I had a stainless rod in my right femur for 19 years. It was the result of a broadside hit from a car. I had no issues at all, and had the rod removed to make way for a new hip. Took 88 swings of a 3-lb. surgial slide hammer to get it out, too.
I carried it on my KLR for a couple of years to use as a prop rod for tire work.
It's bolted to the luggage rack just below the license plate.
As has been stated, it might just come down to the differences in healing between individuals.