Schlieker Peter J, Lampe Frank, Zwirner Johann, Ondruschka Benjamin, Morlock Michael M, Huber Gerd
Hamburg University of Technology, Institute of Biomechanics, Denickestrasse 15, 21073 Hamburg, Germany.
Asklepios Klinik Barmbek, Rübenkamp 220, 22307 Hamburg, Germany; Hamburg University of Applied Sciences, Faculty of Life Sciences, Ulmenliet 20, 21033 Hamburg, Germany.
Clin Biomech (Bristol). 2025 May;125:106530. doi: 10.1016/j.clinbiomech.2025.106530. Epub 2025 Apr 20.
In cementless total hip arthroplasty stems are inserted into the bone by mallet blows. Surgeons are not instructed to adjust the force of their blows to differences among patients especially with regard to weight. Whether this is linked to complications is yet unknown. This study investigated factors that could affect the mechanical behavior of the femur-tissue system.
Four cadavers were subject to two total hip arthroplasties by the same surgeon - one side via a lateral approach and the contralateral side via a direct anterior approach. A mass-spring-damper model was used to replicate the mechanical response of the femur-tissue system of the cadavers and make them comparable.
The mechanical response in terms of mass-spring-damper parameters differed between the approaches (lateral: 16.5 kg, 29.7 N/mm, 467.1 Ns/m; direct anterior: 11.5 kg, 41.7 N/mm, 553.0 Ns/m).
Common metal-on-metal mallet blows in surgery are very short and mostly excite high frequencies that are clearly above the natural frequency of the femur-tissue system. Those overcritical force impulses make the stem slide into the femur before the bone can even start moving. Hence, the individual mechanical behavior of the femur-tissue system can be disregarded provided that the force is applied with very short blows. This needs to be considered for any attempt to replace the mallet in the operation theater (e.g. automated surgical impaction tools) or to modify the mallet (e.g. alternative tip material). Furthermore, it may provide guidance on the fixation of femurs in in vitro testing to mimic surgical reality.
在非骨水泥型全髋关节置换术中，假体柄通过锤击植入骨内。外科医生未被指导根据患者之间的差异（尤其是体重差异）来调整锤击力度。这是否与并发症有关尚不清楚。本研究调查了可能影响股骨 - 组织系统力学行为的因素。
对四具尸体由同一位外科医生进行两次全髋关节置换术，一侧采用外侧入路，对侧采用直接前方入路。使用质量 - 弹簧 - 阻尼器模型来复制尸体股骨 - 组织系统的力学响应并使其具有可比性。
两种入路在质量 - 弹簧 - 阻尼器参数方面的力学响应有所不同（外侧：16.5千克，29.7牛/毫米，467.1牛·秒/米；直接前方：11.5千克，41.7牛/毫米，553.0牛·秒/米）。
手术中常见的金属对金属锤击非常短暂，且大多激发明显高于股骨 - 组织系统固有频率的高频。这些超临界力脉冲使假体柄在骨骼甚至尚未开始移动之前就滑入股骨。因此，只要以非常短暂的锤击施加力，就可以忽略股骨 - 组织系统的个体力学行为。对于手术室中任何试图替代锤子的尝试（例如自动化手术冲击工具）或对锤子进行改进（例如替代尖端材料），都需要考虑这一点。此外，它可能为体外测试中模拟手术实际情况的股骨固定提供指导。
