Etiology and Prevention of Loss of Fixation in Cemented Knee Replacements

描述（由申请人提供）：全膝关节置换术是美国最常见的全关节手术，在过去的二十年中，手术数量急剧增长，每年超过580,000例。尽管骨水泥全膝关节置换术普遍成功，但需要翻修手术的无菌性松动仍然很常见，特别是对于年轻和更活跃的患者。在体内服务后，从骨水泥胫骨托盘组件获得的新试点数据表明，在胫骨托盘下与骨水泥互锁的小梁骨存在广泛的吸收，并且这种吸收可能发生在植入后的最初几年内。工作假设是植入后水泥与骨之间的机械微联锁早期丧失，这导致胫骨托盘组件的功能强度丧失。在临床实践中，失去连接可能会导致组件迁移和无菌松动的风险增加，特别是对于高需求的患者。这项研究计划的目标是使关节置换术在患者的一生中都能成功地发挥作用，而不需要翻修。在这一竞争性更新中，申请人利用从当前资助周期中获得的全髋关节置换术在体内服务后固定的经验，并将这些经验与评估和解决膝关节置换术相关松动问题的新方法相结合。具体目标是：(1)发现体内服务后固定形态的时空变化，特别关注短期的体内服务；(2)确定这些形态变化对固定界面和完整胫骨托架结构/力学功能关系的影响；(3)探讨骨小梁骨从指间骨水泥区吸收的潜在力学机制；(4)确定由于在体内服役而造成的整体构造的功能强度损失；(5)进行转化生物力学研究，通过有针对性的设计改变，通过改善胫骨托盘底部的负载转移（称为a型方案）来减轻骨质流失。如果不能防止托盘下的小梁骨丢失（称为B型情况），则确定“正常”和“高需求”患者所需的远端固定量，以防止松动。实验和计算方法的协同组合用于解决这些目标。

DESCRIPTION (provided by applicant): Total knee replacement is the most common total joint procedure in the United States, and the number of procedures has grown dramatically over the past two decades to over the 580,000 per year. Despite the general success of cemented total knee replacement, aseptic loosening requiring a revision surgery is still common, particularly for younger and more active patients. New pilot data obtained from cemented tibial tray components following in vivo service show that there is extensive resorption of trabecular bone that interlocks with cement under the tibial tray and that this resorption may occur within the first few years following implantation. The working hypothesis is there is an early loss of mechanical micro-interlock between the cement and bone following implantation and this results in a loss of functional strength of the tibial tray component. In clinical practice, loss of interlck could cause an increased risk of component migration and aseptic loosening, particularly for high demand patients. The goal of this research program is to achieve arthroplasties that function successfully for the lifetime of the patient without the need for revision. In this competitive renewal the applicants leverage the experience gained from the current funding cycle on fixation of total hip replacement following in vivo service and combine these with new approaches to assess and address loosening issues associated with knee replacements. The specific aims are to (1) discover the temporal and spatial changes to the fixation morphology following in vivo service with particular attention to short term in vivo service; (2) determine th influence of these morphological changes on the structure/mechanical function relationship for the fixation interfaces and complete tibial tray constructs; (3) explore potential mechanical mechanisms responsible for trabecular bone resorption from interdigitated cement-bone regions; (4) determine the loss of functional strength of whole constructs due to in vivo service; and (5) perform translational biomechanics studies to mitigate bone loss through improved load transfer to the underside of the tibial tray (termed a type A scenario) using targeted design changes. If trabecular bone loss under tray cannot be prevented (termed a type B scenario), determine amount of distal fixation needed to prevent loosening for 'normal' and 'high demand' patients. A synergistic combination of experimental and computational methods is used to address these aims.