Ghosh Rajesh, Gupta Sanjay, Dickinson Alexander, Browne Martin
Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721 302, West Bengal, India.
J Biomech Eng. 2012 Aug;134(8):081003. doi: 10.1115/1.4007173.
A detailed understanding of the changes in load transfer due to implantation is necessary to identify potential failure mechanisms of orthopedic implants. Computational finite element (FE) models provide full field data on intact and implanted bone structures, but their validity must be assessed for clinical relevance. The aim of this study was to test the validity of FE predicted strain distributions for the intact and implanted pelvis using the digital image correlation (DIC) strain measurement technique. FE models of an in vitro hemipelvis test setup were produced, both intact and implanted with an acetabular cup. Strain predictions were compared to DIC and strain rosette measurements. Regression analysis indicated a strong linear relationship between the measured and predicted strains, with a high correlation coefficient (R = 0.956 intact, 0.938 implanted) and a low standard error of the estimate (SE = 69.53 με, 75.09 με). Moreover, close agreement between the strain rosette and DIC measurements improved confidence in the validity of the DIC technique. The FE model therefore was supported as a valid predictor of the measured strain distribution in the intact and implanted composite pelvis models, confirming its suitability for further computational investigations.
深入了解植入导致的载荷传递变化对于确定骨科植入物的潜在失效机制至关重要。计算有限元（FE）模型可提供完整和植入后骨结构的全场数据，但其有效性必须针对临床相关性进行评估。本研究的目的是使用数字图像相关（DIC）应变测量技术测试FE预测的完整和植入骨盆应变分布的有效性。制作了体外半骨盆测试装置的FE模型，包括完整的和植入髋臼杯的模型。将应变预测结果与DIC和应变片测量结果进行比较。回归分析表明，测量应变与预测应变之间存在很强的线性关系，相关系数较高（完整模型R = 0.956，植入模型R = 0.938），估计标准误差较低（SE = 69.53με，75.09με）。此外，应变片和DIC测量结果之间的密切一致性提高了对DIC技术有效性的信心。因此，FE模型被认为是完整和植入复合骨盆模型中测量应变分布的有效预测器，证实了其适用于进一步的计算研究。
