Division of Science for Joint Reconstruction, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan; Sensory & Motor System Medicine, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Acta Biomater. 2019 Mar 1;86:338-349. doi: 10.1016/j.actbio.2018.12.025. Epub 2018 Dec 25.
Although laboratory tests and mid-term clinical outcomes show the clinical safety and remarkable wear resistance of the highly cross-linked polyethylene (HXLPE) acetabular liner with a nanometer-scaled graft layer of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), the wear resistance of the layer under severe abrasive conditions is concerning. We evaluated the effects of a roughened femoral head and the grafting locus on the wear resistance of the PMPC-grafted HXLPE liner and the effect of PMPC grafting on wear resistance of the HXLPE substrate by removing the PMPC-grafted layer using a severely roughened femoral head. Against a moderately roughened femoral head, the PMPC-grafted HXLPE liner showed negative wear, although an untreated HXLPE liner increased the wear by 154.1% compared with wear against a polished femoral head, confirming that PMPC grafts were unaffected. Against a severely roughened femoral head, the PMPC-grafted layer of the head contact area might be removed under severe conditions. However, the wear rate was reduced by 52.5% compared to that of untreated HXLPE liners. Moreover, the head non-contact area-modified PMPC-grafted HXLPE liner against a polished femoral head reduced the wear by 76.8% compared with untreated HXLPE liner; thus, this area may be also important in the development of fluid-film lubrication. STATEMENT OF SIGNIFICANCE: Here we describe effects of a roughened femoral head and the locus of grafting on the wear-resistance of the phospholipid polymer grafted highly cross-linked polyethylene (PMPC-HXLPE) liner. Against a moderately roughened femoral head, the PMPC-HXLPE liner showed negative wear, confirming that PMPC grafts were unaffected. After removing the PMPC layer of the head contact area using a severely roughened femoral head, the wear rate not only exceeded that of untreated HXLPE liners, but was reduced by 52.5%, confirming that PMPC grafting does not affect the wear-resistance of the HXLPE substrate. In addition, the head non-contact area-modified PMPC-HXLPE liner reduced the wear by 76.8%. Thus, this area may also may be important in the development of fluid-film lubrication.
尽管实验室测试和中期临床结果表明，具有纳米级聚（2-甲基丙烯酰氧基乙基磷酸胆碱）（PMPC）接枝层的高度交联聚乙烯（HXLPE）髋臼衬垫具有临床安全性和显著的耐磨性，但在严重磨损条件下，该层的耐磨性令人担忧。我们通过使用严重粗糙化的股骨头去除 PMPC 接枝层，评估了粗糙股骨头和接枝位置对 PMPC 接枝 HXLPE 衬垫耐磨性的影响，以及 PMPC 接枝对 HXLPE 基底耐磨性的影响。与中度粗糙化的股骨头相比，PMPC 接枝 HXLPE 衬垫表现出负磨损，尽管未经处理的 HXLPE 衬垫与抛光股骨头相比，磨损增加了 154.1%，但证实 PMPC 接枝未受影响。与严重粗糙化的股骨头相比，在严重条件下，头部接触区域的 PMPC 接枝层可能会被去除。然而，与未经处理的 HXLPE 衬垫相比，磨损率降低了 52.5%。此外，与抛光股骨头相比，头部非接触区域改性的 PMPC 接枝 HXLPE 衬垫使磨损减少了 76.8%，因此该区域在形成液膜润滑方面也可能很重要。
在这里，我们描述了粗糙化股骨头和接枝位置对磷脂聚合物接枝高度交联聚乙烯（PMPC-HXLPE）衬垫耐磨性的影响。与中度粗糙化的股骨头相比，PMPC-HXLPE 衬垫表现出负磨损，证实 PMPC 接枝未受影响。使用严重粗糙化的股骨头去除头部接触区域的 PMPC 层后，磨损率不仅超过未经处理的 HXLPE 衬垫，而且降低了 52.5%，证实 PMPC 接枝不会影响 HXLPE 基底的耐磨性。此外，头部非接触区域改性的 PMPC-HXLPE 衬垫使磨损减少了 76.8%。因此，该区域在形成液膜润滑方面也可能很重要。
