How do you treat them? 

I have a horse that seems to pop a splint every year. I'm sweating and giving bute right now, but I'm curious if anyone has any other treatments suggestions. It's a small one, and he is only slightly off on it, no heat or swelling that I can see. 

I would be looking at why the horse is popping one every year. There used to be a splint remedy you could buy online. Silver was for cold splints and gold was for fresh ones if I remember right. Your vet can make up a DMSO dex solution as well. 

If he is off on it, I would definitely have it xrayed. Mine fractured his a few years ago...long story short. Took him to the vet for surgery to have it removed and the vet told me to go back home because it had already started calcifying. Wound up saving me quite a bit of $$$. Mine was never off on his though.