Nečas D, Vrbka M, Urban F, Gallo J, Křupka I, Hartl M
Faculty of Mechanical Engineering, Brno University of Technology, Czechia.
Faculty of Mechanical Engineering, Brno University of Technology, Czechia.
J Mech Behav Biomed Mater. 2017 May;69:66-74. doi: 10.1016/j.jmbbm.2016.12.018. Epub 2016 Dec 23.
The aim of the present study is to provide an analysis of protein film formation in hip joint replacements considering real conformity based on in situ observation of the contact zone. The main attention is focused on the effect of implant nominal diameter, diametric clearance and material. For this purpose, a pendulum hip joint simulator equipped with electromagnetic motors enabling to apply continuous swinging flexion-extension motion was employed. The experimental configuration consists of femoral component (CoCrMo, BIOLOX®forte, BIOLOX®delta) and acetabular cup from optical glass fabricated according to the dimensions of real cups. Two nominal diameters were studied, 28 and 36mm, respectively, while different diametric clearances were considered. Initially, a static test focused on the protein adsorption onto rubbing surfaces was performed with 36mm implants. It was found that the development of adsorbed layer is much more stable in the case of metal head, indicating that the adsorption forces are stronger compared to ceramic. A consequential swinging test revealed that the fundamental parameter influencing the protein film formation is diametric clearance. Independently of implant diameter, film was much thicker when a smaller clearance was considered. An increase of implant size from 28mm to 36mm did not cause a substantial difference in film formation; however, the total film thickness was higher for smaller implant. In terms of material, metal heads formed a thicker film, while this fact can be, among others, also attributed to clearance, which is more than two times higher in the case of ceramic implant.
本研究的目的是基于对接触区域的原位观察，对髋关节置换术中考虑实际贴合度的蛋白质膜形成进行分析。主要关注植入物标称直径、直径间隙和材料的影响。为此，采用了配备电磁电机的摆式髋关节模拟器，该模拟器能够施加连续的摆动屈伸运动。实验配置包括股骨部件（钴铬钼合金、BIOLOX®forte、BIOLOX®delta）和根据实际髋臼杯尺寸由光学玻璃制成的髋臼杯。分别研究了28毫米和36毫米两种标称直径，同时考虑了不同的直径间隙。最初，对36毫米植入物进行了一项侧重于蛋白质在摩擦表面吸附的静态测试。结果发现，在金属头的情况下，吸附层的形成要稳定得多，这表明与陶瓷相比，吸附力更强。随后的摆动测试表明，影响蛋白质膜形成的基本参数是直径间隙。与植入物直径无关，当间隙较小时，膜要厚得多。植入物尺寸从28毫米增加到36毫米并没有在膜形成方面造成实质性差异；然而，较小植入物的总膜厚度更高。就材料而言，金属头形成的膜更厚，而这一事实除其他因素外，也可归因于间隙，陶瓷植入物的间隙要高出两倍多。
