Abstract: Intramedullary medical devices (e.g., intramedullary nails) and methods for their use and manufacture are described herein. The intramedullary medical devices described herein may provide sustained compressive forces across a bone fusion site despite bone resorption processes. Through various embodiments, the intramedullary medical devices described herein may provide non-linear force curves relative to displacement. Intramedullary medical devices are described with multiple elements made of different materials. Examples of intramedullary medical devices are described with shape memory alloys.

Abstract: Methods and apparatus described herein may utilize activation of an SMP material to install medical devices with respect to a surgical site. Activation of the SMP material may be performed with the use of a triggering force and/or a constraint applied to the SMP material. Activation using a triggering force and/or a constraint may be used to create varied activation rates in an SMP material and may be combined with temperature or other activation stimuli to create the varied activation rates.