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Bliven EK, Fung A, Baker A, Fleps I, Ferguson SJ, Guy P, Helgason B, Cripton PA. How accurately do finite element models predict the fall impact response of ex vivo specimens augmented by prophylactic intramedullary nailing? J Orthop Res 2024. [PMID: 39354743 DOI: 10.1002/jor.25984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 08/07/2024] [Accepted: 09/17/2024] [Indexed: 10/03/2024]
Abstract
Hip fracture prevention approaches like prophylactic augmentation devices have been proposed to strengthen the femur and prevent hip fracture in a fall scenario. The aim of this study was to validate the finite element model (FEM) of specimens augmented by prophylactic intramedullary nailing in a simulated sideways fall impact against ex vivo experimental data. A dynamic inertia-driven sideways fall simulator was used to test six cadaveric specimens (3 females, 3 males, age 63-83 years) prophylactically implanted with an intramedullary nailing system used to augment the femur. Impact force measurements, pelvic deformation, effective pelvic stiffness, and fracture outcomes were compared between the ex vivo experiments and the FEMs. The FEMs over-predicted the effective pelvic stiffness for most specimens and showed variability in terms of under- and over-predicting peak impact force and pelvis compression depending on the specimen. A significant correlation was found for time to peak impact force when comparing ex vivo and FEM data. No femoral fractures were found in the ex vivo experiments, but two specimens sustained pelvic fractures. These two pelvis fractures were correctly identified by the FEMs, but the FEMs made three additional false-positive fracture identifications. These validation results highlight current limitations of these sideways fall impact models specific to the inclusion of an orthopaedic implant. These FEMs present a conservative strategy for fracture prediction in future applications. Further evaluation of the modelling approaches used for the bone-implant interface is recommended for modelling augmented specimens, alongside the importance of maintaining well-controlled experimental conditions.
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Affiliation(s)
- Emily K Bliven
- School of Biomedical Engineering, University of British Columbia, Vancouver, British Columbia, Canada
| | - Anita Fung
- Institute for Biomechanics, ETH Zürich, Zürich, Switzerland
| | | | - Ingmar Fleps
- Skeletal Mechanobiology & Biomechanics Laboratory, Department of Mechanical Engineering, Boston University, Boston, Massachusetts, USA
| | | | - Pierre Guy
- Division of Orthopaedic Trauma, Department of Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Aging SMART, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Peter A Cripton
- School of Biomedical Engineering, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Aging SMART, University of British Columbia, Vancouver, British Columbia, Canada
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Freitas A, Lobo MDO, Alves GHD, Barbosa RFC, Blanco LGR, Shimano AC. In vitro mechanical analysis of X-shaped femoroplasty with polymethyl methacrylate boundary a fall on the greater trochanter . Injury 2023; 54 Suppl 6:110747. [PMID: 38143120 DOI: 10.1016/j.injury.2023.04.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/10/2023] [Accepted: 04/14/2023] [Indexed: 12/26/2023]
Abstract
To evaluate with mechanical testing (MT) using synthetic femurs, an X-shaped femoroplasty technique with polymethyl methacrylate (PMMA), analyzing the results applied to the prophylaxis of proximal femur (PF) fractures caused by low-energy trauma. MT was performed simulating a fall on the greater trochanter, using fifteen Sawbones™ models. They were divided into three experimental groups (n = 5): control (DP) group, drilled without augmentation (DWA) group, and X-shaped augmentation (DX) group. Maximum load, stiffness, absorbed energy and displacement were analyzed primarily in all groups; and secondarily then, morphology and fracture type were verified in all groups while PMMA volume, temperature and time polymerization were analyzed only in the DX group. The MT results obtained for synthetic models respectively in the DP, DWA, and DX groups were: mean maximum load (5562.0 ± 464.8) N, (4798.0 ± 121.2) N, and (7132.0 ± 206.9) N; mean stiffness values (673 ± 64.34) N/mm, (636 ± 8.7) N/mm, and (738 ± 17.13) N/mm, and mean absorbed energy values (36,203 ± 3819) N.mm, (27,617 ± 3011) N.mm, (44,762 ± 3219) N.mm; mean displacement values (13.6 ± 1.45) N, (11.1 ± 0.5) N, and (13.2 ± 0.69) N. The mean volume, temperature reached during filling in the DX group were 9.8 mL, 42.54ºC with 1' 56" of polymerization. The fracture types were similar between the DP and DWA groups, affecting the trochanteric region, as distinctly to those in the DX group, which were restricted to the femoral neck. The values obtained in MT showed statistical significance when analyzed by one-way ANOVA (5%) for maximum load, stiffness, and absorbed energy between groups. In conclusion, X-shaped PMMA augmentation presents a protective biomechanical characteristic against PF fractures generated in synthetic models by boundary a fall on the greater trochanter.
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Affiliation(s)
- Anderson Freitas
- Hospital Ortopédico e Medicina Especializada (HOME), Orthopedic Trauma Service, Hospital Regional do Gama, Brasília, DF, Brazil.
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Bakhtiarinejad M, Gao C, Farvardin A, Zhu G, Wang Y, Oni JK, Taylor RH, Armand M. A Surgical Robotic System for Osteoporotic Hip Augmentation: System Development and Experimental Evaluation. IEEE TRANSACTIONS ON MEDICAL ROBOTICS AND BIONICS 2023; 5:18-29. [PMID: 37213937 PMCID: PMC10195101 DOI: 10.1109/tmrb.2023.3241589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Minimally-invasive Osteoporotic Hip Augmentation (OHA) by injecting bone cement is a potential treatment option to reduce the risk of hip fracture. This treatment can significantly benefit from computer-assisted planning and execution system to optimize the pattern of cement injection. We present a novel robotic system for the execution of OHA that consists of a 6-DOF robotic arm and integrated drilling and injection component. The minimally-invasive procedure is performed by registering the robot and preoperative images to the surgical scene using multiview image-based 2D/3D registration with no external fiducial attached to the body. The performance of the system is evaluated through experimental sawbone studies as well as cadaveric experiments with intact soft tissues. In the cadaver experiments, distance errors of 3.28mm and 2.64mm for entry and target points and orientation error of 2.30° are calculated. Moreover, the mean surface distance error of 2.13mm with translational error of 4.47mm is reported between injected and planned cement profiles. The experimental results demonstrate the first application of the proposed Robot-Assisted combined Drilling and Injection System (RADIS), incorporating biomechanical planning and intraoperative fiducial-less 2D/3D registration on human cadavers with intact soft tissues.
