Puloski S K, McCalden R W, MacDonald S J, Rorabeck C H, Bourne R B
Division of Orthopaedic Surgery, The University of Western Ontario, London Health Sciences Centre-University, Canada.
J Bone Joint Surg Am. 2001 Mar;83(3):390-7. doi: 10.2106/00004623-200103000-00011.
With extensive use of posterior stabilized total knee arthroplasty implants, it is increasingly important to assess the mechanical performance of this design alternative. The purpose of this study was to examine the wear patterns at the femoral cam-tibial post interface in a series of posterior stabilized prostheses retrieved at revision arthroplasty.
Qualitative and quantitative wear analysis was performed over the surface of the stabilizing posts from twenty-three retrieved total knee components that had been implanted for a mean of 35.6 months (range, 2.3 to 107.2 months). The implants were designs from four different manufacturers. Digital images of the anterior, posterior, medial, and lateral surfaces of the tibial post were made for quantitative analysis and determination of a post wear score. Wear was characterized with a grading system that isolates adhesive, abrasive, and fatigue wear, inferring a weighted score from an estimation of generated polyethylene debris.
Evidence of wear or damage was observed on all twenty-three of the stabilizing posts, including those revised because of infection. On the average, 39.9% (range, 18.5% to 60%) of the post surface demonstrated some form of deformation, with adhesive wear, or burnishing, being the predominant wear mechanism. Seven posts (30%) exhibited severe damage with gross loss of polyethylene. The wear caused premature failure and early revision of two components: one of these failures was related to isolated post wear and the other, to severe post wear and subsequent fracture. Overall, wear was primarily posterior, but wear over the anterior, medial, and lateral surfaces was also notable.
The cam-post articulation in posterior stabilized implants can be an additional source of polyethylene wear debris. The variability in wear patterns observed among designs may be due to differences in cam-post mechanics, post location, and post geometry. The surgeon should be aware that the cam-post interface is not an innocuous articulation, and manufacturers should be motivated to produce implants that maintain the function of the post while limiting wear and surface damage.
随着后稳定型全膝关节置换植入物的广泛应用，评估这种设计方案的机械性能变得越来越重要。本研究的目的是检查在翻修关节成形术中取出的一系列后稳定型假体的股骨凸轮 - 胫骨柱界面处的磨损模式。
对23个取出的全膝关节组件的稳定柱表面进行定性和定量磨损分析，这些组件的平均植入时间为35.6个月（范围为2.3至107.2个月）。这些植入物由四个不同的制造商设计。拍摄胫骨柱前、后、内、外表面的数字图像，用于定量分析和确定柱磨损评分。磨损通过分级系统进行表征，该系统区分粘着磨损、磨料磨损和疲劳磨损，并根据产生的聚乙烯碎片估计得出加权分数。
在所有23个稳定柱上均观察到磨损或损坏的迹象，包括因感染而翻修的那些。平均而言，39.9%（范围为18.5%至60%）的柱表面出现了某种形式的变形，粘着磨损或抛光是主要的磨损机制。七个柱（30%）表现出严重损坏，聚乙烯大量损失。磨损导致两个组件过早失效并提前翻修：其中一次失效与孤立的柱磨损有关，另一次与严重的柱磨损及随后的骨折有关。总体而言，磨损主要发生在后方，但前、内、外表面的磨损也很明显。
后稳定型植入物中的凸轮 - 柱关节可能是聚乙烯磨损碎片的另一个来源。不同设计之间观察到的磨损模式差异可能归因于凸轮 - 柱力学、柱位置和柱几何形状的差异。外科医生应意识到凸轮 - 柱界面并非无害关节，制造商应致力于生产在保持柱功能的同时限制磨损和表面损伤的植入物。
