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Zdero R, Brzozowski P, Schemitsch EH. Biomechanical stress analysis using thermography: A review. J Biomech 2023; 160:111822. [PMID: 37793203 DOI: 10.1016/j.jbiomech.2023.111822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 09/08/2023] [Accepted: 09/26/2023] [Indexed: 10/06/2023]
Abstract
Biomechanics investigators are interested in experimentally measuring stresses experienced by dental structures, whole bones, joint replacements, soft tissues, normal limbs, etc. To do so, various experimental methods have been used that are based on acoustic, optical, piezo-resistive, or other principles, like digital image correlation, fiber optic sensors, photo-elasticity, strain gages, ultrasound, etc. Several biomechanical review papers have surveyed these research technologies, but they do not mention thermography. Thermography can identify temperature anomalies indicating low- or high-stress areas on a bone, implant, prosthesis, etc., which may need to be repaired, replaced, or redesigned to avoid damage, degradation, or failure. In addition, thermography can accurately predict a structure's cyclic fatigue strength. Consequently, this article gives an up-to-date survey of the scientific literature on thermography for biomechanical stress analysis. This review (i) describes the basic physics of thermography, thermo-elastic properties of biomaterials, experimental protocols for thermography, advantages, and disadvantages, (ii) surveys published studies on various applications that used thermography for biomechanical stress measurements, and (iii) discusses general findings and future work. This article is intended to inform biomechanics investigators about the potential of thermography for stress analysis.
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Affiliation(s)
- Radovan Zdero
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada.
| | - Pawel Brzozowski
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada.
| | - Emil H Schemitsch
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada; Division of Orthopaedic Surgery, Western University, London, ON, Canada.
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2
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Zdero R, Brzozowski P, Schemitsch EH. Biomechanical properties of artificial bones made by Sawbones: A review. Med Eng Phys 2023; 118:104017. [PMID: 37536838 DOI: 10.1016/j.medengphy.2023.104017] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/23/2023] [Accepted: 06/27/2023] [Indexed: 08/05/2023]
Abstract
Biomedical engineers and physicists frequently use human or animal bone for orthopaedic biomechanics research because they are excellent approximations of living bone. But, there are drawbacks to biological bone, like degradation over time, ethical concerns, high financial costs, inter-specimen variability, storage requirements, supplier sourcing, transportation rules, etc. Consequently, since the late 1980s, the Sawbones® company has been one of the world's largest suppliers of artificial bones for biomechanical testing that counteract many disadvantages of biological bone. There have been many published reports using these bone analogs for research on joint replacement, bone fracture fixation, spine surgery, etc. But, there exists no prior review paper on these artificial bones that gives a comprehensive and in-depth look at the numerical data of interest to biomedical engineers and physicists. Thus, this paper critically reviews 25 years of English-language studies on the biomechanical properties of these artificial bones that (a) characterized unknown or unreported values, (b) validated them against biological bone, and/or (c) optimized different design parameters. This survey of data, advantages, disadvantages, and knowledge gaps will hopefully be useful to biomedical engineers and physicists in developing mechanical testing protocols and computational finite element models.
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Affiliation(s)
- Radovan Zdero
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada
| | - Pawel Brzozowski
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada.
| | - Emil H Schemitsch
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada; Division of Orthopaedic Surgery, Western University, London, ON, Canada
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Olaya Mira N, Viloria Barragán C, Plata JA. Evaluation of different Jaipur foot-ankle assemblies using infrared thermography. Prosthet Orthot Int 2021; 45:184-188. [PMID: 33028146 DOI: 10.1177/0309364620958510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 08/20/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND Mechanical behavior is difficult to monitor in experimental environments, usually because of geometric or technology implementation limitations. Nevertheless, thermography has been shown to overcome these issues. OBJECTIVES The aim of this study was to evaluate four types of assemblies between a Jaipur foot and a polyethylene tube using infrared thermography in order to find the best mechanical configuration in terms of thermal behavior. STUDY DESIGN Mechanical testing. TECHNIQUE An infrared camera captured short videos every 5 min over 10 h in six different positions (three in the back and three in front of the Jaipur foot) around a prosthesis subjected to repetitive stresses (axial force 980 N) simulating kinematic variables like joint angles. We established a region of interest around the foot-ankle assemblies and calculated maximum temperatures and thermographic indices. RESULTS In this study, the best foot-ankle assembly used epoxy adhesive because it presented the lowest temperature in the six positions and the lowest thermal index. CONCLUSIONS Thermographic techniques can be used to study mechanical behaviors in complex experimental situations.