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Affiliation(s)
- Mahsan Bakhtiarinejad
- Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Cong Gao
- Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Computer Science, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Amirhossein Farvardin
- Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Gang Zhu
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Yu Wang
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Julius K Oni
- Department of Orthopaedic Surgery, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Russell H Taylor
- Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Computer Science, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Mehran Armand
- Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Computer Science, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Orthopaedic Surgery, Johns Hopkins University, Baltimore, MD 21287, USA
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Fung A, Fleps I, Cripton PA, Guy P, Ferguson SJ, Helgason B. The efficacy of femoral augmentation for hip fracture prevention using ceramic-based cements: A preliminary experimentally-driven finite element investigation. Front Bioeng Biotechnol 2023; 11:1079644. [PMID: 36777252 PMCID: PMC9909544 DOI: 10.3389/fbioe.2023.1079644] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 01/06/2023] [Indexed: 01/27/2023] Open
Abstract
Femoral fractures due to sideways falls continue to be a major cause of concern for the elderly. Existing approaches for the prevention of these injuries have limited efficacy. Prophylactic femoral augmentation systems, particularly those involving the injection of ceramic-based bone cements, are gaining more attention as a potential alternative preventative approach. We evaluated the mechanical effectiveness of three variations of a bone cement injection pattern (basic ellipsoid, hollow ellipsoid, small ellipsoid) utilizing finite element simulations of sideways fall impacts. The basic augmentation pattern was tested with both high- and low-strength ceramic-based cements. The cement patterns were added to the finite element models (FEMs) of five cadaveric femurs, which were then subject to simulated sideways falls at seven impact velocities ranging from 1.0 m/s to 4.0 m/s. Peak impact forces and peak acetabular forces were examined, and failure was evaluated using a strain-based criterion. We found that the basic HA ellipsoid provided the highest increases in both the force at the acetabulum of the impacted femur ("acetabular force", 55.0% ± 22.0%) and at the force plate ("impact force", 37.4% ± 15.8%). Changing the cement to a weaker material, brushite, resulted in reduced strengthening of the femur (45.2% ± 19.4% acetabular and 30.4% ± 13.0% impact). Using a hollow version of the ellipsoid appeared to have no effect on the fracture outcome and only a minor effect on the other metrics (54.1% ± 22.3% acetabular force increase and 35.3% ± 16.0% impact force increase). However, when the outer two layers of the ellipsoid were removed (small ellipsoid), the force increases that were achieved were only 9.8% ± 5.5% acetabular force and 8.2% ± 4.1% impact force. These results demonstrate the importance of supporting the femoral neck cortex to prevent femoral fractures in a sideways fall, and provide plausible options for prophylactic femoral augmentation. As this is a preliminary study, the surgical technique, the possible effects of trabecular bone damage during the augmentation process, and the effect on the blood supply to the femoral head must be assessed further.
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Affiliation(s)
- Anita Fung
- Laboratory for Orthopaedic Technology, Institute for Biomechanics, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland,*Correspondence: Anita Fung,
| | - Ingmar Fleps
- Orthopaedic and Developmental Biomechanics Laboratory, Department of Mechanical Engineering, Boston University, Boston, MA, United States
| | - Peter A. Cripton
- Orthopaedic and Injury Biomechanics Group, School of Biomedical Engineering and Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, Vancouver, BC, Canada,Centre for Hip Health and Mobility, University of British Columbia, Vancouver, BC, Canada
| | - Pierre Guy
- Centre for Hip Health and Mobility, University of British Columbia, Vancouver, BC, Canada,Division of Orthopaedic Trauma, Department of Orthopaedics, University of British Columbia, Vancouver, BC, Canada
| | - Stephen J. Ferguson
- Laboratory for Orthopaedic Technology, Institute for Biomechanics, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Benedikt Helgason
- Laboratory for Orthopaedic Technology, Institute for Biomechanics, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
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Prophylactic augmentation implants in the proximal femur for hip fracture prevention: An in silico investigation of simulated sideways fall impacts. J Mech Behav Biomed Mater 2021; 126:104957. [PMID: 34861519 DOI: 10.1016/j.jmbbm.2021.104957] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 11/02/2021] [Accepted: 11/07/2021] [Indexed: 12/26/2022]
Abstract
Femoral fractures from sideways falls in the elderly are associated with significant rates of morbidity and mortality. Approaches to prevent these catastrophic injuries include pharmacological treatments, which have limited efficacy. Prophylactic femoral augmentation systems are a promising alternative that are gaining prominence by addressing the most debilitating osteoporosis-related fracture. We have developed finite element models (FEMs) of a novel experimental sideways fall simulator for cadavers. By virtue of the range of specimens and injury outcomes, these FEMs are well-suited to the evaluation of such implants. The purpose of this study was to use the FEMs to evaluate the mechanical effectiveness of three different prophylactic femoral augmentation systems. Models of the Y-Strut® (Hyprevention®, Pessac, France), Gamma Nail® (Stryker, Kalamazoo, USA), and a simple lag screw femoral fracture implant systems were placed into FEMs of five cadaveric pelvis-femur constructs embedded in a soft tissue surrogate, which were then subject to simulated sideways falls at seven impact velocities. Femur-only FEMs were also evaluated. Peak impact forces and peak acetabular forces were examined, and failure was evaluated using a strain-based criterion. We found that the femoral augmentation systems increased the peak forces prior to fracture, but were unable to prevent fracture for severe impacts. The Gamma Nail® system consistently produced the largest strength increases relative to the unaugmented femur for all five specimens in both the pendulum-drop FEMs and the femur-only simulations. In some cases, the same implant appeared to cause fractures in the acetabulum. The femur-only FEMs showed larger force increases than the pendulum-drop simulations, which suggests that the results of the femur-only simulations may not represent sideways falls as accurately as the soft tissue-embedded pendulum-drop simulations. The results from this study demonstrate the ability to simulate a high energy phenomenon and the effect of implants in an in silico environment. The results also suggest that implants could increase the force applied to the proximal femur during impact. Fracture outcomes from the tested implants can be used to inform the design of future devices, which reaffirms the value of modelling with biofidelic considerations in the implant design process. To the authors' knowledge, this is the first paper to use more complex biofidelic FEMs to assess prophylactic femoral augmentation methods.
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Freitas A, Lessa MDM, de Oliveira SP, Oliveira PFPD, Giordano V, Shimano AC. Mechanical Analysis after Proximal Femoral Reinforcement with Polymethylmethacrylate in Alternated Double Holes. Rev Bras Ortop 2021; 56:641-646. [PMID: 34733437 PMCID: PMC8558925 DOI: 10.1055/s-0040-1714221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 04/15/2020] [Indexed: 11/03/2022] Open
Abstract
Objective To evaluate, through a biomechanical assay, the maximum load, energy, and displacement necessary for the occurrence of fractures in synthetic models of femurs after the removal of cannulated screws and the performance of a reinforcement technique with polymethylmethacrylate (PMMA) in different combined positions. Methods In total, 25 synthetic bones were used, and they were divided into 4 groups: the control group (CG), with 10 models without perforation, and the test groups (A, B and C), with 5 models each. The test groups were fixed with cannulated screws using the Asnis technique, and they had the synthesis removed, and two of the holes formed by the reinforcement technique with PMMA were filled. The biomechanical analysis was performed simulating a fall on the large trochanter using a servo-hydraulic machine. Results All specimens of the CG and of groups A, B and C presented basal-cervical fracture of the femoral neck, except for a single model in group B, which presented a longitudinal fracture. An average of 5.4 mL of PMMA were used to reinforce the groups with filling. According to the analysis of variance (ANOVA) and the Tukey multiple comparison test, at the level of 5%, we observed that the CG presented significant differences in relation to groups A and C in the following parameters: maximum load, energy up to the fracture, and displacement. Conclusion We observed that groups A and C, when compared to the CG, showed significant differences in the observation of displacement, maximum load, and energy until the fracture.
