| Summary: | 碩士 === 國立成功大學 === 醫學工程研究所 === 87 === Severe bone density loss related to stress-shielding is one problem threatening the long-term integrity of total hip arthroplasty. Recently, quantitative bone-remodeling theories, based on the Wolff''s law, have been proposed. These theories integrated with finite element methods are suitable for use in computer-simulation models to investigate the long-term effect of the remodeling process. The purpose of this study was to develop a computer simulation procedure by finite-element methods combined with SED(Strain-Energy-Density) indexed remodeling rules. The models were used to predict the long-term results of the adaptive bone-remodeling process, and the simulation results were compared with clinical follow-up DEXA measurements. The procedure was also used to investigate the effect of mis-position of stem implantation, and to evaluate the difference of density distribution after long-term adaptive bone remodeling.
The simulation results indicated that the procedure could simulate the clinical bone-remodeling phenomenon (bone density was increased in the distal region and reduced in the proximal region). However, it still needs intensive study to understand the influence of the bone-remodeling parameters, and more efforts to decide the suitable values of these parameters for most people. Performing the quantitative comparison between the clinical follow-up DEXA measurement and the computer simulation, it found out that a device which could gain the bone density data more precisely should be used.
When implant position was varied, the interface strain of varus position was reduced, while the stress at medial side was increased. However, since the position variations were minor in this study, the distributions of bone density after long-term remodeling were almost identical.
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