Pienkowski D, Jacob R, Hoglin D, Saum K, Kaufer H, Nicholls P J
Division of Orthopaedic Surgery, Markey Cancer Center, University of Kentucky, Lexington, USA.
J Biomed Mater Res. 1995 Oct;29(10):1167-74. doi: 10.1002/jbm.820291002.
Submicron ultrahigh-molecular-weight polyethylene (UHMWPE) wear particles from total joint prostheses may contribute to implant failure through particle-mediated aseptic loosening. The purpose of this study was to examine the microstructure of virgin UHMWPE powder to determine its morphology for future comparison with wear debris. A new method of low-voltage scanning electron microscopy (LVSEM) in an oil-free vacuum was applied, which produced high-resolution images of UHMWPE micromorphology, while minimizing specimen damage and obviating the need for image processing. GUR 415 UHMWPE virgin powder particles were examined by using routine high-voltage SEM, LVSEM, and image analyses. LVSEM showed that UHMWPE particles were composed of submicron-size spherical subparticles connected by numerous nanometer-size fibrils. These spherical subparticles had a highly textured surface morphology seen only by LVSEM. Fracture of the nanometer-size fibrils was observed. Routine high-voltage SEM obfuscates the intricate and delicate UHMWPE micromorphology as well as the damage done by the accompanying high-voltage electrons. This study suggests that the micromorphology of wear particles previously studied with routine high-voltage SEM was overlooked or damaged, justifies the need for LVSEM in future studies, and raises the question of what is the true morphology of polyethylene wear debris retrieved from human tissues.
全关节假体产生的亚微米级超高分子量聚乙烯（UHMWPE）磨损颗粒可能通过颗粒介导的无菌性松动导致植入失败。本研究的目的是检查原始UHMWPE粉末的微观结构，以确定其形态，以便将来与磨损碎片进行比较。应用了一种在无油真空中进行低电压扫描电子显微镜（LVSEM）的新方法，该方法产生了UHMWPE微观形态的高分辨率图像，同时将样品损伤降至最低并无需进行图像处理。通过常规高电压扫描电子显微镜、LVSEM和图像分析对GUR 415 UHMWPE原始粉末颗粒进行了检查。LVSEM显示，UHMWPE颗粒由通过许多纳米级原纤维连接的亚微米级球形亚颗粒组成。这些球形亚颗粒具有仅通过LVSEM才能看到的高度纹理化的表面形态。观察到纳米级原纤维的断裂。常规高电压扫描电子显微镜掩盖了复杂而精细的UHMWPE微观形态以及伴随的高电压电子造成的损伤。本研究表明，以前用常规高电压扫描电子显微镜研究的磨损颗粒的微观形态被忽视或损坏，证明了未来研究中使用LVSEM的必要性，并提出了从人体组织中回收的聚乙烯磨损碎片的真实形态是什么的问题。
