Over time, a knee replacement will wear away and may become loose which causes pain. A modern knee replacement is expected to last for 15 years.
Revision knee replacement surgery (replacing the original replacement knee) is usually more complicated and a longer procedure than the original surgery and recovery is longer since the soft tissues around the area need more time to settle down. There is no set limit to the number of times a person can have revision surgery, but it is widely accepted that the artificial knee joint becomes less effective each time it is replaced.