Risk what? They guys knees checked out just fine. Oden and Roy were totally different. Portland knew there was a risk with both, but chose to ignore it. In Roy's case it was worth it for a few years, and in Oden's they simply screwed the pooch. From the sound of things, drafting Kanter poses the same risk (medical wise) as any other player in this draft.
Well if you're talking injury in the Knight vs Kanter discussion - I think you'd have to say that Knight would have the upper hand on that one.