Unfortunately it's more often the plastic that the hinges screw into that fails rather than the hinges themselves. You may be able to glue it back together with epoxy (2-part) rapid glue but you will need to add reinforcement, such as by building up the glue around the crack and/or gluing a piece of fibreglass matrix board or a piece of an old de-populated printed circuit board over the crack on the outside of the case.