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Affiliation(s)
- Natali Olaya Mira
- Grupo de Investigación e Innovación Biomédica, Facultad de Ciencias Exactas y Aplicadas, Instituto Tecnológico Metropolitano, Medellín, Colombia.,Laboratorio de Biomecánica y Rehabilitación, Facultad de Ciencias Exactas y Aplicadas, Instituto Tecnológico Metropolitano, Medellín, Colombia
| | - Carolina Viloria Barragán
- Grupo de Investigación e Innovación Biomédica, Facultad de Ciencias Exactas y Aplicadas, Instituto Tecnológico Metropolitano, Medellín, Colombia
| | - Jesus Alberto Plata
- Corporación Mahavir Kmina Artificial Limb Center, Medellín, Colombia.,Grupo de investigación Rehabilitación en Salud, Departamento de Medicina Física y Rehabilitación, Facultad de Medicina, Universidad de Antioquia, Medellin, Colombia
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Biomechanical Consequences of Nail Insertion Point and Anterior Cortical Perforation for Antegrade Femoral Nailing. BIOMED RESEARCH INTERNATIONAL 2020; 2020:5878607. [PMID: 33426057 PMCID: PMC7772046 DOI: 10.1155/2020/5878607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/19/2020] [Accepted: 12/04/2020] [Indexed: 11/17/2022]
Abstract
This biomechanical study assessed the influence of changing antegrade cephalomedullary nail insertion point from anterior to neutral to posterior locations relative to the tip of the greater trochanter with or without anterior cortical perforation in the distal femur. Artificial osteoporotic femurs and cephalomedullary nails were used to create 5 test groups each with 8 specimens: intact femur without a nail or perforation, anterior nail insertion point without perforation, neutral nail insertion point without perforation, posterior nail insertion point without perforation, and posterior nail insertion point with perforation. Nondestructive biomechanical tests were done at 250 N in axial, coronal 3-point bending, sagittal 3-point bending, and torsional loading in order to measure overall stiffness and bone stress. The intact femur group vs. all femur/nail groups had lower stiffness in all loading modes (p ≤ 0.018), as well as higher bone stress in the proximal femur (p ≤ 0.027) but not in the distal femur above the perforation (p = 0.096). Compared to each other, femur/nail groups only showed differences in sagittal 3-point bending stiffness for anterior and neutral vs. posterior nail insertion points without (p ≤ 0.025) and with perforation (p ≤ 0.047). Although it did not achieve statistical significance (p ≥ 0.096), moving the nail insertion point from anterior to neutral to posterior to posterior with perforation did gradually increase bone stress by 45% (proximal femur) and 46% (distal femur). No femur or hardware failures occurred. Moving the nail insertion point and the presence of a perforation had little effect on stiffness, but the increased bone stress may be important as a predictor of fracture. Based on current bone stress results, surgeons should use anterior or neutral nail insertion points to reduce the risk of anterior cortical perforation.
