My AVN is likely a result of oral prednisone steroids taken to treat Sarcoidosis (diagnosed in 2008.) X-rays taken 6 months ago compared to a few days ago show progression of the AVN/bone collapse. He says he won't know until surgery how much good bone there is. He also said that, because sarcoidosis is an auto-immune disease, another flare-up could result in taking more steroids possibly leading to more damage, undermining the HR.
I think I should have asked how many similar cases he has dealt with and what the outcomes were. He did say that out of about 1,000 HR surgeries he's only had to do one conversion. But I didn't ask how many times he's set out to do a resurfacing but ended up doing a replacement. I have a lot of confidence in him and don't know if I'm overthinking it. At some point I have to put it in the hands of the person with knowledge and experience, but it's hard to know when you've done and asked all you can!