1,720,985 research outputs found
Effect of cement-bone interface conditions on stresses in cemented all-polyethylene acetabular cups
No full textSimulation of a knee implanted with an interpositional spacer during a gait cycle using explicit finite element analysis
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Smooth surface micro finite element modelling of a cancellous bone analogue material
No full textTetrahedral finite element meshes with smooth surfaces can be created from computed tomography scans of cancellous bone in order to evaluate its mechanical properties. Image processing before creation of the mesh can affect the accuracy of determined mechanical properties. For a cancellous bone analogue, threshold, mesh density and surface smoothing parameters used in mesh generation were varied and the mechanical properties predicted by the resulting meshes compared to experimental results. This study has shown that threshold selection is vital for accurate determination of volume fraction and resulting mechanical properties. Smoothing of the surface also affects the local accuracy of the models
An ultrasound technique for monitoring polymerisation of acrylic bone cement
No full textThis paper describes a technique for monitoring polymerisation of acrylic bone cements by measuring changes in the characteristics of the transmission of ultrasound through the cement brought about by the polymerisation reaction. To the authors’ knowledge, this is the first time that a technique for the continuous monitoring of the mechanical properties of polymerising bone cement has been presented. The cement exhibits the expected behaviour of low modulus until approximately 300-450s from the time of mixing, after which a period of rapid polymerization occurs. In future work, we aim to extend the technique to allow simultaneous measurements of compressive and shear properties using a combined compression/shear wave transducer
Effect of hip stem taper on cement stresses
No full textThe aim of this study was to use finite element models to investigate the effect of the design of the taper of polished, collarless, total hip replacement femoral components on stresses in the cement mantle surrounding the component. A single-taper prosthesis, double-taper prosthesis, and triple-taper prosthesis were compared. Peak stresses and stress distributions in the cement mantle were found to be a function of taper design, although the differences between designs were minor. Using a probability of failure technique based on the initial cement stress distribution, a triple-taper prosthesis was predicted to cause less cement mantle damage (0.15% of the volume of the cement mantle failing after 20 million loading cycles) than a double-taper prosthesis (0.74%) or a single-taper prosthesis (1.50%). Further research is required to confirm this finding
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