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Min Zhang - One of the best experts on this subject based on the ideXlab platform.
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effect of baseplate positioning on fixation of reverse total shoulder arthroplasty
Clinical Biomechanics, 2019Co-Authors: Min Zhang, Sarah Junaid, Thomas Gregory, Chengkung ChengAbstract:Background: The glenoid component in reverse total shoulder arthroplasty is recommended to be positioned inferiorly or with a downward tilt with the intention of reducing scapular notching. However, it is still unclear whether modifying the position of the glenoid Prosthesis affects implant stability. The aim of this study was to determine the association between implant positioning and glenoid Prosthesis fixation using Grammont reverse total shoulder arthroplasty. Methods: Four positions for the glenoid Prosthesis were studied using the finite element method. The glenosphere was positioned as follows: 1) in the middle of the glenoid fossa, 2) flush with the inferior glenoid rim, 3) with an inferior overhang, 4) with a 15° inferior inclination. Bone-Prosthesis micromotions and strain-induced Bone adaptations were quantified during five daily activities. Findings: When the glenoid component was tilted inferiorly, the activities producing anterior-posterior shear forces (e.g. standing up from an armchair) caused an increase in peak micromotions. In the lateral-middle glenoid, inferior positioning caused a 64.6% reduction in Bone apparent density. In the lateral-inferior glenoid, central positioning led to the most severe Bone resorption, reaching 43.9%. Interpretation: Reducing activities which generate anterior-posterior shear forces on the shoulder joint will increase Bone formation and may improve the primary stability of the implant when fixed in the position with an inferior tilt. Postoperative Bone resorption is highly dependent on implant positioning. Understanding the relationship between Bone resorption and implant positioning will help surgeons improve the long-term stability of reverse total shoulder arthroplasty.
Chengkung Cheng - One of the best experts on this subject based on the ideXlab platform.
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effect of baseplate positioning on fixation of reverse total shoulder arthroplasty
Clinical Biomechanics, 2019Co-Authors: Min Zhang, Sarah Junaid, Thomas Gregory, Chengkung ChengAbstract:Background: The glenoid component in reverse total shoulder arthroplasty is recommended to be positioned inferiorly or with a downward tilt with the intention of reducing scapular notching. However, it is still unclear whether modifying the position of the glenoid Prosthesis affects implant stability. The aim of this study was to determine the association between implant positioning and glenoid Prosthesis fixation using Grammont reverse total shoulder arthroplasty. Methods: Four positions for the glenoid Prosthesis were studied using the finite element method. The glenosphere was positioned as follows: 1) in the middle of the glenoid fossa, 2) flush with the inferior glenoid rim, 3) with an inferior overhang, 4) with a 15° inferior inclination. Bone-Prosthesis micromotions and strain-induced Bone adaptations were quantified during five daily activities. Findings: When the glenoid component was tilted inferiorly, the activities producing anterior-posterior shear forces (e.g. standing up from an armchair) caused an increase in peak micromotions. In the lateral-middle glenoid, inferior positioning caused a 64.6% reduction in Bone apparent density. In the lateral-inferior glenoid, central positioning led to the most severe Bone resorption, reaching 43.9%. Interpretation: Reducing activities which generate anterior-posterior shear forces on the shoulder joint will increase Bone formation and may improve the primary stability of the implant when fixed in the position with an inferior tilt. Postoperative Bone resorption is highly dependent on implant positioning. Understanding the relationship between Bone resorption and implant positioning will help surgeons improve the long-term stability of reverse total shoulder arthroplasty.
Desmond Y R Chong - One of the best experts on this subject based on the ideXlab platform.
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finite element analysis of Bone Prosthesis interface micromotion for cementless talar component fixation through critical loading conditions
International Journal for Numerical Methods in Biomedical Engineering, 2020Co-Authors: Irwan Shah Bin Mohd Moideen, Chin Tat Lim, Raye Chen Hua Yeow, Desmond Y R ChongAbstract:The total ankle replacement (TAR) survivability rate is still suboptimal, and this leads to many orthopaedic surgeons opting arthrodesis as a better option for the ankle arthritis patients. One of the fundamental reasons is due to the lack of primary stability of the Prosthesis fixation at the Bone-Prosthesis interface hence leading to long-term aseptic loosening of the talar component. The commercially available Scandinavian Total Ankle Replacement (STAR) Ankle design and several additional design features (including trabecular metal, side fin, double fin, and polka-dot designs) were studied using finite element analysis, and the Bone-Prosthesis interface relative micromotion (BPIRM) and talar Bone minimum principal stresses were examined and analysed. Three loading conditions at a gait cycle of heel strike, midstance, and toe off with different meniscal bearing displacement were also included as part of the study parameters. The results were correlated to in vitro cadaveric measurements and reported clinical studies. Simulated results showed that the de-bonding relative distance between the Bone and Prosthesis upon loading (COPEN defined by the simulation software) was the main reason constituting to the high interface micromotion between the talar component and talus Bone (which could lead to long-term aseptic loosening). The polka-dot design was shown to induce the lowest BPIRM among all the designs studied.
