- 學位論文
有限元素分析應用於建立扁平足模型
Application of Finite Element Analysis in the Establishment of Flatfoot Deformity Model
摘要
成人扁平足是一種常見的足踝結構逐漸退化疾病，保守治療失效時，需透過矯正手術解除病患的疼痛。但因目前對扁平足的變形與手術矯正的變化瞭解不夠透徹，醫師對最佳的手術方式仍意見分歧。目前臨床上使用二維X光影像分析評估，但足踝結構間的交互作用複雜，需以三維模型來評估與模擬才能更正確地指引臨床的治療。 本研究結合電腦斷層(Computerized tomography, CT)影像與影像處理軟體將63歲男性受試者的足踝CT影像進行三維重建，獲得足踝外型後將其匯入有限元素軟體ANSYS中，使用其CAD軟體加上軟骨使模型更真實，接著設定完邊界條件即可進行模擬，將模擬結果和足壓測力板結果進行模型驗證，確認模型的可行性。 通過模型驗證後，才可進行後續的分析，因為此模型為正常足的結果，本研究仿照真實大體標本創造扁平足的方式，對此模型進行扁平化的步驟，模擬成人扁平足發生的情況，最終目的為建出可使用的扁平足模型，可供醫師進行各種矯正手術的模擬評估，為病患選擇較適合的矯正手術方式。 參考臨床X光影像測量學，距骨和第一蹠骨夾角(Meary's angle)驗證扁平足模型，本研究取第一蹠骨和距骨的主軸夾角，將其投影到上視平面和側視平面進行分析比較，分析結果得知此模型達到成人扁平足變形程度，之後可以利用此模型進行切骨矯正手術分析，進行手術方式的優化。
並列摘要
Adult acquired flatfoot deformity is a common degenerative disease of the ankle structure. When conservative treatment fails, corrective surgery is required to relieve the patient's pain. However, the current understanding of the deformation of flatfoot and changes in surgical correction is not thorough enough, physicians still disagree on the best surgical method. Currently, two-dimensional X-ray image analysis and evaluation are used clinically, but the interaction between the foot and ankle structures is complex, and a three-dimensional model is needed for evaluation and simulation to guide clinical treatment more accurately. This study combined with computerized tomography image and image processing software were used to 3D reconstruct the CT image of the foot and ankle of a 63-year-old male subject. After obtaining the geometry of the foot and ankle, it was imported into the finite element software ANSYS. Using the CAD software to add cartilage makes the model more realistic, and then the simulation can be performed after setting the boundary conditions, and the simulation results and the results of the foot pressure force plate are verified by the model to confirm the feasibility of the model. After model validated, the subsequent analysis can be carried out. Because this model is the result of normal foot, this study imitated the way of creating flatfoot in real cadaver specimens. The steps of flattening this model to simulate the occurrence of adult flatfoot, the ultimate goal is building a flatfoot model that can be used. Doctors can perform a variety of corrective surgery simulation evaluations, and choose a more appropriate corrective surgery method for patients. With reference to clinical X-ray imaging survey, the flatfoot model was verified by the angle between the talus and the first metatarsal (Meary's angle). In this study, the angle between the main axis of the first metatarsal and the talus was taken and projected onto the superior and lateral views for analysis and comparison. The results showed that this model reached the adult flatfoot deformation, and then this model can be used to analyze osteotomy correction surgery and optimize the operation method.
參考文獻
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