Diaz Miguel A, Hsu Jason E, Ricchetti Eric T, Garrigues Grant E, Gutierrez Sergio, Frankle Mark A
Foundation for Orthopaedic Research and Education, Tampa, FL, USA.
Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
JSES Int. 2020 Apr 28;4(2):388-396. doi: 10.1016/j.jseint.2020.02.004. eCollection 2020 Jun.
A linear relationship between baseplate insertion torque and compression force in reverse shoulder arthroplasty (RSA) baseplates with central screw design has been recently established. In this study, we evaluated 3 different baseplate designs and their influence on the torque-compression relationship.
Three different RSA baseplate designs were evaluated through biomechanical testing using a glenoid vault, bone surrogate model. A digital torque gauge was used to measure insertion torque applied to the baseplate, whereas compression data were collected continuously from a load cell. Additionally, 2 predictive models were developed to predict the compression forces of each baseplate design at varying levels of torque.
A linear relationship was found between baseplate compression and insertion torque for all 3 baseplate designs. Both the monoblock and 2-piece locking designs achieved the goal torque of 6.8 Nm, whereas the 2-piece nonlocking design did not due to material strip-out. No significant difference in maximum compression was found between the monoblock and 2-piece locking designs. However, the 2-piece nonlocking design achieved significantly higher compression. Both predictive models were shown to adequately predict compressive forces at different torque inputs for the monoblock and 2-piece locking designs but not the 2-piece nonlocking design.
The torque-compression relationship of a central screw baseplate is significantly affected by baseplate design. A 2-piece nonlocking baseplate reaches higher compression levels and risks material strip-out at lower insertional torques compared with a monoblock and 2-piece locking design. This has implications both on component design and on surgeon tactile feedback during surgery.
最近已证实，采用中心螺钉设计的反肩关节置换术（RSA）基板的基板插入扭矩与压缩力之间存在线性关系。在本研究中，我们评估了3种不同的基板设计及其对扭矩-压缩关系的影响。
使用肩胛盂骨替代模型，通过生物力学测试评估3种不同的RSA基板设计。使用数字扭矩计测量施加在基板上的插入扭矩，而压缩数据则通过称重传感器连续收集。此外，还开发了2种预测模型，以预测每种基板设计在不同扭矩水平下的压缩力。
所有3种基板设计的基板压缩与插入扭矩之间均发现存在线性关系。整体式和两件式锁定设计均达到了6.8 Nm的目标扭矩，而两件式非锁定设计由于材料剥离未达到该目标扭矩。整体式和两件式锁定设计之间在最大压缩方面未发现显著差异。然而，两件式非锁定设计实现了显著更高的压缩。两种预测模型均显示能够充分预测整体式和两件式锁定设计在不同扭矩输入下的压缩力，但不能预测两件式非锁定设计的压缩力。
中心螺钉基板的扭矩-压缩关系受基板设计的显著影响。与整体式和两件式锁定设计相比，两件式非锁定基板在较低插入扭矩下可达到更高的压缩水平，但存在材料剥离风险。这对组件设计以及手术过程中外科医生的触觉反馈均有影响。
