15 results found
Villette C, Zhang J, Phillips A, 2020, Influence of femoral external shape on internal architecture and fracture risk, Biomechanics and Modeling in Mechanobiology, Vol: 19, Pages: 1251-1261, ISSN: 1617-7940
The internal architecture of the femur and its fracture behaviour vary greatly between subjects. Femoral architecture and subsequent fracture risk are strongly influenced by load distribution during physical activities of daily living. The objective of this work is to evaluate the impact of outer cortical surface shape as a key affector of load distribution driving femoral structure and fracture behaviour. Different femur cortical shapes are generated using a statistical shape model. Their mesoscale internal architecture is predicted for the same activity regime using a structural optimisation approach previously reported by the authors and fracture under longitudinal compression is simulated. The resulting total volume of bone is similar in all geometries although substantial differences are observed in distribution between trabecular and cortical tissue. Greater neck-shaft and anteversion angles show a protective effect in longitudinal compression while a thinner shaft increases fracture risk.
Villette CC, Phillips ATM, 2018, Rate and age-dependent damage elasticity formulation for efficient hip fracture simulations, Medical Engineering and Physics, Vol: 61, Pages: 1-12, ISSN: 1350-4533
Prediction of bone failure is beneficial in a range of clinical situations from screening of osteoporotic patients with high fracture risk to assessment of protective equipment against trauma. Computational efficiency is an important feature to consider when developing failure models for iterative applications, such as patient-specific diagnosis or design of orthopaedic devices. The authors previously developed a methodology to generate efficient mesoscale structural full bone models. The aim of this study was to implement a damage elasticity formulation representative of an elasto-plastic material model with age and strain rate dependencies compatible with these structural models. This material model was assessed in the prediction of femoral fractures in longitudinal compression and side fall scenarios. The simulations predicted failure loads and fracture patterns in good agreement with reported results from experimental studies. The observed influence of strain rate on failure load was consistent with literature. The superiority of a simplified elasto-plastic formulation over an elasto-brittle bone material model was assessed. This computationally efficient damage elasticity formulation was capable of capturing fracture development after onset.
Villette CC, Castilho M, Malda J, et al., 2017, Heterogeneous design optimisation of tissue engineering scaffolds: in-vitro assessment of a digital design framework, 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering, Publisher: Taylor & Francis, ISSN: 1025-5842
Villette CC, Phillips ATM, 2017, Microscale poroelastic metamodel for efficient mesoscale bone remodelling simulations., Biomechanics and Modeling in Mechanobiology, Vol: 16, Pages: 2077-2091, ISSN: 1617-7940
Bone functional tissue adaptation is a multiaspect physiological process driven by interrelated mechanical and biological stimuli which requires the combined activity of osteoclasts and osteoblasts. In previous work, the authors developed a phenomenological mesoscale structural modelling approach capable of predicting internal structure of the femur based on daily activity loading, which relied on the iterative update of the cross-sectional areas of truss and shell elements representative of trabecular and cortical bones, respectively. The objective of this study was to introduce trabecular reorientation in the phenomenological model at limited computational cost. To this aim, a metamodel derived from poroelastic microscale continuum simulations was used to predict the functional adaptation of a simplified proximal structural femur model. Clear smooth trabecular tracts are predicted to form in the regions corresponding to the main trabecular groups identified in literature, at minimal computational cost.
