钉道强化股骨近端防旋髓内钉治疗高龄SeinsheimerⅤ型股骨转子下骨折的有限元分析

Bone cement augmented proximal femoral anti-rotation nail for Seinsheimer type Ⅴ subtrochanteric femoral fractures in elderly:A finite element analysis

目的探讨骨水泥钉道强化股骨近端防旋髓内钉治疗高龄SeinsheimerⅤ型股骨转子下骨折的可行性。方法选取1名志愿者的CT资料导入Mimics 19.0和Geomagic studio 2017软件中进行提取、优化,得到右侧股骨三维模型;运用Solidworks 2017软件画出内固定模型并与股骨模型按照标准手术技术装配,以STEP格式导入Hypermesh14.0软件中截骨得到SeinsheimerⅤ型普通股骨近端防旋髓内钉股骨转子下骨折模型,将螺旋刀片近端周围松质骨重新定义为骨水泥,得到钉道强化股骨近端防旋髓内钉模型。设置材料属性参数、边界条件、施加载荷,分别储存为K文件导入LS-DYNA软件求解。结果(1)与普通PFNA模型相比,钉道强化PFNA模型螺旋刀片基本无切割,头颈骨块的内翻和旋转角度较小,虽然局部应力稍大,但整体更趋稳定;(2)骨水泥强大的锚固力能稳定螺旋刀片,增强三点支撑的内侧作用点,并能传导、分散压力。结论与普通股骨近端防旋髓内钉相比,钉道强化股骨近端防旋髓内钉治疗高龄SeinsheimerⅤ型股骨转子下骨折可以有效减少头颈骨块内翻的旋转,避免螺旋刀片切割,更趋稳定。

Objective To investigate the feasibility of bone cement augmented proximal femoral anti-rotation nail in the treatment of Seinsheimer type Ⅴ subtrochanteric fractures in the elderly.Methods The CT data of one volunteer was imported into Mimics 19.0 and Geomagic studio 2017 to extract and optimize the 3D model of the right femur.Draw internal fixation model and assembled with femur model according to the standard operation technology,then imported into Hypermesh 14.0 software to simulating Seinsheimer type Ⅴ subtrochanteric fractures.The cancellous bone around the proximal helical blade was redefined as bone cement,obtaining bone cement augmented proximal femoral anti-rotation nail model.The material property parameters,boundary conditions,and applied loads were set and imported into LS-DYNA software for solution.Results(1)Compared with the common proximal femoral anti-rotation nail model,the helical blade of the bone cement augmented proximal femoral anti-rotation nail model had no cutting,and the varus and rotation angle of the head and neck bone block was smaller.Although the local stress was slightly larger,the whole was more stable.(2)The strong anchoring force of bone cement can stabilize the helical blade,improve the inner action point of the three-point support,and transmit and disperse the pressure.Conclusion Compared with the common proximal femoral anti-rotation nail,the bone cement augmented proximal femoral anti-rotation nail could effectively reduce the varus rotation of the head and neck bone block in the treatment of Seinsheimer type Ⅴ subtrochanteric fractures in elderly patients,avoid the cutting of the spiral blade,and offer enhanced stability.