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Hu Y, Chen H, Liang X, Jia M, Lei J. Microstructure and Biomechanical Properties in Selective Laser Melting of Porous Metal Implants. 3D PRINTING AND ADDITIVE MANUFACTURING 2023; 10:1003-1014. [PMID: 37886414 PMCID: PMC10599443 DOI: 10.1089/3dp.2021.0150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Two kinds of porous structure design strategies, ring-support (RS) and column-support (CS), are proposed for human implants. The accurate design of porosity is realized by adjusting the pore characteristics, such as strut diameter, pore diameter, and unit size. Porous specimens with porosity of 50%, 60%, 70%, and 80% were prepared by selective laser melting. The three-dimensional pore structure is basically consistent with the design characteristics, and the measured porosity is slightly lower than design value. The microstructure, microhardness, and friction and wear properties of the samples were studied. The results show that the performance along the scanning orientation is slightly better than that along the forming orientation. The compression and dynamic elastic modulus of porous specimens with different structures and porosities were analyzed. The CS porous with 60-80% porosity has suitable compressive strength and elastic modulus, which is close to that of human tissue, and effectively avoids the stress shielding phenomenon.
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Affiliation(s)
- Yabao Hu
- School of Mechanical Engineering, Tiangong University, Tianjin, China
| | - Hanning Chen
- School of Mechanical Engineering, Tiangong University, Tianjin, China
- School of Computer Science and Technology, Tiangong University, Tianjin, China
| | - Xiaodan Liang
- School of Computer Science and Technology, Tiangong University, Tianjin, China
| | - Mo Jia
- Northeast Petroleum University, Daqing, China
| | - Jianbo Lei
- Laser Technology Institute, Tiangong University, Tianjin, China
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2
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Chao L, He Y, Gu J, Xie D, Yang Y, Shen L, Wu G, Wang L, Tian Z. Evaluation of Compressive and Permeability Behaviors of Trabecular-Like Porous Structure with Mixed Porosity Based on Mechanical Topology. J Funct Biomater 2023; 14:jfb14010028. [PMID: 36662075 PMCID: PMC9861825 DOI: 10.3390/jfb14010028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 12/26/2022] [Accepted: 12/30/2022] [Indexed: 01/05/2023] Open
Abstract
The mechanical properties and permeability properties of artificial bone implants have high-level requirements. A method for the design of trabecular-like porous structure (TLPS) with mixed porosity is proposed based on the study of the mechanical and permeability characteristics of natural bone. With this technique, the morphology and density of internal porous structures can be adjusted, depending on the implantation requirements, to meet the mechanical and permeability requirements of natural bone. The design parameters mainly include the seed points, topology optimization coefficient, load value, irregularity, and scaling factor. Characteristic parameters primarily include porosity and pore size distribution. Statistical methods are used to analyze the relationship between design parameters and characteristic parameters for precise TLPS design and thereby provide a theoretical basis and guidance. TLPS scaffolds were prepared by selective laser melting technology. First, TLPS under different design parameters were analyzed using the finite element method and permeability simulation. The results were then verified by quasistatic compression and cell experiments. The scaling factor and topology optimization coefficient were found to largely affect the mechanical and permeability properties of the TLPS. The corresponding compressive strength reached 270-580 MPa; the elastic modulus ranged between 6.43 and 9.716 GPa, and permeability was 0.6 × 10-9-21 × 10-9; these results were better than the mechanical properties and permeability of natural bone. Thus, TLPS can effectively improve the success rate of bone implantation, which provides an effective theory and application basis for bone implantation.
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Affiliation(s)
- Long Chao
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Yangdong He
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Jiasen Gu
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Deqiao Xie
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Youwen Yang
- College of Mechanical and Electrical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China
- Correspondence: (Y.Y.); (L.S.)
| | - Lida Shen
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
- Correspondence: (Y.Y.); (L.S.)
| | - Guofeng Wu
- Stomatological Digital Engineering Center, Nanjing Stomatological Hospital, Nanjing 210008, China
| | - Lin Wang
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Zongjun Tian
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
- Nanjing Hangpu Machinery Technology Co., Ltd., Nanjing 211806, China
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Zhang S, Patel D, Brady M, Gambill S, Theivendran K, Deshmukh S, Swadener J, Junaid S, Leslie LJ. Experimental testing of fracture fixation plates: A review. Proc Inst Mech Eng H 2022; 236:1253-1272. [PMID: 35920401 PMCID: PMC9449446 DOI: 10.1177/09544119221108540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Metal and its alloys have been predominantly used in fracture fixation for
centuries, but new materials such as composites and polymers have begun to see
clinical use for fracture fixation during the past couple of decades. Along with
the emerging of new materials, tribological issues, especially debris, have
become a growing concern for fracture fixation plates. This article for the
first time systematically reviews the most recent biomechanical research, with a
focus on experimental testing, of those plates within ScienceDirect and PubMed
databases. Based on the search criteria, a total of 5449 papers were retrieved,
which were then further filtered to exclude nonrelevant, duplicate or
non-accessible full article papers. In the end, a total of 83 papers were
reviewed. In experimental testing plates, screws and simulated bones or cadaver
bones are employed to build a fixation construct in order to test the strength
and stability of different plate and screw configurations. The test set-up
conditions and conclusions are well documented and summarised here, including
fracture gap size, types of bones deployed, as well as the applied load, test
speed and test ending criteria. However, research on long term plate usage was
very limited. It is also discovered that there is very limited experimental
research around the tribological behaviour particularly on the debris’
generation, collection and characterisation. In addition, there is no identified
standard studying debris of fracture fixation plate. Therefore, the authors
suggested the generation of a suite of tribological testing standards on
fracture fixation plate and screws in the aim to answer key questions around the
debris from fracture fixation plate of new materials or new design and
ultimately to provide an insight on how to reduce the risks of debris-related
osteolysis, inflammation and aseptic loosening.
