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Scott CEH, Eaton MJ, Nutton RW, Wade FA, Evans SL, Pankaj P. Metal-backed versus all-polyethylene unicompartmental knee arthroplasty: Proximal tibial strain in an experimentally validated finite element model. Bone Joint Res 2017; 6:22-30. [PMID: 28077394 PMCID: PMC5301904 DOI: 10.1302/2046-3758.61.bjr-2016-0142.r1] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 09/20/2016] [Indexed: 12/02/2022] Open
Abstract
OBJECTIVES Up to 40% of unicompartmental knee arthroplasty (UKA) revisions are performed for unexplained pain which may be caused by elevated proximal tibial bone strain. This study investigates the effect of tibial component metal backing and polyethylene thickness on bone strain in a cemented fixed-bearing medial UKA using a finite element model (FEM) validated experimentally by digital image correlation (DIC) and acoustic emission (AE). MATERIALS AND METHODS A total of ten composite tibias implanted with all-polyethylene (AP) and metal-backed (MB) tibial components were loaded to 2500 N. Cortical strain was measured using DIC and cancellous microdamage using AE. FEMs were created and validated and polyethylene thickness varied from 6 mm to 10 mm. The volume of cancellous bone exposed to < -3000 µε (pathological loading) and < -7000 µε (yield point) minimum principal (compressive) microstrain and > 3000 µε and > 7000 µε maximum principal (tensile) microstrain was computed. RESULTS Experimental AE data and the FEM volume of cancellous bone with compressive strain < -3000 µε correlated strongly: R = 0.947, R2 = 0.847, percentage error 12.5% (p < 0.001). DIC and FEM data correlated: R = 0.838, R2 = 0.702, percentage error 4.5% (p < 0.001). FEM strain patterns included MB lateral edge concentrations; AP concentrations at keel, peg and at the region of load application. Cancellous strains were higher in AP implants at all loads: 2.2- (10 mm) to 3.2-times (6 mm) the volume of cancellous bone compressively strained < -7000 µε. CONCLUSION AP tibial components display greater volumes of pathologically overstrained cancellous bone than MB implants of the same geometry. Increasing AP thickness does not overcome these pathological forces and comes at the cost of greater bone resection.Cite this article: C. E. H. Scott, M. J. Eaton, R. W. Nutton, F. A. Wade, S. L. Evans, P. Pankaj. Metal-backed versus all-polyethylene unicompartmental knee arthroplasty: Proximal tibial strain in an experimentally validated finite element model. Bone Joint Res 2017;6:22-30. DOI:10.1302/2046-3758.61.BJR-2016-0142.R1.
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Affiliation(s)
- C E H Scott
- School of Engineering, University of Edinburgh, Alexander Graham Bell Building, Mayfield Road, Edinburgh EH9 3JL, UK
| | - M J Eaton
- Cardiff School of Engineering, Cardiff University Institute of Mechanical and Manufacturing Engineering, Queen's Buildings, The Parade, Cardiff CF24 3AA, UK
| | - R W Nutton
- Department of Orthopaedics, Royal Infirmary of Edinburgh, 51 Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SA, UK
| | - F A Wade
- Department of Orthopaedics, Royal Infirmary of Edinburgh, 51 Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SA, UK
| | - S L Evans
- Cardiff School of Engineering, Cardiff University Institute of Mechanical and Manufacturing Engineering, Queen's Buildings, The Parade, Cardiff CF24 3AA, UK
| | - P Pankaj
- School of Engineering, University of Edinburgh, Alexander Graham Bell Building, Mayfield Road, Edinburgh EH9 3JL, UK
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Leuridan S, Goossens Q, Pastrav L, Roosen J, Mulier M, Denis K, Desmet W, Sloten JV. Determination of replicate composite bone material properties using modal analysis. J Mech Behav Biomed Mater 2016; 66:12-18. [PMID: 27829191 DOI: 10.1016/j.jmbbm.2016.10.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/24/2016] [Accepted: 10/26/2016] [Indexed: 11/28/2022]
Abstract
Replicate composite bones are used extensively for in vitro testing of new orthopedic devices. Contrary to tests with cadaveric bone material, which inherently exhibits large variability, they offer a standardized alternative with limited variability. Accurate knowledge of the composite's material properties is important when interpreting in vitro test results and when using them in FE models of biomechanical constructs. The cortical bone analogue material properties of three different fourth-generation composite bone models were determined by updating FE bone models using experimental and numerical modal analyses results. The influence of the cortical bone analogue material model (isotropic or transversely isotropic) and the inter- and intra-specimen variability were assessed. Isotropic cortical bone analogue material models failed to represent the experimental behavior in a satisfactory way even after updating the elastic material constants. When transversely isotropic material models were used, the updating procedure resulted in a reduction of the longitudinal Young's modulus from 16.00GPa before updating to an average of 13.96 GPa after updating. The shear modulus was increased from 3.30GPa to an average value of 3.92GPa. The transverse Young's modulus was lowered from an initial value of 10.00GPa to 9.89GPa. Low inter- and intra-specimen variability was found.