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cementless mis mini keel Prosthesis reduces interface micromotion versus standard stemmed tibial components
Journal of Mechanics in Medicine and Biology, 2016Co-Authors: Ulrich Hansen, Desmond Y R Chong, Andrew A. AmisAbstract:Fixation strength of the cementless knee prostheses is dependent on the initial stability of the fixation and minimal relative motion across the Prosthesis–Bone interface. Broad mini-keels have been developed for tibial components to allow minimally invasive knee arthroplasty, but the effect of the change in fixation design is unknown. In this study, Bone–Prosthesis interface micromotions of the mini-keel tibial components (consisting of two designs; one is stemless and another with a stem extension of 45mm) induced by walking and stair climbing were investigated by finite element modeling and compared with standard stemmed design. The Prosthesis surface area amenable for Bone ingrowth for the mini-keel tibial components (both stemmed and unstemmed) was predicted to be at least 67% larger than the standard stemmed implant, thereby reducing the risk of long-term aseptic loosening. It was also found that while different load patterns may have led to diverse predictions of the magnitude of the interface micromotions and the extent of osseointegration onto the Prosthesis, the outcome of design change evaluation in cementless tibial fixations remains unchanged. The mini-keel tibial components were predicted to anchor onto the periprosthetic Bone better than the standard stemmed design under all loading conditions investigated.
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analysis of Bone Prosthesis interface micromotion for cementless tibial Prosthesis fixation and the influence of loading conditions
Journal of Biomechanics, 2010Co-Authors: Desmond Y R Chong, Andrew A. AmisAbstract:Abstract A lack of initial stability of the fixation is associated with aseptic loosening of the tibial components of cementless knee prostheses. With sufficient stability after surgery, minimal relative motion between the Prosthesis and Bone interfaces allows osseointegation to occur thereby providing a strong Prosthesis-to-Bone biological attachment. Finite element modelling was used to investigate the Bone–Prosthesis interface micromotion and the relative risk of aseptic loosening. It was anticipated that by prescribing different joint loads representing gait and other activities, and the consideration of varying tibial–femoral contact points during knee flexion, it would influence the computational prediction of the interface micromotion. In this study, three-dimensional finite element models were set up with applied loads representing walking and stair climbing, and the relative micromotions were predicted. These results were correlated to in-vitro measurements and to the results of prior retrieval studies. Two load conditions, (i) a generic vertical joint load of 3×body weight with 70%/30% M/L load share and antero-posterior/medial-lateral shear forces, acted at the centres of the medial and lateral compartments of the tibial tray, and (ii) a peak vertical joint load at 25% of the stair climbing cycle with corresponding antero-posterior shear force applied at the tibial–femoral contact points of the specific knee flexion angle, were found to generate interface micromotion responses which corresponded to in-vivo observations. The study also found that different loads altered the interface micromotion predicted, so caution is needed when comparing the fixation performance of various reported cementless tibial prosthetic designs if each design was evaluated with a different loading condition.
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Computational Biomechanical Analysis of Fixation Performance and Bone Resorption of Tibial Prosthesis Implantation
ASME 2009 Summer Bioengineering Conference Parts A and B, 2009Co-Authors: Desmond Y R Chong, Ulrich Hansen, Andrew A. AmisAbstract:Long-term survivorship of total knee replacement (TKR) relies on the periprosthetic Bone strength and its initial fixation stability. Aseptic loosening caused by mechanical factors is a recognised failure mode for knee prostheses. Bone resorption due to “stress-shielding” of the stiff stemmed implants will potentially lead to weakened Bone strength, and also presents a challenge for revision surgery. While the Bone cement is commonly used to provide mechanical attachment of the Prosthesis to the Bone, cement fatigue and Bone-cement interface failures would eventually lead to component migration and aseptic loosening of the tibial components. The cementless fixation relies on bony ingrowth into the porous surfaces of the Prosthesis thereby providing a biological attachment. Its fixation strength would depend largely on the initial stability of the fixation, where excessive Bone-Prosthesis relative motion (>50μm) would inhibit the osseointegration process [1]. The above are caused partly by a lack of knowledge of the optimum implant design and fixation technique factors.Copyright © 2009 by ASME
Torner Rubies Ferran - One of the best experts on this subject based on the ideXlab platform.
