Worst way to tell a stress reaction from a stress fracture

I lecture at medical conferences about stress fractures, trying to teach physicians the difference between a stress response, a stress reaction, which is basically an irritated and inflamed metatarsal bone, and a stress fracture where there's actually a crack that can cause real trouble. One of the questions doctors ask me is what's the best way and the worst way to tell a stress reaction from a stress fracture, because it does make a difference. What is the worst way to tell a stress reaction from a stress fracture? Well, that's what we're talking about today on the Doc On The Run podcast.