Engh G A, Dwyer K A, Hanes C K
Anderson Orthopaedic Research Institute, Arlington, Virginia 22206.
J Bone Joint Surg Br. 1992 Jan;74(1):9-17. doi: 10.1302/0301-620X.74B1.1732274.
We examined 86 polyethylene inserts, retrieved from total and unicompartmental knee prostheses after an average of 39.5 months in situ, grading them from 0 to 3 for seven modes of polyethylene degradation. Severe wear, with delamination or deformation, was observed in 51% of the implants, and was associated with time in situ, lack of congruency, thin polyethylene, third-body wear debris, and heat-pressed polyethylene. Significant under-surface cold flow was identified in some areas of unsupported polyethylene, and was associated with delamination in the load-bearing areas of thin inserts above screw holes in the underlying metal tray. We recommend the use of thicker polyethylene inserts, particularly in young, active patients and in designs with screw holes in the tibial baseplate. Thin polyethylene inserts which are at risk for accelerated wear and premature failure should be monitored radiographically at annual intervals.
我们检查了86个聚乙烯衬垫，这些衬垫是从全膝关节和单髁膝关节假体中取出的，平均在位39.5个月，根据七种聚乙烯降解模式将它们从0到3进行分级。在51%的植入物中观察到严重磨损，伴有分层或变形，这与在位时间、不匹配、薄聚乙烯、第三体磨损碎屑和热压聚乙烯有关。在一些无支撑聚乙烯区域发现了明显的表面下冷流，这与下方金属托盘上螺丝孔上方薄衬垫承重区域的分层有关。我们建议使用更厚的聚乙烯衬垫，尤其是在年轻、活跃的患者以及胫骨基板有螺丝孔的设计中。有加速磨损和过早失效风险的薄聚乙烯衬垫应每年进行X线监测。
