Hidayat Taufiq, Ammarullah Muhammad Imam, Ismail Rifky, Saputra Eko, Lamura M Danny Pratama, K N Chethan, Bayuseno Athanasius Priharyoto, Jamari J
Department of Mechanical Engineering, Universitas Muria Kudus, Kudus 59352, Central Java, Indonesia.
Department of Mechanical Engineering, Universitas Diponegoro, Semarang 50275, Central Java, Indonesia.
World J Orthop. 2024 Apr 18;15(4):321-336. doi: 10.5312/wjo.v15.i4.321.
The four components that make up the current dual-mobility artificial hip joint design are the femoral head, the inner liner, the outer liner as a metal cover to prevent wear, and the acetabular cup. The acetabular cup and the outer liner were constructed of 316L stainless steel. At the same time, the inner liner was made of ultra-high-molecular-weight polyethylene (UHMWPE). As this new dual-mobility artificial hip joint has not been researched extensively, more tribological research is needed to predict wear. The thickness of the inner liner is a significant component to consider when calculating the contact pressure.
To make use of finite element analysis to gain a better understanding of the contact behavior in various inner liner thicknesses on a new model of a dual-mobility artificial hip joint, with the ultimate objective of determining the inner liner thickness that was most suitable for this particular type of dual-mobility artificial hip joint.
In this study, the size of the femoral head was compared between two diameters (28 mm and 36 mm) and eight inner liner thicknesses ranging from 5 mm to 12 mm. Using the finite element method, the contact parameters, including the maximum contact pressure and contact area, have been evaluated in light of the Hertzian contact theory. The simulation was performed statically with dissipated energy and asymmetric behavior. The types of interaction were surface-to-surface contact and normal contact behavior.
The maximum contact pressures in the inner liner (UHMWPE) at a head diameter of 28 mm and 36 mm are between 3.7-13.5 MPa and 2.7-10.4 MPa, respectively. The maximum von Mises of the inner liner, outer liner, and acetabular cup are 2.4-11.4 MPa, 15.7-44.3 MPa, and 3.7-12.6 MPa, respectively, for 28 mm head. Then the maximum von Mises stresses of the 36 mm head are 1.9-8.9 MPa for the inner liner, 9.9-32.8 MPa for the outer liner, and 2.6-9.9 MPa for the acetabular cup. A head with a diameter of 28 mm should have an inner liner with a thickness of 12 mm. Whereas the head diameter was 36 mm, an inner liner thickness of 8 mm was suitable.
The contact pressures and von Mises stresses generated during this research can potentially be exploited in estimating the wear of dual-mobility artificial hip joints in general. Contact pressure and von Mises stress reduce with an increasing head diameter and inner liner's thickness. Present findings would become one of the references for orthopedic surgery for choosing suitable bearing geometric parameter of hip implant.
构成当前双动人工髋关节设计的四个部件是股骨头、内衬、作为防止磨损的金属罩的外衬以及髋臼杯。髋臼杯和外衬由316L不锈钢制成。同时，内衬由超高分子量聚乙烯（UHMWPE）制成。由于这种新型双动人工髋关节尚未得到广泛研究，因此需要更多的摩擦学研究来预测磨损情况。在内衬厚度是计算接触压力时需要考虑的一个重要因素。
利用有限元分析更好地了解新型双动人工髋关节模型中不同内衬厚度下的接触行为，最终目标是确定最适合这种特定类型双动人工髋关节的内衬厚度。
在本研究中，比较了两种直径（28mm和36mm）的股骨头以及从5mm到12mm的八种内衬厚度。根据赫兹接触理论，使用有限元方法评估了包括最大接触压力和接触面积在内的接触参数。模拟在静态下进行，考虑了耗散能量和非对称行为。相互作用类型为表面到表面接触和法向接触行为。
在股骨头直径为28mm和36mm时，内衬（UHMWPE）中的最大接触压力分别在3.7 - 13.5MPa和2.7 - 10.4MPa之间。对于28mm直径的股骨头，内衬、外衬和髋臼杯的最大冯·米塞斯应力分别为2.4 - 11.4MPa、15.7 - 44.3MPa和3.7 - 12.6MPa。对于36mm直径的股骨头，内衬、外衬和髋臼杯的最大冯·米塞斯应力分别为1.9 - 8.9MPa、9.9 - 32.8MPa和2.6 - 9.9MPa。直径为28mm的股骨头应配备厚度为12mm的内衬。而当股骨头直径为36mm时，内衬厚度为8mm是合适的。
本研究中产生的接触压力和冯·米塞斯应力一般可用于估计双动人工髋关节的磨损情况。接触压力和冯·米塞斯应力随着股骨头直径和内衬厚度的增加而降低。目前的研究结果将成为骨科手术选择合适髋关节植入物轴承几何参数的参考之一。
