Mukherjee Kaushik, Gupta Sanjay
Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India.
Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India
Proc Inst Mech Eng H. 2016 Oct;230(10):918-29. doi: 10.1177/0954411916661368. Epub 2016 Jul 29.
The importance of clinical studies notwithstanding, the failure assessment of implant-bone structure has alternatively been carried out using finite element analysis. However, the accuracy of the finite element predicted results is dependent on the applied loading and boundary conditions. Nevertheless, most finite element-based evaluations on acetabular component used a few selective load cases instead of the eight load cases representing the entire gait cycle. These in silico evaluations often suffer from limitations regarding the use of simplified musculoskeletal loading regimes. This study attempts to analyse the influence of three different loading regimes representing a gait cycle, on numerical evaluations of acetabular component. Patient-specific computer tomography scan-based models of intact and resurfaced pelvises were used. One such loading regime consisted of the second load case that corresponded to peak hip joint reaction force. Whereas the other loading regime consisted of the second and fifth load cases, which corresponded to peak hip joint reaction force and peak muscle forces, respectively. The third loading regime included all the eight load cases. Considerable deviations in peri-acetabular strains, standard error ranging between 115 and 400 µε, were observed for different loading regimes. The predicted bone strains were lower when selective loading regimes were used. Despite minor quantitative variations in bone density changes (less than 0.15 g cm(-3)), the final bone density pattern after bone remodelling was found to be similar for all the loading regimes. Underestimations in implant-bone micromotions (40-50 µm) were observed for selective loading regimes after bone remodelling. However, at immediate post-operative condition, such underestimations were found to be less (less than 5 µm). The predicted results highlight the importance of inclusion of eight load cases representing the gait cycle for in silico evaluations of resurfaced pelvis.
尽管临床研究很重要，但对植入物 - 骨结构的失效评估也可通过有限元分析进行。然而，有限元预测结果的准确性取决于所施加的载荷和边界条件。尽管如此，大多数基于有限元的髋臼组件评估使用的是少数几个选择性载荷情况，而不是代表整个步态周期的八个载荷情况。这些计算机模拟评估在使用简化的肌肉骨骼载荷模式方面常常存在局限性。本研究试图分析代表步态周期的三种不同载荷模式对髋臼组件数值评估的影响。使用了基于患者特定计算机断层扫描的完整和表面置换骨盆模型。一种这样的载荷模式由对应于髋关节反应力峰值的第二个载荷情况组成。而另一种载荷模式由第二个和第五个载荷情况组成，分别对应于髋关节反应力峰值和肌肉力峰值。第三种载荷模式包括所有八个载荷情况。对于不同的载荷模式，观察到髋臼周围应变存在相当大的偏差，标准误差在115至400 με之间。当使用选择性载荷模式时，预测的骨应变较低。尽管骨密度变化存在微小的定量差异（小于0.15 g/cm³），但发现所有载荷模式下骨重塑后的最终骨密度模式相似。在骨重塑后，对于选择性载荷模式，观察到植入物 - 骨微运动存在低估（40 - 50 µm）。然而，在术后即刻状态下，发现这种低估较少（小于5 µm）。预测结果突出了在计算机模拟评估表面置换骨盆时纳入代表步态周期的八个载荷情况的重要性。