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Affiliation(s)
- Shiling Zhang
- Aston Institute of Materials Research (AIMR), Aston University, Birmingham, UK
| | - Dharmesh Patel
- Invibio Biomaterial Solutions Limited, Hillhouse International, Thornton-Cleveleys, UK
| | - Mark Brady
- Invibio Biomaterial Solutions Limited, Hillhouse International, Thornton-Cleveleys, UK
| | - Sherri Gambill
- Invibio Biomaterial Solutions Limited, Hillhouse International, Thornton-Cleveleys, UK
| | | | - Subodh Deshmukh
- Sandwell and West Birmingham Hospital NHS Trust, Birmingham, UK
| | - John Swadener
- Aston Institute of Materials Research (AIMR), Aston University, Birmingham, UK
| | - Sarah Junaid
- Aston Institute of Materials Research (AIMR), Aston University, Birmingham, UK
| | - Laura Jane Leslie
- Aston Institute of Materials Research (AIMR), Aston University, Birmingham, UK
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Gorgin Karaji Z, Jahanmard F, Mirzaei AH, van der Wal B, Amin Yavari S. A multifunctional silk coating on additively manufactured porous titanium to prevent implant-associated infection and stimulate bone regeneration. ACTA ACUST UNITED AC 2020; 15:065016. [PMID: 32640431 DOI: 10.1088/1748-605x/aba40b] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Despite tremendous progress in the design and manufacturing of metallic implants, they do not outlive the patient. To illustrate, more than half of hip replacements will fail, mainly due to implant infection and loosening. Surface engineering approaches and, in particular, coatings can facilitate implant bio-functionality via the recruitment of more host cells for new bone formation and inhibition of bacterial colonization. Here, we used electrophoretic deposition to apply a silk fibroin solution consisting of tricalcium phosphate (TCP) and vancomycin as a coating on the surface of additively-manufactured porous titanium. Furthermore, the surface properties of the coatings developed and the release kinetics of the vancomycin were studied to evaluate the applied coating. The in vitro antibacterial behavior of the multifunctional coating, as well as the cell viability and osteogenic differentiation of the MC3T3-E1 cell line were extensively studied. The biomaterials developed exhibited an antibacterial behavior with a reduction of up to four orders of magnitude in both planktonic and adherent bacteria for 6 h and 1 d. A live-dead assay, the Alamar Blue activity, the DNA content, and cytoskeleton staining demonstrated a significant increase in the cell density of the coated groups versus the as-manufactured ones. The significantly enhanced calcium deposition and the increase in mineralization for the groups with TCP after 21 and 28 d, respectively, demonstrate upregulation of the MC3T3 cells' osteogenic differentiation. Our results collectively show that the multifunctional coating studied here can be potentially used to develop a new generation of orthopedic implants.
