This thesis documents the development of a three-dimensional finite element model of the wrist. The model has been developed for the purpose of analysing load transmission pathways in the carpus during static loading in a neutral posture. The geometry for this model was obtained from a computed tomography (CT) scan.
The method of converting CT data to a finite element mesh involved a series of steps, several of which required approximations. The effect of these approximations on the final model geometry was not quantified. The steps involved in the geometry conversion utilized proprietary image thresholding software. CATIA™ 5.7. and ANSYS™ 6.0. Customized programs were used for file format conversions and for automating redundant tasks involving geometry manipulation.
The final stage of model development consists of the forearm bones and seven carpal bones: the pisiform is not included. Nonphysiologic constraint on the triquetrum and distal carpal bones was required to obtain solution convergence. The lunate and scaphoid were constrained by bone geometry and ligamentous connection. .Axial load was applied to the capitate to analyse contact patterns in the radius-scaphoid articulation.
Due to the developmental nature of this model not all of the parameters specified have been validated. Internal validation of some parameters indicates the potential for some specifications to cause large variability in contact pressures and compressive stresses in the cartilage elements. Suggestions are provided both for how to continue validating the specified parameters and for external validation of the model. Areas for further investigation and potential improvements to the modeling methods are also indicated.
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|1999||Li G, Gil J, Kanamori A, Woo SL-Y. A validated three-dimensional computational model of a human knee joint. J Biomech Eng. December 1999;121(6):657-662.|