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Black RA, Houston G. 40th Anniversary Issue: Reflections on papers from the archive on "Biomechanics". Med Eng Phys 2020; 72:70-71. [PMID: 31554579 DOI: 10.1016/j.medengphy.2019.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Richard A Black
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, Scotland, UK.
| | - Gregor Houston
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, Scotland, UK
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Bartolomeu F, Fonseca J, Peixinho N, Alves N, Gasik M, Silva F, Miranda G. Predicting the output dimensions, porosity and elastic modulus of additive manufactured biomaterial structures targeting orthopedic implants. J Mech Behav Biomed Mater 2019; 99:104-117. [DOI: 10.1016/j.jmbbm.2019.07.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 07/18/2019] [Accepted: 07/20/2019] [Indexed: 12/17/2022]
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Marco M, Giner E, Caeiro-Rey JR, Miguélez MH, Larraínzar-Garijo R. Numerical modelling of hip fracture patterns in human femur. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2019; 173:67-75. [PMID: 31046997 DOI: 10.1016/j.cmpb.2019.03.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/12/2019] [Accepted: 03/13/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND AND OBJECTIVE Hip fracture morphology is an important factor determining the ulterior surgical repair and treatment, because of the dependence of the treatment on fracture morphology. Although numerical modelling can be a valuable tool for fracture prediction, the simulation of femur fracture is not simple due to the complexity of bone architecture and the numerical techniques required for simulation of crack propagation. Numerical models assuming homogeneous fracture mechanical properties commonly fail in the prediction of fracture patterns. This paper focuses on the prediction of femur fracture based on the development of a finite element model able to simulate the generation of long crack paths. METHODS The finite element model developed in this work demonstrates the capability of predicting fracture patterns under stance loading configuration, allowing the distinction between the main fracture paths: intracapsular and extracapsular fractures. It is worth noting the prediction of different fracture patterns for the same loading conditions, as observed during experimental tests. RESULTS AND CONCLUSIONS The internal distribution of bone mineral density and femur geometry strongly influences the femur fracture morphology and fracture load. Experimental fracture paths have been analysed by means of micro-computed tomography allowing the comparison of predicted and experimental crack surfaces, confirming the good accuracy of the numerical model.
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Affiliation(s)
- Miguel Marco
- Department of Mechanical Engineering, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid, Spain.
| | - Eugenio Giner
- CIIM-Department of Mechanical and Materials Engineering, Universitat Politècnica de València Camino de Vera, 46022 Valencia, Spain
| | - José Ramón Caeiro-Rey
- Orthopedic Surgery and Traumatology Service, Complejo Hospitalario Universitario de Santiago de Compostela, Rúa de Ramón Baltar, s/n, 15706 Santiago de Compostela, A Coruña, Spain
| | - M Henar Miguélez
- Department of Mechanical Engineering, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid, Spain
| | - Ricardo Larraínzar-Garijo
- Orthopaedics and Trauma Department, Surgery Department, Hospital Universitario Infanta Leonor, Complutense University, Madrid, Spain
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Lopes VM, Neto MA, Amaro AM, Roseiro LM, Paulino M. FE and experimental study on how the cortex material properties of synthetic femurs affect strain levels. Med Eng Phys 2017. [DOI: 10.1016/j.medengphy.2017.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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9
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Marco M, Giner E, Larraínzar-Garijo R, Caeiro JR, Miguélez MH. Numerical Modelling of Femur Fracture and Experimental Validation Using Bone Simulant. Ann Biomed Eng 2017. [DOI: 10.1007/s10439-017-1877-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Biomechanical optimization of the angle and position for surgical implantation of a straight short stem hip implant. Med Eng Phys 2017; 39:23-30. [DOI: 10.1016/j.medengphy.2016.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 08/15/2016] [Accepted: 10/09/2016] [Indexed: 11/19/2022]
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11
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Newcomb AGUS, Baek S, Kelly BP, Crawford NR. Effect of screw position on load transfer in lumbar pedicle screws: a non-idealized finite element analysis. Comput Methods Biomech Biomed Engin 2016; 20:182-192. [PMID: 27454197 DOI: 10.1080/10255842.2016.1209187] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Angled screw insertion has been advocated to enhance fixation strength during posterior spine fixation. Stresses on a pedicle screw and surrounding vertebral bone with different screw angles were studied by finite element analysis during simulated multidirectional loading. Correlations between screw-specific vertebral geometric parameters and stresses were studied. Angulations in both the sagittal and axial planes affected stresses on the cortical and cancellous bones and the screw. Pedicle screws pointing laterally (vs. straight or medially) in the axial plane during superior screw angulation may be advantageous in terms of reducing the risk of both screw loosening and screw breakage.
