There is disclosed a method for implanting a device in a fractured bone. The device has an elongated shape and includes a thermo-chemically activated portion including a polymer having a glass transition temperature greater than 37 degrees Celsius. The thermo-chemically activated portion is deformable at a first thermo-chemical state in which the temperature of the polymer is greater than the glass transition temperature. The thermo-chemically activated portion is hard at a second thermo-chemical state in which the temperature of the polymer is lower than the glass transition temperature. The method includes transforming the thermo-chemically activated portion from the second to the first thermo-chemical state. The method includes inserting the device into an intramedullary canal. The method includes transforming the thermo-chemically activated portion from the first to the second thermo-chemical state to harden the thermo-chemically activated portion to a relatively rigid configuration to provide reinforcement to the fractured bone sufficient to promote healing.