What is the reason to go for total knee replacement?

Pain/disability: When to have a knee replacement has to be an individualized decision. Moderate to severe pain and/or loss of the ability to function to one's satisfaction are reasons to have a knee replacement. Failure to get relief with nonsurgical measures is also a reason. Severity of arthritis on an x-ray should not be the primary factor, as many with severe x-ray changes have little pain and good function.

Improved Lifestyle: When knee pain created by arthritis becomes constant, interfering with daily activities and the ability to sleep, then it is time to consider replacement. If medically stable and suitable for postop rehab, then it could be time for replacement.