形状记忆合金骑缝钉内固定在三关节融合术中的力学特性分析

Analysis of Mechanical Properties of Shape-Memory Alloy Staple Internal Fixation in Triple Arthrodesis Surgery

目的研究加压空心螺钉及形状记忆合金骑缝钉在三关节融合术内固定中的生物力学差异,为形状记忆合金骑缝钉的临床应用提供参考。方法选择1例重度僵硬型马蹄足患者的足部二维CT数据,通过Mimics和Geomagic软件构建三关节融合术后模型,并利用SolidWorks 2021软件建立三关节融合内固定几何模型;根据使用固定钉类型和组合方式(加压空心螺钉和形状记忆合金骑缝钉)分为A、B、C、D共4种固定方案;在ABAQUS软件中分析模拟中立位生理载荷下不同内固定方案模型的生物力学特性。结果方案D内固定模型距下、距舟、跟骰关节融合面端面最大位移均大于方案A、B、C;方案D内固定模型距舟关节、跟骰关节融合面内外侧位移之差分别为13.10%、13.60%,与其他3种固定方案相比融合面位移更接近于平行位移;方案D内固定模型距下、距舟、跟骰关节融合面最大von Mises应力均大于方案A、B、C。结论应用方案D(距舟关节和跟骰关节融合面使用骑缝钉内固定,距下关节融合面使用加压空心螺钉内固定)能够使三关节融合术后内固定融合面具有稳定性,并为其提供近似平行微动,产生适当的融合面应力使融合端面接触更紧密,促进骨痂生长,获得更佳的融合效果。

Objective To study the biomechanical differences between hollow compression screws and shapememory alloy staples in triple arthrodesis internal fixation and to provide references for the clinical application of shape-memory alloy staples.Methods Two-dimensional(2D)computed tomography(CT)foot data from a patient with severe horseshoe foot stiffness were selected,and a triple arthrodesis model was established using Mimics and Geomagic software.A geometric triple arthrodesis internal fixation model was established using SolidWorks 2021 software.Four fixation schemes(A,B,C,and D)were established according to the type and combination of fixed screws(hollow compression screws and shape-memory alloy riding nails).The biomechanical characteristics of models with different internal fixation schemes under neutral physiological loading were simulated and analyzed using ABAQUS software.Results The maximum end-face displacements of the fused surfaces of the talocalcaneal talonavicular and calcaneocuboid joints in the internal fixation model of scheme D were greater than those in schemes A,B,and C.The differences between the medial and lateral displacements of the fused surfaces of the talonavicular and calcaneocuboid joints in the internal fixation model of scheme D were 13.10%and 13.60%,respectively.The fused surface displacements were closer to the parallel displacements than those in the other three fixation schemes.The von Mises stresses were greater than those of schemes A,B,and C.Conclusions The application of scheme D(internal fixation at fusion surfaces of the talonavicular and calcaneocuboid joints with staples and at fusion surfaces of the talocalcaneal joints with compression hollow screws)provides stability at fusion surfaces of the internal fixation after triple arthrodesis surgery with near-parallel micromovement,which produces appropriate fusion stresses to make contact at the fusion end closer,promote the growth of bone scabs,and achieve better fusion results.