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Affiliation(s)
- Z Gorgin Karaji
- Department of Mechanical Engineering, Kermanshah University of Technology, Kermanshah 67156-85420, Iran. Department of Orthopedics, University Medical Centre Utrecht, Utrecht 3584 CX, The Netherlands
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A multifaceted biomimetic interface to improve the longevity of orthopedic implants. Acta Biomater 2020; 110:266-279. [PMID: 32344174 DOI: 10.1016/j.actbio.2020.04.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/23/2020] [Accepted: 04/09/2020] [Indexed: 01/22/2023]
Abstract
The rise of additive manufacturing has provided a paradigm shift in the fabrication of precise, patient-specific implants that replicate the physical properties of native bone. However, eliciting an optimal biological response from such materials for rapid bone integration remains a challenge. Here we propose for the first time a one-step ion-assisted plasma polymerization process to create bio-functional 3D printed titanium (Ti) implants that offer rapid bone integration. Using selective laser melting, porous Ti implants with enhanced bone-mimicking mechanical properties were fabricated. The implants were functionalized uniformly with a highly reactive, radical-rich polymeric coating generated using a unique combination of plasma polymerization and plasma immersion ion implantation. We demonstrated the performance of such activated Ti implants with a focus on the coating's homogeneity, stability, and biological functionality. It was shown that the optimized coating was highly robust and possessed superb physico-chemical stability in a corrosive physiological solution. The plasma activated coating was cytocompatible and non-immunogenic; and through its high reactivity, it allowed for easy, one-step covalent immobilization of functional biomolecules in the absence of solvents or chemicals. The activated Ti implants bio-functionalized with bone morphogenetic protein 2 (BMP-2) showed a reduced protein desorption and a more sustained osteoblast response both in vitro and in vivo compared to implants modified through conventional physisorption of BMP-2. The versatile new approach presented here will enable the development of bio-functionalized additively manufactured implants that are patient-specific and offer improved integration with host tissue. STATEMENT OF SIGNIFICANCE: Additive manufacturing has revolutionized the fabrication of patient-specific orthopedic implants. Although such 3D printed implants can show desirable mechanical and mass transport properties, they often require surface bio-functionalities to enable control over the biological response. Surface covalent immobilization of bioactive molecules is a viable approach to achieve this. Here we report the development of additively manufactured titanium implants that precisely replicate the physical properties of native bone and are bio-functionalized in a simple, reagent-free step. Our results show that covalent attachment of bone-related growth factors through ion-assisted plasma polymerized interlayers circumvents their desorption in physiological solution and significantly improves the bone induction by the implants both in vitro and in vivo.
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6
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Jahanmard F, Croes M, Castilho M, Majed A, Steenbergen MJ, Lietaert K, Vogely HC, van der Wal BCH, Stapels DAC, Malda J, Vermonden T, Amin Yavari S. Bactericidal coating to prevent early and delayed implant-related infections. J Control Release 2020; 326:38-52. [PMID: 32580041 DOI: 10.1016/j.jconrel.2020.06.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 05/22/2020] [Accepted: 06/14/2020] [Indexed: 01/01/2023]
Abstract
The occurrence of an implant-associated infection (IAI) with the formation of a persisting bacterial biofilm remains a major risk following orthopedic biomaterial implantation. Yet, progress in the fabrication of tunable and durable implant coatings with sufficient bactericidal activity to prevent IAI has been limited. Here, an electrospun composite coating was optimized for the combinatorial and sustained delivery of antibiotics. Antibiotics-laden poly(ε-caprolactone) (PCL) and poly`1q`(lactic-co glycolic acid) (PLGA) nanofibers were electrospun onto lattice structured titanium (Ti) implants. In order to achieve tunable and independent delivery of vancomycin (Van) and rifampicin (Rif), we investigated the influence of the specific drug-polymer interaction and the nanofiber coating composition on the drug release profile and durability of the polymer-Ti interface. We found that a bi-layered nanofiber structure, produced by electrospinning of an inner layer of [PCL/Van] and an outer layer of [PLGA/Rif], yielded the optimal combinatorial drug release profile. This resulted in markedly enhanced bactericidal activity against planktonic and adherent Staphylococcus aureus for 6 weeks as compared to single drug delivery. Moreover, after 6 weeks, synergistic bacterial killing was observed as a result of sustained Van and Rif release. The application of a nanofiber-filled lattice structure successfully prevented the delamination of the multi-layer coating after press-fit cadaveric bone implantation. This new lattice design, in conjunction with the multi-layer nanofiber structure, can be applied to develop tunable and durable coatings for various metallic implantable devices. This is particularly appealing to tune the release of multiple antimicrobial agents over a period of weeks to prevent early and delayed onset IAI.
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Affiliation(s)
- F Jahanmard
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - M Croes
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - M Castilho
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, the Netherlands; Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - A Majed
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - M J Steenbergen
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, the Netherlands
| | - K Lietaert
- 3D Systems - LayerWise NV, Leuven, Belgium; Department of Metallurgy and Materials Engineering, KU Leuven, Leuven, Belgium
| | - H C Vogely
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - B C H van der Wal
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - D A C Stapels
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - J Malda
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, the Netherlands; Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - T Vermonden
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, the Netherlands
| | - S Amin Yavari
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, the Netherlands.
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7
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Additive Manufacturing of Customized Metallic Orthopedic Implants: Materials, Structures, and Surface Modifications. METALS 2019. [DOI: 10.3390/met9091004] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Metals have been used for orthopedic implants for a long time due to their excellent mechanical properties. With the rapid development of additive manufacturing (AM) technology, studying customized implants with complex microstructures for patients has become a trend of various bone defect repair. A superior customized implant should have good biocompatibility and mechanical properties matching the defect bone. To meet the performance requirements of implants, this paper introduces the biomedical metallic materials currently applied to orthopedic implants from the design to manufacture, elaborates the structure design and surface modification of the orthopedic implant. By selecting the appropriate implant material and processing method, optimizing the implant structure and modifying the surface can ensure the performance requirements of the implant. Finally, this paper discusses the future development trend of the orthopedic implant.
