Thanks for explanation. Having lost my wife certainly understand there are no guarantees with surgery. If you are on roller coaster without meds, then you may not be ready.
That said if bone on bone you must have a very tolerant pain threshold. Are you taking meds? If you are, they may be masking your true pain as they were for me.
this is a very personal situation. Some people are quick healers and others do not tolerate the surgery well. May depend on the experience of your surgeon too. I believe in using the top ones for something important.
I felt better one day after surgery than the day before. As you probably know if you replace both at one time you have one recovery period but what a period. You might check out thy probabilities of success and find what the predictors are for a successful surgery, that may give you more confidence. Of course you can try one first to hedge your bets....
Ed