Just posted a few weeks ago about this - mine look the same, and the car has never hit anything aside from potholes. They are the sacrificial part of the rear suspension and designed to bend.
I see you've got 19s just like me...I bet there are a lot of other cars out there with trailing arms that look the same, the drivers just don't know it yet. Chances are your rear wheels are pretty toed out right now.
The arms are about $50 each.