Such penile trauma happens, but it is pretty rare, and it usually heals, with the worst side effect possibly being a penis with a bit of banana shape (which is not abnormal in healthy men, either).
Hey, tens of thousands of people are killed in car accidents each year. Do you ride in cars? Do you drive? There are risks in anything, but ending up with a bent penis due to normal sex is so far down on the list of risks you shouldn't waste time thinking about it.