The Biomechanical Performance of Different Plate Fixation Configurations to Repair Vancouver Type C Periprosthetic Femur Fractures

Abstract

Objectives The incidence of femoral periprosthetic fractures (PPF) is rising. Vancouver type C PPFs compromise the majority type of fracture associated with high complication rates. The complexity of Vancouver C-type PPFs lies in the presence of the femoral stem in the proximal fracture fragment. This study compares the biomechanical performance of four plate fixation configurations to repair Vancouver type C periprosthetic femur fractures. Methods Six large adult 4th generation biomechanical low-density femur Sawbones instrumented with cemented femoral stems were used to conduct this study. A comminuted Vancouver-type C PPF was simulated and fixed with a plate. Four proximal fragment construct configurations were studied with combinations of unicortical screws, bicortical screws, and cerclage cable fixation. Constructs were loaded in axial compression and four-point bending, and the stiffness was calculated. Results Constructs with bicortical screw fixation had significantly greater stiffness than those with unicortical screw and cerclage cable fixation in axial and four-point bending loads. Constructs with cerclage cable and unicortical screw fixation had greater stiffness than ones with unicortical screw fixation. Conclusion Using bicortical screws in the proximal construct of Vancouver type C PPFs increases construct stiffness in axial and bending loads. Though controversial, using cerclage cables might have a place for construct augmentation when using only unicortical screws or a combination of unicortical and bicortical screws.