重建钢板和Herbert螺钉内固定治疗锁骨中段骨折的有限元分析

Finite element analysis on reconstruction plate and Herbert cannulated screw fixation for midshaft clavicular fractures

目的通过有限元分析Herbert螺钉及重建钢板治疗锁骨中段骨折的生物力学特性,为临床应用提供科学依据。方法利用CT扫描数据,通过Mimics软件建立完整的锁骨三维有限元模型,锁骨中段骨折模型,根据锁骨中段骨折不同的内固定方式,分别建立锁骨中段骨折Herbert螺钉及重建钢板内固定的三维有限元模型,设定边界及载荷条件,评价Von Mises应力分布及位移情况。结果轴向载荷下锁骨远端轴向位移为正常锁骨模型(1.07 mm)>Herbert螺钉固定模型(0.35 mm)>重建钢板固定模型(0.30 mm),垂直载荷下锁骨远端垂直位移为正常锁骨模型(4.60 mm)>Herbert螺钉固定模型(2.09 mm)>重建钢板固定模型(1.29 mm)。轴向载荷锁骨最大应力为重建钢板固定模型(98.68 MPa)>Herbert螺钉固定模型(91.42 MPa)>正常锁骨模型(31.58 MPa);垂直载荷锁骨最大应力为Herbert螺钉固定模型(425.45 MPa)>重建钢板固定模型(202.62 MPa)>正常锁骨模型(141.00 MPa)。内置物最大应力,轴向载荷为重建钢板固定模型(206.56 MPa)>Herbert螺钉固定模型(195.96 MPa),垂直载荷为Herbert螺钉固定模型(752.28 MPa)>重建钢板固定模型(421.7 MPa)。结论 Herbert螺钉内固定治疗锁骨中段骨折,其微创内固定,且可获生物学固定,因此,对于简单移位的锁骨中段骨折采用Herbert螺钉内固定治疗是一种安全有效的固定方法。

Objective To analyze the biomechanical properties on midshaft clavicle fractures fixed by reconstruction plate and Herbert cannulated screw fixation through finite element(FE) analysis, and therefore to provide theoretic reference for clinical application. Methods A 3D FE model of the intact clavicle model and the midshaft clavicular fracture models with reconstruction plate and Herbert cannulated screw fixation were reconstructed using software Mimics based on the 3D CT images of the volunteer's clavicles. The models were compared under the same load conditions in terms of the maximum Von Mises stress of the clavicle and fixations and stress distribution. Results The axial displacement of the distal clavicle under the axial load showed intact clavicle model(1.07 mm) >Herbert model(0.35 mm) >reconstruction plate model(0.30 mm),respectively. While the vertical displacement of the distal clavicle under the vertical load was 4.60 mm for intact clavicle model, 2.09 mm for Herbert model and 1.29 mm for reconstruction plate model, respectively. But the peak stress of the clavicle under the axial load showed reconstruction plate model(98.68 MPa) >Herbert model(91.42 MPa)>intact clavicle model(31.58 MPa), respectively. And the peak stress under the vertical load was 425.45 MPa for Herbert model, 202.62 MPa for reconstruction plate model and 141.00 MPa for intact clavicle model, respectively. For the implants under the axial load, the peak stresses were 195.96 MPa, 206.56 MPa in the Herbert model and reconstruction plate model, respectively, and the peak stress on implants under the vertical load was 752.28 MPa in the Herbert model and 421.7 MPa in the reconstruction plate model, respectively. Conclusion Herbert cannulated screw and reconstruction plate fixation are appropriate for the midshaft clavicular fracture. Herbert screw internal fixation for the midshaft clavicular fracture is the minimally invasive internal fixation, and can achieve biological fixation. Therefore, the fixation appears to be a useful and effective manner for the treatment of the simple displaced fractures of midshaft clavicle.