scholarly journals Finite Element Analysis of Uncemented Total Hip Replacement: the Effect of Bone-Implant Interface

2018 ◽  
Vol 7 (4.26) ◽  
pp. 230 ◽  
Author(s):  
Nur Faiqa Ismail ◽  
Solehuddin Shuib ◽  
Muhd Azman Yahaya ◽  
Ahmad Zafir Romli ◽  
Amran Ahmed Shokri
Keyword(s):  
Finite Element ◽  
Coefficient Of Friction ◽  
Implant Design ◽  
Implant Loosening ◽  
Interference Fit ◽  
Bone Implant ◽  
Hip Implant ◽  
Total Hip ◽  
Finite Element Software ◽  
Press Fit

Most uncemented total hip replacements (THR) rely on press-fit for the initial stability and thus lead to the secondary fixation which is biological fixation. Choosing the accurate interference fit may have a great effect on implant stability and implant loosening prevention. Implant loosening is the most reported problem where it leads the increasing of micromotion at the bone-implant interface due to insufficient primary fixation. By having sufficient stability or fixation after surgery, minimal relative motion between the prosthesis and bone interfaces allows osseointegration to occur. Therefore, it will provide a strong prosthesis-to-bone biological attachment. The aim of this study was to evaluate the effect of bone-implant interface for uncemented hip implant. In this study, a three-dimensional model of hip implant was designed and analysed by using commercial Finite Element Software namely, ANSYS WORKBENCH V15 software in order to investigate the bone-implant interface effect using the chosen implant design. The value of interference fit (δ= 0.01, 0.05, 0.10 and 0.50 mm) and coefficient of friction (δ= 0.15, 0.40 and 1.00) were used to simulate the bone-implant interface. It was found that the interference fit of 0.50 mm was sufficient to achieve the primary fixation and also the best fitting; thus, the implant loosening can be minimized. The interference fit of 0.50 mm was the minimal value to achieve fixation, while the coefficient of friction did not affect the bone-implant interface. 

scholarly journals Finite-element analysis of the influence of tibial implant fixation design of total ankle replacement on bone–implant interfacial biomechanical performance

2020 ◽  
Vol 28 (3) ◽  
pp. 230949902096612
Author(s):  
Jian Yu ◽  
Chao Zhang ◽  
Wen-Ming Chen ◽  
Dahang Zhao ◽  
Pengfei chu ◽  
...  
Keyword(s):  
Finite Element ◽  
Total Ankle Replacement ◽  
Implant Design ◽  
Fixation Method ◽  
Implant Loosening ◽  
Implant Fixation ◽  
Bone Resection ◽  
Bone Implant ◽  
Initial Stability ◽  
Ankle Replacement

Purpose: Implant loosening in tibia after primary total ankle replacement (TAR) is one of the common postoperative problems in TAR. Innovations in implant structure design may ideally reduce micromotion at the bone–implant interface and enhance the bone-implant fixation and initial stability, thus eventually prevents long-term implant loosening. This study aimed to investigate (1) biomechanical characteristics at the bone–implant interface and (2) the influence of design features, such as radius, height, and length. Methods: A total of 101 finite-element models were created based on four commercially available implants. The models predicted micromotion at the bone–implant interface, and we investigated the impact of structural parameters, such as radius, length, and height. Results: Our results suggested that stem-type implants generally required the highest volume of bone resection before implantation, while peg-type implants required the lowest. Compared with central fixation features (stem and keel), peripherally distributed geometries (bar and peg) were associated with lower initial micromotions. The initial stability of all types of implant design can be optimized by decreasing fixation size, such as reducing the radius of the bars and pegs and lowering the height. Conclusion: Peg-type tibial implant design may be a promising fixation method, which is required with a minimum bone resection volume and yielded minimum micromotion under an extreme axial loading scenario. Present models can serve as a useful platform to build upon to help physicians or engineers when making incremental improvements related to implant design.

