股方肌骨瓣移植联合内固定治疗青壮年股骨颈骨折有限元分析

Finite Element Analysis of the Treatment of Femoral Neck Fracture in Young Adults with Quadratus Femoris Bone Flap Transplantation and Internal Fixation

目的应用有限元分析研究股方肌骨瓣移植联合内固定治疗青壮年股骨颈骨折的生物力学特性。方法选取1名健康青年志愿者的股骨原始CT数据,导入Mimics软件,模拟股骨颈骨折、股方肌骨瓣植入及空心钉置入,重建股骨近端三维有限元模型。在股骨头顶端轴向加载1000 N应力,比较空心钉分布(正三角、倒三角)、骨折部位位置(头下型、经颈型、基底型)、前倾角(+5°、+10°、0°、-5°、-10°)和颈干角(+5°、+10°、0°、-5°、-10°)分别不同时,内固定和股骨模型的应力峰值和应力集中点的区别。结果股骨和空心钉应力集中区域均分布于股骨颈及股骨干交界处的外侧皮质。倒三角空心钉的应力最小,峰值为(32.2±0.93)MPa;经颈型骨折的应力最小,峰值为(34.56±0.82)MPa;前倾角和颈干角为正常解剖角度的(对应模型中0°位)应力最小,峰值均为(34.56±0.82)MPa。结论股方肌骨瓣对股骨近端的力学变化影响很小,可以忽略;3枚空心钉的数量刚好,倒三角分布在力学特性和减少股骨头塌陷上好于其他形式;股骨正常的前倾角和颈干角应力最小。

Objective To study the biomechanical characteristics of quadratus femoris bone flap transplantation combined with internal fixation in the treatment of femoral neck fracture in young adults.Methods A three-dimensional finite element model of proximal femur was reconstructed by importing the original CT data of a healthy young volunteer into Mimics software to simulate the femoral neck fracture,quadratus bone flap implantation and cannulated screw placement.The stress of 1000 N was loaded axially on the top of femoral head to study the different distribution(positive triangle,inverted triangle),fracture position(inferior head type,transcervical type,basal type),anteversion angle(+5°,+10°,0°,-5°,-10°)and neck stem angle(+5°,+10°,0°,-5°,-10°)of hollow nails,and to compare the stress peak value and stress concentration point of internal fixation and femoral model.Results The stress concentration areas of femur and cannulated nail were distributed in the lateral cortex at the junction of femoral neck and femoral shaft.The stress of inverted triangle hollow nail is the lowest,the peak value was(32.2±0.93)MPa;the stress of fracture is the lowest,the peak value is(34.56±0.82)MPa;the stress of normal anatomic angle of anteversion and neck stem angle(corresponding to 0°position in the model)was the lowest,the peak value was(34.56±0.82)MPa.Conclusion The quadratus muscle bone flap has little effect on the mechanical changes of the proximal femur.The number of three hollow nails is just right and the inverted triangle distribution is better than other forms in the mechanical characteristics and reducing the collapse of the femoral head.The stress of normal anteversion and the neck shaft angle are the least.