Towards the optimal design of an uncemented acetabular component using genetic algorithms

2019

Proc Inst Mech Eng H

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The aim of this study is to investigate the effects of implant orientation and implant material on tibia bone strain, implant-bone micromotion, maximum contact pressure, and wear depth at the articulating surface due to total ankle replacement. Three-dimensional finite element models of intact and implanted ankle were developed from computed tomography scan data. Four implanted models were developed having varus and valgus orientations of 5°and 10°, respectively. In order to determine the effect of implant material combination on tibia bone strain, micromotion, contact pressure, and wear depth, three other finite element models were developed having a different material combination of the implant. Dorsiflexion, neutral, and plantarflexion positions were considered as applied loading condition, along with muscle force and ligaments. Implant orientation alters the strain distribution in tibia bone. Strain shielding was found to be less in the case of the optimally positioned implant. Apart from the strain, implant orientation also affects implantbone micromotion, contact pressure, and wear depth. Implant materials have less influence on tibia bone strain and micromotion. However, wear depth was reduced when ceramic and carbon fibre-reinforced polyetheretherketone material combination was used. Proper orientation of the implant is important to reduce the strain shielding. The present result suggested that ceramic can be used as an alternative to metal and carbon fibre-reinforced polyetheretherketone as an alternative to ultra-high molecular weight polyethylene to reduce wear, which would be beneficial for long-term success and fixation of the implant.

Section: Wear Depth Assessmentmentioning

confidence: 99%

Effects of implant orientation and implant material on tibia bone strain, implant–bone micromotion, contact pressure, and wear depth due to total ankle replacement

Mondal

2019

Proc Inst Mech Eng H

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“…Apart from the contact pressure, the micromotion between implants is also an important parameter to quantify the wear in the cemented acetabular cup. 47–49 The high (maximum) value of contact pressure and micromotion in this study was found for UHMWPE-CoCrMo compared to other implant material combinations (Figure 11). These values further increased with the increase in the patient’s bodyweight and decrease in bone quality.…”

Section: Discussionmentioning

confidence: 62%

Biomechanical performance of the cemented acetabular cup with combined effects of bone quality, implant material combinations and bodyweight

Kumar

Mondal

2022

Proc Inst Mech Eng H

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The objective of this study is to understand the combined effects of bone quality, implant materials and bodyweight on the biomechanical performance of cemented acetabular cup. Additionally, the performance of the cemented acetabular cup was evaluated for obesity cases or obese people. A total of 84 FE models (based on CT data) were developed based on combinations of three different cancellous bone material distributions to represent bone quality, four different implant material combinations and seven different bodyweights. The biomechanical performance of the acetabular cup was evaluated based on bone stress (both cortical and cancellous bone), cement mantle stress, micromotion and contact pressure between the acetabular cup and femoral head. Cortical bone stress, cancellous bone stress, cement stress, the contact pressure between implants and micromotion between implants are affected by different bone quality, implant material combinations and bodyweights. An increase in bodyweight would increase the cortical bone stress, cancellous bone stress, cement stress, contact pressure between implants and micromotion between implants. However, bodyweight affects the cortical and cancellous bone stress more (stiff rise of the bone stresses; nonlinear relation) as compared to other output parameters (mostly linear relation). Comparing cortical and cancellous bone stress, the stress versus bodyweight curve is much stiffer (stiff rise in the curve) for cortical bone than cancellous bone and that even further increases as bone quality decreases. Especially considering obesity cases or obese people (very high bodyweight), the performance of the cemented acetabular component is poor. Graphical abstract [Formula: see text]

“…The detailed descriptions of the FE modeling procedure of the pelvic bone was presented in earlier studies. [16][17][18][19][20] The generation procedure of the FE model of the pelvic bone was validated and verified experimentally. 21,22 Both intact and implanted pelvic bone model were generated to evaluate causes of failure of the cemented polyethylene acetabular component.…”

Section: Methodsmentioning

confidence: 99%

“…The Young's Modulus of the UHMWPE acetabular component and cement mantle were considered as 1.174 GPa and 2 GPa, respectively and the Poisson's ratio for each of these materials was taken as 0.4 and 0.33. 6,20 The spherical femoral head was made of CoCrMo alloy and for this material, Young's modulus was considered as 210 GPa and Poisson's ratio of 0.3. 16…”

Section: Materials Propertiesmentioning

confidence: 99%

Assessment of failure of cemented polyethylene acetabular component due to bone remodeling: A finite element study

Journal of Orthopaedics

2016

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The aim of the study is to determine failure of the cemented polyethylene acetabular component, which might occur due to excessive bone resorption, cement-bone interface debonding and fatigue failure of the cement mantle. Three-dimensional finite element models of intact and implanted pelvic bone were developed and bone remodeling algorithm was implemented for present analysis. Soderberg fatigue failure diagram was used for fatigue assessment of the cement mantle. Hoffman failure criterion was considered for prediction of cement-bone interface debonding. Results indicate fatigue failure of the cement mantle and implant-bone interface debonding might not occur due to bone remodeling.