A bone fixation system and method for stabilizing a fractured bone by implantation into the intramedullary canal of an implant that is expanded by an implant deformation apparatus, or deformer. The deformer can use mechanical, pneumatic, or hydraulic expansion. Some deformers apply or remove heat. Some implants may include a support structure and a thermo-chemically activated matrix. The support structure may be radially expandable and contractible, and sufficiently flexible to be inserted into the intramedullary canal through an opening which is not parallel to the intramedullary canal. The matrix may attain a first thermo-chemical state via the addition of energy, and a second thermo-chemical state via the dissipation of energy.