When I fell down the nephew's stairs and broke my knee cap, I also busted my head against the wall opposite of where I fell. Tests showed no damage to my head! Wow, that's amazing because I hit it hard. The kneecap break was "clean" so it healed with a cast from foot to top of thigh for 2 months, than a smaller cast so that I could do some PT.
Then on a walker for months. Had to get the leg to bend again. Miraculously it seems it does bend normally now, and is as strong as the other. My head...well, it's always been a little "off" (LOL)