Modeling of Thermoplastic Materials for the Process-Simulation of Press-Fit Interconnections on Moulded Interconnected Devices

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Thomas Fellner ◽  
Elena Zukowski ◽  
Jürgen Wilde ◽  
H. Kück ◽  
H. Richter ◽  
...  
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Base Material ◽  
Creep Model ◽  
Assembly Process ◽  
Temperature Dependent ◽  
Reliability Modeling ◽  
Finite Element Software ◽  
Press Fit ◽  
Temperature Loads

This investigation is aimed at the modeling of both the fabrication process and the reliability of press-fit interconnections on moulded interconnect devices (MID). These are multifunctional three-dimensional substrates, produced by thermoplastic injection moulding for large-series applications. The assembly process and subsequently the durability of press-fit interconnections has been modeled and proved with a finite element software. Especially, a simulation tool for process optimizations was created and applied. In order to obtain realistic results, a creep model for the investigated base material, a liquid-crystal polymer (LCP), was generated and verified by experiments. Required friction coefficients between metal pin and base material were determined by adapting simulations and experiments. Retention forces of pins pressed into substrate holes during as well after the assembly process, and after temperature loads were predicted by simulations. Additionally, the decreasing extraction forces over time due to creep in the thermoplastic base material have been predicted for different storage temperatures as well with finite element analyses. Following, the numerical results of the process and reliability modeling were verified by experiments. It is concluded that the behavior of the mechanical contact of the pin-substrate system, can be suitably described time- and temperature-dependent.

Influence of interference fit size on hole deformation and residual stress in hi-lock bolt insertion

2014 ◽  
Vol 228 (18) ◽  
pp. 3296-3305 ◽  
Author(s):  
Jiefeng Jiang ◽  
Yunbo Bi ◽  
Huiyue Dong ◽  
Yinglin Ke ◽  
Xintian Fan ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Hoop Stress ◽  
Element Model ◽  
Insertion Force ◽  
Interference Fit ◽  
Finite Element Software ◽  
Mechanical Joints ◽  
Hole Wall ◽  
Insertion Process

The interference fit can improve the fatigue performance of mechanical joints and is widely used in aircraft assembly. In this paper, specimens of lap plates and several interference fit sizes were designed, and then the interference fit hi-lock bolt insertion was carried out in an experimental test. Using the commercial finite element software ABAQUS, a two-dimensional axisymmetric finite element model was established to simulate the bolt insertion process. The finite element model was validated by comparison of experimental results and finite element prediction for insertion force and protuberance height. After the interference fitted bolt insertion, the changing characteristics of the non-uniform hole expansion and protuberance were presented with increases in interference fit size. Under low level of interference fit, the tensile hoop stress was produced mainly on the hole wall, and changed into compressive hoop stress when interference fit size is larger. The maximum tensile hoop stress point on faying surfaces went away from the hole wall with interference fit size increasing.

scholarly journals Finite element modeling of a generic stemless hip implant design in comparison with conventional hip implants

2004 ◽  
Vol 40 (15) ◽  
pp. 2027-2047 ◽  
Author(s):  
S.A. Asgari ◽  
A.M.S. Hamouda ◽  
S.B. Mansor ◽  
H. Singh ◽  
E. Mahdi ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Implant Design ◽  
Hip Implants ◽  
Hip Implant ◽  
Element Modeling

Incorporation Of Interference Fit And Cyclic Loading In Simulation Algorithm For Better Prediction Of Micromotion Of Femoral Stems

2012 ◽  
Author(s):  
Mohammed Rafiq Abdul–Kadir ◽  
Ulrich N. Hansen
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Hip Arthroplasty ◽  
Bone Ingrowth ◽  
Fibrous Tissue ◽  
Interference Fit ◽  
Press Fit ◽  
Key Words Hip ◽  
Femoral Stems

Pelonggaran aseptik adalah salah satu daripada sebab utama pembedahan ulangan tulang paha. Ini berlaku disebabkan kegagalan untuk mendapatkan cengkaman pertama yang kuat. Pergerakan antara implan dengan tulang melebihi had tertentu menghalang pertumbuhan tulang dan mengakibatkan pembentukan tisu berbentuk fiber. Dalam kajian ini, satu algoritma dicadangkan untuk meramal pergerakan implan dan seterusnya ketidakstabilan implan. Dengan menggunakan beban fisiologi, pergerakan implan relatif kepada tulang dikira menggunakan algoritma. Implan yang menggunakan sistem cengkaman tekanan telah dibentuk dan beban ulangan dikenakan untuk memberi simulasi yang sebenar. Satu ujikaji ‘in–vitro’ telah dilaksanakan terhadap empat tulang paha manusia untuk mengesahkan algoritma yang dicadangkan. Keputusan ujikaji telah mengesahkan pergerakan implan yang dijangka oleh algoritma ini. Kata kunci: tulang paha, algoritma cengkaman, pengesahan ujikaji Aseptic loosening is one of the major causes for revision surgery in hip arthroplasty. This has been attributed to failure in achieving strong primary fixation. Interface micromotion beyond a certain threshold limit inhibits bone ingrowth and favours the formation of fibrous tissue. In this study, an algorithm was constructed to predict micromotion and therefore instability of femoral stems. Based on common physiological loading, micromotion is calculated throughout the bone–implant interface. Press fit stem insertion was modelled using interference fit and cyclic loading was used to better simulate actual loading configuration. An in–vitro micromotion experiment was carried out on four human cadaveric femurs to validate the micromotion algorithm. A good correlation was obtained between finite element predictions and the in–vitro micromotion experiment. Key words: hip arthroplasty, primary stability, micromotion algorithm, experimental validation, finite element

scholarly journals Optimized trapezoidal-shaped hip implant for total hip arthroplasty using finite element analysis

