Denise, we bought one of these for Kirby and there is STILL a huge portion of it left. Kirby chewed off all the "good" smoked bits and left the rest of the bone to Seamus, who, you can imagine, doesn't inflict much damage on the bone.
But when Kirby would gnaw at it, I never saw any small, sharp piece come off. I think because the bone is so large, it's harder for them to crush it and cause it to shatter. Even our friend's Landseer Newfoundland couldn't cause it to splinter.

She did manage to break off one large piece of it, though.