股骨颈骨折治疗中支持带的生物力学特点

Biomechanical characteristics of retinaculum in the treatment of femoral neck fractures

目的:研究股骨颈骨折治疗中支持带的生物力学特点。方法:通过1名75岁老年女性志愿者的CT数据,经过软件处理,构建完整股骨模型和骨折后3枚空心钉固定模型,并分为有支持带模型和无支持带模型,使用不同模型的Von-Mises力分布和模型位移差异分析其稳定性差异,研究支持带在股骨颈骨折治疗中的力学特点。结果:在完整股骨上,位移最明显部位出现在股骨头的负重区。有支持带模型位移为0.38137 mm,无支持带模型位移为0.38168 mm。Von-Mises力分布最集中的部位在股骨颈内下方,有支持带模型为11.80 MPa,无支持带模型为11.91 MPa。在骨折3枚空心钉内固定模型中,位移最明显部位同样出现在股骨头的负重区。有支持带模型位移为0.45727 mm,无支持带模型位移为0.45863 mm。Von-Mises力分布最集中位置在股骨颈内下方,有支持带模型为59.22 MPa,无支持带模型为59.14 MPa。对于空心钉,Von-Mises力峰值均出现在后上方空心钉,有支持带模型为107.48 MPa,无支持带模型为110.84 MPa。3枚螺钉中前上方螺钉Von-Mises力最小,在有支持带模型和无支持带模型分别为67.88 MPa和68.76 MPa。结论:完整的支持带对正常股骨和经解剖复位的股骨颈骨折内固定术后的稳定性作用小,不能有效提高骨折术后骨折端的稳定性。

Objective To investigate the biomechanical characteristics of retinaculum in the treatment of femoral neck fractures.Methods The CT data of a 75-year-old female volunteer was processed by software to construct an intact femur model and femoral neck fracture model fixed with three cannulated screws,which were divided into models with retinaculum or not.The Von-Mises stress distribution and displacement were compared to analyze the stability differences between the different models to study the mechanical characteristics of the retinaculum in the treatment of femoral neck fractures.Results In the intact femur,the most obvious displacement appeared in the weight-bearing area of the femoral head,with retinaculum 0.38137 mm,and without retinaculum 0.38168 mm.The most concentrated part of the Von-Mises stress distribution was located in the medial and inferior part of the femoral neck,with retinaculum 11.80 MPa,without retinaculum 11.91 MPa.In the femoral neck fracture fixed with three cannulated screws model,the most obvious position of displacement also appeared in the weight-bearing area of the femoral head,with retinaculum 0.45727 mm,without retinaculum 0.45863 mm.The most concentrated part of the Von-Mises located at the medical and inferior part of the femoral neck,with retinaculum 59.22 MPa,without retinaculum 59.14 MPa.For the cannulated screws,the Von-Mises force peaks all appeared in the posterior and superior screw,with retinaculum 107.48 MPa,without retinaculum 110.84 MPa.Among the three screws,the Von-Mises stress of the anterior-superior screw was the smallest,which was 67.88 MPa vs 68.76 MPa in the retinaculum and non-retinaculum groups,respectively.Conclusion The complete retinaculum has little effect on the stability of intact femur and femoral neck fractures with anatomical reduction after internal fixation,and cannot effectively improve the stability of the fracture end after the fracture.