2020 ◽  
Vol 7 (1) ◽  
pp. 1719575
Author(s):  
Chethan K N ◽  
Mohammad Zuber ◽  
Shyamasunder Bhat N ◽  
Satish Shenoy B ◽  
Duncan Shepherd
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Element Analysis ◽  
Hip Implant ◽  
Total Hip

Optimal Material Selection for Total Hip Implant: A Finite Element Case Study

2019 ◽  
Vol 44 (12) ◽  
pp. 10293-10301 ◽  
Author(s):  
Abdullah Tahir Şensoy ◽  
Murat Çolak ◽  
Irfan Kaymaz ◽  
Fehim Findik
Keyword(s):  
Finite Element ◽  
Material Selection ◽  
Hip Implant ◽  
Total Hip ◽  
Selection For ◽  
Optimal Material

Construction of Contact Model of Wheelset Assembly Surface Based on ABAQUS

2014 ◽  
Vol 577 ◽  
pp. 236-239
Author(s):  
Jun Xiao ◽  
Kai Qiang Zhou ◽  
Ren Zhou ◽  
Zhen Dong Lu ◽  
Meng Meng Yang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Finite Element ◽  
Friction Coefficient ◽  
Strain State ◽  
Element Model ◽  
Improve Quality ◽  
Finite Element Software ◽  
Press Fit ◽  
Mating Surface

In order to improve quality of wheelset assembly, a method for calculating interference between two sliding asperities that corresponding to the wheelset assembly interference is presented. A finite element model of sliding spherical asperity has been built with the finite element software ABAQUS to analyze the interaction among mating surface roughness, stress-strain state and press-fit curve. This study shows that final fitting force greatly increases with roughness when roughness is lower then 1.8μm and it is unpredicted when roughness is higher. Contact stress and friction coefficient between mating surfaces increase with roughness.

Cortical Bone Viscoelasticity and Fixation Strength of Press-Fit Femoral Stems: A Finite Element Model

2005 ◽  
Vol 128 (1) ◽  
pp. 7-12 ◽  
Author(s):  
T. R. Shultz ◽  
J. D. Blaha ◽  
T. A. Gruen ◽  
T. L. Norman
Keyword(s):  
Finite Element ◽  
Stress Relaxation ◽  
Finite Element Model ◽  
Cortical Bone ◽  
Coefficient Of Friction ◽  
Viscoelastic Behavior ◽  
Element Model ◽  
Press Fit ◽  
Initial Fixation ◽  
Push Out

Many cementless implant designs rely upon a diaphyseal press-fit in conjunction with a porous coated implant surface to achieve primary or short term fixation, thereby constraining interface micromotion to such a level that bone ingrowth and consequent secondary or long-term fixation, i.e., osseointegration, can occur. Bone viscoelasticity, however, has been found to affect stem primary stability by reducing push-out load. In this investigation, an axisymmetric finite element model of a cylindrical stem and diaphyseal cortical bone section was created in order to parametrically evaluate the effect of bone viscoelasticity on stem push-out while controlling coefficient of friction (μ=0.15, 0.40, and 1.00) and stem-bone diametral interference (δ=0.01, 0.05, 0.10, and 0.50mm). Based on results from a previous study, it was hypothesized that stem-bone interference (i.e., press-fit) would elicit a bone viscoelastic response which would reduce the initial fixation of the stem as measured by push-out load. Results indicate that for all examined combinations of μ and δ, bone viscoelastic behavior reduced the push-out load by a range of 2.6–82.6% due to stress relaxation of the bone. It was found that the push-out load increased with μ for each value of δ, but minimal increases in the push-out load (2.9–4.9%) were observed as δ was increased beyond 0.10mm. Within the range of variables reported for this study, it was concluded that bone viscoelastic behavior, namely stress relaxation, has an asymptotic affect on stem contact pressure, which reduces stem push-out load. It was also found that higher levels of coefficient of friction are beneficial to primary fixation, and that an interference “threshold” exists beyond which no additional gains in push-out load are achieved.

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