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Affiliation(s)
- Anderson Freitas
- Instituto de Pesquisa e Ensino, Hospital Ortopédico e Medicina Especializada (IPE-HOME-DF), Brasília, DF, Brasil
| | | | | | | | - Vincenzo Giordano
- Coordenador do Programa de Residência Médica em Ortopedia e Traumatologia, Hospital Municipal Miguel Couto (HMMC-RJ), Rio de Janeiro, RJ, Brasil
| | - Antônio Carlos Shimano
- Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (FMRP/USP), Ribeirão Preto, SP, Brasil
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Farvardin A, Bakhtiarinejad M, Murphy RJ, Basafa E, Khanuja H, Oni JK, Armand M. A biomechanically-guided planning and execution paradigm for osteoporotic hip augmentation: Experimental evaluation of the biomechanics and temperature-rise. Clin Biomech (Bristol, Avon) 2021; 87:105392. [PMID: 34174676 PMCID: PMC8550980 DOI: 10.1016/j.clinbiomech.2021.105392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Augmentation of the proximal femur with bone cement (femoroplasty) has been identified as a potential preventive approach to reduce the risk of fracture. Femoroplasty, however, is associated with a risk of thermal damage as well as the leakage of bone cement or blockage of blood supply when large volumes of cement are introduced inside the bone. METHODS Six pairs of cadaveric femora were augmented using a newly proposed planning paradigm and an in-house navigation system to control the location and volume of the injected cement. To evaluate the risk of thermal damage, we recorded the peak temperature of bone at three regions of interest as well as the exposure time for temperature rise of 8 °C, 10 °C, and 12 °C in these regions. Augmentation was followed by mechanical testing to failure resembling a sideway fall on the greater trochanter. FINDINGS Results of the fracture tests correlated with those of simulations for the yield load (R2 = 0.77) and showed that femoroplasty can significantly improve the yield load (42%, P < 0.001) and yield energy (139%, P = 0.062) of the specimens. Meanwhile, temperature recordings of the bone surface showed that the areas close to the greater trochanter will be exposed to more critical temperature rise than the trochanteric crest and femoral neck areas. INTERPRETATION The new planning paradigm offers a more efficient injection strategy with injection volume of 9.1 ml on average. Meanwhile, temperature recordings of bone surfaces suggest that risk of thermal necrosis remains as a concern with femoroplasty using Polymethylmethacrylate.
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Affiliation(s)
- Amirhossein Farvardin
- Department of Mechanical Engineering, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA; Laboratory for Computational Sensing and Robotics, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA.
| | - Mahsan Bakhtiarinejad
- Department of Mechanical Engineering, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA; Laboratory for Computational Sensing and Robotics, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA
| | - Ryan J Murphy
- Auris Health, Inc., 150 Shoreline Dr, Redwood City, CA 94065, USA
| | - Ehsan Basafa
- Auris Health, Inc., 150 Shoreline Dr, Redwood City, CA 94065, USA
| | - Harpal Khanuja
- Department of Orthopaedic Surgery, Johns Hopkins University, 601 N. Caroline Street, Baltimore, MD 21287, USA
| | - Juluis K Oni
- Department of Orthopaedic Surgery, Johns Hopkins University, 601 N. Caroline Street, Baltimore, MD 21287, USA
| | - Mehran Armand
- Department of Mechanical Engineering, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA; Laboratory for Computational Sensing and Robotics, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA; Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723, USA; Department of Orthopaedic Surgery, Johns Hopkins University, 601 N. Caroline Street, Baltimore, MD 21287, USA
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Horbach AJ, Staat M, Pérez-Viana D, Simmen HP, Neuhaus V, Pape HC, Prescher A, Ciritsis B. Biomechanical in vitro examination of a standardized low-volume tubular femoroplasty. Clin Biomech (Bristol, Avon) 2020; 80:105104. [PMID: 32712527 DOI: 10.1016/j.clinbiomech.2020.105104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 06/03/2020] [Accepted: 07/09/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Osteoporosis is associated with the risk of fractures near the hip. Age and comorbidities increase the perioperative risk. Due to the ageing population, fracture of the proximal femur also proves to be a socio-economic problem. Preventive surgical measures have hardly been used so far. METHODS 10 pairs of human femora from fresh cadavers were divided into control and low-volume femoroplasty groups and subjected to a Hayes fall-loading fracture test. The results of the respective localization and classification of the fracture site, the Singh index determined by computed tomography (CT) examination and the parameters in terms of fracture force, work to fracture and stiffness were evaluated statistically and with the finite element method. In addition, a finite element parametric study with different position angles and variants of the tubular geometry of the femoroplasty was performed. FINDINGS Compared to the control group, the work to fracture could be increased by 33.2%. The fracture force increased by 19.9%. The used technique and instrumentation proved to be standardized and reproducible with an average poly(methyl methacrylate) volume of 10.5 ml. The parametric study showed the best results for the selected angle and geometry. INTERPRETATION The cadaver studies demonstrated the biomechanical efficacy of the low-volume tubular femoroplasty. The numerical calculations confirmed the optimal choice of positioning as well as the inner and outer diameter of the tube in this setting. The standardized minimally invasive technique with the instruments developed for it could be used in further comparative studies to confirm the measured biomechanical results.
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Affiliation(s)
- Andreas J Horbach
- FH Aachen University of Applied Sciences, Institute of Bioengineering, Biomechanics Lab., Heinrich-Mußmann-Straße 1, 52428 Jülich, Germany.
| | - Manfred Staat
- FH Aachen University of Applied Sciences, Institute of Bioengineering, Biomechanics Lab., Heinrich-Mußmann-Straße 1, 52428 Jülich, Germany.
| | - Daniel Pérez-Viana
- FH Aachen University of Applied Sciences, Institute of Bioengineering, Biomechanics Lab., Heinrich-Mußmann-Straße 1, 52428 Jülich, Germany.
| | - Hans-Peter Simmen
- Universitätsspital Zürich, Trauma Unit, Rämistrasse 100, 8091 Zürich, Switzerland.
| | - Valentin Neuhaus
- Universitätsspital Zürich, Trauma Unit, Rämistrasse 100, 8091 Zürich, Switzerland.
| | - Hans-Christoph Pape
- Universitätsspital Zürich, Trauma Unit, Rämistrasse 100, 8091 Zürich, Switzerland.
| | - Andreas Prescher
- Institute of Anatomy and Cell Biology, Rheinisch-Westfälische Technische Hochschule Aachen University, Wendlingweg 2, 52074 Aachen, Germany.
| | - Bernhard Ciritsis
- Ente Ospedaliero Cantonale Ospedale di Bellinzona e Valli, Trauma Unit, Via Ospedale 12, 6500 Bellinzona, Switzerland; Centro Ortopedico di Quadrante, Lungolago Buozzi 25, 28887 Omegna (VB), Italy.
