Well, this is one that will certainly be in the discussion for nastiest sports injury of all-time. I don't think it's quite on the same level as Napoleon McCallum's leg injury with the Raiders, or Clint Malarchuk getting his throat slashed in an NHL game, but it's probably the worst I've seen in basketball. I'd definitely put it above Joe Theismann's broken leg, which for some reason seems to be the most famous even though there have been worse ones.
(Warning: if you are easily grossed out, do not watch this; it will definitely turn your stomach. Slow-mo replay is at about 1:00)
You gotta feel sorry for the guy. Although if he's lucky and all it is is a broken bone, that could heal in a few months and not be career-threatening. I'm no Pacers fan, but hope it goes as well as possible for him.