Xu Jia-Zhuang, Wannomae Keith K, Muratoglu Orhun K, Oral Ebru
Harris Orthopaedic Laboratory, Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts, 02114.
Polymer Science and Engineering, Sichuan University, Chengdu, China.
J Orthop Res. 2018 Jul;36(7):1860-1867. doi: 10.1002/jor.23835. Epub 2018 Jan 3.
Vitamin E stabilization successfully improved long-term oxidation resistance of wear-resistant ultra-high-molecular-weight polyethylene (UHMWPE) used for joint implants. Stabilization can be achieved by blending an antioxidant into the UHMWPE resin powder before consolidation and irradiation. Balancing the wear resistance and vitamin E content in the blend is the current challenge with this approach, because vitamin E hinders crosslinking of UHMWPE during irradiation, which decreases wear resistance. The vitamin E concentration in the blend is generally limited to less than 0.3 wt%. Wear- and oxidation-resistant UHMWPE has been obtained previously by consolidating blends of pre-irradiated UHMWPE powders (XPE) into an unmodified polyethylene matrix (PE), where the improvement in wear rate depended on the radiation dose and fraction of XPE. We hypothesized that increasing the vitamin E content in the unirradiated matrix would not compromise wear and would further improve the oxidative stability of XPE/PE blends. Pin-on-disk wear testing showed that the XPE/PE blends containing 0.1-1.0 wt% vitamin E in the matrix had comparable wear rates. We used an aggressive accelerated aging test in the presence of the pro-oxidant squalene and oxidation induction time (OIT) test and found that higher amounts of vitamin E resulted in stronger oxidation resistance for XPE/PE blends. The mechanical strength and toughness of the blends were not affected by changing the vitamin E content in the matrix. Stabilizing UHMWPE with higher vitamin E content may extend the service life of UHMWPE implants. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1860-1867, 2018.
维生素E稳定化成功提高了用于关节植入物的耐磨超高分子量聚乙烯（UHMWPE）的长期抗氧化性能。通过在固结和辐照前将抗氧化剂混入UHMWPE树脂粉末中可实现稳定化。平衡共混物中的耐磨性和维生素E含量是这种方法目前面临的挑战，因为维生素E会阻碍UHMWPE在辐照过程中的交联，从而降低耐磨性。共混物中维生素E的浓度通常限制在低于0.3 wt%。先前通过将预辐照的UHMWPE粉末（XPE）共混物固结到未改性的聚乙烯基体（PE）中获得了耐磨且抗氧化的UHMWPE，其中磨损率的改善取决于辐射剂量和XPE的比例。我们假设增加未辐照基体中维生素E的含量不会损害耐磨性，并且会进一步提高XPE/PE共混物的氧化稳定性。销盘磨损试验表明，基体中含有0.1-1.0 wt%维生素E的XPE/PE共混物具有相当的磨损率。我们在存在促氧化剂角鲨烯的情况下使用了激进的加速老化试验和氧化诱导时间（OIT）试验，发现较高含量的维生素E会使XPE/PE共混物具有更强的抗氧化性。共混物的机械强度和韧性不受基体中维生素E含量变化的影响。用更高含量的维生素E稳定UHMWPE可能会延长UHMWPE植入物的使用寿命。© 2017骨科学研究协会。由威利期刊公司出版。《矫形外科学研究》36:1860-1867，2018年。