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Estudio mediante elementos finitos de prótesis tumorales de rodilla en niños y adolescentes
'Edicions de la Universitat de Barcelona', 2016Co-Authors: Torner Rubies FerranAbstract:INTRODUCCIÓN: Se considera a Ferguson (1861) el primer comunicante de una resección de rodilla, Verneuil (1863) el autor de la primera artroplastia de interposición y Gluck (1890) responsable de las primeras artroplastias protésicas. Los sarcomas óseos primarios en niños y adolescentes se localizan habitualmente alrededor de la rodilla, existiendo diferentes modelos comercializados de megaprótesis tumorales para pacientes jóvenes o niños esqueléticamente inmaduros. Los análisis de elementos finitos han sido progresivamente incorporados en el campo de la cirugía ortopédica y traumatología para el estudio de implantes de diversas formas y solicitaciones mecánicas. HIPÓTESIS DE TRABAJO: La diferente colocación del implante protésico endomedular y la posición de la rodilla, alteran la distribución de tensiones en el conjunto hueso-prótesis. OBJETIVOS DE LA TESIS: 1.- Realizar un modelo informático de prótesis total de rodilla con vástagos endomedulares largos dotada de constricción y estudiarla mediante un análisis de elementos finitos. 2.- Localizar las zonas de la prótesis total de rodilla y del hueso receptor donde se acumulan mayores tensiones. 3.- Demostrar que el centrado del vástago protésico en el canal medular modifica la transmisión de esfuerzos en el conjunto articular. 4.- Valorar si el grado de flexión de la rodilla modifica las tensiones sobre el conjunto Hueso-prótesis total de rodilla. 5.- Realizar una valoración clínica en pacientes menores de dieciocho años del comportamiento de las prótesis totales de rodilla tumorales. RESULTADOS: Estudio experimental: Los materiales más rígidos (metal) soportan una mayor tensión y los materiales más elásticos (plástico) presentan unas mayores deformaciones. El mayor nivel de tensión se produce en el extremo de la prótesis. Las magnitudes máximas de las deformidades que se producen en todas las piezas son similares, independientemente de si la prótesis está centrada, variando las tensiones en la parte metálica de la prótesis. Estudio clínico: Se han estudiado 14 casos de pacientes menores de 18 años portadores de artroplastia tumoral de rodilla. Patología: Osteosarcoma 12; Sarcoma de Ewing: 2 Afectación tumoral femoral/tibial: 8/6 Se han valorado los parámetros clínicos de dolor; arco de movilidad; marcha; utilización de escaleras y grado de satisfacción. CONCLUSIONES: 1.- Se ha obtenido un modelo informático de prótesis total de rodilla dotada de constricción, de vástagos endomedulares largos y ha sido estudiado mediante un sistema de análisis por elementos finitos. 2.- Del conjunto de materiales que componen la articulación protésica, aquellos que son más rígidos (materiales metálicos) soportan una mayor tensión, mientras que los más elásticos (materiales plásticos) presentan una mayor variación de deformaciones que alivian los esfuerzos recibidos. 3.- La parte crítica de la estructura hueso-prótesis es la sección en la que finaliza el vástago de la prótesis, ya que en ella se produce una fuerte variación en la rigidez, lo que conlleva un mayor nivel de tensiones. 4.- Las magnitudes máximas de las deformaciones que se producen en todas las piezas, independientemente que se encuentre la prótesis centrada o no, son similares, aunque sus distribuciones varían. 5.- En los materiales plásticos y en el fémur, no se aprecia una variación importante de tensiones por la diferente posición de la prótesis. Sin embargo, en la parte metálica de la prótesis descentrada sí que existen aumentos considerables de tensión. 6.- Las tensiones en el conjunto aumentan con el grado de flexión tanto si los vástagos protésicos están centrados como si no lo están. 7.- Los parámetros clínicos de dolor, arco de movilidad de la rodilla, marcha, utilización de escaleras y grado de satisfacción han presentado unos buenos resultados en la mayoría de los casos de artroplastias tumorales de rodilla en pacientes menores de dieciocho años al año de la intervención quirúrgica.Introduction Primary Bone sarcomas in children and adolescents are usually located around the knee. Different models of megaProsthesis are available for the treatment of young patients. Finite element analysis has been used to study implants in orthopedic surgery and traumatology. Hypothesis The different positioning of the intramedullary stem and the prosthetic knee position, modifies the stress distribution. Material and Methods experimental study: An finite element analysis of a knee Prosthesis in different position has been made. clinical study: We have studied 14 cases of patients under 18 years of age with knee megaProsthesis after knee tumor resection.