Utzschneider Sandra, Harrasser Norbert, Schroeder Christian, Mazoochian Farhad, Jansson Volkmar
Orthopaedic Department, Grosshadern Medical Center, University of Munich, Marchioninistr. 15, 81377 Munich, Germany.
Clin Biomech (Bristol). 2009 Aug;24(7):583-8. doi: 10.1016/j.clinbiomech.2009.04.007. Epub 2009 May 17.
Compared to conventional ultra-high molecular weight polyethylene (UHMWPE), crosslinked polyethylene showed significantly reduced wear rate in hip simulation and early prospective-randomized clinical studies. The crosslinking process can reduce the mechanical properties of UHMWPE, particularly the fatigue strength. UHMWPE fatigue occurs more frequently in the knee joint than in the hip joint due to its higher contact stresses and there is therefore an increased concern of mechanical failure. Therefore, the purpose of this study was to determine the wear behaviour and the wear rates of different current knee designs and bearing materials.
In a knee-joint-simulator four kinds of crosslinked polyethylene (one produced by sequential irradiation and annealing process, three by different remelting processes, including fixed- and mobile-bearing-types) and two UHMWPE- (fixed- and mobile-bearing) inserts were tested with the appropriate femoral and tibial component recommended from the manufacturer.
All types of crosslinked polyethylene produced statistically significant (P<0.05) lower wear rates than the conventional UHMWPEs without any traces of fatigue. There were no differences in the wear rates between fixed-and mobile-bearings (crosslinked polyethylenes and UHMWPEs; P>0.05). The crosslinked polyethylene tibial inserts manufactured by sequential irradiation and annealing (X3) combined with the Scorpio-knee-design had the lowest wear rates (P<0.05) overall.
Fixed- as well as mobile-bearing crosslinked polyethylene tibial inserts are suitable for total knee arthroplasty and showed reduced wear rates compared with conventional UHMWPE. The combination of the fixed-bearing Scorpio-knee-design with a sequential irradiated and annealed crosslinked polyethylene tibial insert (X3) seems to have an advantage in wear generation compared with other fixed- and mobile-bearing knee designs.
与传统超高分子量聚乙烯（UHMWPE）相比，交联聚乙烯在髋关节模拟和早期前瞻性随机临床研究中显示出磨损率显著降低。交联过程会降低UHMWPE的机械性能，尤其是疲劳强度。由于膝关节接触应力较高，UHMWPE疲劳在膝关节比在髋关节更频繁发生，因此对机械故障的担忧增加。因此，本研究的目的是确定当前不同膝关节设计和轴承材料的磨损行为及磨损率。
在膝关节模拟器中，对四种交联聚乙烯（一种通过顺序辐照和退火工艺生产，三种通过不同的重熔工艺生产，包括固定和活动轴承类型）以及两种UHMWPE（固定和活动轴承）衬垫进行测试，使用制造商推荐的合适股骨和胫骨部件。
所有类型的交联聚乙烯磨损率均显著低于传统UHMWPE（P<0.05），且无任何疲劳痕迹。固定和活动轴承（交联聚乙烯和UHMWPE）之间的磨损率无差异（P>0.05）。通过顺序辐照和退火制造的交联聚乙烯胫骨衬垫（X3）与天蝎座膝关节设计相结合，总体磨损率最低（P<0.05）。
固定和活动轴承的交联聚乙烯胫骨衬垫均适用于全膝关节置换术，与传统UHMWPE相比磨损率降低。与其他固定和活动轴承膝关节设计相比，固定轴承天蝎座膝关节设计与顺序辐照和退火的交联聚乙烯胫骨衬垫（X3）组合在磨损产生方面似乎具有优势。
