Description

Current hip replacement implants are made of fully solid materials which all have stiffness considerably higher than that of bone. This mechanical mismatch can cause significant bone resorption secondary to stress shielding, which can lead to serious complications such as peri-prosthetic fracture during or after revision surgery.

To solve this problem, our research introduces the concept of structural optimization when creating bone implants. Our implant micro-architecture is optimized to locally mimic bone tissue properties which results in minimum bone resorption secondary to stress shielding. We also present a systematic approach for the design of a 3D printed fully porous hip implant that encompasses the whole activity spectrum of implant development.

Below you can find publications of bone replacement implants, e.g. hip, knee, fusion cage, that demonstrate the merit and the potential of optimizing material architecture to maximize clinical performance, such as reducing implant micromotion and/or achieving a substantial reduction of bone resorption secondary to stress shielding.

 

Relevant publications

Moussa A, Melancon D, El Elmi A, Pasini D, Topology optimization of imperfect lattice materials built with process-induced defects via Powder Bed Fusion, Additive Manufacturing, Vol 37, 101608, 2021.

Moussa A, Rahman S, Xu H, Tanzer M, Pasini D, Topology optimization of 3D-printed structurally porous cage for acetabular reinforcement in total hip arthroplasty, Journal of the Mechanical Behavior of Biomedical Materials, Vol. 105, 103705, 2020. 

Asgari M, Abi-Rafeh J., Hendy G.H., Pasini D, Material anisotropy and elasticity of cortical and trabecular bone in the adult mouse femur via AFM indentation, Journal of the Mechanical Behavior of Biomedical Materials, Vol 93, pp. 81-92, 2019. 

Rahimizadeh A, Nourmohammadi Z, Arabnejad S, Tanzer M, Pasini D, Porous architected biomaterial for a tibial-knee implant with minimum bone resorption and bone-implant interface micromotion, Journal of the Mechanical Behavior of Biomedical Materials,Vol. 78, pp. 465–479, 2018. 

Wang Y, Arabnejad S, Tanzer M, Pasini D, Hip implant design with three-dimensional porous architecture of optimized graded density, ASME Journal of Mechanical Design, Special Issue: Design of Engineered Materials and Structures, Vol 140(11), 111406, pp. 1-13, 2018. 

Melancon D., Bagheri Z.S., Johnston R.B., Liu L., Tanzer M., Pasini D., Mechanical characterization of structurally porous biomaterials built via additive manufacturing: experiments, predictive models, and design maps for load-bearing bone replacement implants, Acta Biomaterialia,  Vol. 63, pp. 350-368, 2017. 

Arabnejad S, Johnston B, Tanzer M, Pasini D, Fully Porous 3D Printed Titanium Femoral Stem to Reduce Stress-shielding Following Total Hip Arthroplasty, Journal of Orthopaedic Research, Vol 35 (8), 1774–1783, 2017.

Arabnejad S, Johnston RB, Pura JA, Singh B, Tanzer M, Pasini D, High-Strength Porous Biomaterials for Bone Replacement: a Strategy to Assess the Interplay between Cell Morphology, Mechanical Properties, Bone Ingrowth and Manufacturing Constraints, Acta Biomaterialia 30: 345–356, 2016. 

Arabnejad S, Pasini D, The Fatigue Design of a Bone Preserving Hip Implant with Functionally Graded Cellular Material, ASME Journal of Medical Devices 7(2): 020908, 2013. 

Arabnejad S, Pasini D, Multiscale Design and Multiobjective Optimization of Orthopaedic Hip Implants with Functionally Graded Cellular Material, ASME Journal of Biomechanical Engineering 134(3): 031004, 2012.