Cadaver-Specific Models for Finite-Element Analysis of Iliopsoas Impingement in Dual-Mobility Hip Implants

Stress shielding is a well-known failure factor in hip implants. This work proposes a design concept for hip implants, using a combination of metallic stem with a polymer coating (polyether ether ketone (PEEK)). The proposed design concept is simulated using titanium alloy stems and PEEK coatings with thicknesses varying from 100 to 400 μm. The Finite Element analysis of the cancellous bone surrounding the implant shows promising results. The effective von Mises stress increases between 81 and 92% for the complete volume of cancellous bone. When focusing on the proximal zone of the implant, the increased stress transmission to the cancellous bone reaches between 47 and 60%. This increment in load transferred to the bone can influence mineral bone loss due to stress shielding, minimizing such effect, and thus prolonging implant lifespan.

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Mechanical implications of interfacial defects between femoral hip implants and cement: A finite element analysis of interfacial gaps and interfacial porosity

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1243/09544119jeim362 ◽

2008 ◽

Vol 222 (7) ◽

pp. 1037-1047 ◽

Cited By ~ 1

Author(s):

T Scheerlinck ◽

J Broos ◽

D Janssen ◽

N Verdonschot

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Fatigue Cracks ◽

Cement Mantle ◽

Rotational Stability ◽

Hip Implants ◽

Analysis Model ◽

Implant Surface ◽

Element Analysis ◽

Computed Tomography Image

Two types of defect between femoral hip implants and cement have been identified. Interfacial porosity arises from cement shrinkage during curing and presents as pores randomly located along the stem. Interfacial gaps are much larger stem—cement separations caused by air introduced during stem insertion. To investigate the mechanical consequences of both types of defect, a finite element analysis model was created on the basis of a computed tomography image of a Charnley—Kerboul stem, and alternating torsional and transverse loads were applied. The propagation of fatigue cracks within the cement and the rotational stability of the stem were assessed in models simulating increasing amounts of interfacial gaps and pores. Anterior gaps covering at least 30 per cent of the implant surface promoted cement cracks and destabilized the stem. Anterolateral gaps were less destabilizing, but had more potential to promote cracks. In both cases, cracks occurred mainly outside gap regions, in areas where the stem contacted the cement during cyclic loading. Although random interfacial pores did not destabilize the implant, they acted as crack initiators even at low fractions (10 per cent). In conclusion, random interfacial pores were more harmful for the cement mantle integrity than were larger regions of interfacial gaps, although gaps were more detrimental for the rotational stability of the stem.

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Patient-specific finite element analysis of femurs with cemented hip implants

Clinical Biomechanics ◽

10.1016/j.clinbiomech.2018.06.012 ◽

2018 ◽

Vol 58 ◽

pp. 74-89 ◽

Cited By ~ 10

Author(s):

Yekutiel Katz ◽

Omri Lubovsky ◽

Zohar Yosibash

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Patient Specific ◽

Hip Implants ◽

Element Analysis

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Hip implants VII: Finite element analysis and optimization of cross-sections

Materials & Design (1980-2015) ◽

10.1016/j.matdes.2007.09.002 ◽

2008 ◽

Vol 29 (7) ◽

pp. 1438-1446 ◽

Cited By ~ 40

Author(s):

Anthony L. Sabatini ◽

Tarun Goswami

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Cross Sections ◽

Hip Implants ◽

Element Analysis

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Finite element analysis of Ti6Al4V porous structures for low-stiff hip implant application

International Journal for Simulation and Multidisciplinary Design Optimization ◽

10.1051/smdo/2021014 ◽

2021 ◽

Vol 12 ◽

pp. 12

Author(s):

Porika Rakesh ◽

Bidyut Pal

Keyword(s):

Mechanical Properties ◽

Finite Element Analysis ◽

Finite Element ◽

Hip Implants ◽

Porous Structures ◽

Element Analysis ◽

Hip Implant ◽

Femur Bone ◽

Body Center Cubic ◽

Effective Mechanical Properties

Solid metallic hip implants have much higher stiffness than the femur bone, causing stress-shielding and subsequent implant loosening. The development of low-stiff implants using metallic porous structures has been reported in the literature. Ti6Al4V alloy is a commonly used biomaterial for hip implants. In this work, Body-Center-Cubic (BCC), Cubic, and Spherical porous structures of four different porosities (82%, 76%, 70%, and 67%) were investigated to establish the range of ideal porosities of Ti6Al4V porous structures that can match the stiffness of the femur bone. The effective mechanical properties have been determined through Finite Element Analysis (FEA) under uniaxial compressive displacement of 0.32 mm. FEA predictions were validated with the analytical calculations obtained using Gibson and Ashby method. The effective mechanical properties of 82%, 76%, 70%, and 67% porous BCC and Cubic structures were found to match the mechanical properties of cortical bone closely. They were also well comparable to the Gibson-Ashby method-based calculations. BCC and Cubic porous structures with 67–82% porosity can mimic the stiffness of the femur bone and are suitable for low-stiff hip implant applications.

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Finite Element Analysis of Surface Modification of Titanium Alloy Used for Hip Implant

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1016.1544 ◽

2021 ◽

Vol 1016 ◽

pp. 1544-1548

Author(s):

Aleksandra Vulović ◽

Fernando Gustavo Warchomicka ◽

Nenad Filipović

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Shear Stress ◽

Surface Modification ◽

Stress Distribution ◽

Hip Implants ◽

Element Analysis ◽

Bone Implant ◽

Hip Implant ◽

Different Types

Titanium and its alloys, especially Ti-6Al-4V have found application as hip implants due to their mechanical properties, excellent biocompatibility, and corrosion resistance. The use of cementless hip implants has increased over the years as it is thought that this type is more durable compared to cemented hip implants. Cementless hip implants have a porous surface that allows the bone to grow into it and form a strong bone–implant connection. The goal of this study is the use of Finite Element Method simulations to obtain information about how different types of surface topography of a TI-6Al-4V hip implant affect the shear stress, which is used to access the bone-implant connection. Finite Element Analysis is used to analyze the stress distribution in three simple surface modifications in a hip implant under different types of loads. The optimal surface modification out of these three is obtained based on the shear stress distribution, as it is known that lower shear stress promotes bone ingrowth. In this study, we have considered the interaction between cortical bone and implant surface. Material properties and boundary conditions used for the simulations have been adapted from literature.

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