Knee replacements have a high probability of being successful but there can be a some pretty serious complications. Try to have the surgery done by a surgeon who does a lot of these surgeries. If you can, find a specialty hospital that does only hip and knee replacements. I may need to have my knee replacement "revised" after 18 years of use. The complication I am most concerned about is a perioperative infection that requires taking the implant out, antibiotics for several months and then going back to try it again. If this happens you will need help. The risk is relatively low for a new TKR (in the 2% range) but it can happen. Talk to the surgeon, find out their infection rate. The more surgeries performed by the surgeon and facility, generally the better the outcome you will have. If you do not have a caregiver, count on going to a skilled nursing facility. Talk to the surgeons staff ahead of time about this. Really work hard at physical therapy rehab after surgery and work hard ahead of the surgery to strengthen the muscles. You also might try physical therapy before considering surgery.