Biomechanics Section, Department of Mechanical Engineering, KU Leuven, Celestijnenlaan 300C, 3001, Leuven, Belgium.
Department of Traumatology, University Hospitals Gasthuisberg, Leuven, Belgium.
Sci Rep. 2022 May 9;12(1):7602. doi: 10.1038/s41598-022-11667-x.
Femoroplasty is a procedure where bone cement is injected percutaneously into a weakened proximal femur. Uncertainty exists whether femoroplasty provides sufficient mechanical strengthening to prevent fractures in patients with femoral bone metastases. Finite element models are promising tools to evaluate the mechanical effectiveness of femoroplasty, but a thorough validation is required. This study validated a voxel-based finite element model against experimental data from eight pairs of human cadaver femurs with artificial metastatic lesions. One femur from each pair was left untreated, while the contralateral femur was augmented with bone cement. Finite element models accurately predicted the femoral strength in the defect (R = 0.96) and augmented (R = 0.93) femurs. The modelled surface strain distributions showed a good qualitative match with results from digital image correlation; yet, quantitatively, only moderate correlation coefficients were found for the defect (mean R = 0.78) and augmented (mean R = 0.76) femurs. This was attributed to the presence of vessel holes in the femurs and the jagged surface representation of our voxel-based models. Despite some inaccuracies in the surface measurements, the FE models accurately predicted the global bone strength and qualitative deformation behavior, both before and after femoroplasty. Hence, they can offer a useful biomechanical tool to assist clinicians in assessing the need for prophylactic augmentation in patients with metastatic bone disease, as well as in identifying suitable patients for femoroplasty.
股骨成形术是一种通过皮骨将骨水泥注入到脆弱的股骨近端的手术。对于股骨转移瘤患者，股骨成形术是否能提供足够的机械强化以防止骨折，目前仍存在不确定性。有限元模型是评估股骨成形术机械效果的有前途的工具，但需要进行彻底的验证。本研究使用基于体素的有限元模型对 8 对具有人工转移性病变的人类尸体股骨的实验数据进行了验证。每对股骨中的一根未经处理，而对侧股骨则用骨水泥增强。有限元模型准确地预测了缺陷（R=0.96）和增强（R=0.93）股骨中的股骨强度。模拟的表面应变分布与数字图像相关的结果具有良好的定性匹配；然而，对于缺陷（平均 R=0.78）和增强（平均 R=0.76）股骨，仅发现中等程度的相关系数。这归因于股骨中的血管孔和基于体素模型的锯齿表面表示。尽管表面测量存在一些不准确性，但 FE 模型准确地预测了股骨成形术前后的整体骨强度和定性变形行为。因此，它们可以为临床医生提供一种有用的生物力学工具，以帮助评估患有转移性骨病的患者是否需要预防性增强，以及识别适合股骨成形术的患者。
