Biomechanics Section, KU Leuven, Celestijnenlaan 300C, 3001 Leuven, Belgium.
Materialise NV, Technologielaan 15, 3001 Leuven, Belgium.
J Orthop Res. 2019 Mar;37(3):681-688. doi: 10.1002/jor.24240. Epub 2019 Feb 28.
Short stem hip implants are becoming increasingly popular since they preserve bone stock and presumably reduce stress-shielding. However, concerns remain whether they are suitable for a wide range of patients with varying anatomy. The aim of this study was to investigate how femoral anatomy influences stress-shielding induced by a short calcar-guided stem across a set of 90 CT-based femur models. A computational tool was developed that automatically selected the optimal size and position of the stem. Finite element models of the intact and implanted femurs were constructed and subjected to walking loads. Stress-shielding was evaluated in relevant volumes of interest of the proximal femur. After a detailed anatomical analysis, linear regression was performed to find potential correlations between anatomy and stress-shielding. Stress-shielding was found to be highest in the proximal regions on the medial and posterior side. A highly significant negative relationship was observed between stress-shielding and bone density; a strong positive relationship was observed with stem size and the valgus orientation of the stem with respect to the femur. The results reveal how anatomy influences stress-shielding, and they highlight the importance of evaluating new implant designs across a large population taking into account the anatomical variability. The study demonstrates that such large population studies can be conducted in an efficient way using an automated workflow. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-8, 2019.
短柄髋关节植入物越来越受欢迎，因为它们可以保留骨量，并降低应力遮挡。然而，人们仍然担心它们是否适合具有不同解剖结构的广泛患者。本研究旨在研究股骨解剖结构如何影响短柄导针引导的股骨假体的应力遮挡。开发了一种计算工具，可自动选择最佳的柄尺寸和位置。构建了完整和植入股骨的有限元模型，并施加行走负荷。评估了近端股骨的相关感兴趣区域的应力遮挡。经过详细的解剖分析，进行线性回归以找到解剖结构与应力遮挡之间的潜在相关性。在股骨的内侧和后侧的近端区域发现了最高的应力遮挡。在应力遮挡和骨密度之间观察到高度显著的负相关；在柄的尺寸和柄相对于股骨的外翻角度之间观察到强的正相关。结果揭示了解剖结构如何影响应力遮挡，并强调了在考虑解剖结构变异性的情况下，对新植入物设计进行大规模人群评估的重要性。该研究表明，使用自动化工作流程可以有效地进行此类大型人群研究。©2019 矫形研究学会。由 Wiley Periodicals, Inc. 出版。J Orthop Res 9999：1-8，2019。
