MacLeod A, Simpson A H R W, Pankaj P
The University of Edinburgh.
Department of Orthopaedic Surgery, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SB, UK.
Bone Joint Res. 2018 Jan;7(1):111-120. doi: 10.1302/2046-3758.71.BJR-2017-0074.R2.
Secondary fracture healing is strongly influenced by the stiffness of the bone-fixator system. Biomechanical tests are extensively used to investigate stiffness and strength of fixation devices. The stiffness values reported in the literature for locked plating, however, vary by three orders of magnitude. The aim of this study was to examine the influence that the method of restraint and load application has on the stiffness produced, the strain distribution within the bone, and the stresses in the implant for locking plate constructs.
Synthetic composite bones were used to evaluate experimentally the influence of four different methods of loading and restraining specimens, all used in recent previous studies. Two plate types and three screw arrangements were also evaluated for each loading scenario. Computational models were also developed and validated using the experimental tests.
The method of loading was found to affect the gap stiffness strongly (by up to six times) but also the magnitude of the plate stress and the location and magnitude of strains at the bone-screw interface.
This study demonstrates that the method of loading is responsible for much of the difference in reported stiffness values in the literature. It also shows that previous contradictory findings, such as the influence of working length and very large differences in failure loads, can be readily explained by the choice of loading condition. 2018;7:111-120.
二次骨折愈合受到骨固定系统刚度的强烈影响。生物力学测试被广泛用于研究固定装置的刚度和强度。然而，文献中报道的锁定钢板的刚度值相差三个数量级。本研究的目的是检验约束和加载方法对锁定钢板结构产生的刚度、骨内应变分布以及植入物应力的影响。
使用合成复合骨通过实验评估四种不同的加载和约束标本方法的影响，所有这些方法都在之前的近期研究中使用过。对于每种加载情况，还评估了两种钢板类型和三种螺钉排列方式。还开发了计算模型并通过实验测试进行了验证。
发现加载方法对间隙刚度有很大影响（高达六倍），而且对钢板应力的大小以及骨 - 螺钉界面处应变的位置和大小也有影响。
本研究表明，加载方法是文献中报道的刚度值存在诸多差异的主要原因。它还表明，以前相互矛盾的研究结果，如工作长度的影响和破坏载荷的巨大差异，可以很容易地通过加载条件的选择来解释。2018年；7：111 - 120。