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Gao C, Farvardin A, Grupp RB, Bakhtiarinejad M, Ma L, Thies M, Unberath M, Taylor RH, Armand M. Fiducial-Free 2D/3D Registration for Robot-Assisted Femoroplasty. ACTA ACUST UNITED AC 2020; 2:437-446. [PMID: 33763632 DOI: 10.1109/tmrb.2020.3012460] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Femoroplasty is a proposed alternative therapeutic method for preventing osteoporotic hip fractures in the elderly. Previously developed navigation system for femoroplasty required the attachment of an external X-ray fiducial to the femur. We propose a fiducial-free 2D/3D registration pipeline using fluoroscopic images for robot-assisted femoroplasty. Intraoperative fluoroscopic images are taken from multiple views to perform registration of the femur and drilling/injection device. The proposed method was tested through comprehensive simulation and cadaveric studies. Performance was evaluated on the registration error of the femur and the drilling/injection device. In simulations, the proposed approach achieved a mean accuracy of 1.26±0.74 mm for the relative planned injection entry point; 0.63±0.21° and 0.17±0.19° for the femur injection path direction and device guide direction, respectively. In the cadaver studies, a mean error of 2.64 ± 1.10 mm was achieved between the planned entry point and the device guide tip. The biomechanical analysis showed that even with a 4 mm translational deviation from the optimal injection path, the yield load prior to fracture increased by 40.7%. This result suggests that the fiducial-less 2D/3D registration is sufficiently accurate to guide robot assisted femoroplasty.
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Affiliation(s)
- Cong Gao
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA 21211
| | - Amirhossein Farvardin
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA 21211
| | - Robert B Grupp
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA 21211
| | - Mahsan Bakhtiarinejad
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA 21211
| | - Liuhong Ma
- Department of Cranio-maxillo-facial Surgery Center, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, CHN,100144
| | - Mareike Thies
- Pattern Recognition Lab, Friedrich-Alexander-Universitt Erlangen-Nrnberg, Erlangen, Germany 91058
| | - Mathias Unberath
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA 21211
| | - Russell H Taylor
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA 21211
| | - Mehran Armand
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA 21211; Department of Orthopaedic Surgery and Johns Hopkins Applied Physics Laboratory, Baltimore, MD, USA 21224
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Sas A, Tanck E, Sermon A, van Lenthe GH. Finite element models for fracture prevention in patients with metastatic bone disease. A literature review. Bone Rep 2020; 12:100286. [PMID: 32551337 PMCID: PMC7292864 DOI: 10.1016/j.bonr.2020.100286] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 05/04/2020] [Accepted: 05/25/2020] [Indexed: 12/17/2022] Open
Abstract
Patients with bone metastases have an increased risk to sustain a pathological fracture as lytic metastatic lesions damage and weaken the bone. In order to prevent fractures, prophylactic treatment is advised for patients with a high fracture risk. Mechanical stabilization of the femur can be provided through femoroplasty, a minimally invasive procedure where bone cement is injected into the lesion, or through internal fixation with intra- or extramedullary implants. Clinicians face the task of determining whether or not prophylactic treatment is required and which treatment would be the most optimal. Finite element (FE) models are promising tools that could support this decision process. The aim of this paper is to provide an overview of the state-of-the-art in FE modeling for the treatment decision of metastatic bone lesions in the femur. First, we will summarize the clinical and mechanical results of femoroplasty as a prophylactic treatment method. Secondly, current FE models for fracture risk assessment of metastatic femurs will be reviewed and the remaining challenges for clinical implementation will be discussed. Thirdly, we will elaborate on the simulation of femoroplasty in FE models and discuss future opportunities. Femoroplasty has already proven to effectively relieve pain and improve functionality, but there remains uncertainty whether it provides sufficient mechanical strengthening to prevent pathological fractures. FE models could help to select appropriate candidates for whom femoroplasty provides sufficient increase in strength and to further improve the mechanical benefit by optimizing the locations for cement augmentation.
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Affiliation(s)
- Amelie Sas
- Biomechanics Section, KU Leuven, Leuven, Belgium
| | - Esther Tanck
- Orthopaedic Research Laboratory, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - An Sermon
- Department of Traumatology, University Hospitals Gasthuisberg, Leuven, Belgium and Department of Development and Regeneration, KU Leuven, Leuven, Belgium
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Howe JG, Hill RS, Stroncek JD, Shaul JL, Favell D, Cheng RR, Engelke K, Genant HK, Lee DC, Keaveny TM, Bouxsein ML, Huber B. Treatment of bone loss in proximal femurs of postmenopausal osteoporotic women with AGN1 local osteo-enhancement procedure (LOEP) increases hip bone mineral density and hip strength: a long-term prospective cohort study. Osteoporos Int 2020; 31:921-929. [PMID: 31802158 PMCID: PMC7170985 DOI: 10.1007/s00198-019-05230-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 11/07/2019] [Indexed: 12/14/2022]
Abstract
UNLABELLED This first-in-human study of AGN1 LOEP demonstrated that this minimally-invasive treatment durably increased aBMD in femurs of osteoporotic postmenopausal women. AGN1 resorption was coupled with new bone formation by 12 weeks and that new bone was maintained for at least 5-7 years resulting in substantially increased FEA-estimated femoral strength. INTRODUCTION This first-in-human study evaluated feasibility, safety, and in vivo response to treating proximal femurs of postmenopausal osteoporotic women with a minimally-invasive local osteo-enhancement procedure (LOEP) to inject a resorbable triphasic osteoconductive implant material (AGN1). METHODS This prospective cohort study enrolled 12 postmenopausal osteoporotic (femoral neck T-score ≤ - 2.5) women aged 56 to 89 years. AGN1 LOEP was performed on left femurs; right femurs were untreated controls. Subjects were followed-up for 5-7 years. Outcomes included adverse events, proximal femur areal bone mineral density (aBMD), AGN1 resorption, and replacement with bone by X-ray and CT, and finite element analysis (FEA) estimated hip strength. RESULTS Baseline treated and control femoral neck aBMD was equivalent. Treated femoral neck aBMD increased by 68 ± 22%, 59 ± 24%, and 58 ± 27% over control at 12 and 24 weeks and 5-7 years, respectively (p < 0.001, all time points). Using conservative assumptions, FEA-estimated femoral strength increased by 41%, 37%, and 22% at 12 and 24 weeks and 5-7 years, respectively (p < 0.01, all time points). Qualitative analysis of X-ray and CT scans demonstrated that AGN1 resorption and replacement with bone was nearly complete by 24 weeks. By 5-7 years, AGN1 appeared to be fully resorbed and replaced with bone integrated with surrounding trabecular and cortical bone. No procedure- or device-related serious adverse events (SAEs) occurred. CONCLUSIONS Treating femurs of postmenopausal osteoporotic women with AGN1 LOEP results in a rapid, durable increase in aBMD and femoral strength. These results support the use and further clinical study of this approach in osteoporotic patients at high risk of hip fracture.
