不同骨强度下全膝置换过程中发生股骨前皮质切迹的三维有限元分析

Three-dimensional finite element analysis of anterior femoral notching during total knee arthroplasty at different bone strengths

背景:全膝关节置换后发生膝关节股骨假体周围骨折是常见并发症之一,目前对不同骨质强度条件下发生膝关节股骨假体周围骨折的生物力学研究欠缺,三维有限元分析可为临床提供生物力学基础。目的:探讨不同骨质强度下全膝关节置换过程中发生股骨前皮质切迹的生物力学变化,为临床预防膝关节置换后发生膝关节股骨假体周围骨折提供力学理论基础。方法:获取健康成年人的股骨CT数据,运用Mimics、Geomagic studio、Solidworks软件建立膝关节股骨侧置换三维模型,然后构建不同深度的股骨前皮质切迹模型,将模型导入到ANSYS软件并分析不同骨强度、不同股骨前皮质切迹深度对股骨髁上生物应力的影响,并分析股骨前皮质切迹骨水泥填补前、后的股骨前髁截面应力变化。结果与结论:①任何骨质强度下,髁上应力都随股骨前皮质切迹深度加深而增加;在正常骨质情况下,当股骨前皮质切迹深度在3 mm和4 mm间有一个应力突变点;在骨质疏松情况下,当股骨前皮质切迹深度在2 mm和3 mm间有一个应力突变点;②膝关节置换过程中发生股骨前皮质切迹且深度超过骨皮质厚度时,随着骨质强度降低,股骨髁上应力逐渐增大;③使用骨水泥填补股骨前皮质切迹深度为3 mm的模型,股骨前髁截面应力下降;④结果显示,膝关节置换过程中应该避免股骨前皮质切迹出现,特别是骨质疏松患者;如术中出现股骨前皮质切迹且深度超过骨皮质厚度时,可以采用骨水泥均匀填充股骨前皮质切迹以降低股骨髁上应力,降低膝关节股骨假体周围骨折的发生率。

BACKGROUND:Periprosthetic fracture of the femoral of the knee after total knee arthroplasty is one of the common complications,and there is a lack of biomechanical research on the periprosthetic fractures of the femoral of the knee under different bone strength conditions.The three-dimensional finite element analysis can provide a biomechanical basis for clinical practice.OBJECTIVE:To investigate the biomechanical changes of anterior femoral notching after total knee arthroplasty under different bone strengths,and to provide a mechanical basis for the clinical prevention of supracondylar femoral periprosthetic fractures after knee arthroplasty.METHODS:The femoral CT data of healthy adults were obtained,and the three-dimensional model of femoral lateral replacement of the knee joint was established by Mimics,Geomagic studio,and Solidworks software.Anterior femoral notching models of different depths were constructed,and the models were imported into ANSYS software to analyze the changes of biological stress on the femoral condyle with different bone strengths and different anterior femoral notching depths.The stress changes of the femoral anterior condyle section after and before the filling of anterior femoral notching with bone cement were analyzed.RESULTS AND CONCLUSION:(1)Under any bone strength,the supracondylar stress increased with the depth of anterior femoral notching.In normal bone conditions,there was a stress abrupt change point when the anterior femoral notching depth was between 3 mm and 4 mm.In the case of osteoporosis,there was a stress abrupt point when the anterior femoral notching depth was between 2 mm and 3 mm.(2)When anterior femoral notching occurred during knee arthroplasty and the depth exceeded the thickness of the bone cortex,the supracondylar stress of the femoral gradually increased as the bone strength decreased.(3)The stress of the anterior femoral condyle section decreased when the model with an anterior femoral notching depth of 3 mm was filled with bone cement.(4)The results show that anterior femoral notching should be avoided during knee arthroplasty,especially in patients with osteoporosis.If anterior femoral notching occurs during surgery,bone cement can be used to evenly fill the anterior femoral notching to reduce the supracondylar stress of the femur and reduce the incidence of periprosthetic fractures of the femoral joint.