in some patients with knee arthritis and may delay the need for knee replacement surgery.
• Knee Arthroscopy
  Exactly how effective knee arthroscopy is for treatment of arthritis is debatable. For some specific symptoms, it may be helpful.
• Knee Osteotomy
  While most patients are not good candidates for this alternative to knee replacement, it can be effective for young patients with limited arthritis.
• Knee Replacement Surgery
  In this procedure, the cartilage is removed and a metal & plastic implant is placed in the knee.
• Partial Knee Replacement
  Also called a unicompartmental knee replacement, this is replacement of one part of the knee. It is a surgical option for the treatment of limited knee arthritis.

_{Sources:
BJ Cole and CD Harner "Degenerative arthritis of the knee in active patients: evaluation and management" J. Am. Acad. Ortho. Surg., Nov 1999; 7: 389 - 402.}