Methods and apparatus for installing intramedullary medical devices (e.g., intramedullary nails) are described herein. Intramedullary medical devices in accordance with this disclosure provide sustained compressive forces across a bone fusion site despite bone resorption processes. Intramedullary medical devices in accordance with this disclosure include pseudo-elastic shape memory alloys containing nickel and titanium. Portions of intramedullary medical devices, including shape memory alloy elements in the intramedullary medical devices, may have strains imparted upon them through the methods and apparatus described herein. Further aspects of surgery techniques are also performed and controlled through the methods and apparatus described herein.