Intraprosthetic screw fixation increases primary fixation stability in periprosthetic fractures of the femur - a biomechanical study

Abstract

Background: The purpose of this study was to develop a new fixation technique for the treatment of periprosthetic fractures using intraprosthetic screw fixation. The goal was to biomechanically evaluate the increase in primary fixation stability compared to unicortical locked-screw plating.

Methods: A Vancouver C periprosthetic fracture was simulated in femur prosthesis constructs. Fixation was then performed with either unicortical locked-screw plating using the LISS-plate or with intraprosthetic screw fixation. Fixation stability was compared in an axial load-to-failure model.

Results: The intraprosthetic fixation model was superior to the unicortical locked-screw fixation in all tested devices. The intraprosthetic fixation model required 11,807N±1596N for failure and the unicortical locked-screw plating required 7649N±653N (p=0.002).

Conclusion: Intraprosthetic screw anchorage with a special prosthesis drill enhances the primary stability in treating periprosthetic fractures by internal fixation.

Keywords: Intraprosthetic screw fixation; LISS-plate; Locking-screw plating; Periprosthetic fracture.