Does the Lateral Plate need to Overlap the Stem to Mitigate Stress Concentration When Treating Vancouver C Periprosthetic Supracondylar Femur Fracture?

The effect of construct length on cortical strain and load to failure between locked compression plating and cemented femoral stem in a fall model was analyzed. Eight Sawbone femurs with cemented stems were instrumented with increasing fixation lengths starting 8 cm distal to stem tip and progressing proximally to overlapping constructs. Uniaxial strain gauges measured cortical strain. Load to failure was performed with 8 cm gap between implants, 2 cm gap, and proximally overlapping configurations. Strain was significantly reduced as the 8 cm gap transitioned to an overlapped construct with most comparisons. Load to failure in the overlapped construct was 273% greater compared to 2 cm gap construct. Overlapping the stem with a locking compression plate resulted in reduced strain and increased load to failure.