Determining the best time to have a knee replacement is based on a combination of factors. We will first determine why your knee hurts and swells. It could be many things, such as osteoarthritis, rheumatoid arthritis or gout. It also depends upon what other treatment you’ve tried. There are many non-operative treatments for arthritis and those should be tried prior to having your knee replaced. We will also take into account the degree of your disability from your condition as well as the severity on x-ray. Only after all of these factors have been considered, can a doctor provide a thoughtful answer to when your knee should be replaced.