You haven't given enough information about the injury. What specifically did you fracture and to what degree? Did you just do X-Ray or MRI? Have you seen an Orthopedist?
Though morally ambiguous, pretty much this. You should report it, and the AFI says you have to, but if you don't, will anyone ever find out and would your Commander enforce administrative action?
The Air Force probably will eventually discover it, but it'll likely be much later with a token finger wagging.