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8
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Mechanical performance of additively manufactured meta-biomaterials. Acta Biomater 2019; 85:41-59. [PMID: 30590181 DOI: 10.1016/j.actbio.2018.12.038] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 11/27/2018] [Accepted: 12/21/2018] [Indexed: 12/11/2022]
Abstract
Additive manufacturing (AM) (=3D printing) and rational design techniques have enabled development of meta-biomaterials with unprecedented combinations of mechanical, mass transport, and biological properties. Such meta-biomaterials are usually topologically ordered and are designed by repeating a number of regular unit cells in different directions to create a lattice structure. Establishing accurate topology-property relationships is of critical importance for these materials. In this paper, we specifically focus on AM metallic meta-biomaterials aimed for application as bone substitutes and orthopaedic implants and review the currently available evidence regarding their mechanical performance under quasi-static and cyclic loading conditions. The topology-property relationships are reviewed for regular beam-based lattice structures, sheet-based lattice structures including those based on triply periodic minimal surface, and graded designs. The predictive models used for establishing the topology-property relationships including analytical and computational models are covered as well. Moreover, we present an overview of the effects of the AM processes, material type, tissue regeneration, biodegradation, surface bio-functionalization, post-manufacturing (heat) treatments, and loading profiles on the quasi-static mechanical properties and fatigue behavior of AM meta-biomaterials. AM meta-biomaterials exhibiting unusual mechanical properties such as negative Poisson's ratios (auxetic meta-biomaterials), shape memory behavior, and superelasitcity as well as the potential applications of such unusual behaviors (e.g. deployable implants) are presented too. The paper concludes with some suggestions for future research. STATEMENT OF SIGNIFICANCE: Additive manufacturing enables fabrication of meta-biomaterials with rare combinations of topological, mechanical, and mass transport properties. Given that the micro-scale topological design determines the macro-scale properties of meta-biomaterials, establishing topology-property relationships is the central research question when rationally designing meta-biomaterials. The interest in understanding the relationship between the topological design and material type on the one hand and the mechanical properties and fatigue behavior of meta-biomaterials on the other hand is currently booming. This paper presents and critically evaluates the most important trends and findings in this area with a special focus on the metallic biomaterials used for skeletal applications to enable researchers better understand the current state-of-the-art and to guide the design of future research projects.
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Abstract
Additively manufactured (AM, =3D printed) porous metallic biomaterials with topologically ordered unit cells have created a lot of excitement and are currently receiving a lot of attention given their great potential for improving bone tissue regeneration and preventing implant-associated infections.
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Affiliation(s)
- Amir A. Zadpoor
- Department of Biomechanical Engineering
- Faculty of Mechanical, Maritime, and Materials Engineering
- Delft University of Technology (TU Delft)
- Delft
- The Netherlands
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Ti-24Nb-4Zr-8Sn Alloy Pedicle Screw Improves Internal Vertebral Fixation by Reducing Stress-Shielding Effects in a Porcine Model. BIOMED RESEARCH INTERNATIONAL 2018; 2018:8639648. [PMID: 29581988 PMCID: PMC5822754 DOI: 10.1155/2018/8639648] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/09/2018] [Accepted: 01/11/2018] [Indexed: 12/29/2022]
Abstract
To ensure the biomechanical properties of Ti-24Nb-4Zr-8Sn, stress-shielding effects were compared between Ti-24Nb-4Zr-8Sn and Ti-6Al-4V fixation by using a porcine model. Twelve thoracolumbar spines (T12–L5) of 12-month-old male pigs were randomly divided into two groups: Ti-24Nb-4Zr-8Sn (EG, n = 6) and Ti-6Al-4V (RG, n = 6) fixation. Pedicle screw was fixed at the outer edge of L4-5 vertebral holes. Fourteen measuring points were selected on the front of transverse process and middle and posterior of L4-5 vertebra. Electronic universal testing machine was used to measure the strain resistance of measuring points after forward and backward flexion loading of 150 N. Meanwhile, stress resistance was compared between both groups. The strain and stress resistance of measurement points 1, 2, 5, 6, 9, and 10–14 in Ti-24Nb-4Zr-8Sn fixation was lower than that of Ti-6Al-4V fixation after forward and backward flexion loading (P < 0.05). The strain and stress resistance of measurement points 3, 4, 7, and 8 was higher in Ti-24Nb-4Zr-8Sn fixation than that of Ti-6Al-4V fixation (P < 0.05). Stress-shielding effects of Ti-24Nb-4Zr-8Sn internal fixation were less than that of Ti-6Al-4V internal fixation. These results suggest that Ti-24Nb-4Zr-8Sn elastic fixation has more biomechanical goals than conventional Ti-6Al-4V internal fixation by reducing stress-shielding effects.