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Affiliation(s)
- Anna G U S Newcomb
- a Spinal Biomechanics Laboratory, Department of Neurosurgery Research , Barrow Neurological Institute, St. Joseph's Hospital and Medical Center , Phoenix , AZ , USA
| | - Seungwon Baek
- a Spinal Biomechanics Laboratory, Department of Neurosurgery Research , Barrow Neurological Institute, St. Joseph's Hospital and Medical Center , Phoenix , AZ , USA
| | - Brian P Kelly
- a Spinal Biomechanics Laboratory, Department of Neurosurgery Research , Barrow Neurological Institute, St. Joseph's Hospital and Medical Center , Phoenix , AZ , USA
| | - Neil R Crawford
- a Spinal Biomechanics Laboratory, Department of Neurosurgery Research , Barrow Neurological Institute, St. Joseph's Hospital and Medical Center , Phoenix , AZ , USA
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12
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Goshulak P, Samiezadeh S, Aziz MS, Bougherara H, Zdero R, Schemitsch EH. The biomechanical effect of anteversion and modular neck offset on stress shielding for short-stem versus conventional long-stem hip implants. Med Eng Phys 2016; 38:232-40. [DOI: 10.1016/j.medengphy.2015.12.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Revised: 10/22/2015] [Accepted: 12/06/2015] [Indexed: 12/22/2022]
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Bagheri ZS, Tavakkoli Avval P, Bougherara H, Aziz MSR, Schemitsch EH, Zdero R. Biomechanical analysis of a new carbon fiber/flax/epoxy bone fracture plate shows less stress shielding compared to a standard clinical metal plate. J Biomech Eng 2015; 136:091002. [PMID: 24828985 DOI: 10.1115/1.4027669] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 05/14/2014] [Indexed: 11/08/2022]
Abstract
Femur fracture at the tip of a total hip replacement (THR), commonly known as Vancouver B1 fracture, is mainly treated using rigid metallic bone plates which may result in "stress shielding" leading to bone resorption and implant loosening. To minimize stress shielding, a new carbon fiber (CF)/Flax/Epoxy composite plate has been developed and biomechanically compared to a standard clinical metal plate. For fatigue tests, experiments were done using six artificial femurs cyclically loaded through the femoral head in axial compression for four stages: Stage 1 (intact), stage 2 (after THR insertion), stage 3 (after plate fixation of a simulated Vancouver B1 femoral midshaft fracture gap), and stage 4 (after fracture gap healing). For fracture fixation, one group was fitted with the new CF/Flax/Epoxy plate (n = 3), whereas another group was repaired with a standard clinical metal plate (Zimmer, Warsaw, IN) (n = 3). In addition to axial stiffness measurements, infrared thermography technique was used to capture the femur and plate surface stresses during the testing. Moreover, finite element analysis (FEA) was performed to evaluate the composite plate's axial stiffness and surface stress field. Experimental results showed that the CF/Flax/Epoxy plated femur had comparable axial stiffness (fractured = 645 ± 67 N/mm; healed = 1731 ± 109 N/mm) to the metal-plated femur (fractured = 658 ± 69 N/mm; healed = 1751 ± 39 N/mm) (p = 1.00). However, the bone beneath the CF/Flax/Epoxy plate was the only area that had a significantly higher average surface stress (fractured = 2.10 ± 0.66 MPa; healed = 1.89 ± 0.39 MPa) compared to bone beneath the metal plate (fractured = 1.18 ± 0.93 MPa; healed = 0.71 ± 0.24 MPa) (p < 0.05). FEA bone surface stresses yielded peak of 13 MPa at distal epiphysis (stage 1), 16 MPa at distal epiphysis (stage 2), 85 MPa for composite and 129 MPa for metal-plated femurs at the vicinity of nearest screw just proximal to fracture (stage 3), 21 MPa for composite and 24 MPa for metal-plated femurs at the vicinity of screw farthest away distally from fracture (stage 4). These results confirm that the new CF/Flax/Epoxy material could be a potential candidate for bone fracture plate applications as it can simultaneously provide similar mechanical stiffness and lower stress shielding (i.e., higher bone stress) compared to a standard clinical metal bone plate.
