I trained for (and completed a half-marathon) ... I'm also 5.5 years post-op, so what works for me may not work for you. And it took time playing with different ways of doing things to find what worked for me.
The day before long runs (and my races) I focus on drinking a lot of water and eating healthy carbs. Typically a small pasta dinner.
About an hour before my running I eat either a banana or some oatmeal. During my running, I eat Shot Bloks (by Cliff) and drink a lot of water. I seem to drink way more water than my non-post op running friends, not sure why. Within 10 mins of finishing I drink endurox (icky, but works!) and on my way home I usually eat a banana.
Some friends who aren't as far out from surgery have tried different lower sugar options that worked for them, but I did fine with the main stream ones.
Good luck!!
Christy