When is a boot better than crutches for tibial stress fracture in a runner?

A stress fracture in your tibia, or shin bone, is a bad injury. You definitely don't want the crack to grow to the point where it could break.  The big question is what will make a tibial stress fracture better, faster...crutches or a fracture walking boot?  When is a fracture walking boot better than crutches for a tibial stress fracture if you're a runner?  That's what we're talking about today on the Doc On The Run Podcast.