Chain Entanglements and Radiation Crosslinking: Novel Approaches for Improving UHMWPE Wear and Fatigue Properties in Total Knee Replacements

链缠结和辐射交联：改善全膝关节置换术中 UHMWPE 磨损和疲劳性能的新方法

• 批准号: EP/E028039/1
• 负责人: Jun Jie Wu
• 金额: $ 28.02万
• 依托单位: Durham University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FE028039%2F1
• 关键词: Chain; Entanglements; Radiation; Crosslinking; Novel

The natural human knee is a complex and heavily loaded joint. Therefore, for functional reasons, freedom of movement and stability are important for artificial knee joints. Due to this demand, high stresses are placed on the articulation of the artificial knee joints. Polyethylene (with very high molecular weight, termed as UHMWPE) has been the material of choice for the load-bearing articulating surface in artificial knee joints. As a result, excessive wear and fatigue of the tibial polyethylene bearing are common and result in artificial knee joint failure. Polyethylene-related total knee failures have limited the lifetime of total knee joint replacements.However, there is an increasing demand for total knee replacement operations which now account for nearly half of all joint replacements in the UK. In fact, approximately one million UHMWPE components are implanted worldwide on a yearly basis. Also the number of operations carried out in those aged 55-64 has been rising significantly. The application of joint replacement to younger (aged < 64 years) and more active people plus the general increase in life expectancy make it an urgent need for longer lasting polyethylene with better wear and fatigue resistance. The Project is focused on reducing the incidence of material failure. The hypothesis to be examined is that the cause of material failure of UHMWPE knee-joint components lies in the precise time-temperature history employed during manufacture of the UHMWPE components from the virgin UHMWPE powder. Recent work has shown that toughness at macroscopic UHMWPE welded interface increases with welding time and temperature. This suggests that the toughness of UHMWPE powder particle interfaces may vary similarly with compression moulding time and temperature. Hence there is a need to optimise processing conditions to provide interfaces with adequate toughness at locations in tibial components where stress intensities are high. Radiation crosslinking of UHMWPE for artificial knee joints is still controversial and there is a debate over whether radiation crosslinking is beneficial. While crosslinking reduces UHMWPE wear, the method of post irradiation processing of the material to eliminate residual free radicals can affect the long-term performance of the material in the body. Radiation crosslinking will be incorporated and assessed in the Project in order to resolve the scientific controversy regarding its effects on wear and fatigue.The proposed project seeks to answer two important questions. 1) Does improved interface bonding improve the endurance of UHMWPE tibial components and to what extent? 2) Can an appropriate additional radiation crosslinking treatment be beneficial? The Project uses two novel approaches. One is to improve material integrity using computer-aided methodology for generating a range of actual customised tibial component with varying degrees of interface bonding. The other is to combine improved material integrity with state-of-art post irradiation treatment in order to reduce wear rate and improve fatigue resistance. A side-by-side comparison of a range of non-crosslinked and radiation cross-linked components, based upon evaluation of wear behaviour, wear particles and fatigue strength will be made. Identification of optimised manufacturing conditions will reduce the currently high rate of revision operations.

自然人膝关节是一个复杂且负载沉重的关节。因此，出于功能原因，活动自由度和稳定性对于人工膝关节很重要。由于这种需求，高应力被施加在人工膝关节的关节上。聚乙烯（分子量非常高，称为UHMWPE）一直是人工膝关节承重关节面的首选材料。因此，胫骨聚乙烯衬垫的过度磨损和疲劳是常见的，并导致人工膝关节失效。聚乙烯相关的全膝关节失效限制了全膝关节置换术的使用寿命。然而，全膝关节置换术的需求不断增加，目前占英国所有关节置换术的近一半。事实上，全球每年植入约100万个UHMWPE部件。另外，55-64岁年龄段的人接受手术的数量也在显著增加。关节置换术应用于更年轻（年龄< 64岁）和更活跃的人群，加上预期寿命的普遍增加，使得迫切需要具有更好耐磨性和抗疲劳性的更持久的聚乙烯。该项目的重点是减少材料故障的发生率。待检查的假设是，UHMWPE膝关节部件材料失效的原因在于使用原始UHMWPE粉末制造UHMWPE部件期间使用的精确时间-温度历史。最近的研究表明，宏观UHMWPE焊接界面的韧性随焊接时间和温度的增加而增加。这表明UHMWPE粉末颗粒界面的韧性可能随压缩模塑时间和温度类似地变化。因此，需要优化加工条件，以在胫骨部件中应力强度高的位置处提供具有足够韧性的界面。人工膝关节用超高分子量聚乙烯的辐射交联仍有争议，关于辐射交联是否有益也存在争议。虽然交联可减少UHMWPE磨损，但对材料进行辐照后处理以消除残留自由基的方法可能会影响材料在体内的长期性能。辐射交联将被纳入该项目并进行评估，以解决有关其对磨损和疲劳影响的科学争议。拟议项目旨在回答两个重要问题。1)改善界面粘合是否能提高UHMWPE胫骨部件的耐久性，以及在多大程度上？2)适当的额外辐射交联处理是否有益？该项目采用了两种新颖的方法。一种是使用计算机辅助方法提高材料完整性，以生成一系列具有不同界面结合程度的实际定制胫骨部件。另一种是将联合收割机改进的材料完整性与最先进的后辐照处理相结合，以降低磨损率并提高抗疲劳性。将根据磨损行为、磨损颗粒和疲劳强度的评价，对一系列非交联和辐射交联组件进行并行比较。确定优化的制造条件将降低目前较高的翻修率。

项目成果

Improvements on Wear Performance of Ultra-High Molecular Weight Polyethylene through Precise Temperature-Time Moulding Conditions

通过精确的温度-时间成型条件改善超高分子量聚乙烯的耐磨性能

• 发表时间: 2011
• 期刊: Proceedings of Annual Meeting of the Society for Biomaterials
• 作者: Wang QQ

HyperMacs to HyperBlocks: A Novel Class of Branched Thermoplastic Elastomer

• DOI: 10.1021/ma901819f
• 发表时间: 2009-11-24
• 期刊: MACROMOLECULES
• 影响因子: 5.5
• 作者: Hutchings, Lian R.;Dodds, Jonathan M.;Smith, Emily
• 通讯作者: Smith, Emily

Effect of Roughened Counterpart on Behaviors of Vitamin E Infused Ultra-High Molecular Weight Polyethylene

粗糙化对应物对维生素 E 注入超高分子量聚乙烯行为的影响

• 发表时间: 2011
• 期刊: Proceedings of Annual Meeting of the Society for Biomaterials
• 作者: Wang QQ

Biotribological and Structural Characterisations of 28mm Diameter ZTA-ZTA Hip Joints Under Standard and Aggressive Wear Conditions Using Prosim Hip Simulator

使用 Prosim 髋关节模拟器在标准和剧烈磨损条件下测量 28 毫米直径 ZTA-ZTA 髋关节的生物摩擦学和结构特征

• 发表时间: 2011
• 期刊: Journal of Bone and Joint Surgery (Br)
• 作者: Giddings D

Premature failure of Kinemax Plus total knee replacements.

Kinemax Plus 全膝关节置换术过早失效。

• DOI: 10.1302/0301-620x.91b5.21525
• 发表时间: 2009
• 期刊: The Journal of bone and joint surgery. British volume
• 作者: Reay E