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Affiliation(s)
- Steven Leuridan
- KU Leuven, Department of Mechanical Engineering, Biomechanics Section, Celestijnlaan 300C - box 2419, 3000 Leuven, Belgium.
| | - Quentin Goossens
- KU Leuven, Department of Mechanical Engineering, Biomechanics Section, Celestijnlaan 300C - box 2419, 3000 Leuven, Belgium; KU Leuven, Department of Mechanical Engineering Technology, Andreas Vesaliusstraat 13 - box 2600, 3000 Leuven, Belgium.
| | - Leonard Pastrav
- KU Leuven, Department of Mechanical Engineering Technology, Andreas Vesaliusstraat 13 - box 2600, 3000 Leuven, Belgium.
| | - Jorg Roosen
- University Hospitals Leuven, Department of Orthopedics, Weligerveld 1, 3212 Leuven, Belgium.
| | - Michiel Mulier
- University Hospitals Leuven, Department of Orthopedics, Weligerveld 1, 3212 Leuven, Belgium.
| | - Kathleen Denis
- KU Leuven, Department of Mechanical Engineering Technology, Andreas Vesaliusstraat 13 - box 2600, 3000 Leuven, Belgium.
| | - Wim Desmet
- KU Leuven, Department of Mechanical Engineering, Production Engineering, Machine Design and Automation Section, Celestijnlaan 300C - box 2420, 3000 Leuven, Belgium.
| | - Jos Vander Sloten
- KU Leuven, Department of Mechanical Engineering, Biomechanics Section, Celestijnlaan 300C - box 2419, 3000 Leuven, Belgium.
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Gustafson HM, Cripton PA, Ferguson SJ, Helgason B. Comparison of specimen-specific vertebral body finite element models with experimental digital image correlation measurements. J Mech Behav Biomed Mater 2016; 65:801-807. [PMID: 27776322 DOI: 10.1016/j.jmbbm.2016.10.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 09/07/2016] [Accepted: 10/06/2016] [Indexed: 11/15/2022]
Abstract
The purpose of this study was to load cadaveric vertebral bodies (n=6) in compression and compare the response, measured with digital image correlation (DIC) on the cortex, with the predicted response from specimen-specific vertebral finite element (FE) models. Five modulus-density relationships were evaluated, and for the strongest modulus-density relationship, the correlation between the DIC and FE displacements had R2 values from 0.75 to 0.93. The stiffnesses derived from the DIC measurements were strongly predicted by the FE stiffnesses (R2=0.90). DIC provides full-field measurements of surface displacement, eliminating the influence of system compliance, for validation of specimen-specific models.
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Affiliation(s)
- Hannah M Gustafson
- Mechanical Engineering, University of British Columbia, 818 W. 10th Ave., Vancouver, BC, Canada V5Z 1M9.
| | - Peter A Cripton
- Mechanical Engineering, University of British Columbia, 818 W. 10th Ave., Vancouver, BC, Canada V5Z 1M9.
| | - Stephen J Ferguson
- Institute for Biomechanics, ETH-Zürich, HPP-O22, Hönggerbergring 64, CH-8093 Zürich, Switzerland.
| | - Benedikt Helgason
- Institute for Biomechanics, ETH-Zürich, HPP-O22, Hönggerbergring 64, CH-8093 Zürich, Switzerland.
