Computational nodal displacement analysis of acetabulum fossa for injection molded cemented polyethylene acetabular liner

Vignesh, R and Sharma, V and Basu, B (2023) Computational nodal displacement analysis of acetabulum fossa for injection molded cemented polyethylene acetabular liner. In: Journal of the Mechanical Behavior of Biomedical Materials, 147 .

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Abstract

The acetabular liner (AL) is one of the key components that determine the functionality and durability of the total hip joint replacement (THR) device. The performance of Ultra high molecular weight polyethylene (UHMWPE)-based AL depends critically on the manufacturing route and its properties, which are evaluated pre-clinically using a host of experimental and computational analyses. The conventional manufacturing of an AL involves multiple stages, including extrusion/compression molding followed by machining, which is time/cost intensive and leads to material loss. In such a scenario, injection molding is a promising alternative, yet its feasbility remains unexplored for the manufacturing of AL for THA applications. Against this backdrop, the two-fold objectives of this work are to report our recent efforts to establish the efficacy of the injection molding of new generation UHMWPE biomaterial; HU (60 wt HDPE- 40 wt UHMWPE blend) for manufacturing AL prototype and to present the key biomechanical response analysis of this prototype, in silico. A range of manufacturing relevant material properties, as well as customized mold design to manufacture HU-based AL with external design features, are discussed. Such guidelines are particularly relevant to mold polymeric parts with a higher thickness (>8 mm). As part of the pre-clinical validation of AL with new design features, a less explored in silico approach to assess biomechanical micro-strain in the acetabulum fossa is presented, and the results are analysed in accordance with the mechanostat theory. The outcomes revealed that for a 100 kg subject weight, average micro-strain in the remodelling region was 1132, while it was determined as 723 for a 55 kg subject weight. Such results highlight the influence of subject weight on micro-strain generation and distribution in the acetabulum fossa. The von Mises stress in AL also increased with subject weight from 17 MPa in a subject weight of 55 kg to 28 MPa in a subject weight of 100 kg. Taken together, this work demonstrates the feasibility and competence of this new generation biomaterial in terms of implant manufacturing via injection molding with a clinically desired biomechanical response. © 2023 Elsevier Ltd

Item Type:	Journal Article
Publication:	Journal of the Mechanical Behavior of Biomedical Materials
Publisher:	Elsevier Ltd
Additional Information:	The Copyright for this article belongs to Elsevier Ltd.
Keywords:	Arthroplasty; Computation theory; High density polyethylenes; Hip prostheses; Injection molding; Knee prostheses; Molds; Nonmetallic matrix composites; Shrinkage; Ultrahigh molecular weight polyethylenes, Acetabular liner; Acetabular liners; Biomechanical response; Finite element analyse; In-silico; Melt viscosities; Micro-strain; Nodal analysis; Subject weights, Finite element method
Department/Centre:	Division of Chemical Sciences > Materials Research Centre Division of Interdisciplinary Sciences > Centre for Biosystems Science and Engineering
Date Deposited:	09 Nov 2023 09:26
Last Modified:	09 Nov 2023 09:26
URI:	https://eprints.iisc.ac.in/id/eprint/83306

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