踇外翻微创截骨术后绷带和克氏针固定截骨端生物力学的三维有限元分析

Three-Dimensional finite element analysis of biomechanics of osteotomy ends after minimally invasive hallux valgus osteotomy with bandage and Kirschner wire fixation

目的研究绷带和克氏针固定微创截骨术后截骨端最大位移及应力分布情况,以及克氏针的最大应力及分布情况。方法招募1位轻中度踇外翻患者,通过其足部CT图像建立踇外翻三维有限元模型,经三维有限元技术模拟微创截骨后绷带和克氏针固定,分析固定术后足部跖屈位截骨端最大位移及应力分布情况。结果绷带固定截骨端最大等效应力为7.8615 MPA,克氏针固定截骨端最大等效应力为14.253 MPA。绷带固定截骨端总位移为0.26896 mm,克氏针固定截骨端总位移为0.022779 mm。克氏针在截骨端附近的最大应力高达154.7 MPa。结论克氏针固定较绷带固定能更好维持截骨断端稳定性,但绷带固定也符合骨折二期愈合理论,对断端愈合无不利影响。克氏针本身存在应力集中现象,有潜在断裂风险。

Objective To analyze the maximum displacement and stress distribution of osteotomy ends after minimally invasive osteotomy with bandage and Kirschner wire fixation,as well as the maximum stress and distribution of the wire.Methods A patient with mild-to-moderate hallux valgus was recruited and a three-dimensional finite element model was established by CT images of his foot.The maximum displacement and stress distribution of the osteotomy end in the plantar flexion of the foot were analyzed by three-dimensional finite element simulation.Results The maximum equivalent stress at the osteotomy end fixed with bandage and Kirschner wire was 7.8615MPa and 14.253MPa,respectively.The total displacement of osteotomy end fixed with bandage and Kirschner wire was 0.26896mm and 0.022779mm,respectively.The maximum stress of Kirschner wire near the osteotomy end was 154.7MPa.Conclusion Kirschner wire fixation is better than bandage fixation in maintaining the stability of the osteotomy fracture,but bandaging fixation also achieves secondary fracture healing without a negative influence on fracture healing.The stress concentration of Kirschner wire itself has a potential fracture risk.