DePuy Synthes, St Anthony's Road, Leeds, LS11 8DT, United Kingdom.
Med Eng Phys. 2023 Aug;118:104020. doi: 10.1016/j.medengphy.2023.104020. Epub 2023 Jul 8.
Despite the clinical success of tapered splined titanium stems, a knowledge gap still exists between spline design and its primary mechanical stability, which is critical to the long-term success of revision hip arthroplasty. Additionally, almost all published pre-clinical studies relied on resource-intensive benchtop and cadaveric testing. Hence, the present study developed a novel computational model to investigate effects of spline geometry and configuration on axial and torsional stability of tapered stem. Dynamic explicit Finite Element Analysis coupled with a state-of-the-art adaptive meshing technique was used to simulate the highly non-linear contacts and large bony material deformations. Hybridising primary straight splines with secondary angled splines results in 41% and 10% increases of peak insertion force and post-seating moment than the predicate device for the same seating position. The primary straight splines cut at multiple circumferential bony locations, enhancing torsional stability; while the alternatively placed secondary angled splines form wedges with the bone, providing reliable seating and additional torsional resistance. To the best knowledge of the author, this is the first in-silico investigation of its kind to simulate multi-strike seating and torsional resistance of revision hip stems, offering an effective and efficient platform for future multi-factorial parametric study and uncertainty quantification.
尽管锥形齿钛合金干骨柄在临床上取得了成功，但齿设计与其主要机械稳定性之间仍存在知识差距，这对翻修髋关节置换术的长期成功至关重要。此外，几乎所有已发表的临床前研究都依赖于资源密集型的台架和尸体测试。因此，本研究开发了一种新的计算模型，以研究齿几何形状和配置对锥形干骨柄轴向和扭转稳定性的影响。动态显式有限元分析结合最先进的自适应网格技术，用于模拟高度非线性接触和大骨材料变形。将主要直齿与次要斜齿混合，与预测设备相比，在相同的入座位置下，峰值插入力和入座后扭矩分别增加了 41%和 10%。主要的直齿在多个圆周骨位置切割，增强了扭转稳定性；而交替放置的次要斜齿与骨骼形成楔形，提供可靠的入座和额外的扭转阻力。据作者所知，这是首次对翻修髋关节干进行多冲击入座和扭转阻力的计算机模拟，为未来的多因素参数研究和不确定性量化提供了一个有效和高效的平台。
