以有限元素法探討步態站立期間足底筋膜之生物力學行為

The Biomechanical Behavior of Plantar Fascia during Stance Phase of Gait Cycle - A Finite Element Analysis

陳政偉(Cheng-Wei Chen)

指導教授 ： 陳文斌 ； 鄧復旦

國立臺北科技大學/機電學院/機電整合研究所/碩士(2012年)

https://doi.org/10.6841/NTUT.2012.00047

摘要

足底筋膜是維持足弓穩定的重要組織，並提供足部所需的彈性，藉以消散活動時必須承載的衝擊能量。不正常負載或是重覆損傷可能導致足底筋膜炎的形成。根據過去的相關體外實驗可以發現在步態站立期間，足底筋膜上主要有兩個負載因素，其一為足部平貼期後自身重量承載；另一為足跟離地後期趾骨牽引足底筋膜產生的絞盤效應所導致。然而，該類研究結果僅為探討足底筋膜整體之受力，無法確切了解步態站立期間足底筋膜各區域承受負載的變化。因此，本研究以動態有限元素分析之方式，探討足底筋膜在步態站立期間的生物力學行為，以及其對於足部生物力學的影響。
本研究建立含完整足底筋膜之三維六面體有限元素足底模型，改善過去相關研究以樑元素代替足底筋膜的缺點，並給予其非線性之材料設定，使分析更接近實際的組織特性。此外，以本實驗室自行開發的軟組織力量位移探測裝置配合超音波影像系統，量測足底軟組織的機械性質，以提供有限元素模型更完整的材料參數。邊界條件的部分，則依據一般步行速度下步態實驗所獲得的運動學參數，作為有限元素分析之設定。
研究結果顯示，步態站立期間足底筋膜上負載分佈情形，後期足部推進階段受絞盤效應影響於足底筋膜與跟骨連接處，產生張力負載峰值1082.4N，且von Mises 應力分佈由內至外分別為15.58MPa 15.0 及11.42MPa，與臨床上常見發生足底筋膜炎位置相符。此研究分析結果，經過步態實驗之光球軌跡、地板反作用力及足壓實驗的驗證，可提供作為臨床治療足底筋膜炎以生物力學運動控制為治療策略的重要量化參考資訊。

關鍵字

足底筋膜炎 ； 步態站立期 ； 絞盤效應 ； 有限元素分析

並列摘要

The plantar fascia is an important soft tissue for stabilization of the foot arch. It can provide the flexibility to dissipate impact energy during gait cycle. Abnormal load or repeated injuries are the possible factors for plantar fasciitis. According to previous in vitro studies, there are two major loading factors causing plantar fasciitis during gait cycle. One is the weight-bearing load following the mid-stance phase of gait. The other is the windlass effect caused by phalanges winding the plantar fascia during heel rise and terminal period of gait. Although the loading on the plantar fascia during gait cycle
was revealed in previous in vitro study, it didn’t describe the magnitude and position of the loads applied on the plantar fascia. Therefore, the aim of the current study was to use dynamic finite element analysis to investigate the biomechanical behavior of the plantar fascia during stance phase of gait cycle, and it’s biomechanical effect on the
foot.
This study established a three-dimensional finite element foot model with complete plantar fascia structure, and the non-linear material properties of the soft tissues were
considered. This model was better than the models created in previous literature which used simple truss element to represent the plantar fascia. In addition, an in-house
material testing machine which integrated with ultrasonic graphic system was used to determine the material property of plantar soft tissue. The use of these non-linear
material properties could increase the accuracy of the simulation results. The loading and boundary conditions for the finite element analysis of the foot were adopted from the kinematic and kinetic data obtained from gait analysis.
The force and stress distributions on the plantar fascia during stance phase were obtained from the dynamic finite element analysis. Because of the windlass effect, a
tension force of 1082.4N was found near the junction of plantar fascia and calcaneus during push off. The peak von Mises stress distributions of plantar fascia were
15.58MPa, 15.0MPa and 11.42MPa from medial to lateral aspects of the foot, respectively. The location of the stress concentration on the plantar fascia was consistent with the commonly found locations of plantar fasciitis. The results of this study were validated by comparing the experimental kinematic data, ground reaction force, and plantar pressure distributions. These quantitative data can provide reference for clinicians who treat plantar fasciitis with the strategy of using biomechanical control on the footwear.

並列關鍵字

Plantar fascia ； Gait ； Windlass mechanism ； Finite element analysis

參考文獻

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