CHI from trauma is generally blunt trauma in origin. Looking at the diagram below I would expect to see both unilateral OR bilateral depending on the patient.
https://tse1.mm.bing.net/th?id=OIP....EsDH&w=147&h=105&c=8&rs=1&qlt=90&pid=3.1&rm=2
Hang on... need to get my microscope out!