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Bagheri ZS, El Sawi I, Bougherara H, Zdero R. Biomechanical fatigue analysis of an advanced new carbon fiber/flax/epoxy plate for bone fracture repair using conventional fatigue tests and thermography. J Mech Behav Biomed Mater 2014; 35:27-38. [PMID: 24727574 DOI: 10.1016/j.jmbbm.2014.03.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/02/2014] [Accepted: 03/09/2014] [Indexed: 12/25/2022]
Abstract
The current study is part of an ongoing research program to develop an advanced new carbon fiber/flax/epoxy (CF/flax/epoxy) hybrid composite with a "sandwich structure" as a substitute for metallic materials for orthopedic long bone fracture plate applications. The purpose of this study was to assess the fatigue properties of this composite, since cyclic loading is one of the main types of loads carried by a femur fracture plate during normal daily activities. Conventional fatigue testing, thermographic analysis, and scanning electron microscopy (SEM) were used to analyze the damage progress that occurred during fatigue loading. Fatigue strength obtained using thermography analysis (51% of ultimate tensile strength) was confirmed using the conventional fatigue test (50-55% of ultimate tensile strength). The dynamic modulus (E(⁎)) was found to stay almost constant at 47GPa versus the number of cycles, which can be related to the contribution of both flax/epoxy and CF/epoxy laminae to the stiffness of the composite. SEM images showed solid bonding at the CF/epoxy and flax/epoxy laminae, with a crack density of only 0.48% for the plate loaded for 2 million cycles. The current composite plate showed much higher fatigue strength than the main loads experienced by a typical patient during cyclic activities; thus, it may be a potential candidate for bone fracture plate applications. Moreover, the fatigue strength from thermographic analysis was the same as that obtained by the conventional fatigue tests, thus demonstrating its potential use as an alternate tool to rapidly evaluate fatigue strength of composite biomaterials.
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Affiliation(s)
- Zahra S Bagheri
- Department of Mechanical and Industrial Engineering (Eric Palin Hall), Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B-2K3
| | - Ihab El Sawi
- Department of Mechanical and Industrial Engineering (Eric Palin Hall), Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B-2K3
| | - Habiba Bougherara
- Department of Mechanical and Industrial Engineering (Eric Palin Hall), Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B-2K3.
| | - Radovan Zdero
- Department of Mechanical and Industrial Engineering (Eric Palin Hall), Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B-2K3; Martin Orthopaedic Biomechanics Lab, St. Michael׳s Hospital, Toronto, ON, Canada M5B-1W8
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Siddiqui FS, Shah S, Nicayenzi B, Schemitsch EH, Zdero R, Bougherara H. Biomechanical analysis using infrared thermography of a traditional metal plate versus a carbon fibre/epoxy plate for Vancouver B1 femur fractures. Proc Inst Mech Eng H 2013; 228:107-13. [DOI: 10.1177/0954411913501489] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Traditional high-stiffness metal plates for Vancouver B1 femur shaft fractures below the tip of a hip implant can cause stress shielding, bone resorption, and implant loosening. This is the first study to compare the biomechanics of a traditional metal plate versus a low-stiffness carbon fibre/epoxy composite plate for this injury. A total hip replacement was implanted in two previously validated intact artificial femurs. Femurs were fitted with either a metal or composite plate and had a 5 mm fracture gap created to simulate a Vancouver B1 shaft fracture. Femurs were cyclically loaded using 5 Hz at 7° of adduction with an average axial load of 800 N (range = 400–1200 N). Overall mechanical stiffnesses and femur and plate thermographic stresses were obtained. Femur/metal plate stiffness (698 N/mm) was only 12% higher than femur/composite plate stiffness (625 N/mm). The femur with the composite plate had 22.7% higher combined average stress compared to the femur with the metal plate, having specific differences of 29.5% (anterior view), 33.9% (posterior view), 1.0% (medial view), and 26.4% (lateral view). The composite plate itself had an average 21.1% reduction in stress compared to the metal plate. The composite plate reduced stress shielding, yet provided adequate stiffness.
