Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts, USA.
J Orthop Res. 2013 Jan;31(1):59-66. doi: 10.1002/jor.22195. Epub 2012 Jul 30.
Limiting cross-linking to the articular surfaces of ultrahigh molecular weight polyethylene (UHMWPE) to increase wear resistance while preventing detrimental effects of cross-linking on mechanical strength has been a desirable goal. A surface cross-linked UHMWPE can be achieved by blending UHMWPE with a free radical scavenger, such as vitamin E, consolidating the blend into an implant shape, extracting the vitamin E from the surface, and radiation cross-linking the surface extracted blend. This process results in high cross-link density in the vitamin E-depleted surface region because vitamin E hinders cross-linking during irradiation. In this study, we described the properties of successful extraction media and the manipulation of the wear and mechanical properties of extracted, irradiated blends. We showed that these formulations could have similar wear and significantly improved mechanical properties compared to currently available highly cross-linked UHMWPEs. We believe that these materials can enable thinner implant forms and more anatomical designs in joint arthroplasty and may provide a feasible alternative to metal-on-metal implants.
限制超高分子量聚乙烯（UHMWPE）的交联反应仅发生在关节表面，以提高耐磨性，同时防止交联对机械强度产生不利影响，这一直是一个理想的目标。通过将 UHMWPE 与自由基清除剂（如维生素 E）混合，将混合物压制成植入物形状，从表面提取维生素 E，然后对表面提取的混合物进行辐射交联，可以实现表面交联的 UHMWPE。由于维生素 E 在辐照过程中阻碍交联，因此在维生素 E 耗尽的表面区域会形成高交联密度。在这项研究中，我们描述了成功的提取介质的特性，以及对提取后、辐照后的混合物的磨损和机械性能的控制。我们表明，与目前可用的高度交联的 UHMWPE 相比，这些配方的磨损性能相似，但机械性能有了显著提高。我们相信，这些材料可以使关节置换术中的植入物更薄，设计更符合解剖学，并且可能为金属对金属植入物提供一种可行的替代方案。
