A knee replacement is a surgical procedure involving the replacement of the faulty knee joint with a prosthetic. During a total knee replacement, the end of the femur bone is removed and replaced with a metal shell. The end of the lower leg bone (tibia) is also removed and replaced with a plastic piece with a metal stem. Depending on the condition of the kneecap portion of the knee joint, a plastic "button" may also be added under the kneecap surface.

Reasons that you may benefit from total knee replacement commonly include:

• Severe knee pain that limits your everyday activities, including walking, climbing stairs, and getting in and out of chairs. You may find it hard to walk more than a few blocks without significant pain and you may need to use a cane or walker.
• Moderate or severe knee pain while resting, either day or night
• Chronic knee inflammation and swelling that does not improve with rest or medications
• Knee deformity: a bowing in or out of your knee
• Knee stiffness: inability to bend and straighten your knee
• Failure to obtain pain relief from nonsteroidal anti-inflammatory drugs. These medications, including aspirin and ibuprofen, often are most effective in the early stages of arthritis. Their effectiveness in controlling knee pain varies greatly from person to person. These drugs may become less effective for patients with severe arthritis.
• Failure to substantially improve with other treatments such as cortisone injections, physical therapy, or other surgeries.