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Affiliation(s)
- Faisal S Siddiqui
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON, Canada
| | - Suraj Shah
- Martin Orthopaedic Biomechanics Lab, Li Ka Shing Institute, St. Michael’s Hospital, Toronto, ON, Canada
| | - Bruce Nicayenzi
- Martin Orthopaedic Biomechanics Lab, Li Ka Shing Institute, St. Michael’s Hospital, Toronto, ON, Canada
| | - Emil H Schemitsch
- Martin Orthopaedic Biomechanics Lab, Li Ka Shing Institute, St. Michael’s Hospital, Toronto, ON, Canada
| | - Radovan Zdero
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON, Canada
- Martin Orthopaedic Biomechanics Lab, Li Ka Shing Institute, St. Michael’s Hospital, Toronto, ON, Canada
| | - Habiba Bougherara
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON, Canada
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Ravariu C, Bondarciuc A. The sensitivity in the IR spectrum of the intact and pathological tissues by laser biophotometry. Lasers Med Sci 2013; 29:581-8. [PMID: 23748801 DOI: 10.1007/s10103-013-1358-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 05/28/2013] [Indexed: 10/26/2022]
Abstract
In this paper, we use the laser biophotometry for in vivo investigations, searching the most sensitive interactions of the near-infrared spectrum with different tissues. The experimental methods are based on the average reflection coefficient (ARC) measurements. For healthy persons, ARC is the average of five values provided by the biophotometer. The probe is applied on dry skin with minimum pilosity, in five regions: left-right shank, left-right forearm, and epigastrium. For the pathological tissues, the emitting terminal is moved over the suspected area, controlling the reflection coefficient level, till a minimum value occurs, as ARC-Pathological. Then, the probe is moved on the symmetrical healthy region of the body to read the complementary coefficient from intact tissue, ARC-Intact, from the same patient. The experimental results show an ARC range between 67 and 59 mW for intact tissues and a lower range, up to 58-42 mW, for pathological tissues. The method is efficient only in those pathological processes accompanied by variable skin depigmentation, water retention, inflammation, thrombosis, or swelling. Frequently, the ARC ranges are overlapping for some diseases. This induces uncertain diagnosis. Therefore, a statistical algorithm is adopted for a differential diagnosis. The laser biophotometry provides a quantitative biometric parameter, ARC, suitable for fast diagnosis in the internal and emergency medicine. These laser biophotometry measurements are representatives for the Romanian clinical trials.
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Affiliation(s)
- Cristian Ravariu
- BioNEC Group, Faculty of Electronics, Politehnica University Bucharest, Splaiul Independentei 313, Buchares, 06004, Romania,
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Preliminary Deformational Studies on a Finite Element Model of the Nasal Septum Reveals Key Areas for Septal Realignment and Reconstruction. J Med Eng 2013; 2013:250274. [PMID: 27006910 PMCID: PMC4782633 DOI: 10.1155/2013/250274] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 03/15/2013] [Accepted: 03/18/2013] [Indexed: 11/18/2022] Open
Abstract
Background. With the current lack of clinically relevant classification methods of septal deviation, computer-generated models are important, as septal cartilage is indistinguishable on current imaging methods, making preoperative planning difficult. Methods. Three-dimensional models of the septum were created from a CT scan, and incremental forces were applied. Results. Regardless of the force direction, with increasing force, the septum first tilts (type I) and then crumples into a C shape (type II) and finally into an S shape (type III). In type I, it is important to address the dislocation in the vomer-ethmoid cartilage junction and vomerine groove, where stress is concentrated. In types II and III, there is intrinsic fracture and shortening of the nasal septum, which may be dislocated off the anterior nasal spine. Surgery aims to relieve the posterior buckling and dislocation, with realignment of the septum to the ANS and possible spreader grafts to buttress the fracture sites. Conclusion. By identifying clinically observable septal deviations and the areas of stress concentration and dislocation, a straighter, more stable septum may be achieved.