Villette CC, Phillips ATM, 2015, Informing phenomenological structural bone remodelling with a mechanistic poroelastic model, Biomechanics and Modeling in Mechanobiology, Vol: 15, Pages: 69-82, ISSN: 1617-7959
t Studies suggest that fluid motion in the extracellularspace may be involved in the cellular mechanosensitivityat play in the bone tissue adaptation process. Previously,the authors developed a mesoscale predictive structuralmodel of the femur using truss elements to represent trabecularbone, relying on a phenomenological strain-basedbone adaptation algorithm. In order to introduce a responseto bending and shear, the authors considered the use of beamelements, requiring a new formulation of the bone adaptationdrivers. The primary goal of the study presented herewas to isolate phenomenological drivers based on the resultsof a mechanistic approach to be used with a beam elementrepresentation of trabecular bone in mesoscale structuralmodelling. A single-beam model and a microscale poroelasticmodel of a single trabecula were developed. A mechanisticiterative adaptation algorithm was implemented based onfluid motion velocity through the bone matrix pores to predictthe remodelled geometries of the poroelastic trabeculaunder 42 different loading scenarios. Regression analyseswere used to correlate the changes in poroelastic trabeculathickness and orientation to the initial strain outputsof the beam model. Linear (R2 > 0.998) and third-orderpolynomial (R2 > 0.98) relationships were found betweenchange in cross section and axial strain at the central axis,and between beam reorientation and ratio of bending strainto axial strain, respectively. Implementing these relationships into the phenomenological predictive algorithm for themesoscale structural femur has the potential to produce amodel combining biofidelic structure and mechanical behaviourwith computational efficiency.
Villette CC, Phillips ATM, Zaharie DT, 2015, Frangible optimised lower limb surrogate for assessing underbelly blast injury, International Research Council on Biomechanics of Injury
Phillips ATM, Villette CC, Modenese L, 2015, Femoral bone mesoscale structural architecture prediction using musculoskeletal and finite element modelling, International Biomechanics, Vol: 2, Pages: 43-61, ISSN: 2333-5432
Through much of the anatomical and clinical literature bone is studied with a focus on its structural architecture, while it is rare for bone to be modelled using a structural mechanics as opposed to a continuum mechanics approach in the engineering literature. A novel mesoscale structural model of the femur is presented in which truss and shell elements are used to represent trabecular and cortical bone, respectively. Structural optimisation using a strain-based bone adaptation algorithm is incorporated within a musculoskeletal and finite element modelling framework to predict the structure of the femur subjected to two loading scenarios; a single load case corresponding to the frame of maximum hip joint contact force during walking and a full loading regime consisting of multiple load cases from five activities of daily living. The use of the full loading regime compared to the single load case has a profound influence on the predicted trabecular and cortical structure throughout the femur, with dramatic volume increases in the femoral shaft and the distal femur, and regional increases at the femoral neck and greater trochanter in the proximal femur. The mesoscale structural model subjected to the full loading regime shows agreement with the observed structural architecture of the femur while the structural approach has potential application in bone fracture prediction, prevention and treatment. The mesoscale structural approach achieves the synergistic goals of computational efficiency similar to a macroscale continuum approach and a resolution nearing that of a microscale continuum approach.
Villette CC, Phillips ATM, 2015, Predictive mesoscale structural modelling of bone informed by microscale poroelastic analyses, XXV congress of the International Society of Biomechanics
Zaharie D, Villette C, Phillips A, 2015, FRANGIBLE OPTIMISED LOWER LIMB SURROGATE FOR ASSESSING INJURY CAUSED BY UNDERBELLY BLAST, XV International Symposium on Computer Simulation in Biomechanics
Villette CC, Phillips ATM, Modenese L, 2014, Combined musculoskeletal and finite element predictive modelling of bone structure and simple fracture analysis, 12th international symposium on Computer Methods in Biomechanics and Biomedical Engineering
Villette CC, Phillips ATM, 2014, Towards a patient-specific combined musculoskeletal and finite element model of bone structure, 2nd UK Patient Specific Modelling Meeting - IPEM conferences
Villette CC, Phillips ATM, 2014, Combined finite element and musculoskeletal predictive structural modelling of the femur: Potential mechanobiology applications, 11th World Congress on Computational Mechanics
Villette CC, Phillips ATM, 2014, Combined predictive structural finite element and musculoskeletal modeling of bone structure for study of fracture under solid blast condition, IStructE Young Researchers' Conference
Prinold JAI, Villette CC, Bull AMJ, 2013, The influence of extreme speeds on scapula kinematics and the importance of controlling the plane of elevation, CLINICAL BIOMECHANICS, Vol: 28, Pages: 973-980, ISSN: 0268-0033
Villette CC, Phillips ATM, Modenese L, 2013, Combined Musculoskeletal and Finite Element Modelling of the Femur, XXIV Congress of the International Society of Biomechanics
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