The effect of cannulated screw material on stress transfer parameter in orthotropic femur bone with Pauwels type-III fracture

Abstract This study sought to investigate the effect of different materials on the stress transfer parameter (STP) of multiple cannulated screw fixation for shear dominant intracapsular hip fracture. Through finite element analysis (FEA), two different material for basic commercial 7.0 mm cannulated screw implant were modeled: titanium and stainless steel. The cannulated screws were fixed into a Pauwels type III fractured femur model with a basic inverted triangle configuration. Bone was assumed to be orthotropic to provide a more accurate representation of bone’s elastic symmetry and the STPs of each screw were calculated based from the simulated von Mises stresses. Based from the results, titanium showed higher average STP value (0.284) for all three screws in compared to stainless steel (0.211). Despite of the differences, the STP distribution pattern were the same for all screw models where it was the highest near the tip of the screw and gradually decreases when nearer to the fractured location. In this study, titanium cannulated screw implant showed the most favorable result as higher STP unit interval value may correlate to better osseointegration between the bone and the surface of implant. This study also showed that the orientation of the implant fixation may also be an important factor in varying the STP values which will be studied further in the future. © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of Biomedical and Advanced Materials (Biocam 2017).