Failure Mechanisms of Revision Joint Replacement

修正关节置换术的失效机制

• 批准号: 6644097
• 负责人: Joan E Bechtold
• 金额: $ 27.11万
• 依托单位: HENNEPIN HEALTHCARE RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6644097
• 关键词: biological models; biomaterial compatibility; biomaterial evaluation; biomaterial interface interaction; bone transplantation; dogs; growth factor; hydroxyapatites; implant; joint prosthesis; longitudinal animal study; mechanical stress; medical implant science; medical rehabilitation related tag; radiography; titanium

Our long term goal is to improve the success of revision joint replacements. In our original application we identified that a major deficit of revision implants is their diminished osteogenic performance. The objective for this proposal is to investigate autologous means for improving bony fixation in the revision implant. Specifically, we will study hypotheses addressing these three aims, (1) to improve access (of native growth factors, cells, marrow) to the implant interface by disrupting the sclerotic concentric bone (CB) barrier that forms during aseptic loosening, (2) to improve utilization and adhesion of native growth factors and cells via osteoconductive coatings encouraging bone growth directly on the implant surface, and (3) to augment the interface with local application of concentrated autologous growth factors. Aim 1: We will study improved access by determining if implant fixation parameters improve with a surgical procedure to disrupt the CB barrier. Aim 2: We will study hydroxyapatite (HA) and an immobilized RGD peptide surface (RGD) to determine if they improve utilization/adhesion as compared to titanium (Ti). Aim 3: We will study whether augmentation of the interface with autologous blood factors (concentrate of buffy coat in allograft carrier) improves interface fixation as compared to allograft alone, or to the ungrafted interface. We will use our experimental model of the primary and revision settings (established during the original proposal). This model uses the team's loaded micromotion device with over a decade of previous use (6.0mm diameter PMMA cylinder pistoning 500 microns for eight weeks with polyethylene particles, in 0.75mm gap) to engender a revision cavity with a bony and tissue response representative of an aseptically loosened human implant. At revision surgery, the PMMA implant is replaced with a prescribed implant/graft treatment (the primary site receives the same implant/graft treatment). Groupings are (a) stable, loaded Ti, HA and RGD implants, (b) with no graft, and allograft with or without growth factors, (c) in the primary setting, and the revision settings with and without disruption of the CB barrier. These 18 groups will be statistically compared with groups from the original proposal, to determine effectiveness, interactions and synergies of treatments. Outcome measures are histomorphometric (percent bone area and implant contact in zones, and connectivity) and mechanical (pushout strength, stiffness, energy, bone permeability). Also, the CB rim will be studied histomorphometrically and with an analytic mechanical model. The diverse set of unique competencies of our team, our established experimental model, and our long history of successful collaboration, bode well for our continuing investigations to improve the longevity of clinically vexing revision implants.

我们的长期目标是提高翻修关节置换术的成功率。 在我们最初的申请中，我们发现翻修植入物的主要缺陷是其成骨性能降低。 本提案的目的是研究改善翻修植入物中骨固定的自体方法。 具体来说，我们将研究解决这三个目标的假设，（1）改善访问通过破坏在无菌性松动过程中形成的骨同心圆（CB）屏障，将（天然生长因子、细胞、骨髓的）生长因子和细胞粘附到植入物界面，（2）通过骨传导涂层改善天然生长因子和细胞的利用和粘附，促进骨直接在植入物表面生长，和（3）通过局部应用浓缩的自体生长因子来增强界面。 目的1：我们将通过确定植入物固定参数是否通过外科手术改善以破坏CB屏障来研究改善的入路。 目标二：我们将研究羟基磷灰石（HA）和固定化的RGD肽表面（RGD），以确定它们是否与钛（Ti）相比提高了利用率/粘附力。 目标3：我们将研究与单独的同种异体移植物或未移植的界面相比，用自体血液因子（同种异体移植物载体中的血沉棕黄层浓缩物）增强界面是否改善界面固定。 我们将使用我们的实验模型的主要和修订设置（在最初的建议）。 该模型使用团队的加载微动装置，该装置已使用十多年（直径6.0 mm的PMMA圆柱体，活塞500微米，持续8周，聚乙烯颗粒，间隙为0.75 mm），以产生翻修腔，骨和组织反应代表无菌松动的人体植入物。 在翻修手术中，PMMA植入物被替换为规定的植入物/移植物治疗（原发部位接受相同的植入物/移植物治疗）。 分组为：（a）稳定、负载的Ti、HA和RGD植入物，（B）无移植物，以及含或不含生长因子的同种异体移植物，（c）初次手术，以及CB屏障破坏和未破坏的翻修手术。 这18个组将与原始提案中的组进行统计学比较，以确定治疗的有效性、相互作用和协同作用。 结局指标为组织形态学（骨面积百分比和植入物接触区和连接性）和机械（推出强度、刚度、能量、骨渗透性）。 此外，CB轮辋将进行组织形态计量学研究，并与分析力学模型。 我们团队的各种独特能力，我们建立的实验模型，以及我们长期成功合作的历史，预示着我们将继续研究，以提高临床上令人烦恼的翻修植入物的寿命。