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18
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Morison Z, Olsen M, Higgins GA, Zdero R, Schemitsch EH. The biomechanical effect of notch size, notch location, and femur orientation on hip resurfacing failure. IEEE Trans Biomed Eng 2013; 60:2214-21. [PMID: 23481682 DOI: 10.1109/tbme.2013.2251745] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
For hip resurfacing, this is the first biomechanical study to assess anterior and posterior femoral neck notching and femur flexion and extension. Forty-seven artificial femurs were implanted with the Birmingham hip resurfacing (BHR) using a range of notch sizes (0, 2, and 5 mm), notch locations (superior, anterior, and posterior), and femur orientations (neutral stance, flexion, and extension). Implant preparation was done using imageless computer navigation, and mechanical tests measured stiffness and strength. For notch size and location, in neutral stance the unnotched group had 1.9 times greater strength than the 5-mm superior notch group (4539 N versus 2423 N, p=0.047), and the 5-mm anterior notch group had 1.6 times greater strength than the 5-mm superior notch group, yielding a borderline statistical difference (3988 N versus 2423 N, p = 0.056). For femur orientation, in the presence of a 5-mm anterior notch, femurs in neutral stance had 2.2 times greater stiffness than femurs in 25° flexion (1542 N/mm versus 696 N/mm, p = 0.000). Similarly, in the presence of a 5-mm posterior notch, femurs in neutral stance had 2.8 times greater stiffness than femurs in 25° extension (1637 N/mm versus 575 N/mm, p = 0.000). No other statistical differences were noted. All femurs failed through the neck. The results have implications for BHR surgical techniques and recommended patient activities.
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Affiliation(s)
- Zachary Morison
- Martin Orthopaedic Biomechanics Laboratory, St. Michael's Hospital, Toronto, ON M5B 1W8, Canada.
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Zdero R, Saidi K, Mason SA, Schemitsch EH, Naudie DDR. A biomechanical comparison of four different cementless press-fit stems used in revision surgery for total knee replacements. Proc Inst Mech Eng H 2013. [PMID: 23185955 DOI: 10.1177/0954411912453246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Few biomechanical studies exist on femoral cementless press-fit stems for revision total knee replacement (TKR) surgeries. The aim of this study was to compare the mechanical quality of the femur-stem interface for a series of commercially available press-fit stems, because this interface may be a 'weak link' which could fail earlier than the femur-TKR bond itself. Also, the femur-stem interface may become particularly critical if distal femur bone degeneration, which may necessitate or follow revision TKR, ever weakens the femur-TKR bond itself. The authors implanted five synthetic femurs each with a Sigma Short Stem (SSS), Sigma Long Stem (SLS), Genesis II Short Stem (GSS), or Genesis II Long Stem (GLS). Axial stiffness, lateral stiffness, 'offset load' torsional stiffness, and 'offset load' torsional strength were measured with a mechanical testing system using displacement control. Axial (range = 1047-1461 N/mm, p = 0.106), lateral (range = 415-462 N/mm, p = 0.297), and torsional (range = 115-139 N/mm, p > 0.055) stiffnesses were not different between groups. The SSS had higher torsional strength (863 N) than the other stems (range = 167-197 N, p < 0.001). Torsional failure occurred by femoral 'spin' around the stem's long axis. There was poor linear correlation between the femur-stem interface area versus axial stiffness (R = 0.38) and torsional stiffness (R = 0.38), and there was a moderate linear correlation versus torsional strength (R = 0.55). Yet, there was a high inverse linear correlation between interfacial surface area versus lateral stiffness (R = 0.79), although this did not result in a statistical difference between stem groups (p = 0.297). These press-fit stems provide equivalent stability, except that the SSS has greater torsional strength.
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Affiliation(s)
- Radovan Zdero
- Biomechanics Lab, St. Michael's Hospital, Toronto, ON, Canada
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