Medical insurance, which many if not most older people have, covers quite a lot of the costs. There is a ‘gap’ between what they pay you back and the actual cost but it isn’t that huge. If it was, no one would have the operations. The system here is not ideal and if you don’t have private cover you are in for long waiting times unless it is life- threatening. There are some very,very good surgeons but they are in high demand. I would be nervous of 2 knees at once because you would be confined to a wheelchair. The rehab places are very good round here at least, though. By all accounts knee replacements are more difficult and longer to recover from than hip replacements.