title: A numerical investigation into the influence of the properties of cobalt chrome cellular structures on the load transfer to the periprosthetic femur following total hip arthroplasty.
abstract: Stress shielding of the periprosthetic femur following total hip arthroplasty is a problem that can promote the premature loosening of femoral stems. In order to reduce the need for revision surgery it is thought that more flexible implant designs need to be considered. In this work, the mechanical properties of laser melted square pore cobalt chrome molybdenum cellular structures have been incorporated into the design of a traditional monoblock femoral stem. The influence of incorporating the properties of cellular structures on the load transfer to the periprosthetic femur was investigated using a three dimensional finite element model. Eleven different stiffness configurations were investigated by using fully porous and functionally graded approaches. This investigation confirms that the periprosthetic stress values depend on the stiffness configuration of the stem. The numerical results showed that stress shielding is reduced in the periprosthetic Gruen zones when the mechanical properties of cobalt chrome molybdenum cellular structures are used. This work identifies that monoblock femoral stems manufactured using a laser melting process, which are designed for reduced stiffness, have the potential to contribute towards reducing stress shielding.
authors.affiliation: Department of Engineering, University of Wolverhampton, Telford TF2 9NT, UK. Electronic address: Kevin.Hazlehurst@wlv.ac.uk.
authors.forename: Kevin Brian
authors.initials: KB
authors.lastname: Hazlehurst
authors.affiliation: School of Engineering and Informatics, University of Sussex, Brighton BN1 9QJ, UK.
authors.forename: Chang Jiang
authors.initials: CJ
authors.lastname: Wang
authors.affiliation: Department of Engineering, University of Wolverhampton, Telford TF2 9NT, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Stanford
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D002858:Chromium Alloys; D003198:Computer Simulation; D055119:Elastic Modulus; D005269:Femur; D020342:Finite Element Analysis; D005615:Freezing; D006622:Hip Prosthesis; D006801:Humans; D007834:Lasers; D055595:Mechanical Phenomena; D008962:Models, Theoretical; D016062:Porosity; D011474:Prosthesis Design; D013314:Stress, Mechanical; D014800:Vitallium / Q000737:chemistry*
chemical_list: D002858:Chromium Alloys; D014800:Vitallium
keywords: Cellular structures; Femoral stem; Finite element analysis