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Affiliation(s)
- J G Howe
- AgNovos Healthcare LLC, Rockville, MD, USA
| | - R S Hill
- AgNovos Healthcare LLC, Rockville, MD, USA.
| | | | - J L Shaul
- AgNovos Healthcare LLC, Rockville, MD, USA
| | - D Favell
- AgNovos Healthcare LLC, Rockville, MD, USA
| | - R R Cheng
- AgNovos Healthcare LLC, Rockville, MD, USA
| | - K Engelke
- Bioclinica-Synarc, Inc., Hamburg, Germany
- FAU University Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
| | - H K Genant
- University of California San Francisco, San Francisco, CA, USA
- Bioclinica-Synarc, Inc., Newark, CA, USA
| | - D C Lee
- O.N. Diagnostics, Berkeley, CA, USA
| | - T M Keaveny
- University of California Berkeley, Berkley, CA, USA
| | - M L Bouxsein
- Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - B Huber
- Mansfield Orthopedics, Morrisville, VT, USA
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12
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Sas A, Van Camp D, Lauwers B, Sermon A, van Lenthe GH. Cement augmentation of metastatic lesions in the proximal femur can improve bone strength. J Mech Behav Biomed Mater 2020; 104:103648. [DOI: 10.1016/j.jmbbm.2020.103648] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 01/15/2020] [Accepted: 01/18/2020] [Indexed: 12/16/2022]
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Farvardin A, Basafa E, Bakhtiarinejad M, Armand M. Significance of preoperative planning for prophylactic augmentation of osteoporotic hip: A computational modeling study. J Biomech 2019; 94:75-81. [PMID: 31371101 PMCID: PMC6736717 DOI: 10.1016/j.jbiomech.2019.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 12/22/2022]
Abstract
A potential effective treatment for prevention of osteoporotic hip fractures is augmentation of the mechanical properties of the femur by injecting it with bone cement. This therapy, however, is only in research stage and can benefit substantially from computational simulations to optimize the pattern of cement injection. Some studies have considered a patient-specific planning paradigm for Osteoporotic Hip Augmentation (OHA). Despite their biomechanical advantages, customized plans require advanced surgical systems for implementation. Other studies, therefore, have suggested a more generalized injection strategy. The goal of this study is to investigate as to whether the additional computational overhead of the patient-specific planning can significantly improve the bone strength as compared to the generalized injection strategies attempted in the literature. For this purpose, numerical models were developed from high resolution CT images (n = 4). Through finite element analysis and hydrodynamic simulations, we compared the biomechanical efficiency of the customized cement-based augmentation along with three generalized injection strategies developed previously. Two series of simulations were studied, one with homogeneous and one with inhomogeneous material properties for the osteoporotic bone. The customized cement-based augmentation inhomogeneous models showed that injection of only 10 ml of bone cement can significantly increase the yield load (79.6%, P < 0.01) and yield energy (199%, P < 0.01) of an osteoporotic femur. This increase is significantly higher than those of the generalized injections proposed previously (23.8% on average). Our findings suggest that OHA can significantly benefit from a patient-specific plan that determines the pattern and volume of the injected cement.
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Affiliation(s)
- Amirhossein Farvardin
- Department of Mechanical Engineering, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA; Laboratory for Computational Sensing and Robotics, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA.
| | - Ehsan Basafa
- Auris Health, Inc., 150 Shoreline Dr, Redwood City, CA 94065, USA
| | - Mahsan Bakhtiarinejad
- Department of Mechanical Engineering, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA; Laboratory for Computational Sensing and Robotics, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA
| | - Mehran Armand
- Department of Mechanical Engineering, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA; Laboratory for Computational Sensing and Robotics, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA; Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723, USA; Department of Orthopaedic Surgery, Johns Hopkins University, 601 N. Caroline Street, Baltimore, MD 21287, USA
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14
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Freitas A, Ramos LS, Dantas ÉL, Giordano Neto V, Godinho PF, Shimano AC. Biomechanical Test after Hip Cannulated Screw Removal (in vitro Analysis). Rev Bras Ortop 2019; 54:416-421. [PMID: 31435108 PMCID: PMC6701975 DOI: 10.1055/s-0039-1693046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 09/03/2018] [Indexed: 11/01/2022] Open
Abstract
Objective This study aims to evaluate, through biomechanical tests, the resistance and energy required for proximal femoral fracture in synthetic bones after removing cannulated screws shaped as an inverted triangle, comparing the obtained results to those of a reinforcement technique with polymethylmethacrylate (PMMA) as bone cement. Methods Twenty synthetic bones were used: 10 units for the control group (CG), 5 units for the test group without reinforcement (TGW/O), and 5 units for the test group using a reinforcement technique with PMMA (TGW). The biomechanical analysis simulated a fall on the large trochanter using a servo-hydraulic machine. Results All TGW/O and CG specimens had a basicervical fracture. Three TGW specimens presented a basicervical fracture, and two suffered a fracture near the fixation point of the device (femoral diaphyseal region), with one of them being associated with a femoral neck fracture. A mean PMMA volume of 8.2 mL was used to fill the 3 screw holes in the TGW group. According to the one-way analysis of variance (ANOVA) and the Tukey multiple comparisons tests at a 5% level, the TGW presented a statistically significant difference when compared with the other groups in all parameters: maximal load ( p = 0.001) and energy until fracture ( p = 0.0001). Conclusion The simple removal of the cannulated screws did not reduce significantly the maximum load and energy for fracture occurrence, but the proximal femoral reinforcement with PMMA significantly increased these parameters, modifying the fracture pattern.