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Grassi L, Väänänen SP, Ristinmaa M, Jurvelin JS, Isaksson H. How accurately can subject-specific finite element models predict strains and strength of human femora? Investigation using full-field measurements. J Biomech 2016; 49:802-806. [DOI: 10.1016/j.jbiomech.2016.02.032] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 02/11/2016] [Accepted: 02/12/2016] [Indexed: 11/25/2022]
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55
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Girardi BL, Attia T, Backstein D, Safir O, Willett TL, Kuzyk PR. Biomechanical comparison of the human cadaveric pelvis with a fourth generation composite model. J Biomech 2016; 49:537-42. [DOI: 10.1016/j.jbiomech.2015.12.050] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 11/18/2015] [Accepted: 12/28/2015] [Indexed: 10/22/2022]
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Palanca M, Tozzi G, Cristofolini L. The use of digital image correlation in the biomechanical area: a review. Int Biomech 2015. [DOI: 10.1080/23335432.2015.1117395] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Affiliation(s)
- Marco Palanca
- School of Engineering and Architecture, University of Bologna, Bologna, Italy
| | - Gianluca Tozzi
- School of Engineering, University of Portsmouth, Portsmouth, UK
| | - Luca Cristofolini
- School of Engineering and Architecture, Department of Industrial Engineering, University of Bologna, Bologna, Italy
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57
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Extracting accurate strain measurements in bone mechanics: A critical review of current methods. J Mech Behav Biomed Mater 2015; 50:43-54. [DOI: 10.1016/j.jmbbm.2015.06.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 06/01/2015] [Accepted: 06/02/2015] [Indexed: 11/19/2022]
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58
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Generation of 3D shape, density, cortical thickness and finite element mesh of proximal femur from a DXA image. Med Image Anal 2015; 24:125-134. [DOI: 10.1016/j.media.2015.06.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Revised: 06/03/2015] [Accepted: 06/11/2015] [Indexed: 11/19/2022]
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Chanda S, Dickinson A, Gupta S, Browne M. Full-field in vitro measurements and in silico predictions of strain shielding in the implanted femur after total hip arthroplasty. Proc Inst Mech Eng H 2015; 229:549-59. [DOI: 10.1177/0954411915591617] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/19/2015] [Indexed: 11/16/2022]
Abstract
Alterations in bone strain as a result of implantation may contribute towards periprosthetic bone density changes after total hip arthroplasty. Computational models provide full-field strain predictions in implant–bone constructs; however, these predictions should be verified using experimental models wherever it is possible. In this work, finite element predictions of surface strains in intact and implanted composite femurs were verified using digital image correlation. Relationships were sought between post-implantation strain states across seven defined Gruen zones and clinically observed longer-term bone density changes. Computational predictions of strain distributions in intact and implanted femurs were compared to digital image correlation measurements in two regions of interest. Regression analyses indicated a strong linear correlation between measurements and predictions (R = 0.927 intact, 0.926 implanted) with low standard error (standard error = 38 µε intact, 26 µε implanted). Pre- to post-operative changes in measured and predicted surface strains were found to relate qualitatively to clinically observed volumetric bone density changes across seven Gruen zones: marked proximal bone density loss corresponded with a 50%−64% drop in surface strain, and slight distal density changes corresponded with 4%−14% strain increase. These results support the use of digital image correlation as a pre-clinical tool for predicting post-implantation strain shielding, indicative of long-term bone adaptations.
