Zhang Jian-Feng, Hu Yong-Cheng, Wang Bao-Cang, Wang Lei, Wang Hui, Li Yong, Yan Ming, Liu Hong-Tao
Department of Osteopathy, The Second Hospital of Tangshan, Tangshan, China.
Department of Orthopaedic Oncology, Tianjin Hospital, Tianjin, China.
Orthop Surg. 2020 Jun;12(3):946-956. doi: 10.1111/os.12685. Epub 2020 May 7.
To evaluate the mechanical properties and provide a theoretical basis of a diaphyseal prosthesis with tooth mechanism using the finite element analysis method from the point of view of biomechanics.
A 3D digital femur model was generated based on a 28-year-old healthy man's femoral computed tomography (CT) data in Mimics 17.0 and the customized diaphyseal prostheses with/without tooth mechanism were designed in SolidWorks 2016. The 3D femur model after 8 cm osteotomy in the middle of its shaft and the prostheses with/without tooth mechanism was imported into Abaqus 2016 and the finite element analysis models were established. Three biomechanical tests (compression test, torsion test, and 3P-bending test) under broken load were simulated in FEA to evaluate the performance of the prostheses.
The stress distributions of the two prostheses were similar and the maximum von Mises stresses placed on them were very close in each test. The maximum von Mises stresses on the prosthesis with tooth mechanism were 31.55, 319.7, and 447.4 MPa, respectively, and those on the prosthesis without tooth mechanism were 26.26, 300.4, and 455.2 MPa, respectively, in the compression, torsion, and 3P-bending tests. The maximum von Mises stresses on them were far below the ultimate tensile strength or ultimate compressive strength of the titanium alloy.
The diaphyseal prosthesis with tooth mechanism is helpful to adjust the rotation of the long bone during operation. Compared with the conventional diaphyseal prosthesis (without tooth mechanism), the diaphyseal prosthesis with tooth mechanism also has a good biomechanical performance and does not increase the risk of prosthetic failure.
从生物力学角度，采用有限元分析方法评估带齿机构的骨干假体的力学性能并提供理论依据。
基于一名28岁健康男性的股骨计算机断层扫描（CT）数据，在Mimics 17.0中生成三维数字股骨模型，并在SolidWorks 2016中设计定制的带/不带齿机构的骨干假体。将股骨中段截骨8 cm后的三维股骨模型以及带/不带齿机构的假体导入Abaqus 2016中，建立有限元分析模型。在有限元分析中模拟三种在破坏载荷下的生物力学测试（压缩测试、扭转测试和三点弯曲测试），以评估假体的性能。
两种假体的应力分布相似，在每次测试中施加在它们上面的最大冯·米塞斯应力非常接近。在压缩、扭转和三点弯曲测试中，带齿机构假体上的最大冯·米塞斯应力分别为31.55、319.7和447.4 MPa，不带齿机构假体上的最大冯·米塞斯应力分别为26.26、300.4和455.2 MPa。它们上面的最大冯·米塞斯应力远低于钛合金的极限抗拉强度或极限抗压强度。
带齿机构的骨干假体有助于在手术过程中调整长骨的旋转。与传统的骨干假体（不带齿机构）相比，带齿机构的骨干假体也具有良好的生物力学性能，并且不会增加假体失败的风险。