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Affiliation(s)
- Anderson Freitas
- Instituto de Pesquisa e Ensino do Hospital Ortopédico e Medicina Especializada (IPE-HOME-DF), Brasília, DF, Brasil
| | - Lucas S Ramos
- Serviço de Ortopedia e Traumatologia, Hospital Regional do Gama (HRG-DF), Brasília, DF, Brasil
| | - Érgon Lab Dantas
- Serviço de Ortopedia e Traumatologia, Hospital Regional do Gama (HRG-DF), Brasília, DF, Brasil
| | - Vincenzo Giordano Neto
- Serviço de Ortopedia e Traumatologia, Hospital Municipal Miguel Couto (HMMC-RJ), Rio de Janeiro, RJ, Brasil
| | - Patrick F Godinho
- Instituto de Pesquisa e Ensino do Hospital Ortopédico e Medicina Especializada (IPE-HOME-DF), Brasília, DF, Brasil
| | - Antônio C Shimano
- Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP-RP), Riberião Preto, SP, Brasil
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15
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Kok J, Širka A, Grassi L, Raina DB, Tarasevičius Š, Tägil M, Lidgren L, Isaksson H. Fracture strength of the proximal femur injected with a calcium sulfate/hydroxyapatite bone substitute. Clin Biomech (Bristol, Avon) 2019; 63:172-178. [PMID: 30903873 DOI: 10.1016/j.clinbiomech.2019.03.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/05/2019] [Accepted: 03/11/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Available interventions for preventing fragility hip fractures show limited efficacy. Injection of a biomaterial as bone substitute could increase the fracture strength of the hip. This study aimed to show the feasibility of injecting a calcium sulfate/hydroxyapatite based biomaterial in the femoral neck and to calculate the consequent change in strength using the finite element method. METHODS Five patients were injected with 10 ml calcium sulfate/hydroxyapatite in their femoral neck. Quantitative CT scans were taken before and after injection. Five additional patients with fragility hip fractures were also scanned and the images from the non-fractured contralateral sides were used. Finite element models were created for all proximal femora with and without injection and the models were tested under stance and sideways fall loading until fracture. The change in fracture strength caused by the injection was calculated. Additionally, perturbations in volume, location, and stiffness of the injected material were created to investigate their contribution to the fracture strength increase. FINDINGS The 10 ml injection succeeded in all patients. Baseline simulations showed theoretical fracture strength increases of 0-9%. Volume increase, change in location and increase in stiffness of the material led to increases in fracture strength of 1-27%, -8-26% and 0-17%, respectively. Altering the location of the injection to a more lateral position and increasing the stiffness of the material led to increases in fracture strength of up to 42%. INTERPRETATION This study shows that an injection of calcium sulfate/hydroxyapatite is feasible and can theoretically increase the hip's fracture strength.
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Affiliation(s)
- Joeri Kok
- Department of Biomedical Engineering, Lund University, Box 118, 221 00 Lund, Sweden.
| | - Aurimas Širka
- Department of Orthopedics and Traumatology, Lithuanian University of Health Sciences, A. Mickevičiaus g. 9, LT 44307 Kaunas, Lithuania
| | - Lorenzo Grassi
- Department of Biomedical Engineering, Lund University, Box 118, 221 00 Lund, Sweden.
| | - Deepak Bushan Raina
- Department of Orthopedics, Clinical Sciences, Lund University, Box 118, 221 00 Lund, Sweden.
| | - Šarūnas Tarasevičius
- Department of Orthopedics and Traumatology, Lithuanian University of Health Sciences, A. Mickevičiaus g. 9, LT 44307 Kaunas, Lithuania
| | - Magnus Tägil
- Department of Orthopedics, Clinical Sciences, Lund University, Box 118, 221 00 Lund, Sweden.
| | - Lars Lidgren
- Department of Orthopedics, Clinical Sciences, Lund University, Box 118, 221 00 Lund, Sweden
| | - Hanna Isaksson
- Department of Biomedical Engineering, Lund University, Box 118, 221 00 Lund, Sweden; Department of Orthopedics, Clinical Sciences, Lund University, Box 118, 221 00 Lund, Sweden.
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16
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Freitas A, Breta JB, Júnior J, Shimano AC, Daher WR, Bessa M, De Alcantara WP, Ramos LS, Dantas EL, Aquino RJ. Biomechanical Test Following Removal of a Dynamic Hip Screw: In Vitro Analysis. Cureus 2018; 10:e3680. [PMID: 30761232 PMCID: PMC6367115 DOI: 10.7759/cureus.3680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The objective of this study was to evaluate, by means of a static flexural test, the biomechanical parameters necessary for the occurrence of a proximal femoral fracture in a synthetic bone model after the removal of a dynamic hip screw (DHS) and comparing the results obtained with a reinforcement technique using polymethylmethacrylate (PMMA). Twenty synthetic bones made of the same material and from the same manufacturer were used: ten units as the control group (CG), five units as the test group without reinforcement (TG), and five units as the test group with reinforcement (TGR). The biomechanical analysis was performed simulating a fall over the trochanter using a servo-hydraulic machine. In the control group, the assay was performed with its integrity preserved. In the TG and TGR groups, a DHS model was introduced, and the tests were performed as follows: TG after simple removal of the synthesis material, and in the TGR group, after removal of the synthesis material and filling the orifice of the femoral neck with PMMA. All groups presented with a basicervical fracture of the femoral neck. The CG group presented a mean of 935 newtons (N) of maximum load and 7.0 joules (J) of energy for fracture occurrence. TG and TGR groups presented, respectively, a maximum load of 750 N and 1,068 N, and energy of 6.0 J and 7.3 J. According to the one-way analysis of variance (ANOVA), there was no significant difference in flow load (p = 0.16), energy to flow (p = 0.16), stiffness (p = 0.28), maximum load (p = 0.10), and energy to fracture (p = 0.54) between the studied groups. The removal of the DHS implant from the synthetic bone did not present a significant increase of the maximum load and the energy necessary for the occurrence of a fracture with the use of the PMMA reinforcement technique.
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Affiliation(s)
- Anderson Freitas
- Orthopaedics, Hospital of Orthopedic and Specialized Medicine, Brasilia, BRA
| | | | | | | | - Walter R Daher
- Orthopedics and Traumatology, Hospital Regional Do Gama, Brasilia, BRA
| | - Munir Bessa
- Orthopedics and Traumatology, Hospital Regional De Ceilândia, Brasilia, BRA
| | | | | | - Ergon L Dantas
- Orthopedics and Traumatology, Hospital Regional Do Gama, Brasilia, BRA
| | - Ruben J Aquino
- Orthopedics and Traumatology, Hospital Regional Do Gama, Brasilia, BRA
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17
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Farvardin A, Nejad MB, Pozin M, Armand M. A BIOMECHANICAL AND THERMAL ANALYSIS FOR BONE AUGMENTATION OF THE PROXIMAL FEMUR. INTERNATIONAL MECHANICAL ENGINEERING CONGRESS AND EXPOSITION : [PROCEEDINGS]. INTERNATIONAL MECHANICAL ENGINEERING CONGRESS AND EXPOSITION 2018; 3:V003T04A061. [PMID: 31360933 PMCID: PMC6663307 DOI: 10.1115/imece2018-88583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this study, we aim to create and validate a Finite Element (FE) model to estimate the bone temperature after cement injection and compare the simulation temperature results with experimental data in three key locations of the proximal femur. Simulation results suggest that the maximum temperature-rise measured at the bone surface is 10°C which occurs about 12 minutes after the injection. Temperature profiles measured during the experiment showed an agreement with those of the simulation with an average error of 1.73°C Although additional experiments are required to further validate the model, results of this study suggest that this model is a promising tool for bone augmentation planning to lower the risk of thermal necrosis.