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Zhang L, Ke X, Lin L, Xiao J, Yang X, Wang J, Yang G, Xu S, Gou Z, Shi Z. Systematic evaluation of the osteogenic capacity of low-melting bioactive glass-reinforced 45S5 Bioglass porous scaffolds in rabbit femoral defects. Biomed Mater 2017; 12:035010. [DOI: 10.1088/1748-605x/aa6b5c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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12
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Kadkhodapour J, Montazerian H, Darabi AC, Zargarian A, Schmauder S. The relationships between deformation mechanisms and mechanical properties of additively manufactured porous biomaterials. J Mech Behav Biomed Mater 2017; 70:28-42. [DOI: 10.1016/j.jmbbm.2016.09.018] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/31/2016] [Accepted: 09/10/2016] [Indexed: 11/29/2022]
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13
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Meyers N, Sukopp M, Jäger R, Steiner M, Matthys R, Lapatki B, Ignatius A, Claes L. Characterization of interfragmentary motion associated with common osteosynthesis devices for rat fracture healing studies. PLoS One 2017; 12:e0176735. [PMID: 28453556 PMCID: PMC5409164 DOI: 10.1371/journal.pone.0176735] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 04/14/2017] [Indexed: 01/21/2023] Open
Abstract
Rat models are widely used in preclinical studies investigating fracture healing. The interfragmentary movement at a fracture site is critical to the course of healing and therefore demands definition in order to aptly interpret the experimental results. Estimation of this movement requires knowledge of the fixation stiffness and loading. The characteristic loading for the rat femur has been estimated, but the stiffness of fixation used in rat studies has yet to be fully described. This study aimed to determine the 6 degree of freedom stiffness of four commonly used implants, two external fixators (RatExFix and UlmExFix), a locking plate, and a locking intramedullary nail, in all degrees of freedom and estimate the interfragmentary movement under specific physiological loads. The external fixator systems allow the greatest movement. Mounted 45° anterolateral on the femur, the RatExFix allows an average of 0.88 mm of motion in each anatomic direction while the stiffer UlmExFix allows about 0.6 mm of motion. The nail is far stiffer than the other implants investigated while the plate allows movement of an intermediate magnitude. Both the nail and plate demonstrate higher axial than shear stiffness. The relatively large standard deviations in external fixator shear motion imply strong dependence on bone axis alignment across the gap and the precise orientation of the specimen relative to the loading. The smaller standard deviation associated with the nail and plate results from improved alignment and minimization of the influence of rotational positioning of the specimen due to the reduced implant eccentricity relative to the specimen axis. These results show that the interfragmentary movement is complex and varies significantly between fixation devices but establishes a baseline for the evaluation of the results of different studies.
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Affiliation(s)
- Nicholaus Meyers
- Institute of Orthopedic Research and Biomechanics, Center of Musculoskeletal Research Ulm, University Hospital Ulm, Ulm, Baden-Württemberg, Germany
- * E-mail:
| | - Matthias Sukopp
- Institute of Orthopedic Research and Biomechanics, Center of Musculoskeletal Research Ulm, University Hospital Ulm, Ulm, Baden-Württemberg, Germany
| | - Rudolf Jäger
- Department of Orthodontics, University Hospital Ulm, Ulm, Baden-Württemberg, Germany
| | - Malte Steiner
- Institute of Orthopedic Research and Biomechanics, Center of Musculoskeletal Research Ulm, University Hospital Ulm, Ulm, Baden-Württemberg, Germany
| | | | - Bernd Lapatki
- Department of Orthodontics, University Hospital Ulm, Ulm, Baden-Württemberg, Germany
| | - Anita Ignatius
- Institute of Orthopedic Research and Biomechanics, Center of Musculoskeletal Research Ulm, University Hospital Ulm, Ulm, Baden-Württemberg, Germany
| | - Lutz Claes
- Institute of Orthopedic Research and Biomechanics, Center of Musculoskeletal Research Ulm, University Hospital Ulm, Ulm, Baden-Württemberg, Germany
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14
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Hedayati R, Janbaz S, Sadighi M, Mohammadi-Aghdam M, Zadpoor A. How does tissue regeneration influence the mechanical behavior of additively manufactured porous biomaterials? J Mech Behav Biomed Mater 2017; 65:831-841. [DOI: 10.1016/j.jmbbm.2016.10.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 10/04/2016] [Accepted: 10/10/2016] [Indexed: 02/05/2023]
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15
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Geometry Design Optimization of Functionally Graded Scaffolds for Bone Tissue Engineering: A Mechanobiological Approach. PLoS One 2016; 11:e0146935. [PMID: 26771746 PMCID: PMC4714836 DOI: 10.1371/journal.pone.0146935] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 12/25/2015] [Indexed: 12/22/2022] Open
Abstract
Functionally Graded Scaffolds (FGSs) are porous biomaterials where porosity changes in space with a specific gradient. In spite of their wide use in bone tissue engineering, possible models that relate the scaffold gradient to the mechanical and biological requirements for the regeneration of the bony tissue are currently missing. In this study we attempt to bridge the gap by developing a mechanobiology-based optimization algorithm aimed to determine the optimal graded porosity distribution in FGSs. The algorithm combines the parametric finite element model of a FGS, a computational mechano-regulation model and a numerical optimization routine. For assigned boundary and loading conditions, the algorithm builds iteratively different scaffold geometry configurations with different porosity distributions until the best microstructure geometry is reached, i.e. the geometry that allows the amount of bone formation to be maximized. We tested different porosity distribution laws, loading conditions and scaffold Young’s modulus values. For each combination of these variables, the explicit equation of the porosity distribution law–i.e the law that describes the pore dimensions in function of the spatial coordinates–was determined that allows the highest amounts of bone to be generated. The results show that the loading conditions affect significantly the optimal porosity distribution. For a pure compression loading, it was found that the pore dimensions are almost constant throughout the entire scaffold and using a FGS allows the formation of amounts of bone slightly larger than those obtainable with a homogeneous porosity scaffold. For a pure shear loading, instead, FGSs allow to significantly increase the bone formation compared to a homogeneous porosity scaffolds. Although experimental data is still necessary to properly relate the mechanical/biological environment to the scaffold microstructure, this model represents an important step towards optimizing geometry of functionally graded scaffolds based on mechanobiological criteria.