(Osteosarcoma 12 patients; Ewing Sarcoma 2 patients). Conclusions 1. A computer model of constricted total knee Prosthesis with long intramedullary stems has been obtained and studied by a finite element analysis. 2. The more rigid materials (metallic materials) support greater tension, while the more elastic (plastics) have a greater variation of strain. 3. The critical part of the Bone-Prosthesis structure is located at the end of the Prosthesis stem. 4. Tensions increase with the degree of knee flexion in all models. 5. The clinical parameters of pain, range of knee motion, walking distance, use of stairs and satisfaction have shown good results in most cases of knee replacements in patients under eighteen year of age
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Estudio mediante elementos finitos de prótesis tumorales de rodilla en niños y adolescentes
'Edicions de la Universitat de Barcelona', 2016Co-Authors: Torner Rubies FerranAbstract:[spa] INTRODUCCIÓN: Se considera a Ferguson (1861) el primer comunicante de una resección de rodilla, Verneuil (1863) el autor de la primera artroplastia de interposición y Gluck (1890) responsable de las primeras artroplastias protésicas. Los sarcomas óseos primarios en niños y adolescentes se localizan habitualmente alrededor de la rodilla, existiendo diferentes modelos comercializados de megaprótesis tumorales para pacientes jóvenes o niños esqueléticamente inmaduros. Los análisis de elementos finitos han sido progresivamente incorporados en el campo de la cirugía ortopédica y traumatología para el estudio de implantes de diversas formas y solicitaciones mecánicas. HIPÓTESIS DE TRABAJO: La diferente colocación del implante protésico endomedular y la posición de la rodilla, alteran la distribución de tensiones en el conjunto hueso-prótesis. OBJETIVOS DE LA TESIS: 1.- Realizar un modelo informático de prótesis total de rodilla con vástagos endomedulares largos dotada de constricción y estudiarla mediante un análisis de elementos finitos. 2.- Localizar las zonas de la prótesis total de rodilla y del hueso receptor donde se acumulan mayores tensiones. 3.- Demostrar que el centrado del vástago protésico en el canal medular modifica la transmisión de esfuerzos en el conjunto articular. 4.- Valorar si el grado de flexión de la rodilla modifica las tensiones sobre el conjunto Hueso-prótesis total de rodilla. 5.- Realizar una valoración clínica en pacientes menores de dieciocho años del comportamiento de las prótesis totales de rodilla tumorales. RESULTADOS: Estudio experimental: Los materiales más rígidos (metal) soportan una mayor tensión y los materiales más elásticos (plástico) presentan unas mayores deformaciones. El mayor nivel de tensión se produce en el extremo de la prótesis. Las magnitudes máximas de las deformidades que se producen en todas las piezas son similares, independientemente de si la prótesis está centrada, variando las tensiones en la parte metálica de la prótesis. Estudio clínico: Se han estudiado 14 casos de pacientes menores de 18 años portadores de artroplastia tumoral de rodilla. Patología: Osteosarcoma 12; Sarcoma de Ewing: 2 Afectación tumoral femoral/tibial: 8/6 Se han valorado los parámetros clínicos de dolor; arco de movilidad; marcha; utilización de escaleras y grado de satisfacción. CONCLUSIONES: 1.- Se ha obtenido un modelo informático de prótesis total de rodilla dotada de constricción, de vástagos endomedulares largos y ha sido estudiado mediante un sistema de análisis por elementos finitos. 2.- Del conjunto de materiales que componen la articulación protésica, aquellos que son más rígidos (materiales metálicos) soportan una mayor tensión, mientras que los más elásticos (materiales plásticos) presentan una mayor variación de deformaciones que alivian los esfuerzos recibidos. 3.- La parte crítica de la estructura hueso-prótesis es la sección en la que finaliza el vástago de la prótesis, ya que en ella se produce una fuerte variación en la rigidez, lo que conlleva un mayor nivel de tensiones. 4.