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Affiliation(s)
- Amirhossein Farvardin
- Laboratory for Computational Sensing & Robotics, Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, United States
| | - Mahsan Bakhtiari Nejad
- Laboratory for Computational Sensing & Robotics, Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Michael Pozin
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, United States
| | - Mehran Armand
- Laboratory for Computational Sensing & Robotics, Department of Mechanical Engineering, Johns Hopkins University, Johns Hopkins University Applied Physics, Laboratory, Laurel, Maryland, United States
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18
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Freitas A, Camargo WS, Aquino RJ, Giordano V, Bonavides AF, Shimano AC. PRELIMINARY MECHANICAL TEST OF PROXIMAL FEMUR REINFORCEMENT WITH CEMENTED X-SHAPED PMMA. ACTA ORTOPEDICA BRASILEIRA 2018; 26:231-235. [PMID: 30210250 PMCID: PMC6131274 DOI: 10.1590/1413-785220182604187691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Objective: To evaluate the mechanical behavior of the proximal end of the femur submitted to the X-shaped polymethylmethacrylate (PMMA) reinforcement technique. Methods: Fifteen synthetic femurs, with a Nacional® density of 10 PCF, were divided into two groups: the DX group, with 5 units that were submitted to PMMA reinforcement, and the DP group, with 10 units, which were evaluated intact. The volume of PMMA required, the maximum load, and the absorbed energy to fracture were analyzed by means of a static mechanical bending test simulating a fall on the greater trochanter. Results: A mean of 6 ml of PMMA was used to model the X-reinforcement; it was observed that the DX group presented significantly higher maximum load (median = 1553 N, p = 0.005) and absorbed energy to fracture (median = 9.7 J; p = 0.050) than the DP group (median = 905 N and 6.6 J). Conclusion: X-reinforcement of the proximal end of synthetic femurs showed a statistically significant increase in the maximum load and absorbed energy to fracture in the mechanical assay when compared to the control group. Level of Evidence III, Experimental study.
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Affiliation(s)
- Anderson Freitas
- Instituto de Pesquisa e Ensino do Hospital Ortopédico e Medicina Especializada (IPE-HOME), Brasília, DF, Brazil
| | | | | | | | | | - Antônio Carlos Shimano
- Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil
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Discrete particle model for cement infiltration within open-cell structures: Prevention of osteoporotic fracture. PLoS One 2018; 13:e0199035. [PMID: 29898001 PMCID: PMC5999107 DOI: 10.1371/journal.pone.0199035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 05/30/2018] [Indexed: 11/19/2022] Open
Abstract
This paper proposes a discrete particle model based on the random-walk theory for simulating cement infiltration within open-cell structures to prevent osteoporotic proximal femur fractures. Model parameters consider the cement viscosity (high and low) and the desired direction of injection (vertical and diagonal). In vitro and in silico characterizations of augmented open-cell structures validated the computational model and quantified the improved mechanical properties (Young's modulus) of the augmented specimens. The cement injection pattern was successfully predicted in all the simulated cases. All the augmented specimens exhibited enhanced mechanical properties computationally and experimentally (maximum improvements of 237.95 ± 12.91% and 246.85 ± 35.57%, respectively). The open-cell structures with high porosity fraction showed a considerable increase in mechanical properties. Cement augmentation in low porosity fraction specimens resulted in a lesser increase in mechanical properties. The results suggest that the proposed discrete particle model is adequate for use as a femoroplasty planning framework.
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Santana Artiles ME, Venetsanos DT. Numerical investigation of the effect of bone cement porosity on osteoporotic femoral augmentation. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2989. [PMID: 29603673 DOI: 10.1002/cnm.2989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/19/2018] [Accepted: 03/24/2018] [Indexed: 06/08/2023]
Abstract
Femoroplasty is the injection of bone cement into the proximal femur, enhances the bone load capacity, and is typically applied to osteoporotic femora. To minimize the required injected volume of bone cement and maximize the load capacity enhancement, an optimization problem must be solved, where the modulus of elasticity of the augmented bone is a key element. This paper, through the numerical investigation of a fall on the greater trochanter of an osteoporotic femur, compares different ways to calculate this modulus and introduces an approach, based on the concept of bone cement porosity, which provides results statistically similar to those obtained with other considerations. Based on this approach, the present paper quantifies the correlation between degree of osteoporosis and optimum volume of bone cement. It concludes with an exhaustive search that reveals the effect of the bone cement porosity on the optimum volume of PMMA, for various combinations of the frontal and transverse angles of the fall on the greater trochanter.
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Affiliation(s)
- María E Santana Artiles
- School of Engineering, Faculty of Science, Engineering and Computing, Kingston University, Friars Ave., Roehampton Vale Campus, SW15 3DW, London, UK
| | - Demetrios T Venetsanos
- School of Mechanical, Aerospace and Automotive Engineering, Faculty of Engineering, Environment & Computing, Coventry University, Gulson Road, CV1 2JH, Coventry, UK
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21
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Freitas A, Silva LCDA, Godinho NDV, Farvardin A, Armand M, Paula APDE. EVALUATION OF A BONE REINFORCEMENT TECHNIQUE USING FINITE ELEMENT ANALYSIS. ACTA ORTOPEDICA BRASILEIRA 2018; 26:59-62. [PMID: 29977147 PMCID: PMC6025497 DOI: 10.1590/1413-785220182601181560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Objectives: To compare the results of a simulated fall on the greater trochanter in the proximal portion of a synthetic femur before and after femoral reinforcement with tricalcium phosphate bone cement (TP) and polymethyl methacrylate (PMMA), using finite element analysis (FEA). Methods: Using two synthetic proximal femurs, a FEA simulating a fall on the greater trochanter was performed, using the Bi-directional Evolutionary Structural Optimization (BESO) program. For this analysis, the femurs were filled with TP and PMMA after perforations were created in the trochanteric region and neck. The results were compared with the strength values obtained from testing the control specimen, a synthetic bone without reinforcement. Results: FEA showed a value of 600 N prior to reinforcement. After cementing with PMMA, the load increased by 57.5% (945 N), and by 53% (920 N) after cementing with TP. Conclusion: Synthetic femurs gained resistance to fracture-causing forces in a simulated fall on the trochanter after bone reinforcement with PMMA and TP. Level of Evidence III; Experimental study.
