A device for treating bone in a living body includes (a) comprises an implant configured for attachment to a bone； (b) a first sensor measuring a strain on a first portion of the implant, the first portion of the implant being configured to be mechanically coupled to a weakened portion of a bone when the implant is coupled to the bone in a target position in combination； and (c) a second sensor measuring strain in a non-weakened portion of the bone.
