鈦合金骨釘骨板內鎖機構的冷焊(cold welding)問題是常常需要注意的情形。而亂牙(cross-threading)是造成需要強制破壞骨板以取出骨釘的主因之一。造成冷焊的力學指標是材料的塑性變形。造成塑性變形的幾項問題主因設計上的差異使骨釘的拉壓與剪切應力分佈的不同。本研究使用有限元素分析對骨釘骨板內鎖機構以Von Mises應力分析做初步的調查，分析四種不同介面的骨釘骨板機構之塑性變形情況。最後就植入後之骨板在人體內內部應力與變形狀態與文獻做比較。 The mechanical failure induced by the cold welding of the titanium-based material was one of the major concerns of the plate-screw system with the interlocking mechanism. One of the factors attributed to such the problem was the cross threading at the screw-plate junction. The cross threading was the interference between the threads of both screw and plate and then induced the plastic yielding. This study utilized the finite-element method to investigate the effect of the interlocking mechanism on the stress distribution at the screw-plate junction and to investigate the plastic deformation in four kinds of the interlocking mechanism. Finally, we compare the stress distribution and the state of deformation between bone plate which is computed by SolidWorks with the reference.
