Supplemental material, sj-pdf-1-pih-10.1177_09544119211011309 for Evaluation of mechanical proper... more Supplemental material, sj-pdf-1-pih-10.1177_09544119211011309 for Evaluation of mechanical properties of Ti-25Nb BCC porous cell structure and their association with structure porosity: A combined finite element analysis and analytical approach for orthopedic application by Soham Chowdhury, Amit Anand, Adhish Singh and Bidyut Pal in Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine
Finite element method was applied to model damage development in the femoral neck during a sidewa... more Finite element method was applied to model damage development in the femoral neck during a sideways fall. The femoral failure was simulated using the maximum principal strain criterion. The evolution of damage was consistent with previous studies. It was initiated by compressive failure at the junction of the superior aspect of the femoral neck and the greater trochanter. It was followed by tensile failure that occurred at the inferior aspect of the femoral neck before a complete transcervical fracture was observed. The estimated failure line was less than 50° from the horizontal plane (Pauwels type II).
Journal of Bone and Joint Surgery-british Volume, 2016
Revision knee prostheses are often augmented with intramedullary stems to provide stability follo... more Revision knee prostheses are often augmented with intramedullary stems to provide stability following bone loss. However, there are concerns with the use of such stems, including loosening caused by strain-shielding, end-of-stem pain, and removal of healthy bone surrounding the medullary canal. Extracortical fixation plates may present an alternative. The aim of the study was to quantitatively evaluate and compare strain-shielding in the tibia following implantation of a knee replacement component augmented with either a conventional intramedullary stem (design1), or extracortical plates (design2) on the medial and lateral surfaces. Eight composite synthetic tibiae were implanted with one of the two designs, painted with a speckle pattern, loaded in axial compression (peak 2.5 kN) using a materials test machine, and imaged with a 5-megapixel digital image correlation (DIC) system throughout loading. Bone loss was simulated in all models by removing a volume of metaphyseal bone. For ...
Journal of The Institution of Engineers (India): Series C, 2020
Biomechanical analysis, numerical and experimental, has been extensively used for more than 3 dec... more Biomechanical analysis, numerical and experimental, has been extensively used for more than 3 decades to investigate the mechanical behaviour of bone and implant–bone structures in joint replacement. In this review article, a detailed overview of the state-of-the-art techniques used for the development and pre-clinical testing of orthopaedic implants has been presented, with special focus on the hip-joint and hip implants. The efficacies of biomechanical analysis in analysing failure mechanisms in joint replacement, its clinical relevance, challenges and limitations, and future directions have been highlighted. Finite element (FE) modelling and analysis have contributed immensely towards testing of clinical hypotheses and evaluation of implant designs. Over the last few decades, the size and sophistication of the FE models have increased considerably. A critical analysis of the currently available subject-specific FE modelling techniques has been presented including, development of computed tomography-scan-based FE models of bone and implant, assignment of heterogeneous bone material properties, loading and boundary conditions. The relationship between stress–strain analysis and implant failure needs careful interpretation for clinical relevance. Verification and validation of these models are essential for assessing the validity of the predicted results. The salient features of adaptive simulations including bone remodelling and tissue differentiation and its prominence in investigating potential failure mechanisms and implant design evaluations have been discussed. The key considerations for design and development of orthopaedic implants have been suggested. It is envisaged that the FE simulations would be more holistic in nature, incorporating the complexities and variabilities of the clinical problems.
Journal of orthopaedic research : official publication of the Orthopaedic Research Society, 2017
Proximal femoral fractures can be categorised into two main types: neck and intertrochanteric fra... more Proximal femoral fractures can be categorised into two main types: neck and intertrochanteric fractures accounting for 53% and 43% of all proximal femoral fractures, respectively. The possibility to predict the type of fracture a specific patient is predisposed to would allow drug and exercise therapies, hip protector design and prophylactic surgery to be better targeted for this patient rendering fracture preventing strategies more effective. This study hypothesized that the type of fracture is closely related to the patient-specific femoral structure and predictable by finite element (FE) methods. Fourteen femora were DXA scanned, CT scanned and mechanically tested to fracture. FE-predicted fracture patterns were compared to experimentally observed fracture patterns. Measurements of strain patterns to explain neck and intertrochanteric fracture patterns were performed using a digital volume correlation (DVC) technique and compared to FE-predicted strains and experimentally observe...
Short-stem resurfaced femoral implant has been found to be a promising alternative to the long-st... more Short-stem resurfaced femoral implant has been found to be a promising alternative to the long-stem design, due to reduced risk of initial femoral neck fracture and more physiological load transfer. The clinical effect of metal ion release and continued concerns regarding the use of Metal-on-Metal bearing warrants an investigation of an alternative material, like ceramics, as a low-wear bearing couple. The objective of this study was to investigate the effect of a short-stem ceramic resurfacing implant, in comparison with the metallic design, with regard to stress-strain related failure mechanisms and bone adaptation. The maximum principal (tensile) stress in the ceramic implant, occurring at the stem-cup junction, was found to increase from 73 MPa at the post-operative condition to 86 MPa after bone remodelling. However, the tensile stresses generated in the cement mantle were low, around 3 MPa. The elevated bone strains occurring at the proximal femoral neck-cup junction region we...
