The J. Vernon Luck Sr., MD, Orthopaedic Research Center at Orthopaedic Hospital, UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, David Geffen School of Medicine, Los Angeles, CA 90007, USA.
Clin Orthop Relat Res. 2012 Feb;470(2):329-38. doi: 10.1007/s11999-011-2057-x.
Numerous studies indicate highly crosslinked polyethylenes reduce the wear debris volume generated by hip arthroplasty acetabular liners. This, in turns, requires new methods to isolate and characterize them.
QUESTIONS/PURPOSES: We describe a method for extracting polyethylene wear particles from bovine serum typically used in wear tests and for characterizing their size, distribution, and morphology.
Serum proteins were completely digested using an optimized enzymatic digestion method that prevented the loss of the smallest particles and minimized their clumping. Density-gradient ultracentrifugation was designed to remove contaminants and recover the particles without filtration, depositing them directly onto a silicon wafer. This provided uniform distribution of the particles and high contrast against the background, facilitating accurate, automated, morphometric image analysis. The accuracy and precision of the new protocol were assessed by recovering and characterizing particles from wear tests of three types of polyethylene acetabular cups (no crosslinking and 5 Mrads and 7.5 Mrads of gamma irradiation crosslinking).
The new method demonstrated important differences in the particle size distributions and morphologic parameters among the three types of polyethylene that could not be detected using prior isolation methods.
The new protocol overcomes a number of limitations, such as loss of nanometer-sized particles and artifactual clumping, among others.
The analysis of polyethylene wear particles produced in joint simulator wear tests of prosthetic joints is a key tool to identify the wear mechanisms that produce the particles and predict and evaluate their effects on periprosthetic tissues.
大量研究表明，高度交联的聚乙烯可减少髋关节置换髋臼衬垫产生的磨损碎屑量。这反过来又需要新的方法来分离和表征它们。
问题/目的：我们描述了一种从通常用于磨损试验的牛血清中提取聚乙烯磨损颗粒的方法，并对其大小、分布和形态进行了特征描述。
使用优化的酶消化方法完全消化血清蛋白，该方法可防止最小颗粒的损失，并最大程度地减少其团聚。设计密度梯度超速离心法以去除污染物并回收颗粒，无需过滤，直接将其沉积在硅片上。这提供了颗粒的均匀分布和与背景的高对比度，便于准确、自动的形态计量图像分析。通过从三种类型的聚乙烯髋臼杯（无交联以及 5 Mrads 和 7.5 Mrads 伽马射线交联）的磨损试验中回收和表征颗粒，评估了新方案的准确性和精密度。
新方法显示了三种类型的聚乙烯之间在颗粒尺寸分布和形态参数方面的重要差异，这些差异无法通过先前的分离方法检测到。
新方案克服了许多限制，例如纳米级颗粒的损失和人为团聚等。
对关节假体模拟器磨损试验中产生的聚乙烯磨损颗粒的分析是识别产生颗粒的磨损机制、预测和评估其对假体周围组织影响的关键工具。
