A New Method of In Vitro Wear Assessment of the UHMWPE Tibial Insert in Total Knee Replacement
A New Method of In Vitro Wear Assessment of the UHMWPE Tibial Insert in Total Knee Replacement
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DOI：
10.1111/j.1525-1594.2008.00656.x
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发表时间：
2008-12-01
影响因子：
2.4
通讯作者：
Viceconti, Marco
中科院分区：
文献类型：
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作者：
Affatato, Saverio;Cristofolini, Luca;Viceconti, Marco
用四工位膝关节模拟机测定了超高相对分子质量聚乙烯(UHMWPE)胫骨假体的磨损量。根据国际标准化组织14243-1，2，3标准，轴承承受屈曲/伸展(0至58度)、前后平移(0至-5.2 mm)、内外旋转(-1.9度至+5.7度)和2.6kN的最大轴向载荷。磨损试验以1.1赫兹的频率进行500万次循环，并用重量法测定插入件(n=3)的磨损量。这项研究的新颖性是开发了一种特殊的装置，以尽可能真实地模拟活体条件；这涉及到由合格的整形外科医生使用经批准的方法将股骨假体固定到人造股骨模型的远端。在500万次循环后，样品#1、#2和#3的平均重量损失分别为11.16、19.74和12.61 mg。对每个测试样本的目测和无损检查显示出相似的磨痕，这些磨痕与体内两年后回收的嵌入物上的磨痕非常相似。这些结果表明了新的体外UHMWPE磨损评估方法的有效性。此外，将目前的体外结果与以前相关研究中报道的结果进行比较，可以深入了解将股骨假体固定到模拟器上的方法对胫骨嵌体的磨损程度和模式的影响。
The wear of the ultra-high-molecular-weight polyethylene (UHMWPE) tibial insert was determined using a four-station knee simulator. The bearings were subjected to flexion/extension (between 0 and 58 degrees), anterior-posterior translation (between 0 and -5.2 mm), internal-external rotation (between -1.9 degrees and +5.7 degrees), and a maximum axial load of 2.6 KN, as per ISO 14243-1,2,3. The wear tests were run at a frequency of 1.1 Hz for 5 million cycles, and the wear of the inserts (n = 3) was determined using the gravimetric method. The novelty of the study was a special setup developed to simulate, as realistically as possible, in vivo conditions; this involved fixing the femoral component to the distal end of a synthetic femur model by a qualified orthopedic surgeon using an approved method. After 5 million cycles, the mean weight losses were 11.16, 19.74, and 12.61 mg for specimens #1, #2, and #3, respectively. Visual and nondestructive inspections for each of the test specimens showed similar wear tracks and these were very similar to those seen on inserts retrieved after 2 years in vivo. These results show the efficacy of the new in vitro UHMWPE wear assessment method. Furthermore, a comparison between the present in vitro results and those reported in a relevant previous study provide some insight into the influence of the method used to fix the femoral component to the simulator on the wear magnitude and patterns of the tibial insert.