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Affiliation(s)
- Anderson Freitas
- . Hospital Ortopédico e Medicina Especializada, Brasília, DF, Brazil.,. Hospital Regional do Gama, Brasília, DF, Brazil
| | | | | | - Amirhossein Farvardin
- . Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Mehran Armand
- . Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Ana Patrícia DE Paula
- . Postgraduate program, Fundação de Ensino e Pesquisa em Ciências da Saúde (FEPECS), Brasília, DF, Brazil
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Paiva LM, Macedo Neto SLD, Souto DRDM, Ferreira GNB, Costa HID, Freitas A. Static bending test after proximal femoral nail (PFN) removal - in vitro analysis. Rev Bras Ortop 2017; 52:52-56. [PMID: 28971087 PMCID: PMC5620003 DOI: 10.1016/j.rboe.2017.01.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 01/26/2017] [Indexed: 11/25/2022] Open
Abstract
Objective To evaluate, through biomechanical testing, the resistance to and energy required for the occurrence of proximal femoral fracture in synthetic bone after removal of a proximal femoral nail model (PFN), comparing the results obtained with a reinforcement technique using polymethylmethacrylate (PMMA). Methods Fifteen synthetic bones were used: five units for the control group (CG), five for the test group without reinforcement (TGNR), and five for the test group with reinforcement (TGR). The biomechanical analysis was performed simulating a fall on the trochanter using a servo-hydraulic machine. In the GC, the assay was performed with the PFN intact. In the TGNR and TGR groups, a model of PFN was introduced and the tests were performed in the TGNR, after simple removal of the synthesis material, and in the TGR, after removal of the same PFN model and filling of the cavity in the femoral neck with PMMA. Results All groups presented a basicervical fracture. The CG presented a mean of 1427.39 Newtons (N) of maximum load and 10.14 Joules (J) of energy for the occurrence of the fracture. The TGNR and TGR presented 892.14 N and 1477.80 N of maximum load, and 6.71 J and 11.99 J of energy, respectively. According to the Kruskal–Wallis ANOVA, there was a significant difference in the maximum load (p = 0.009) and energy (p = 0.007) between these groups. Conclusion The simple removal of a PFN in synthetic bone showed a significant reduction of the maximum load and energy for the occurrence of fracture, which were re-established with a reinforcement technique using PMMA.
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Varga P, Inzana JA, Schwiedrzik J, Zysset PK, Gueorguiev B, Blauth M, Windolf M. New approaches for cement-based prophylactic augmentation of the osteoporotic proximal femur provide enhanced reinforcement as predicted by non-linear finite element simulations. Clin Biomech (Bristol, Avon) 2017; 44:7-13. [PMID: 28282569 DOI: 10.1016/j.clinbiomech.2017.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 02/27/2017] [Accepted: 03/01/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND High incidence and increased mortality related to secondary, contralateral proximal femoral fractures may justify invasive prophylactic augmentation that reinforces the osteoporotic proximal femur to reduce fracture risk. Bone cement-based approaches (femoroplasty) may deliver the required strengthening effect; however, the significant variation in the results of previous studies calls for a systematic analysis and optimization of this method. Our hypothesis was that efficient generalized augmentation strategies can be identified via computational optimization. METHODS This study investigated, by means of finite element analysis, the effect of cement location and volume on the biomechanical properties of fifteen proximal femora in sideways fall. Novel cement cloud locations were developed using the principles of bone remodeling and compared to the "single central" location that was previously reported to be optimal. FINDINGS The new augmentation strategies provided significantly greater biomechanical benefits compared to the "single central" cement location. Augmenting with approximately 12ml of cement in the newly identified location achieved increases of 11% in stiffness, 64% in yield force, 156% in yield energy and 59% in maximum force, on average, compared to the non-augmented state. The weaker bones experienced a greater biomechanical benefit from augmentation than stronger bones. The effect of cement volume on the biomechanical properties was approximately linear. Results of the "single central" model showed good agreement with previous experimental studies. INTERPRETATION These findings indicate enhanced potential of cement-based prophylactic augmentation using the newly developed cementing strategy. Future studies should determine the required level of strengthening and confirm these numerical results experimentally.
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Affiliation(s)
| | | | - Jakob Schwiedrzik
- Institute of Surgical Technology and Biomechanics, University of Bern, Switzerland
| | - Philippe K Zysset
- Institute of Surgical Technology and Biomechanics, University of Bern, Switzerland
| | | | - Michael Blauth
- Department for Trauma Surgery, Medical University Innsbruck, Austria
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Paiva LM, Macedo Neto SLD, Souto DRDM, Ferreira GNB, Costa HID, Freitas A. Ensaio estático de flexão após retirada de haste do fêmur proximal (PFN) – Análise in vitro. Rev Bras Ortop 2017. [DOI: 10.1016/j.rbo.2017.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Varga P, Hofmann-Fliri L, Blauth M, Windolf M. Prophylactic augmentation of the osteoporotic proximal femur-mission impossible? BONEKEY REPORTS 2016; 5:854. [PMID: 28018586 DOI: 10.1038/bonekey.2016.86] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/01/2016] [Indexed: 11/09/2022]
Abstract
The high incidence of secondary hip fractures and the associated markedly increased mortality call for preventive actions that could help to avoid these injuries. By providing immediate strengthening and not relying on patient compliance, internal prophylactic augmentation of the osteoporotic proximal femur may overcome the main limitations of systemic bone drugs and wearable protective pads. However, such a method would have to provide sufficient and reliable strengthening effect with minimal risks and side effects to justify the need of an invasive treatment. The requirements for an internal reinforcement approach are thus strict and include mechanical, biological, clinical, ethical and financial criteria. Here we first attempt to describe the properties of an ideal augmentation method. Previously published methodologies and techniques developed at our research institute, including approaches using cements, metals, other materials or combined approaches, are then reviewed and evaluated according to these aspects. We conclude that none of the discussed methodologies appears to be able to deliver a sufficiently high gain-versus-risk ratio that could justify the clinical application and thus augmentation of the osteoporotic proximal femur remains a challenge. Finally, we provide suggestions for the development and evaluation of future strategies.
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Affiliation(s)
- Peter Varga
- AO Research Institute Davos , Davos Platz, Switzerland
| | | | - Michael Blauth
- Department for Trauma Surgery, Medical University Innsbruck , Innsbruck, Austria
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Unmet needs and current and future approaches for osteoporotic patients at high risk of hip fracture. Arch Osteoporos 2016; 11:37. [PMID: 27800591 PMCID: PMC5306171 DOI: 10.1007/s11657-016-0292-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 10/25/2016] [Indexed: 02/03/2023]
Abstract
UNLABELLED This review provides a critical analysis of currently available approaches to increase bone mass, structure and strength through drug therapy and of possible direct intra-osseous interventions for the management of patients at imminent risk of hip fracture. PURPOSE Osteoporotic hip fractures represent a particularly high burden in morbidity-, mortality- and health care-related costs. There are challenges and unmet needs in the early prevention of hip fractures, opening the perspective of new developments for the management of osteoporotic patients at imminent and/or at very high risk of hip fracture. Amongst them, preventive surgical intervention needs to be considered. METHODS A European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO)/International Osteoporosis Foundation (IOF) working group reviewed the presently available intervention modalities including preventive surgical options for hip fragility. This paper represents a summary of the discussions. RESULTS Prevention of hip fracture is currently based on regular physical activity; prevention of falls; correction of nutritional deficiencies, including vitamin D repletion; and pharmacological intervention. However, efficacy of these various measures to reduce hip fractures is at most 50% and may need months or years before becoming effective. To face the challenges of early prevention of hip fractures for osteoporotic patients at imminent and/or at very high risk of hip fracture, preventive surgical intervention needs further investigation. CONCLUSION Preventive surgical intervention needs to be appraised for osteoporotic patients at imminent and/or at very high risk of hip fracture.
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