Supplemental material, sj-pdf-1-pih-10.1177_09544119211011309 for Evaluation of mechanical proper... more Supplemental material, sj-pdf-1-pih-10.1177_09544119211011309 for Evaluation of mechanical properties of Ti-25Nb BCC porous cell structure and their association with structure porosity: A combined finite element analysis and analytical approach for orthopedic application by Soham Chowdhury, Amit Anand, Adhish Singh and Bidyut Pal in Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine
Finite element method was applied to model damage development in the femoral neck during a sidewa... more Finite element method was applied to model damage development in the femoral neck during a sideways fall. The femoral failure was simulated using the maximum principal strain criterion. The evolution of damage was consistent with previous studies. It was initiated by compressive failure at the junction of the superior aspect of the femoral neck and the greater trochanter. It was followed by tensile failure that occurred at the inferior aspect of the femoral neck before a complete transcervical fracture was observed. The estimated failure line was less than 50° from the horizontal plane (Pauwels type II).
Journal of Bone and Joint Surgery-british Volume, 2016
Revision knee prostheses are often augmented with intramedullary stems to provide stability follo... more Revision knee prostheses are often augmented with intramedullary stems to provide stability following bone loss. However, there are concerns with the use of such stems, including loosening caused by strain-shielding, end-of-stem pain, and removal of healthy bone surrounding the medullary canal. Extracortical fixation plates may present an alternative. The aim of the study was to quantitatively evaluate and compare strain-shielding in the tibia following implantation of a knee replacement component augmented with either a conventional intramedullary stem (design1), or extracortical plates (design2) on the medial and lateral surfaces. Eight composite synthetic tibiae were implanted with one of the two designs, painted with a speckle pattern, loaded in axial compression (peak 2.5 kN) using a materials test machine, and imaged with a 5-megapixel digital image correlation (DIC) system throughout loading. Bone loss was simulated in all models by removing a volume of metaphyseal bone. For ...
Journal of The Institution of Engineers (India): Series C, 2020
Biomechanical analysis, numerical and experimental, has been extensively used for more than 3 dec... more Biomechanical analysis, numerical and experimental, has been extensively used for more than 3 decades to investigate the mechanical behaviour of bone and implant–bone structures in joint replacement. In this review article, a detailed overview of the state-of-the-art techniques used for the development and pre-clinical testing of orthopaedic implants has been presented, with special focus on the hip-joint and hip implants. The efficacies of biomechanical analysis in analysing failure mechanisms in joint replacement, its clinical relevance, challenges and limitations, and future directions have been highlighted. Finite element (FE) modelling and analysis have contributed immensely towards testing of clinical hypotheses and evaluation of implant designs. Over the last few decades, the size and sophistication of the FE models have increased considerably. A critical analysis of the currently available subject-specific FE modelling techniques has been presented including, development of computed tomography-scan-based FE models of bone and implant, assignment of heterogeneous bone material properties, loading and boundary conditions. The relationship between stress–strain analysis and implant failure needs careful interpretation for clinical relevance. Verification and validation of these models are essential for assessing the validity of the predicted results. The salient features of adaptive simulations including bone remodelling and tissue differentiation and its prominence in investigating potential failure mechanisms and implant design evaluations have been discussed. The key considerations for design and development of orthopaedic implants have been suggested. It is envisaged that the FE simulations would be more holistic in nature, incorporating the complexities and variabilities of the clinical problems.
Journal of orthopaedic research : official publication of the Orthopaedic Research Society, 2017
Proximal femoral fractures can be categorised into two main types: neck and intertrochanteric fra... more Proximal femoral fractures can be categorised into two main types: neck and intertrochanteric fractures accounting for 53% and 43% of all proximal femoral fractures, respectively. The possibility to predict the type of fracture a specific patient is predisposed to would allow drug and exercise therapies, hip protector design and prophylactic surgery to be better targeted for this patient rendering fracture preventing strategies more effective. This study hypothesized that the type of fracture is closely related to the patient-specific femoral structure and predictable by finite element (FE) methods. Fourteen femora were DXA scanned, CT scanned and mechanically tested to fracture. FE-predicted fracture patterns were compared to experimentally observed fracture patterns. Measurements of strain patterns to explain neck and intertrochanteric fracture patterns were performed using a digital volume correlation (DVC) technique and compared to FE-predicted strains and experimentally observe...
Short-stem resurfaced femoral implant has been found to be a promising alternative to the long-st... more Short-stem resurfaced femoral implant has been found to be a promising alternative to the long-stem design, due to reduced risk of initial femoral neck fracture and more physiological load transfer. The clinical effect of metal ion release and continued concerns regarding the use of Metal-on-Metal bearing warrants an investigation of an alternative material, like ceramics, as a low-wear bearing couple. The objective of this study was to investigate the effect of a short-stem ceramic resurfacing implant, in comparison with the metallic design, with regard to stress-strain related failure mechanisms and bone adaptation. The maximum principal (tensile) stress in the ceramic implant, occurring at the stem-cup junction, was found to increase from 73 MPa at the post-operative condition to 86 MPa after bone remodelling. However, the tensile stresses generated in the cement mantle were low, around 3 MPa. The elevated bone strains occurring at the proximal femoral neck-cup junction region we...
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