步態站立期間後足足底軟組織不同層面之應力分佈探討

The Evaluation of Stress Distribution of the Different Layers in Rearfoot Plantar Soft Tissue during Stance Phase

劉奕奎(I-Kuei Liu)

指導教授 ： 陳文斌

中原大學/工學院/生物醫學工程學系/碩士(2008年)

https://doi.org/10.6840/cycu200900349

摘要

以解剖學的觀點而言，足跟脂肪墊可分為靠近皮膚表層較薄的微腔室及靠近跟骨較厚的大腔室。過去多數研究基於某些簡化假設或限制條件，往往將其視為單一結構及均質材料特性，鮮少針對人體步行時不同層面之力學行為進行探討。因此本研究之目的為使用有限元素法模擬正常步態後足著地至平貼期前之運動，探討後足底軟組織不同層面之力學行為。
研究方法為使用磁振造影系統擷取一健康成年男性右足影像，建構包含不同層面軟組織之右足三維六面體有限元素模型。配合軟組織荷重測量裝置結合超音波影像系統，測量不同層面軟組織之實際材料特性。透過動作分析系統及測力板，獲得實際之足部運動軌跡及地板反作用力。此外，以足底壓力量測實驗之結果，進行有限元素分析結果之驗證比較。
研究結果顯示，最大應力集中處位於跟骨內側粗隆周圍，約250KPa。此外，內部亦有高剪應力發生，約150 KPa。當足底軟組織受力時，主要之應變發生在大腔室，約佔總應變之90%；反觀，微腔室應變僅10%。因此，考量後足足底軟組織為一非均質複合式材料，不僅更能符合足底軟組織實際之受力情形，其應變與實際利用超音波影像系統所量測之結果亦為相近。本研究所提供足底受力之量化參數，可作為臨床上對於足部病變預防及治療之參考依據。

關鍵字

脂肪墊 ； 有限元素分析 ； 足底軟組織 ； 足部生物力學

並列摘要

Based on the anatomical definition, the human heel fat pad consists of the microchamber layer lying beneath the plantar skin and the macrochamber layer lying near the calcaneus. In previous studies, the heel pad is often considered as a simple structure with homogeneous material owing to some simplifications and limitations. There is few study investigated the biomechanical behavior of the heel pad with both the microchamber and macrochamber layers during human locomotion. Therefore, the purpose of this study was to evaluate the biomechanical behavior of the detailed plantar heel soft tissue structure during stance phase by finite element analysis.
In order to construct the detailed finite element model of the rearfoot, magnetic resonance imaging (MRI) system was used to capture the right foot images from a healthy male subject. A specially-designed loading device was integrated with an ultrasonic imaging system to measure the material properties of different plantar soft tissue layers as well. Motion analysis was performed to obtain the kinematic and kinetic data of the right foot of the same subject who received MRI scanning. Finally, the results from finite element analysis were compared with the data from plantar pressure measurement to verify the accuracy of computer simulation.
The result show that the maximum stress which concentrated around the medial calcaneal tuberosity was about 250 KPa. Moreover, there was a high shear stress of 150 KPa found in the inner soft tissue. About 90% of the heel fat pad strain was found in the macrochamber layer when the plantar soft tissue was subjected to loading. On the other hand, only about 10% of the heel fat pad strain was found in the microchamber layer. Therefore, when considering the plantar soft tissue as a nonhomogeneous material not only can present the realistic loading response of the plantar soft tissue, but also show similar strain results from both finite element analysis and experimental measurement. For this reason, the presented quantitative data in the current study can provide meaningful reference for the prevention and treatment of foot disease for clinical applications.

並列關鍵字

Heel pad ； Finite element analysis ； Plantar soft tissue ； Foot biomechanics

參考文獻

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