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Affiliation(s)
- Souptick Chanda
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Alexander Dickinson
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
| | - Sanjay Gupta
- Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Martin Browne
- Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
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PALANCA MARCO, BRUGO TOMMASOMARIA, CRISTOFOLINI LUCA. USE OF DIGITAL IMAGE CORRELATION TO INVESTIGATE THE BIOMECHANICS OF THE VERTEBRA. J MECH MED BIOL 2015. [DOI: 10.1142/s0219519415400047] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Digital image correlation (DIC) is being introduced to the biomechanical field. However, as DIC relies on a number of major assumptions, it requires a careful optimization in order to obtain accurate and precise results. The first step was the preparation of the speckle pattern by an airbrush spray gun following a factorial design to explore the different settings: the different speckle patterns created were analyzed to achieve the optimal speckle size, with minimal dispersion of speckle sizes. A benchmark test, with an aluminum specimen prepared with the speckle pattern, was conducted in which the errors affecting the computed strain were measured in a zero-displacement, zero-strain condition. The software parameters (facet size, step, and local regression) were singularly analyzed in order to understand their behavior on the final output. Moreover, the hardware parameters (camera gain, exposure, lens distortion) were analyzed. The output showed that a careful optimization allowed the reducing the systematic and random errors, respectively, from 150 to 10 microstrain and from 600 to 110 microstrain. Finally, the acquired know-how was applied to a biological specimen (human vertebra).
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Affiliation(s)
- MARCO PALANCA
- School of Engineering and Architecture, University of Bologna, Via Terracini 28, Bologna 40131, Italy
| | - TOMMASO MARIA BRUGO
- School of Engineering and Architecture, University of Bologna, Via Terracini 28, Bologna 40131, Italy
| | - LUCA CRISTOFOLINI
- Department of Industrial Engineering, School of Engineering and Architecture, University of Bologna, Via Risorgimento 2, Bologna 40136, Italy
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61
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Vazquez M, Evans BAJ, Riccardi D, Evans SL, Ralphs JR, Dillingham CM, Mason DJ. A new method to investigate how mechanical loading of osteocytes controls osteoblasts. Front Endocrinol (Lausanne) 2014; 5:208. [PMID: 25538684 PMCID: PMC4260042 DOI: 10.3389/fendo.2014.00208] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 11/18/2014] [Indexed: 01/08/2023] Open
Abstract
Mechanical loading, a potent stimulator of bone formation, is governed by osteocyte regulation of osteoblasts. We developed a three-dimensional (3D) in vitro co-culture system to investigate the effect of loading on osteocyte-osteoblast interactions. MLO-Y4 cells were embedded in type I collagen gels and MC3T3-E1(14) or MG63 cells layered on top. Ethidium homodimer staining of 3D co-cultures showed 100% osteoblasts and 86% osteocytes were viable after 7 days. Microscopy revealed osteoblasts and osteocytes maintain their respective ovoid/pyriform and dendritic morphologies in 3D co-cultures. Reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR) of messenger ribonucleic acid (mRNA) extracted separately from osteoblasts and osteocytes, showed that podoplanin (E11), osteocalcin, and runt-related transcription factor 2 mRNAs were expressed in both cell types. Type I collagen (Col1a1) mRNA expression was higher in osteoblasts (P < 0.001), whereas, alkaline phosphatase mRNA was higher in osteocytes (P = 0.001). Immunohistochemistry revealed osteoblasts and osteocytes express E11, type I pro-collagen, and connexin 43 proteins. In preliminary experiments to assess osteogenic responses, co-cultures were treated with human recombinant bone morphogenetic protein 2 (BMP-2) or mechanical loading using a custom built loading device. BMP-2 treatment significantly increased osteoblast Col1a1 mRNA synthesis (P = 0.031) in MLO-Y4/MG63 co-cultures after 5 days treatment. A 16-well silicone plate, loaded (5 min, 10 Hz, 2.5 N) to induce 4000-4500 με cyclic compression within gels increased prostaglandin E2 (PGE2) release 0.5 h post-load in MLO-Y4 cells pre-cultured in 3D collagen gels for 48, 72 h, or 7 days. Mechanical loading of 3D co-cultures increased type I pro-collagen release 1 and 5 days later. These methods reveal a new osteocyte-osteoblast co-culture model that may be useful for investigating mechanically induced osteocyte control of osteoblast bone formation.
