title: Multiscale design and multiobjective optimization of orthopedic hip implants with functionally graded cellular material.
abstract: Revision surgeries of total hip arthroplasty are often caused by a deficient structural compatibility of the implant. Two main culprits, among others, are bone-implant interface instability and bone resorption. To address these issues, in this paper we propose a novel type of implant, which, in contrast to current hip replacement implants made of either a fully solid or a foam material, consists of a lattice microstructure with nonhomogeneous distribution of material properties. A methodology based on multiscale mechanics and design optimization is introduced to synthesize a graded cellular implant that can minimize concurrently bone resorption and implant interface failure. The procedure is applied to the design of a 2D left implanted femur with optimized gradients of relative density. To assess the manufacturability of the graded cellular microstructure, a proof-of-concept is fabricated by using rapid prototyping. The results from the analysis are used to compare the optimized cellular implant with a fully dense titanium implant and a homogeneous foam implant with a relative density of 50%. The bone resorption and the maximum value of interface stress of the cellular implant are found to be over 70% and 50% less than the titanium implant while being 53% and 65% less than the foam implant.
authors.affiliation: Mechanical Engineering Department, McGill University, Montreal, Quebec, Canada. sajad.arabnejadkhanoki@mail.mcgill.ca
authors.forename: Sajad
authors.initials: S
authors.lastname: Arabnejad Khanoki
authors.forename: Damiano
authors.initials: D
authors.lastname: Pasini
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects; D001862:Bone Resorption / Q000209:etiology / Q000517:prevention & control; D005269:Femur / Q000503:physiopathology; D020342:Finite Element Analysis; D006615:Hip; D006801:Humans; D011126:Polypropylenes / Q000737:chemistry; D016062:Porosity; D011474:Prosthesis Design / Q000379:methods*; D011475:Prosthesis Failure; D013314:Stress, Mechanical
chemical_list: D011126:Polypropylenes