Advancing Hemiarthroplasty: Predicting in vivo performance of cartilage bearing systems through benchtop and ex vivo testing.

摘要 该研究项目的最终目标是提高半关节置换术的性能。半关节置换术 包括用人造承重面替换其中一个关节面。它提供了一个明显的好处 在局部软骨受损的患者中，最大限度地保护关节内健康的骨和软骨 未来的治疗方案。半关节置换术是置换个别患病腕骨的固有方法。 (腕部)或踝部(脚部)骨骼，与相邻骨骼有多个关节。目前， 半关节置换术的结果因所涉及的关节和所用支撑面的类型而有很大不同 与相对的软骨形成关节。失败最常见的原因是对侧关节退变。 浮出水面。提高半关节置换术性能的一个关键挑战是识别轴承表面的能力 这将保持健康的软骨。有许多候选生物材料可能适合用作 半关节置换术轴承表面，包括金属、陶瓷和聚合物，以及专用涂层， 例如氮化钛和热解碳。然而，这些材料的性能好坏参半， 这在很大程度上是由于缺乏标准化和经验证的测试方法。因此，具体目标是 这个项目的目的是开发一个模型，在这个模型中，台式和体外测试可以预测软骨对 半关节置换术轴承系统在适合大型动物模型中磨损。这一目标将通过以下方式实现 完成三个具体目标。首先，我们将对八种材料的材料和力学性能进行表征 候选半人工关节轴承表面(2个金属、4个聚合物、1个陶瓷和1个热解碳)使用 标准台式机械试验(粗糙度、润湿性、模数、硬度和磨损试验 皮质骨)。在第二部分，我们将描述每一位候选人的软骨承载能力。 生物材料通过在关节运动模拟生物摩擦试验机中与牛软骨塞进行磨损测试，使用 蛋白多糖/糖胺聚糖(PG/GAG)和羟脯氨酸作为软骨基质降解和修复的指标 活/死分析是衡量细胞损伤的一种方法。在第三题中，我们将测试目标1和目标2中的8个材料中的4个 作为尤卡坦小型猪新型单室胫骨半关节置换术模型的承重面，测量 软骨损伤(宏观和微观)、滑膜炎症、软骨厚度和骨赘状骨 在52周时形成。最后，我们将开发一个统计模型，其中来自目标1和目标2的数据可以 用于预测目标3中的结果。本提案中概述的工作将产生一个模型，其中工作台和 体外试验可以预测半关节置换术后的软骨反应。该项目将提供一个至关重要的工具 需要加快设计、开发和FDA批准新的半关节置换术轴承表面， 为数百万患有退行性关节疾病的患者带来了显著的好处。

ABSTRACT The ultimate goal of this research program is to advance hemiarthroplasty performance. Hemiarthroplasty involves replacement of one of the articular joint surfaces with an artificial bearing surface. It offers a clear benefit in patients with localized cartilage damage, preserving the healthy bone and cartilage in the joint to maximize future treatment options. And hemiarthroplasty is inherent in the replacement of individually diseased carpal (wrist) or tarsal (foot) bones, which have multiple articulations with neighboring bones. Currently, hemiarthroplasty outcomes vary dramatically by the joint involved and by the type of bearing surface used to articulate with the opposing cartilage. Failure most often occurs by degeneration of the opposing articular surface. A critical challenge in advancing hemiarthroplasty performance is the ability to identify bearing surfaces that will maintain healthy cartilage. There are numerous candidate biomaterials that might be suitable for use as hemiarthroplasty bearing surfaces, including metals, ceramics, and polymers, as well as specialized coatings, such as titanium nitride and pyrolytic carbon. However, the performance of these materials has been mixed, due in large part to the lack of standardized and validated testing methodologies. Accordingly, the specific objective of this project is to develop a model where benchtop and ex vivo testing can predict the cartilage response to hemiarthroplasty bearing system wear in a fit-for-purpose large animal model. This goal will be achieved by completing three specific aims. In the first, we will characterize the material and mechanical properties of eight candidate hemiarthroplasty bearing surfaces (2 metals, 4 polymers, 1 ceramic, and 1 pyrolytic carbon) using standard benchtop mechanical tests (roughness, wettability, modulus, hardness, and wear testing against cortical bone). In the second, we will characterize the cartilage bearing performance of each of the candidate biomaterials by wear testing them against bovine cartilage plugs in a joint motion-simulating biotribometer, using proteoglycan/glycosaminoglycan (PG/GAG) and hydroxyproline as measures of cartilage matrix degradation and live/dead assays as a measure of cell damage. In the third, we will test four of the 8 materials from Aims 1 & 2 as bearing surfaces in a novel unicompartmental tibial hemiarthroplasty model in the Yucatan minipig, measuring cartilage damage (macro- and microscopic), synovial inflammation, cartilage thickness, and osteophyte bone formation at 52 weeks. And finally, we will develop a statistical model where the data from Aims 1 and 2 can be used to predict the outcome in Aim 3. The work outlined in this proposal will yield a model where benchtop and ex vivo testing can predict the cartilage response to hemiarthroplasty. This project will provide a crucial tool needed to accelerate the design, development, and FDA clearance of new hemiarthroplasty bearing surfaces, resulting in a significant benefit for millions of patients afflicted with degenerative joint disease.