Superhard Nanocrystalline Coated Prosthesis

描述(申请人提供)：将开发纳米晶同金属(与基材相同且无界面)涂层，以减少矫形假体中超高相对分子质量聚乙烯(UHMWPE)的磨损。超高相对分子质量聚乙烯(UHMWPE)磨损是导致假体失效的主要原因，而配对钴铬表面的粗糙度被认为是UHMWPE磨损的主要原因。第三身体磨损颗粒，如骨水泥成分，会刮伤关节表面，使其变得粗糙，并加速UHMWPE磨损。将传统的硬质陶瓷涂层应用于金属表面的尝试没有成功，因为由于涂层和衬底材料的不同以及热和晶格的不匹配，在实现足够的附着力方面存在困难。 我们首次证明，沉积在Co-Cr-Mo基片上的纳米晶(3-40 nm颗粒)的硬度接近于某些陶瓷的硬度(18-26 Gpa，提高了400%)，没有与金属基片粘结的相关问题。(钛和不锈钢也得到了类似的结果)。在第一阶段后的工作中，我们已经展示了在钴铬股骨头上均匀沉积超硬同金属涂层。正在进行的髋关节模拟试验表明，与未涂层的钴铬合金相比，同种金属钴或股骨头的UHWMPE磨损减少了75%。此外，原子力显微镜显示，同种金属涂层保持了与原始高度抛光的钴铬涂层相同的低表面粗糙度。这些结果清楚地证明了所提出技术的可行性。 第二阶段将优化同种金属涂层的沉积工艺，并在Hip模拟测试中对其进行评估，该测试将由医疗器械测试与创新中心和一家大型整形外科公司的Stephen Li完成。

DESCRIPTION (provided by applicant): Nanocrystalline homometallic (same as the substrate and without interface) coatings will be developed to reduce wear of ultra-high molecular weight polyethylene (UHMWPE) in orthopedic prostheses. UHMWPE wear is a primary cause of prosthesis failure, and roughness of the mating Co-Cr surface has been identified as a major contributing factor to UHMWPE wear. Third-body wear particles, such as bone cement constituents, scratch the articulating surface, roughening it and accelerating UHMWPE wear. Attempts to apply conventional hard ceramic coatings to the metallic surfaces have not been successful because of difficulties in achieving adequate adhesion due to dissimilarity of coating and substrate materials and thermal and lattice mismatches. We have demonstrated, for the first time, that nanocrystalline (3-40 nm grains) Co-Or deposited onto Co-Cr-Mo substrates possesses hardness close to that of some ceramics (18-26 GPa, 400% increase), without the associated problems with adhesion to metallic substrates. (Similar results have also been obtained for Ti and stainless steel). In post Phase I work, we have demonstrated uniform deposition of superhard homometallic coatings onto Co-Cr femoral hip heads. Ongoing hip simulation tests have demonstrated up to 75% reduction in UHWMPE wear against homometallic Co-Or femoral heads vs. uncoated Co-Cr. Additionally, atomic force microscopy shows that the homometallic coatings retain the same low surface roughness as the original, highly polished Co-Cr. These results clearly demonstrate feasibility of the proposed technology. Phase 2 will optimize the processes involved in deposition of homometallic coatings and evaluate them in Hip Simulation tests, which will be done by Stephen Li at the Medical Device Testing and Innovation and a major Orthopedic Company.