Can i prevent rib fractures from becoming malunions?

Not really: Uncommon for rib malunions to be a problem unless there was severe displacement in the original injury. I recently read a journal article arguing for operative fixation in select cases but I have never considered this in twenty years of practice and can't remember seeing a painful malunion though it may happen rarely.

Uncommon: It is fairly uncommon to have a rib fracture go on to a malunion. On the other hand, other than avoiding an injury such as a fall, there is not much that can be done to avoid them.