My dad has one that has small OCD's in both hocs, but he just injects the front joints with depo-medrol every time he runs. That just blocks the pain. It hasn't gotten any worse, but no better either. When he was young they thought about surgery and they sent pictures to the Elgin Clinic (supposed to be the best in Texas) to see what they recommended. They said they could be removed or scraped out or something, but they weren't real big, so they said to just wait and it wouldn't bother him that much. And it hasn't, he's run pretty good every time. But your deal sounds a lot worse. If its that big, its gotta hurt.
I don't know anything about OCD's, but they're pretty rare I guess. I worked for a vet this summer and my dad's was the only case we had. But it sounds like you're doing the right thing, time off and adequan, so I'd just wait to see what the experts say at the conference.