TOTAL SURGICAL REPLACEMENT OF THE HIP JOINT

该建议涉及影响骨的某些设计变量 初次非骨水泥型全髋关节置换术后的重塑。 使用 全髋关节置换术中的非骨水泥技术增加了对 应力诱导的骨重建、固定和长期生物相容性。 不同严重程度的近端皮质吸收已被报告， 各种非骨水泥型股骨柄，由CoCr或Ti6 Al 4V制成。 皮质骨吸收可导致宿主骨的衰竭， 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 了解应力引起的骨变化与骨损伤之间的关系， 非骨水泥型全髋关节置换术（THA）后的股骨近端， 植入物设计。 我们建议通过研究来调查这种关系 骨重建作为与股骨柄相关的横截面刚度的函数 模量和股骨柄几何形状。 将检验两个假设。 (1)的弹性模量和几何形状。 可以调节股骨柄，以最大限度地减少长期股骨重塑 变化 (2)假体引起的变化与 股骨的力学环境与皮质形态的适应性变化 是非线性的。 具体来说，我们计划评估大规模 股骨柄（i）弹性模量和（ii）几何形状的变化（在本研究中， 植入物的质心和弯曲轴相对于那些 的股骨）对犬模型中骨形态变化的影响，而 考虑到茎部位置的个体差异， 股管 这些数据将用于确定是否存在关系 假体引起的股骨应力/应变变化与 骨形态的变化是线性或非线性的。 因此，两个关键的临床问题是（i）骨重建如何随时间变化， 潜在临床可行性的相对股骨柄刚度范围， (ii)股骨柄几何形状是否影响非骨水泥型股骨柄植入后的近端骨丢失 THA？ 为了解决这些问题，将使用犬初次THA模型， 该杆刚度将在10倍范围内变化。 在一个单独 实验中，茎的形状会有所不同。 实验终点将是 对处理的结构响应（例如，皮质区的变化， 厚度和孔隙率以及髓骨密度）。 数据将 分析以测试设计变量对重塑的影响， 反应，并确定如何机械假体诱导 股骨力学环境的变化对应于骨 适应性反应 这些实验的目的是为了推导出 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.