van Duren Bernard H, Ilo Kevin, Walker Sophie, Higgins Mark, Bloch Benjamin V, Manktelow Andrew R, Pandit Hemant G
Nottingham Elective Orthopaedic Services, Nottingham University Hospitals NHS Trust, Nottingham, UK.
Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds, UK.
Bone Joint Res. 2025 May 19;14(5):477-484. doi: 10.1302/2046-3758.145.BJR-2024-0273.R1.
Periprosthetic fracture is a major contributor to reoperation with polished taper slip (PTS) cemented stems, which is the most used fixation technique in many countries. A clear cause for this has yet to be established. A significant variation exists between PTS stem designs, associated fractured rates among them, and the design of introducers used. Achieving a conforming implant-cement interface (ICI) is crucial to ensure optimal function of PTS implants. Movement of the stem within the setting cement during surgery should be uniplanar, and should not be associated with any unplanned deviations. This is in part controlled by the stem introducer design, which potentially contributes to excess movement and ICI compromise. The aim of this study was to assess movement when using different introducer designs.
We compared four stem introducer designs used with two commonly used PTS stems. The stems were mounted using a silicone rubber compound to simulate setting cement at different timepoints (early = soft, late = hard). The stem tips were left clear, and an inertial measurement unit attached to measure acceleration, angular velocity, and rotation. Participating surgeons (n = 16) were asked to maintain stem position for ten seconds before releasing the introducer.
Simulation of soft cement conditions showed a mean root mean square (RMS) value ranging from 0.10 g to 0.30 g for acceleration, 12.75°/s to 67.94°/s for angular velocity, and 2.02° to 6.03° for rotation with significant differences noted between different stem introducers. Simulation of later insertion during the curing process (hard) showed a similar pattern, with a lower overall range of motion.
Our results showed that introducer design had a significant impact on stem movement within the setting cement. Furthermore, its removal earlier in the setting reaction resulted in increased movement. These findings highlight the importance of instrument design and correct technique in achieving the optimal ICI.
假体周围骨折是导致使用抛光锥形滑移（PTS）骨水泥型股骨柄进行再次手术的主要原因，而PTS骨水泥型股骨柄是许多国家最常用的固定技术。目前尚未明确其确切原因。PTS股骨柄设计、相关骨折发生率以及所使用的插入器设计之间存在显著差异。实现贴合的植入物 - 骨水泥界面（ICI）对于确保PTS植入物的最佳功能至关重要。手术过程中，股骨柄在凝固的骨水泥内的移动应是单平面的，且不应伴有任何意外偏差。这部分受股骨柄插入器设计的控制，而插入器设计可能导致过度移动并损害ICI。本研究的目的是评估使用不同插入器设计时的移动情况。
我们比较了与两种常用PTS股骨柄一起使用的四种股骨柄插入器设计。使用硅橡胶化合物安装股骨柄，以模拟在不同时间点（早期 = 软，晚期 = 硬）凝固的骨水泥。股骨柄尖端保持清晰，并连接一个惯性测量单元以测量加速度、角速度和旋转。要求参与的外科医生（n = 16）在松开插入器之前将股骨柄位置保持十秒。
软骨水泥条件模拟显示，加速度的均方根（RMS）值范围为0.10 g至0.30 g，角速度为12.75°/秒至67.9°/秒，旋转为2.02°至6.03°，不同股骨柄插入器之间存在显著差异。固化过程后期插入（硬）的模拟显示出类似模式，但总体运动范围较小。
我们的结果表明，插入器设计对凝固骨水泥内的股骨柄移动有显著影响。此外，在凝固反应早期移除插入器会导致移动增加。这些发现突出了器械设计和正确技术在实现最佳ICI方面的重要性。
