股骨為人類身上最粗的骨頭，當人在運動時其不只受到軸向壓力，也因為其解剖學形狀和周圍肌肉的影響，股骨也受彎曲作用。當股骨骨折時主要會使用鎖定式骨板進行治療，因此在骨折發生初期，患者的生活日常作動皆是以骨板來承載身體的重量，假若骨板設計上的缺陷、又或是外科醫師使用鎖定骨板方式時的方式不當，進而在長時間的走路或過度使用後而導致骨板發生疲勞破壞的情形，則患者將必須再次接受手術，導致痊癒時間的延遲。
本研究主要可以分為兩個部分，第一個是探討骨板設計之好壞，第二部分則是探討骨螺絲工作長度對骨板應力之影響，而這兩部份又分由兩個面向來判斷，分別是ANSYS有限元素模擬以及生物力學實驗測試。本研究以不同之骨折位置來探討骨板設計之優劣，並在不同骨折位置搭配上不同工作長度之螺絲打法來探討其對所對應的應力大小。
透過有限元素分析結果顯示，應力集中在螺絲洞上緣，且多數模型最大應力皆在骨折切口處，且研究發現骨板最弱處位在骨板最薄的位置。在機械實驗方面，較薄的骨板確實受到較大的應力，但位在骨幹中段的骨板應力卻是最大的。影響此結果的因素是由於位在股骨近端與中段之骨板有較長的力臂，故受力最大。在工作長度上，股骨遠端之骨折模型給予較長的工作長度有助於應力之降低，反之則不然，此現象可歸咎於骨板受力狀態的改變。

Femurs are the thickest bones in human bodies. When people are in motion, femurs suffer not only axial load, but also bending load due to its anatomical shape and surrounding muscles. When the femur fractures, the locking plate is mainly used for treatment. Therefore, the daily activities of the patient rely on the plate to carry the weight of the body after the occurrence of the bone fracture. However, if there is a defect in the design of the plate, or any locking method improperly, then the plate will under fatigued and damaged after frequently walking or excessively using. This may result in failure of the treatment and another operation will be needed once again.
There are two parts in this study. The first one is about the weak point of the plate, and the second is to investigate the effect of the different screw working length. The two parts are divided into ANSYS finite element simulation and biomechanics experimental test, respectively. In this study, different fracture positions are used to explore the advantages and disadvantages of plate design, and explore different working lengths with screws corresponding stress.
From the result of finite element analysis, the stress concentration is on the screw-hole edges, and most of the maximum stresses are near the fracture gap. It finds out that the weak point of the plate is the screw-hole edges at the thinnest part of the plate. In mechanical tests, although there is a great stress at the thinnest part of the plate, the maximum stress is at the screw-hole near the middle diaphysis. This is a result of a larger moment arm. In aspect of the working length, longer working length has a good effect at the distal fracture model, but goes worse at a proximal fracture. This comes to a result of a transform of loading.

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