Experimental evidence demonstrates that a loss of stoichiometry at the surface of oxide bioceramic femoral heads enhances the oxidation rate of polyethylene acetabular liners in artificial hip joints. Contradicting the common notion that ceramics are bioinert, three independent experiments confirmed substantial chemical interactions between the ceramic femoral heads and their polyethylene counterparts. The experiments reported herein included hydrothermal tests, frictional tests, and hip-simulator experiments. It was discovered that oxide and non-oxide femoral heads differently affected the oxidation processes at the surface of the polyethylene liners, all other testing parameters being equal. Analytical data from X-ray photoelectron (XPS), cathodoluminescence (CL), Fourier-transform infrared (FTIR), and Raman spectroscopies unequivocally and consistently showed that the oxidation rate of polyethylene liners was greater when coupled with oxide as opposed to non-oxide ceramic heads. XPS analyses of O-Al-O bond fractions at the surface of a zirconia-toughened alumina (ZTA) short-term (20 months in vivo) femoral heads retrieval showed a ~50% reduction in favor of oxygen vacancy O-Al-V_O and hydroxylated Al-O-H bonds. Off-stoichiometry drifts were confirmed in vitro under both static and dynamic conditions. They triggered oxidation and tangibly affected an advanced highly cross-linked sequentially irradiated and annealed ultra-high molecular weight polyethylene (UHMWPE) liner (increase in oxidation index up to ΔOI~1.2 after 5 × 10⁵ cycles under dynamic swing conditions). Second-generation UHMWPE liners infused with vitamin E were also affected by the free flow of oxygen from the oxide femoral heads, although to a lesser extent. The fundamental findings of this study, which were also confirmed on retrievals, call for revised standards in material design and testing. Adopting these new criteria will provide an improved understanding of the importance of off-stoichiometry at the head/liner interface and may lead to significant extensions in artificial joint lifetimes.

实验证据表明，氧化物生物陶瓷股骨头表面化学计量的损失会提高人工髋关节中聚乙烯髋臼内衬的氧化速率。与通常认为陶瓷具有生物惰性的观点相反，三个独立的实验证实了陶瓷股骨头与其聚乙烯对应物之间存在实质性的化学相互作用。本文报道的实验包括水热试验，摩擦试验和臀部模拟器试验。已经发现，在所有其他测试参数相同的情况下，氧化物和非氧化物的股骨头对聚乙烯衬里表面的氧化过程有不同的影响。X射线光电子（XPS），阴极发光（CL），傅立叶变换红外（FTIR），拉曼光谱法和拉曼光谱法明确一致地表明，与氧化物结合时，与非氧化物陶瓷头相比，聚乙烯衬里的氧化速率更高。短期（20个月）氧化锆增韧氧化铝（ZTA）表面的O-Al-O键组分的XPS分析体内）股骨头检索显示有利于氧空位O型的Al-V的降低〜50％_ö和羟基化的Al-OH键。在体外在静态和动态条件下都证实了化学计量偏离。它们触发了氧化作用，并切实影响了先进的高度交联的顺序辐照并退火的超高分子量聚乙烯（UHMWPE）衬里（在5×10 ⁵后，氧化指数增加至ΔOI〜1.2动态摆动条件下的循环）。注入了维生素E的第二代UHMWPE衬里也受到来自氧化物股骨头的氧气自由流动的影响，尽管程度较小。这项研究的基本发现在检索中也得到了证实，要求对材料设计和测试进行修订。采用这些新标准将使人们更好地理解头部/衬管界面处的非化学计量比的重要性，并可能导致人工关节寿命的显着延长。