Lots of people will go to India or Thailand for their joint replacements... you can fly there, have a month-long vacation, the surgery, a month-long recovery, and fly back for less than the cost of just the surgery in the US.
This will be true of those with more $$$ for sure, but the average citizen on average income probably won’t consider it.
What stops Indian or Thai doctors from botching the job?
Where's the accountability?
Can you sue them for malpractice? What?