TOTAL SURGICAL REPLACEMENT OF THE HIP JOINT

本提案涉及影响骨骼的某些设计变量 初次非骨水泥型全髋关节置换术后的重建。对.的使用 非骨水泥技术在全髋关节置换术中引起高度关注 应力诱导的骨重建、固定和长期生物相容性。 据报道，近端皮质吸收的严重程度各不相同， 各种无骨水泥的股骨柄，由CoCo或Ti6Al4V制成。 皮质吸收可导致宿主骨衰竭、骨移植失败 假体装置，并提出了巨大的问题，进一步 重建。这项建议的目的是为了获得更好的 应激诱导的骨量变化与骨量的关系 非骨水泥型全髋关节置换术后股骨近端 种植体设计。我们建议通过研究来研究这种关系 与茎相关的横截面刚度对骨重塑的影响 模数和阀杆几何形状。 我们将检验两个假设。(1)材料的弹性模数和几何形状 可以调节股骨干，以最大限度地减少长期股骨重塑 改变。(2)假体引起的运动功能改变之间的关系 股骨的力学环境与皮质形态的适应性变化 是非线性的。具体地说，我们计划评估大型 树干(I)弹性模数和(Ii)几何形状的变化(在本研究中， 植入物质心和弯曲轴相对于它们的位置 股骨)对犬模型骨形态变化的影响，而 说明了词干在 股骨管。这些数据将用于确定关系是否 假体引起的股骨应力/应变变化与股骨头损伤的关系 骨形态的改变是线性或非线性的。 因此，两个关键的临床问题是(I)骨重建如何变化。 可能的临床可行性和相对干性的范围 (Ii)无牙骨质修复后，柄的几何形状是否影响近端的骨丢失 是吗？为了解决这些问题，将使用犬的主要全肝移植模型。 阀杆刚度将在10倍的范围内变化。在一个单独的 实验中，茎的形状会有所不同。实验端点将是 对处理的结构反应(例如，皮质面积的变化， 厚度、孔隙率和髓质骨密度)。数据将是 分析测试设计变量对改建的影响 反应并从机械上确定假体如何诱导 股骨力学环境的变化与骨骼的变化相对应 适应性反应。这些实验的目标是推导出原理 这将具有临床意义。

This proposal is concerned with certain design variables affecting bone remodeling following primary cementless total hip arthroplasty. The use of cementless techniques in total hip arthroplasty heightens concern with stress-induced bone remodeling, fixation, and long term biocompatibility. Proximal cortical resorption of varying severity has been reported with a variety of cementless femoral stems, made from CoCr or from Ti6Al4V. Cortical resorption can lead to failure of the host bone, failure of the prosthetic device, and presents enormous problems for further reconstruction. The purpose of this proposal is to gain a better understanding of the relationship between stress-induced bony changes in the proximal femur following cementless total hip arthroplasty (THA) and implant design. We propose to investigate this relationship by studying bone remodeling as a function of cross-sectional stiffness related to stem modulus and stem geometry. Two hypotheses will be tested. (1) The elastic modulus and geometry of the femoral stem can be modulated to minimize long-term femoral remodeling changes. (2) The relationship between prosthetic-induced changes in the femur's mechanical environment and adaptive changes in cortical morphology is non-linear. Specifically, we plan to evaluate the effect of large variations in stem (i) elastic modulus and (ii) geometry (in this study, the location of the implant's centroids and bending axes relative to those of the femur) on changes in bone morphology in a canine model, while accounting for individual variation in the position of the stem within the femoral canal. These data will be used to determine if the relationship between the prosthesis-induced changes in femoral stress/strain and the changes in bone morphology is linear or non-linear. Thus, two key clinical questions are (i) how does bone remodeling vary over the range of relative stem stiffness of potential clinical feasibility and (ii) does stem geometry influence proximal bone loss following cementless THA? To address these issues, a canine primary THA model will be used in which stem stiffness will be varied over a 10-fold range. In a separate experiment, stem shape will be varied. The experimental endpoints will be the structural responses to the treatments (e.g., change in cortical area, thickness and porosity and medullary bone density). The data will be analyzed to test for the effects of the design variables on the remodeling response and to determine mechanistically how the prosthesis-induced changes in the mechanical environment of the femur correspond to the bony adaptive response. The goal of these experiments is to derive principles which will have clinical implications.