Everyone hates when your bone breaks and you have to be in prone all the time.
If you have a broken bone though, find a field hospital (theres one right across the cherno hospital), and when you're near it, you can select to heal at USMC Field Hospital or something like that.
You will have the broken bone icon still showing but you will be able to walk and won't break a bone no matter how many zombies will hit you.
EDIT: This stops working if you disconnect or die.