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Boccaccio A, Uva AE, Fiorentino M, Lamberti L, Monno G. A Mechanobiology-based Algorithm to Optimize the Microstructure Geometry of Bone Tissue Scaffolds. Int J Biol Sci 2016; 12:1-17. [PMID: 26722213 PMCID: PMC4679394 DOI: 10.7150/ijbs.13158] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/23/2015] [Indexed: 01/02/2023] Open
Abstract
Complexity of scaffold geometries and biological mechanisms involved in the bone generation process make the design of scaffolds a quite challenging task. The most common approaches utilized in bone tissue engineering require costly protocols and time-consuming experiments. In this study we present an algorithm that, combining parametric finite element models of scaffolds with numerical optimization methods and a computational mechano-regulation model, is able to predict the optimal scaffold microstructure. The scaffold geometrical parameters are perturbed until the best geometry that allows the largest amounts of bone to be generated, is reached. We study the effects of the following factors: (1) the shape of the pores; (2) their spatial distribution; (3) the number of pores per unit area. The optimal dimensions of the pores have been determined for different values of scaffold Young's modulus and compression loading acting on the scaffold upper surface. Pores with rectangular section were predicted to lead to the formation of larger amounts of bone compared to square section pores; similarly, elliptic pores were predicted to allow the generation of greater amounts of bone compared to circular pores. The number of pores per unit area appears to have rather negligible effects on the bone regeneration process. Finally, the algorithm predicts that for increasing loads, increasing values of the scaffold Young's modulus are preferable. The results shown in the article represent a proof-of-principle demonstration of the possibility to optimize the scaffold microstructure geometry based on mechanobiological criteria.
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Affiliation(s)
- Antonio Boccaccio
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, 70126 Bari, Italy
| | - Antonio Emmanuele Uva
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, 70126 Bari, Italy
| | - Michele Fiorentino
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, 70126 Bari, Italy
| | - Luciano Lamberti
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, 70126 Bari, Italy
| | - Giuseppe Monno
- Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, 70126 Bari, Italy
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Huang H, Xiang C, Zeng C, Ouyang H, Wong KKL, Huang W. Patient-specific geometrical modeling of orthopedic structures with high efficiency and accuracy for finite element modeling and 3D printing. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2015; 38:743-53. [PMID: 26577713 DOI: 10.1007/s13246-015-0402-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 11/05/2015] [Indexed: 11/30/2022]
Abstract
We improved the geometrical modeling procedure for fast and accurate reconstruction of orthopedic structures. This procedure consists of medical image segmentation, three-dimensional geometrical reconstruction, and assignment of material properties. The patient-specific orthopedic structures reconstructed by this improved procedure can be used in the virtual surgical planning, 3D printing of real orthopedic structures and finite element analysis. A conventional modeling consists of: image segmentation, geometrical reconstruction, mesh generation, and assignment of material properties. The present study modified the conventional method to enhance software operating procedures. Patient's CT images of different bones were acquired and subsequently reconstructed to give models. The reconstruction procedures were three-dimensional image segmentation, modification of the edge length and quantity of meshes, and the assignment of material properties according to the intensity of gravy value. We compared the performance of our procedures to the conventional procedures modeling in terms of software operating time, success rate and mesh quality. Our proposed framework has the following improvements in the geometrical modeling: (1) processing time: (femur: 87.16 ± 5.90 %; pelvis: 80.16 ± 7.67 %; thoracic vertebra: 17.81 ± 4.36 %; P < 0.05); (2) least volume reduction (femur: 0.26 ± 0.06 %; pelvis: 0.70 ± 0.47, thoracic vertebra: 3.70 ± 1.75 %; P < 0.01) and (3) mesh quality in terms of aspect ratio (femur: 8.00 ± 7.38 %; pelvis: 17.70 ± 9.82 %; thoracic vertebra: 13.93 ± 9.79 %; P < 0.05) and maximum angle (femur: 4.90 ± 5.28 %; pelvis: 17.20 ± 19.29 %; thoracic vertebra: 3.86 ± 3.82 %; P < 0.05). Our proposed patient-specific geometrical modeling requires less operating time and workload, but the orthopedic structures were generated at a higher rate of success as compared with the conventional method. It is expected to benefit the surgical planning of orthopedic structures with less operating time and high accuracy of modeling.
