动力髋螺钉固定股骨转子间骨折的有限元分析

目的研究后内侧骨折块对股骨转子间骨折动力髋螺钉(DHS)固定后的生物力学影响。方法利用股骨CT数据建立一组股骨近端的三维有限元模型,在此基础上制作股骨转子间骨折累及小转子和内侧骨皮质的骨折模型,对骨折模型进行DHS固定,并对DHS固定模型进行有限元分析。结果股骨转子间骨折累及单纯小转子骨折后,股骨内侧皮质应力和外侧DHS钢板所承受的应力大小无明显变化。当累及1/2内侧皮质时,内侧应力升高约28%,外侧DHS钢板所承受的应力升高约9%;当内侧皮质完全累及时,前内侧皮质的交界处应力升高约125%,外侧DHS钢板所承受的应力升高约96%。结论股骨转子间骨折伴单纯小转子骨折可以不予固定;而当内侧皮质累及时,无论是累及1/2还是累及全部内侧骨皮质,均需复位固定后内侧骨皮质。

Finite element analysis of the intertrochanteric fractures fixed with dynamic hip screw

Objective To research the biomechanical influence of posteriomedial fractures on the intertrochanteric fractures fixed with dynamic hip screw(DHS).Methods Three dimensional finite element models of intact and osteotomied proximal femurs were established from computerized tomographic(CT) scanning images,and finite element analysis was undertaken.Results The stress of the DHS endured and the medial femoral cortex was not significantly changed after isolated lesser trochanteric fracture.With half of the medial cortex involved,the stress of the DHS endured and the medial femoral cortex increased by 9% and 28%.When the entire medial cortex was involved,the stress of the DHS endured and the medial femoral cortex increased by 96% and 125%.Conclusions Intertrochanteric fractures with isolated lesser trochanteric fracture will not be fixed is safe.And when the medial cortex involved,both involving half of or involving entire medial cortex,need to restore the continuity of the cortex.