低弹性模量新型组合式锁定加压钢板固定股骨粉碎性骨折的三维有限元分析

目的 通过有限元分析的方法观察低弹性模量Ti2448的新型组合式锁定加压钢板(NALCP)固定股骨粉碎性骨折的应力分布情况。方法 采用64排螺旋CT对1名健康成年男性股骨进行层厚为5 mm(拆薄图像层厚0.625 mm)扫描,获得股骨CT数据,通过Mimics 10.0、Geomagic studio 12.0等逆向工程软件获得股骨有限元模型,模拟股骨中段粉碎性骨折,分别采用Ti-6Al-4V(普通弹性模量,为110 GPa)及Ti2448(低弹性模量,为30 GPa)两种弹性模量方案钢板模拟手术固定,加以缓慢行走单腿股骨载荷及扭转载荷,分析两种弹性模量钢板及股骨的应力分布情况。结果 两种载荷情况下,两种固定方案钢板应力分布变化趋势均匀,骨折断端周围为应力集中区域,最大应力集中点位置均位于滑槽钢板与主钢板锁定孔,两种方案主钢板应力变化不大。与Ti-6Al-4V钢板方案相比,Ti2448滑槽钢板最大应力在缓慢行走载荷和扭转载荷下分别减少了20.6%和15.2%,而骨折块轴向最大应力则分别增加了95.8%和95.7%。 结论 低弹性模量NALCP既能够为股骨干32-C2.1型骨折提供坚强的力学稳定性,又能增加骨折断端力学刺激,并能有效固定骨碎块。

Finite element analysis of new design assembly locking compression plate with low modulus titanium alloy in the treatment of middle femoral comminuted fracture

Objective To explore the stress distribution of new design assembly locking compression plate (NALCP) with different modulus in the treatment of middle femoral comminuted fracture by finite element analysis (FEA). Methods A male volunteer received CT scanning with 0.625 mm slice thickness. The CT data was converted to middle femoral comminuted fracture FEA model by Mimics, Geomagic studio 12.0, etc. The femoral fracture was fixated by Ti-6Al-4V (high modulus group, E=110 GPa) and Ti2448 (low modulus group, E=30 GPa) respectively, and loads were applied on the three models to simulate a person slowly walking by one leg or torsion. The stress distribution of the plate and bone was observed. Results In two conditions, the stress distribution tendency of the three kinds of plates was uniformity roughly. The maximum stress was situated in the locking-hole which links the main plate and the runner plate. The stress forces of the main plate in two groups were almost the same. In two conditions of slow walking by one leg or torsion, compared with group Ti-6Al-4V, the maximum stress of runner plate in group Ti2448 were reduced 20.6% and 15.2%, and the axial maximum stress of the bone block were increased 95.8% and 95.7%. Conclusions NALCP with low modulus titanium alloy would provide adequate mechanical stability and stress stimulation, which would apt to fixate the bone block.