He didn't do them at the same time, but he did have them replaced one right after the other, like you describe. The first knee went OK. Rehab time was every bit of 6 mo. But the 2nd one was a nightmare. It never did heal/recover, and he was left with more pain and stiffness than before. He went to orthos in most every major city he visited over the next several years, and none could tell him what was wrong or why. After about five years, he got frustrated and decided to have the bad one re-replaced. This time, he had it done at MCV in Richmond. When they got in there, they found the problem...the epoxy they used to bond the replacement knee to the bone had never cured. It was still gummy because the original surgeon didn't mix the epoxy correctly. So every time he bent his knee, the metal parts were shifting slightly. But none of this will show up on an x-ray or MRI since those are static images. The surgeon that did the re-replacement described what he found as unconscionable, and would support my dad if he wanted to file a malpractice suit. Today, things are pretty good. But I think the takeaway from my father's experience is if you need a knee replacement, have it done at UVA or Duke or MCV or some similar renowned medical facility and not at your local hospital. As an aside, I had a similar experience with a colonoscopy. The local hospital found some unsettling stuff and recommended I have surgery to remove 3/4 of my large intestine. That kind of surgery is a big deal, and they recommended I go to Duke to have it done. I went to Duke for a consult, and they suggested I repeat the colonoscopy there at Duke to see if they could address the issues without surgery. They were able to take care of everything, and I just had a 6-mo follow up at Duke to confirm they got everything, and all was good. If you need anything medically major or scary done, I'm now a believer in going to Duke (or some other facility of that caliber) vs. leaving it to your local docs.