We adopted our 50ish pound lab mix at 8 months old, the Humane Society said he was an owner surrender and did not tell us he was a runner.

He was hit by a car doing 50 (clipped him and flipped him) and he spent about two weeks not wanting to move and we figured he wasn't going to make it. We had to carry him out to do his business as he couldn't do the porch steps. One day he got up and acted like nothing happened and shows no lasting effects.

He didn't learn from it. He will still bolt out the door if given even a tenth of a chance and crosses the same highway at a dead run.

I hope your pup recovers fully.