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Affiliation(s)
- Huajun Huang
- Department of Orthopedics, The Third Affiliated Hospital of Southern Medical University (Academy of Orthopedics · Guangdong Province), Guangzhou, 510630, China.
| | - Chunling Xiang
- Department of Orthopedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Canjun Zeng
- Department of Orthopedics, The Third Affiliated Hospital of Southern Medical University (Academy of Orthopedics · Guangdong Province), Guangzhou, 510630, China.,Department of Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, School of Basic Medical Sciences, Southern Medical University, North-1838, Guangzhou, 510515, China
| | - Hanbin Ouyang
- Department of Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, School of Basic Medical Sciences, Southern Medical University, North-1838, Guangzhou, 510515, China
| | - Kelvin Kian Loong Wong
- Engineering Computational Biology, School of Computer Science and Software Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6000, Australia
| | - Wenhua Huang
- Department of Anatomy, Guangdong Provincial Key Laboratory of Medical Biomechanics, School of Basic Medical Sciences, Southern Medical University, North-1838, Guangzhou, 510515, China.
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18
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Taniguchi N, Fujibayashi S, Takemoto M, Sasaki K, Otsuki B, Nakamura T, Matsushita T, Kokubo T, Matsuda S. Effect of pore size on bone ingrowth into porous titanium implants fabricated by additive manufacturing: An in vivo experiment. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 59:690-701. [PMID: 26652423 DOI: 10.1016/j.msec.2015.10.069] [Citation(s) in RCA: 371] [Impact Index Per Article: 41.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 09/24/2015] [Accepted: 10/23/2015] [Indexed: 01/01/2023]
Abstract
Selective laser melting (SLM) is an additive manufacturing technique with the ability to produce metallic scaffolds with accurately controlled pore size, porosity, and interconnectivity for orthopedic applications. However, the optimal pore structure of porous titanium manufactured by SLM remains unclear. In this study, we evaluated the effect of pore size with constant porosity on in vivo bone ingrowth in rabbits into porous titanium implants manufactured by SLM. Three porous titanium implants (with an intended porosity of 65% and pore sizes of 300, 600, and 900μm, designated the P300, P600, and P900 implants, respectively) were manufactured by SLM. A diamond lattice was adapted as the basic structure. Their porous structures were evaluated and verified using microfocus X-ray computed tomography. Their bone-implant fixation ability was evaluated by their implantation as porous-surfaced titanium plates into the cortical bone of the rabbit tibia. Bone ingrowth was evaluated by their implantation as cylindrical porous titanium implants into the cancellous bone of the rabbit femur for 2, 4, and 8weeks. The average pore sizes of the P300, P600, and P900 implants were 309, 632, and 956μm, respectively. The P600 implant demonstrated a significantly higher fixation ability at 2weeks than the other implants. After 4weeks, all models had sufficiently high fixation ability in a detaching test. Bone ingrowth into the P300 implant was lower than into the other implants at 4weeks. Because of its appropriate mechanical strength, high fixation ability, and rapid bone ingrowth, our results indicate that the pore structure of the P600 implant is a suitable porous structure for orthopedic implants manufactured by SLM.
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Affiliation(s)
- Naoya Taniguchi
- Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507, Japan.
| | - Shunsuke Fujibayashi
- Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507, Japan.
| | - Mitsuru Takemoto
- Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507, Japan.
| | - Kiyoyuki Sasaki
- Sagawa Printing Co., Ltd., 5-3, Inui, Morimoto-Cho, Mukou-Shi, Kyoto 617-8588, Japan.
| | - Bungo Otsuki
- Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507, Japan.
| | - Takashi Nakamura
- National Hospital Organization Kyoto Medical Center, 1-1, Mukaihatacho, Hukakusa, Hushimi, Kyoto 612-8555, Japan.
| | - Tomiharu Matsushita
- Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.
| | - Tadashi Kokubo
- Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.
| | - Shuichi Matsuda
- Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507, Japan.
