Tips for explaining AVN to others? How to get over not knowing the cause?

I had both hips replaced this year and will be going back to work in about a month. I’m anxious about people asking me what happened, why my hips were replaced, and mostly about why I got AVN. So far I’ve been telling people the truth which is that I do not know but it could have been caused or made worse by various factors: prednisone and other medications that likely compromised my bone health, periods of heavy alcohol use and smoking, and possible genetic predisposition (unknown bio father).

Does anyone have any tips for how to politely answer this question when you don’t have a clear answer? I’d rather not to disclose to most (especially coworkers) that I struggled in the past with drinking. My mom has concluded that it was caused by drinking which frustrated me because I told the ortho surgeon how much I drank & smoked and they said it wasn’t enough to cause AVN on its own but it was likely a contributing factor.

I’m also struggling with the answer to this question for myself. I feel 90% at peace with the reality that I’ll probably never know the exact cause, but occasionally I still fixate on wanting to know the cause. How do you find closure about this without a definite answer?