Yes and no. I mean would he do that if his stifle was still off, do I ride him, this just makes more questions about him, and I'm tired of the questions:)
Becky
In my opinion? Yes ride him... and don't worry about the stifle too much. Just be aware of it and if he takes a hitchy step then you know that's why. Where it might affect his hopes as a barrel horse, it shouldn't change him as a trail horse at all, you can go that way with him for awhile and see.
My vet and I talked quite awhile about Cyn's... and while I think she is more mild, she only seems to get hitchy trying to back up or pivot on it, he re-explained that all horses have locking stifles, that's why they can sleep standing up. It doesn't hurt when it locks up, he just has to have the muscling to pull it out of the socket, and if he steps wrong, he might get stuck for a stride or two till he can free it. But it isn't necessarily an unsoundness.