The ball joint stud doesn't normally bend after a wallop, it usually either pops the balljoint out of its socket, which would make the car undriveable, or the wishbone gets twisted or bent back. Looking at the pic, it looks more like a deformed wishbone or split rear bush.
Subframes can be bent, what exactly gets damaged can depend on the angle of the impact, but as Jocko says, the wishbone is the weaker part. Normal course of action would be to replace everything that is obviously damaged, then take some geometry measurements.