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Affiliation(s)
- Marisol Vazquez
- Arthritis Research UK Biomechanics and Bioengineering Centre, School of Biosciences, Cardiff University, Cardiff, UK
| | - Bronwen A. J. Evans
- Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Cardiff, UK
| | - Daniela Riccardi
- Division of Pathophysiology and Repair, School of Biosciences, Cardiff University, Cardiff, UK
| | - Sam L. Evans
- Institute of Mechanical and Manufacturing Engineering, School of Engineering, Cardiff University, Cardiff, UK
| | - Jim R. Ralphs
- Division of Pathophysiology and Repair, School of Biosciences, Cardiff University, Cardiff, UK
| | | | - Deborah J. Mason
- Division of Pathophysiology and Repair, School of Biosciences, Cardiff University, Cardiff, UK
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Grassi L, Väänänen SP, Amin Yavari S, Jurvelin JS, Weinans H, Ristinmaa M, Zadpoor AA, Isaksson H. Full-Field Strain Measurement During Mechanical Testing of the Human Femur at Physiologically Relevant Strain Rates. J Biomech Eng 2014; 136:1901145. [DOI: 10.1115/1.4028415] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 08/27/2014] [Indexed: 11/08/2022]
Abstract
Understanding the mechanical properties of human femora is of great importance for the development of a reliable fracture criterion aimed at assessing fracture risk. Earlier ex vivo studies have been conducted by measuring strains on a limited set of locations using strain gauges (SGs). Digital image correlation (DIC) could instead be used to reconstruct the full-field strain pattern over the surface of the femur. The objective of this study was to measure the full-field strain response of cadaver femora tested at a physiological strain rate up to fracture in a configuration resembling single stance. The three cadaver femora were cleaned from soft tissues, and a white background paint was applied with a random black speckle pattern over the anterior surface. The mechanical tests were conducted up to fracture at a constant displacement rate of 15 mm/s, and two cameras recorded the event at 3000 frames per second. DIC was performed to retrieve the full-field displacement map, from which strains were derived. A low-pass filter was applied over the measured displacements before the crack opened in order to reduce the noise level. The noise levels were assessed using a dedicated control plate. Conversely, no filtering was applied at the frames close to fracture to get the maximum resolution. The specimens showed a linear behavior of the principal strains with respect to the applied force up to fracture. The strain rate was comparable to the values available in literature from in vivo measurements during daily activities. The cracks opened and fully propagated in less than 1 ms, and small regions with high values of the major principal strains could be spotted just a few frames before the crack opened. This corroborates the hypothesis of a strain-driven fracture mechanism in human bone. The data represent a comprehensive collection of full-field strains, both at physiological load levels and up to fracture. About 10,000 points were tracked on each bone, providing superior spatial resolution compared to ∼15 measurements typically collected using SGs. These experimental data collection can be further used for validation of numerical models, and for experimental verification of bone constitutive laws and fracture criteria.
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Affiliation(s)
- Lorenzo Grassi
- Division of Solid Mechanics, Lund University, Lund 22363, Sweden
- Department of Biomedical Engineering, Lund University, BMC D13, Sölvegatan 19, Lund 22184, Sweden e-mail:
| | - Sami P. Väänänen
- Department of Applied Physics, University of Eastern Finland, Kuopio 70211, Finland
| | - Saber Amin Yavari
- Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - Jukka S. Jurvelin
- Department of Applied Physics, University of Eastern Finland, Kuopio 70211, Finland
| | - Harrie Weinans
- Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
- Department of Orthopaedics, UMC Utrecht 3508 GA, The Netherlands
| | - Matti Ristinmaa
- Division of Solid Mechanics, Lund University, Lund 22363, Sweden
| | - Amir A. Zadpoor
- Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - Hanna Isaksson
- Division of Solid Mechanics, Lund University, Lund 22363, Sweden
- Department of Biomedical Engineering, Lund University, Lund 22184, Sweden
- Department of Orthopaedics, Lund University, Lund 22184, Sweden
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63
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Samiezadeh S, Tavakkoli Avval P, Fawaz Z, Bougherara H. Biomechanical assessment of composite versus metallic intramedullary nailing system in femoral shaft fractures: A finite element study. Clin Biomech (Bristol, Avon) 2014; 29:803-10. [PMID: 24951320 DOI: 10.1016/j.clinbiomech.2014.05.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 05/02/2014] [Accepted: 05/07/2014] [Indexed: 02/07/2023]
