One way to stop the potential for such injuries would be to outlaw jumping up for the ball - you must catch with your feet on the ground. I know this will be contentious, but if safety is the overriding concern...
Also, when scrums deteriorate and a free kick is awarded, you can re-set (sometimes with the same result, leading to a penalty) or you can kick - likely with loss of possession - or tap - lottery. Why not re-set 10ms from the point of the infringement (unless already 5m form try line) - at least offending side are then penalised with loss of territory...