- Las magnitudes máximas de las deformaciones que se producen en todas las piezas, independientemente que se encuentre la prótesis centrada o no, son similares, aunque sus distribuciones varían. 5.- En los materiales plásticos y en el fémur, no se aprecia una variación importante de tensiones por la diferente posición de la prótesis. Sin embargo, en la parte metálica de la prótesis descentrada sí que existen aumentos considerables de tensión. 6.- Las tensiones en el conjunto aumentan con el grado de flexión tanto si los vástagos protésicos están centrados como si no lo están. 7.- Los parámetros clínicos de dolor, arco de movilidad de la rodilla, marcha, utilización de escaleras y grado de satisfacción han presentado unos buenos resultados en la mayoría de los casos de artroplastias tumorales de rodilla en pacientes menores de dieciocho años al año de la intervención quirúrgica.[eng] Introduction Primary Bone sarcomas in children and adolescents are usually located around the knee. Different models of megaProsthesis are available for the treatment of young patients. Finite element analysis has been used to study implants in orthopedic surgery and traumatology. Hypothesis The different positioning of the intramedullary stem and the prosthetic knee position, modifies the stress distribution. Material and Methods experimental study: An finite element analysis of a knee Prosthesis in different position has been made. clinical study: We have studied 14 cases of patients under 18 years of age with knee megaProsthesis after knee tumor resection.(Osteosarcoma 12 patients; Ewing Sarcoma 2 patients). Conclusions 1. A computer model of constricted total knee Prosthesis with long intramedullary stems has been obtained and studied by a finite element analysis. 2. The more rigid materials (metallic materials) support greater tension, while the more elastic (plastics) have a greater variation of strain. 3. The critical part of the Bone-Prosthesis structure is located at the end of the Prosthesis stem. 4. Tensions increase with the degree of knee flexion in all models. 5. The clinical parameters of pain, range of knee motion, walking distance, use of stairs and satisfaction have shown good results in most cases of knee replacements in patients under eighteen year of age
Jing Wang - One of the best experts on this subject based on the ideXlab platform.
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metal artifact reduction of orthopedics metal artifact reduction algorithm in total hip and knee arthroplasty
Medicine, 2020Co-Authors: Kesong Zhang, Qing Han, Hao Jiang, Yong Zhang, Kerong Yang, Bingpeng Chen, Jing WangAbstract:The purpose of this study was to investigate metal artifact reduction effect of orthopedics metal artifact reduction (O-Mar) algorithm in computer tomography (CT) image of patients who have undergone total hip arthroplasty (THA) or total knee arthroplasty (TKA).35 cases of patients who underwent TKA or THA have been recruited in this study. CT image of hip or knee joint was obtained with Philips 256-row CT scanner. Tube voltages of 120 and 140 kilovolt peak (KVP) were set. Afterwards, CT image was reconstructed by O-Mar algorithm to reduce metal artifact. Grade of image quality and severity of metal artifact would be taken into qualitative evaluation. While, quantitative evaluation mainly included measurement of metal artifact volume and 2D measurement of average CT value in region of interest (ROI). The visibility of interface between Bone-prostheses was also estimated.Result of qualitative analysis indicated that score of CT quality was improved and grade of metal artifact was decreased significantly with O-Mar. Quantitative analysis illustrated that volume of beam-hardening (B-H) metal artifact decreased remarkably after reconstruction of O-Mar (P < .001). In addition, O-Mar algorithm reduced 83.3% to 83.7% volume of photon-starvation (P-S) metal artifact. As for result of 2D measurement, CT value in ROI was closer to standard value in O-Mar group CT image (P < .001). Meanwhile, error of CT value also decreased significantly after reconstruction of O-Mar algorithm. Visibility rate of Bone-Prosthesis interface improved from 34.3% (Non-O-Mar) to 66.7% (O-Mar).O-Mar algorithm could significantly reduce metal artifact in CT image of THA and TKA in both 2D and three-dimensional (3D) level. Therefore, better image quality and visibility of Bone-prostheses interface could be presented. In this study, O-Mar was proved as an efficient metal artifact reduction method in CT image of THA and TKA.