Fixation of periprosthetic femoral shaft fractures: A biomechanical comparison of two techniques

Objective: To determine which of two currently used techniques for the treatment of periprosthetic femoral shaft fractures provides the greater fixation rigidity and strength. Design: A laboratory study using six matched pairs of femurs. Methods: Embalmed femur prosthesis constructs had a simulated periprosthetic fracture created and were fixed with a plate with proximal cables and distal bicortical screws (Ogden concept) or two allograft struts and cables. Fixation stability was compared in various loading modalities before and after cycling. They were then tested to failure. Outcome Measurements: Fixation rigidity was defined as the ratio of applied load to the amount of displacement at the fracture. Results: In all loading modalities, the Ogden construct was more rigid than the allograft strut fixation. The Ogden construct required 1,295 newtons for failure and the allograft strut fixation required 950 newtons (p < 0.05). Conclusion: The Ogden construct provided a more rigid and stronger initial fixation of a periprosthetic fracture than did the allograft construct.