Intramedullary nails are the gold standard of fracture fixation, yet problems can still arise due to their manufacture in discrete lengths. Patient outcomes are less favorable when implanted with an improper length nail, and the wide range of discrete length options can increase the size hospital inventory. Prototypes of adjustable-length intramedullary nails were developed and tested in axial compression, torsion, and four-point bending. These prototypes are comparable to conventional nails in axial and bending stiffness. The torsional stiffness of the prototypes is less than that of conventional nails, but may be sufficient for clinical use.