I know with my grandfather, he had to go through a total knee replacement on both knees. It was a long recovery but he says it was one of the best decisions he made. The only problem he had afterwards was the bill. We felt for a long time that his bill was overpriced and because his doctor refused his insurance, (said it was too much paperwork) we ended up having no choice but to pay out of pocket because there aren't that many doctors around his home area that can do what he needed done... After searching around for answers to our bill though we came across a knee replacement cost estimator. Quite simply, a calculator that takes into consideration your location, age, pre-exisiting conditions and even your insurance and then creates an estimated bill for the surgery. It actually proved one and for all the cost was exactly as it should have been. Knowing that, we were surprised but still at ease with everything and made the payments necessary to cover the costs of the surgery.
I'll share it with you too if you're concerned about the costs or if anyone is honestly, but it really helped me so I hope it helps you too, good luck!!
http://www.healthline.com/surgery/total-knee-replacement/costs