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A Novel Rat Model of Intramedullary Tibia Fracture Fixation Using Polyetheretherketone Threaded Rod. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2015; 3:e417. [PMID: 26180718 PMCID: PMC4494487 DOI: 10.1097/gox.0000000000000386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 04/15/2015] [Indexed: 12/15/2022]
Abstract
Supplemental Digital Content is available in the text. Background: The rat fracture fixation models have been widely adopted, but current implant designs suffer from operational difficulty, massive soft-tissue dissection, and radiological intervention. The authors developed a new tibia fracture-healing model using minor invasive intramedullary fixations with polyetheretherketone (PEEK) threaded rods, which have excellent x-ray translucency and no magnetic resonance artifact. Methods: Tibia fractures of 6 adult male Sprague-Dawley rats were fixed with intramedullary PEEK threaded rods. X-ray examination was performed at 0, 4, and 8 weeks postoperatively. Histological analysis was conducted via hematoxylin-eosin staining of nondecalcified tissue sections. Results: Radiological fracture healing was observed at 8 weeks postoperatively. Histology demonstrated fracture gap bridging and bone ingrowth adjacent to PEEK. Conclusion: This innovative model is simple and effective, providing a new selection in future biomedical research.
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van der Stok J, Lozano D, Chai YC, Amin Yavari S, Bastidas Coral AP, Verhaar JA, Gómez-Barrena E, Schrooten J, Jahr H, Zadpoor AA, Esbrit P, Weinans H. Osteostatin-Coated Porous Titanium Can Improve Early Bone Regeneration of Cortical Bone Defects in Rats. Tissue Eng Part A 2015; 21:1495-506. [DOI: 10.1089/ten.tea.2014.0476] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Johan van der Stok
- Orthopaedic Research Laboratory, Department of Orthopaedics, Erasmus University Rotterdam Medical Centre, Rotterdam, The Netherlands
| | - Daniel Lozano
- Laboratorio de Metabolismo Mineral y Óseo, Instituto de Investigación Sanitaria (IIS)–Fundación Jiménez Díaz and Instituto de Salud Carlos III (RETICEF), Madrid, Spain
- Grupo de Investigación de Cirugía Osteo-Articular, Instituto de Investigación Hospital Universitario La Paz (IdiPAZ), Madrid, Spain
| | - Yoke Chin Chai
- Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Centre, KU Leuven, Leuven, Belgium
- Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, Leuven, Belgium
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia
| | - Saber Amin Yavari
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Angela P. Bastidas Coral
- Orthopaedic Research Laboratory, Department of Orthopaedics, Erasmus University Rotterdam Medical Centre, Rotterdam, The Netherlands
| | - Jan A.N. Verhaar
- Orthopaedic Research Laboratory, Department of Orthopaedics, Erasmus University Rotterdam Medical Centre, Rotterdam, The Netherlands
| | - Enrique Gómez-Barrena
- Department of Orthopaedic Surgery and Traumatology, Hospital La Paz-IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Jan Schrooten
- Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Centre, KU Leuven, Leuven, Belgium
- Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, Leuven, Belgium
- Department of Materials Engineering, KU Leuven, Belgium
| | - Holger Jahr
- Orthopaedic Research Laboratory, Department of Orthopaedics, Erasmus University Rotterdam Medical Centre, Rotterdam, The Netherlands
- Department of Orthopaedic Surgery, University Hospital RWTH, Aachen, Germany
| | - Amir A. Zadpoor
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Pedro Esbrit
- Laboratorio de Metabolismo Mineral y Óseo, Instituto de Investigación Sanitaria (IIS)–Fundación Jiménez Díaz and Instituto de Salud Carlos III (RETICEF), Madrid, Spain
| | - Harrie Weinans
- Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
- Department of Orthopaedics, Utrecht University Medical Centre, Utrecht, The Netherlands
- Department of Rheumatology, Utrecht University Medical Centre, Utrecht, The Netherlands
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21
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Additively manufactured porous tantalum implants. Acta Biomater 2015; 14:217-25. [PMID: 25500631 DOI: 10.1016/j.actbio.2014.12.003] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 11/25/2014] [Accepted: 12/04/2014] [Indexed: 12/27/2022]
Abstract
The medical device industry's interest in open porous, metallic biomaterials has increased in response to additive manufacturing techniques enabling the production of complex shapes that cannot be produced with conventional techniques. Tantalum is an important metal for medical devices because of its good biocompatibility. In this study selective laser melting technology was used for the first time to manufacture highly porous pure tantalum implants with fully interconnected open pores. The architecture of the porous structure in combination with the material properties of tantalum result in mechanical properties close to those of human bone and allow for bone ingrowth. The bone regeneration performance of the porous tantalum was evaluated in vivo using an orthotopic load-bearing bone defect model in the rat femur. After 12 weeks, substantial bone ingrowth, good quality of the regenerated bone and a strong, functional implant-bone interface connection were observed. Compared to identical porous Ti-6Al-4V structures, laser-melted tantalum shows excellent osteoconductive properties, has a higher normalized fatigue strength and allows for more plastic deformation due to its high ductility. It is therefore concluded that this is a first step towards a new generation of open porous tantalum implants manufactured using selective laser melting.
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22
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Abstract
A review of how the geometrical design of scaffolds influences the bone tissue regeneration process.
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Affiliation(s)
- Amir A. Zadpoor
- Department of Biomechanical Engineering
- Faculty of Mechanical
- Maritime
- and Materials Engineering
- Delft University of Technology (TU Delft)
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