I can only understand this if they were incapcitated, unconscious... I mean just kick it off, it weighs a few ounces. How does a rabbit do enough damage to require amputation of the effing leg!?! Think how small a rabbits mouth is, they dont each meat so it would take them a long time to chow down on your leg. Theyre weaker than a cat, unless its one of those massive hares, and have you ever heard a cat mauling someones leg off? I need to see either the size of this rabbit, or the size of this person.
Plus amputation could be due to an out of control infection or something like that. Wounds are complicated.