股骨為人類身上最粗的骨頭，當人在站立或運動時，其不只受到軸向壓
力，也因為其解剖學形狀和周圍肌肉拉力的影響，股骨也受彎曲作用。鎖定式
骨板是目前主要治療方式，所以在骨折發生初期，患者行走、動作皆是以靠著
骨板來承載身體的重量。若是因骨板設計上的缺陷、又或是外科醫師對於鎖定
骨板方式的技術與知識有所不足，經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，其又可由
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；第二
部分則是探討骨螺絲工作長度對骨板應力之影響，此部分僅有生物力學實驗測
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骨幹中段之骨板有較長的力臂且其又位於股
骨解剖學上前彎之中點，故受力最大。在工作長度上，位置較低之骨折模型給
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 stand and move,
our femurs suffer not only axial load but also the bending load because of their
anatomical shapes and the muscles that pulling around. Nowadays locking plates are
the most popular treatments for the destruction of a femur. After the occurrence of the
bone fracture, the main support of the body weight when the patients stand and walk
all relies on the plate at the early stage of recovery. However if there is any
shortcoming of the plate design or any lack knowledge of the usage of the plates, the
plates will be broken under a fatigue load 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 a plate.
We use finite element analysis to infer the weakest part of a plate and then we validate
the result by biomechanical tests. In the second part, we investigate the effect of the
different screw working length only by biomechanical tests.
From the result of finite element analysis, the stress concentration is on the
screw-hole edges and most of the maximum stress 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 lever arm and the inferior bending of the bone. In aspect of the
working length, an longer working length has a good effect at the low fracture model,
but goes worse at a higher fracture. This comes to a result of a transform of loading.

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