Couple of points here.....
1. There's really only one place on the hindquarter that is a vitally fatal shot and that's the femoral artery, which you DIDN'T hit BTW, because he'd of been dead in short order and you'd have had a blood trail that a blind man could follow.
(Side bar here......This is why purposely aiming for the femoral artery is NOT a good shot choice because you either kill them dead, or if you are an inch off you have what you just did.)
2. Now, I have seen rear leg shots that did cause death, but by secondary factors like gangrene. These shots were with firearms however. Bullet/slug wounds cause MASSIVE tissue damage/destruction which can easily infect and decay. Not a good death at all if they are not in the vitals. Broadheads...sharp ones....cause a relatively "clean" wound which are much easier for a deer to recover from if the point of impact was not in a vital area. I've seen and gutted a few deer that had old entire broadheads still in them that just cysted over.
What you can do from this experience is LEARN all you can from it. There's not one of us here that's hunted a lot that hasn't had similar experiences. Every track I go on whether it's from a deer that I hit or a friends I consider to be an educational opportunity that can be had nowhere else. Not in books, or video or even in cyberspace!
I've been hunting deer for 45 years and have lived "right in amongst 'em" for the past 24, and even with all that I can honestly say that the vast majority by far of what I know about them I learned from tracking them.
Good luck in all of your future hunts and don't ever hesitate to ask us anything. We don't know it all for sure but we're more than willing to share what we do.
Offer No Apologies.....
NRA Endowment Life Member