Jakubowitz Eike, Liehn Louisa, Jahnke Alexander, Wöstmann Bernd, Rickert Markus, Niem Thomas
Laboratory for Biomechanics and Biomaterials (LBB), Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, 30628 Hannover, Germany; Laboratory of Biomechanics, Department of Orthopaedics, Justus-Liebig-University, Paul-Meimberg-Strasse 3, 35392 Giessen, Germany.
Laboratory of Biomechanics, Department of Orthopaedics, Justus-Liebig-University, Paul-Meimberg-Strasse 3, 35392 Giessen, Germany.
J Mech Behav Biomed Mater. 2017 May;69:57-65. doi: 10.1016/j.jmbbm.2016.12.011. Epub 2016 Dec 21.
Aseptic loosening at alloy-cement interfaces constitutes a main failure mechanism of cemented total hip replacements (THR). As a potential solution we investigated the effect of metal primers containing phosphoric and phosphonic acid on shear bond strength (SBS) of bone cement to THR alloys (CoCrMo, TiAlNb) and pure tin (Sn) substrates (20×8×3 mm). Metal surfaces were modified by polishing or AlO blasting and primer application. Substrates without primer treatment served as references. Cylindrical cement pins (Ø 5mm) were polymerised onto substrate surfaces and aging (1, 5, 14 and 150 days) was simulated in aqueous NaCl solution (0.9%) before SBS determination and failure mode evaluation. Regardless of surface roughness and aging time, SBS for THR alloys and Sn was always significantly higher with primer treatment. Compared to untreated reference specimens (≤0.2MPa) SBS values increased even up to 350 fold (TiAlNb, 14 days) or 400 fold (CoCrMo, 5 days). In general, the phosphoric acid containing primer revealed significant higher SBS values on THR alloys compared to the phosphonic acid containing one. AlO blasted specimens showed generally higher SBS values than polished ones with the exception of Sn which showed high SBS values in general. With primer treatment on polished Sn a significant reduction of SBS could not be detected even up to 150 days, whereas THR alloys showed only an SBS improvement in the short term (≤14 days). A NaCl-pitting corrosion probably led to an increasing and durable SBS on polished Sn surfaces over time. Compared to modern THR in clinical practice that shows survival rates of 10, 15, 20 or more years, the receivable bond strength enhancements described in this study appeared to be very short. The improved SBS on THR alloys lasted only a few days before it was lost again. In contrast, the phosphoric acid primer treatment of polished Sn appeared to be very promising and may play a key role in further investigations dealing with the prevention of the stem-cement debonding in THR.
合金 - 骨水泥界面处的无菌性松动是骨水泥型全髋关节置换术（THR）的主要失效机制。作为一种潜在的解决方案，我们研究了含磷酸和膦酸的金属底漆对骨水泥与THR合金（钴铬钼合金、钛铝铌合金）以及纯锡（Sn）基底（20×8×3毫米）之间剪切粘结强度（SBS）的影响。通过抛光或氧化铝喷砂处理以及涂覆底漆来对金属表面进行改性。未进行底漆处理的基底作为对照。将圆柱形骨水泥销（直径5毫米）聚合到基底表面，并在测定SBS和评估失效模式之前，在0.9%的NaCl水溶液中模拟老化（1天、5天、14天和150天）。无论表面粗糙度和老化时间如何，经底漆处理后，THR合金和Sn的SBS总是显著更高。与未处理的对照样本（≤0.2MPa）相比，SBS值甚至提高了350倍（钛铝铌合金，14天）或400倍（钴铬钼合金，5天）。总体而言，与含膦酸的底漆相比，含磷酸的底漆在THR合金上显示出显著更高的SBS值。除了Sn总体上显示出高SBS值外，氧化铝喷砂处理的样本通常比抛光样本具有更高的SBS值。对于抛光的Sn进行底漆处理，即使长达150天也未检测到SBS有显著降低，而THR合金仅在短期内（≤14天）显示出SBS的提高。随着时间的推移，NaCl点蚀腐蚀可能导致抛光Sn表面的SBS不断增加且持久。与临床实践中显示10年、15年、20年或更长时间生存率的现代THR相比，本研究中所述的可接受的粘结强度增强似乎非常短暂。THR合金上提高的SBS仅持续了几天就再次丧失。相比之下，对抛光Sn进行磷酸底漆处理似乎非常有前景，并且可能在进一步研究预防THR中柄 - 骨水泥脱粘方面发挥关键作用。
