Ultra‐high molecular weight polyethylene (UHMWPE) is used as a bearing surface of joint prostheses and has been reported to absorb lipids such as squalene (SQ) and cholesterol esters in vivo. These lipids have been suggested by in vitro studies using SQ as a model lipid to have the potential to induce polymer degradation. However, the impact of lipid‐induced degradation on the strength and wear resistance of UHMWPE is unknown. In this study, lipid‐induced degradation was simulated by SQ absorption and subsequent accelerated aging, and its influence on the strength and wear resistance of UHMWPE was investigated using wear, fatigue crack growth, and delamination testing. Lipid‐induced degradation was found to have little impact on fatigue crack growth rates and delamination resistance. These results were consistent with previous reports that lipid‐induced degradation is localized near the surface. However, we also found that lipid‐induced degradation increased the wear rate of both non‐crosslinked and crosslinked UHMWPE by a factor of 2.5 and 14, respectively. These results indicate that lipid‐induced degradation may affect the durability and long‐term clinical outcome of joint replacements due to increased wear of UHMWPE.

中文翻译：

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由于脂质诱导的降解，用于关节假体的 UHMWPE 强度和耐磨性降低的体外估计。

超高分子量聚乙烯 (UHMWPE) 用作关节假体的轴承表面，据报道可在体内吸收角鲨烯 (SQ) 和胆固醇酯等脂质。使用 SQ 作为模型脂质的体外研究表明，这些脂质具有诱导聚合物降解的潜力。然而，脂质诱导降解对 UHMWPE 强度和耐磨性的影响尚不清楚。在这项研究中，通过 SQ 吸收和随后的加速老化模拟了脂质诱导的降解，并使用磨损、疲劳裂纹扩展和分层测试研究了其对 UHMWPE 强度和耐磨性的影响。发现脂质诱导的降解对疲劳裂纹扩展速率和抗分层性几乎没有影响。这些结果与之前的报道一致，即脂质诱导的降解位于表面附近。然而，我们还发现脂质诱导的降解使非交联和交联 UHMWPE 的磨损率分别增加了 2.5 和 14 倍。这些结果表明，由于 UHMWPE 的磨损增加，脂质诱导的降解可能会影响关节置换物的耐久性和长期临床结果。