Haraguchi Ⅱ型后踝骨折两种内固定方式的生物力学研究

A biomechanical comparison of two types of internal fixation for posterior malleolar fracture

[目的]研究Haraguchi Ⅱ型后踝骨折两种内固定方式的生物力学特征,寻找最佳内固定方法,为临床应用提供基础理论依据。[方法]通过20具踝关节人工骨制作Haraguchi Ⅱ型后踝骨折模型,分别采用后踝空心钉+内踝空心钉(A组10具)和后踝重建钢板固定+内踝空心钉(B组10具)固定,进行生物力学实验应力分析。比较各组内固定方式的优劣性。[结果]应力强度、刚度、抗扭转力学性能、接触力学等一系列生物力学性能显示:B组与A组呈显著性差异(P<0.05),B组明显优于A组,而B组强刚度和应力水平均接近于正常组。[结论]Haraguchi Ⅱ型后踝骨折采用后踝重建钢板具有优越的生物力学性能,比后踝空心钉内固定方式更好,是一种比较理想的术式,对临床具有指导意义。

[ Objective ] To investigate the biomechanical characteristics of two type of internal fixations for posterior mal- leolar fractures of Haraguchi type Ⅱ , and to find out the better fixation procedure. [Method] Twenty-eight artificial ankle bone were divided into the trial group （n=20） and the normal control groups （n=8） . After making Haraguehi type Ⅱ posteri- or malleolar fracture models in the trial group, fracture was fixed with posterior cannular screw combined with medial eannular screw in 10 samples （the trial A group）, while posterior plate combined with medial cannular screw in the remaining lO sam- ples （the trial B group） . The biomechanieal tests were performed to find out the advantages and disadvantages of the two kinds of fixation. [Results] The trial B group was superior to the trial A group in stress intensity, stiffness, anti-torsional torque and contact property, with statistically significant difference in each parameter （P〈0.05） . Addiionally, the stress in- tensity and stiffness in the trial B group were much close to those in the normal control group. [Conclusion] For fixation of Haraguchi type Ⅱ posterior ankle fracture, posterior reconstructive plate has advantage in biomechanical properties over poste- rior eannular screw.