Abstract
BACKGROUND Intramedullary nails are the primary choice for treating long bone fractures. However, complications following nail surgery including non-union, delayed union, and fracture of the bone or the implant still exist. Reducing nail stiffness while still maintaining sufficient stability seems to be the ideal solution to overcome the abovementioned complications. METHODS In this study, a new hybrid concept for nails made of carbon fibers/flax/epoxy was developed in order to reduce stress shielding. The mechanical performance of this new implant in terms of fracture stability and load sharing was assessed using a comprehensive non-linear FE model. This model considers several mechanical factors in nine fracture configurations at immediately post-operative, and in the healed bone stages. RESULTS Post-operative results showed that the hybrid composite nail increases the average normal force at the fracture site by 319.23N (P<0.05), and the mean stress in the vicinity of fracture by 2.11MPa (P<0.05) at 45% gait cycle, while only 0.33mm and 0.39mm (P<0.05) increases in the fracture opening and the fragments' shear movement were observed. The healed bone results revealed that implantation of the titanium nail caused 20.2% reduction in bone stiffness, while the composite nail lowered the stiffness by 11.8% as compared to an intact femur. INTERPRETATION Our results suggest that the composite nail can provide a preferred mechanical environment for healing, particularly in transverse shaft fractures. This may help bioengineers better understand the biomechanics of fracture healing, and aid in the design of effective implants.
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Affiliation(s)
- Saeid Samiezadeh
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON, Canada
| | - Pouria Tavakkoli Avval
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON, Canada
| | - Zouheir Fawaz
- Department of Aerospace Engineering, Ryerson University, Toronto, ON, Canada
| | - Habiba Bougherara
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON, Canada.
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Malinzak RA, Small SR, Rogge RD, Archer DB, Oja JW, Berend ME, Ritter MA. The effect of rotating platform TKA on strain distribution and torque transmission on the proximal tibia. J Arthroplasty 2014; 29:541-7. [PMID: 24290741 DOI: 10.1016/j.arth.2013.08.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/23/2013] [Accepted: 08/26/2013] [Indexed: 02/01/2023] Open
Abstract
Limited experimental data exist comparing the mechanical response of the tibial cortex between fixed and rotating platform (RP) total knee arthroplasty (TKA), particularly in the revision setting. We asked if RP-TKA significantly affects tibiofemoral torque and cortical stain response in both the primary and revision settings. Fixed and RP tibial trays were implanted into analogue tibias and biomechanically tested under axial and torsional loading. Torque and strain response were analyzed using digital image correlation. Fixed bearing designs exhibited 13.8 times greater torque (P<0.01), and 69% (P<0.01) higher cortical strain than RP designs. Strain response was similar in the primary and revision cohorts. The decrease in torque transfer could act as a safeguard to reduce stress, micromotion and torsional fatigue in scenario of poor bone stock.
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Affiliation(s)
- Robert A Malinzak
- Joint Replacement Surgeons of Indiana Foundation, Inc., Mooresville, Indiana
| | - Scott R Small
- Joint Replacement Surgeons of Indiana Foundation, Inc., Mooresville, Indiana
| | - Renee D Rogge
- Department of Applied Biology and Biomedical Engineering, Rose-Hulman Institute of Technology, Terre Haute, Indiana
| | - Derek B Archer
- Department of Applied Biology and Biomedical Engineering, Rose-Hulman Institute of Technology, Terre Haute, Indiana
| | - Jordan W Oja
- Department of Applied Biology and Biomedical Engineering, Rose-Hulman Institute of Technology, Terre Haute, Indiana
| | - Michael E Berend
- Joint Replacement Surgeons of Indiana Foundation, Inc., Mooresville, Indiana
| | - Merrill A Ritter
- Joint Replacement Surgeons of Indiana Foundation, Inc., Mooresville, Indiana
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65
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Repeatability of digital image correlation for measurement of surface strains in composite long bones. J Biomech 2013; 46:1928-32. [DOI: 10.1016/j.jbiomech.2013.05.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 05/24/2013] [Accepted: 05/24/2013] [Indexed: 11/21/2022]
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