Faculty of Biomedical Engineering, Amirkabir University of Technology, 424 Hafez Ave, Tehran, Iran.
Orthopedic Research Center, Department of Orthopedic Surgery, Mashhad University of Medical Sciences, Ahmad Abad Street. Ghaem Hospital, Mashhad, Iran.
Comput Biol Med. 2019 Sep;112:103360. doi: 10.1016/j.compbiomed.2019.103360. Epub 2019 Jul 16.
Cement augmentation following benign bone tumor surgery, i.e. curettage and cementation, is recommended in patients at high risk of fracture. Nonetheless, identifying appropriate cases and devices for augmentation remains debatable. Our goal was to develop a validated biomechanical tool to: predict the post-surgery strength of a femoral bone, assess the precision and accuracy of the predicted strength, and discover the mechanisms of reconstruction failure, with the aim of finding a safe biomechanical fixation. Tumor surgery was mimicked in quantitative-CT (QCT) scanned cadaveric human distal femora, and subsequently tested in compression to measure bone strength (F). Finite element (FE) models considering bone material non-homogeneity and non-linearity were constructed to predict bone strength (F). Analyses of contact, damage, and crack initiation at the bone-cement interface (BCI) were completed to investigate critical failure locations. Results of paired t-tests did not show a significant difference between F and F (P > 0.05); linear regression analysis resulted in good correlation between F and F (R = 0.94). Evaluation of the models precision using linear regression analysis yielded R = 0.89, with the slope = 1.08 and intercept = -324.16 N. FE analyses showed the initiation of damage and crack and a larger cement debonding area at the proximal end and most interior part of BCI, respectively. Therefore, we speculated that devices that reinforce critical failure locations offer the most biomechanical advantage. The QCT-based FE method proved to be a reliable tool to predict distal femoral strength, identify some causes of reconstruction failure, and assist in a safer selection of fixation devices to reduce post-operative fracture risk.
良性骨肿瘤手术后（即刮除和骨水泥填充）进行骨水泥增强，适用于高骨折风险的患者。然而，确定合适的病例和增强装置仍然存在争议。我们的目标是开发一种经过验证的生物力学工具：预测股骨手术后的强度，评估预测强度的精度和准确性，并发现重建失败的机制，旨在找到安全的生物力学固定。在定量 CT（QCT）扫描的尸体人类股骨远端模拟肿瘤手术，随后进行压缩测试以测量骨强度（F）。构建了考虑骨材料非均匀性和非线性的有限元（FE）模型来预测骨强度（F）。完成了骨-水泥界面（BCI）的接触、损伤和裂纹起始分析，以研究关键失效位置。配对 t 检验的结果表明 F 和 F 之间没有显著差异（P>0.05）；线性回归分析表明 F 和 F 之间具有良好的相关性（R=0.94）。使用线性回归分析评估模型精度，得到 R=0.89，斜率=1.08，截距=-324.16 N。FE 分析显示，在 BCI 的近端和最内部部分分别出现了损伤和裂纹的起始以及更大的水泥脱粘区域。因此，我们推测，加固关键失效位置的装置提供了最大的生物力学优势。基于 QCT 的 FE 方法被证明是一种可靠的工具，可以预测股骨远端的强度，确定一些重建失败的原因，并有助于更安全地选择固定装置，以降低术后骨折风险。
