A comprehensive approach to constructing human long bone models: From CT to FE.

摘要

Generic finite element (FE) bone models are valid for answering many general biomechanics questions, but additional research and clinical benefits can be obtained by models tailored to specific individuals. This thesis introduced a single comprehensive technique encompassing in vivo geometry and material properties with physiological loading conditions.;A semi-automated subject-specific (SASS) modeling technique was introduced for constructing in vivo knee bone geometry from computed tomography (CT) images. It improved upon current techniques to better capture the smooth natural curves and the thin cortex of the knee bones. The SASS method rapidly constructed the complex 3-D surface geometries with accuracy within 2 image pixel lengths. The geometry was complemented with personalized bone tissue properties that were both orthotropic and heterogeneous. The method uniquely modeled heterogeneity with bone groups based on similar density and location within the knee. The modeling of heterogeneity was optimized to produce accurate stress predictions with minimal computational time.;The technique also ensured that the model incorporated loading conditions representative of daily physical activities. Particular emphasis was placed on the inclusion of muscle and ligament forces, which was necessary to predict a more physiologically representative stress condition. A preliminary experimental verification was performed and showed promising results regarding the ability of the FE models to mimic the real bone.;Subject-specific models created using the SASS technique are an alternative to generic models as a research and clinical tool. The technique sets the stage for future use of subject-specific models in cross-sectional studies of knee prosthesis and fixation device design.