正常人與全膝關節置換病患在坐到站動作中膝關節韌帶之有限元素分析

Abstract

膝關節退化性關節炎，此疾病是因為關節面軟骨破壞，導致潤滑程度不夠，而骨頭互相摩擦使病患在行走時感到疼痛。目前治療膝關節軟骨退化性關節炎方法是進行全膝關節置換手術，手術過程必須將前十字韌帶切除。但是在膝關節缺少前十字韌帶的情形下，膝關節的被動穩定會受到影響。想要了解其影響度，就必須想辦法量測膝關節剩餘韌帶受力情形。量測方法有分侵入式量測法與非侵入式量測。這兩種量測技術都有其優缺點，但在這電腦普及的時代，利用建構模型採取有限元素分析的方法日益興盛。 本實驗室利用已經驗證過的有限元素分析流程應用在活體上，實驗方式利用電腦斷層掃瞄與核磁共振掃描重建膝關節模型，利用膝關節穩定器(KT-2000)關節取得韌帶材料性質，動態X光影像與電腦模型比對技術得到活體功能性動作的運動學資訊。本研究的實驗對象為正常人與全膝關節置換手術病患。在坐到站動作中透過本實驗室有限元素分析流程進行分析。透過正常人與全膝關節置換病患在前十字韌帶的差異，來探討在缺少前十字韌帶的情形。對於聚乙烯內襯厚薄的改變進行討論對全膝關節置換病患膝關節韌帶的影響。透過敏感度測試去探討，何種因素會影響有限元素分析結果。透過鬆弛度測試結果，再利用本研究定義的鬆弛度範圍去探討在坐到站瞬間的穩定度，並配合動作分析結果去探討在坐到站瞬間韌帶與肌肉如何去抵抗外力。 將本實驗室有限元素分析流程應用於活體實驗上，確實重現正常人與全膝關節置換病患在坐到站過程中的韌帶受力情形。敏感度測試結果顯示，在設定有限元素的邊界條件時，需多加注意在垂直軸上的位移與冠狀軸上的位移。鬆弛度測試結果顯示，全膝關節置換病患缺少前十字韌帶情況下，鬆弛度範圍比正常人平均值大。顯示全膝關節置換病患比正常人在坐到站瞬間較不穩定。 關鍵字：有限元素法、坐到站、全膝關節置換手術、人工膝關節、活體量測、退化性關節炎、敏感度測試、鬆弛度測試、鬆弛度範圍

Osteoarthritic knees is because the joint surface cartilage is destroyed, cause enough lubrication, and the bones rub against each other so that patients feel pain when walking. The treatment of osteoarthritis of the knee cartilage methods for total knee replacement surgery, the surgical procedure must be anterior cruciate ligament resection. However, in the case of the absence of the anterior cruciate ligament in knee, passive stability will be affected in knee. Want to understand the affect, we must think of a way to measure forces situation of residual ligaments in knee. The measurement method is divided into invasive measurement method and the non-invasive measurement. These two measurement techniques have their advantages and disadvantages, but in this era of widespread use of computers, finite element analysis method is burgeoning. The laboratory using validated finite element analysis process used in vivo experiment. Experiments using computer tomography and magnetic resonance imaging scanreconstruction knee model. Joint knee stability (KT-2000) obtain the ligament material properties. Dynamic X-ray images and computer models image registration obtain kinematics information in function of motion. Subjects are normal people and total knee replacement patients. Using laboratory finite element analysis process to analysis subjects in sit-to-stand. Through normal and total knee replacement patients anterior cruciate ligament differences to explore in the absence of the anterior cruciate ligament situation. Discuss the affects of total knee replacement patients that change insert thickness. Sensitivity tests to investigate the factors which will affect the results of finite element analysis. Through laxity test results, and then use the definition of stability in this study to explore the range of laxity in sit-to-stand, and with the results of the motion analysis to investigate ligaments and muscles how to resist external forces in instant of sit-to-stand. The laboratory will be used in finite element analysis process in vivo experiments, really reproduce ligaments forces of normal and total knee replacement patients during sit-to-stand. Sensitivity test results showed that the finite element in setting the boundary conditions, the need to pay more attention to the displacement in the vertical axis and coronal axis displacement. Laxity test results showed that total knee replacement patients lack the anterior cruciate ligament , the range of laxity more than mean of normal. Total knee replacement patients more unstable than normal in instant of sit-to-stand. Key Words: Finite element analysis, Sit to stand, Total knee replacement surgery, The in vivo measurement, Osteoarthritis, Sensitivity test, laxity test, range of laxity