Influence of Different Boundary Conditions in Finite Element Analysis on Pelvic Biomechanical Load Transmission

Abstract

Objective: To observe the effects of boundary conditions and connect conditions on biomechanics predictions in finite element (FE) pelvic models.Methods: Three FE pelvic models were constructed to analyze the effect of boundary conditions and connect conditions in the hip joint: an intact pelvic model assumed contact of the hip joint on both sides (Model I); and a pelvic model assumed the hip joint connecting surfaces fused together with (Model II) or without proximal femurs (Model III). The model was validated by bone surface strains obtained from strain gauges in an in vitro pelvic experiment. Vertical load was applied to the pelvic specimen, and the same load was simulated in the FE model. Results:There was a strong correlation between the FE analysis results of Model I and the experimental results (R 2 = 0.979); meanwhile, the correlation coefficient and the linear regression function increased slightly with increasing load force. Comparing the three models, the stress values in the point near the pubic symphysis in Model III were 48.52 and 39.1% lower, respectively, in comparison with Models I and II. Furthermore, the stress values on the dome region of the acetabulum in Models II and III were 103.61 and 390.53% less than those of Model I. Besides, the posterior acetabular wall stress values of Model II were 197.15 and 305.17% higher than those of Models I and III, respectively.Conclusions: These findings suggest that the effect of the connect condition in the hip joint should not be neglected, especially in studies related to clinical applications.

In-silico pelvis and sacroiliac joint motion—A review on published research using numerical analyses

“…Equally, minute sample sizes (Bruna-Rosso et al, 2016;Shi et al, 2014) for validation or non-physiological loading conditions with rigidly-fixed innominate bones (Bruna-Rosso et al, 2016) lower the significance of existing studies, including our own previous findings, as in-silico deformations vary by up to two magnitudes comparing the evident movement to the in-silico models (Hammer et al, 2013;Sichting et al, 2014). Of the 33 computational studies of the pelvis, only seven make an attempt to perform a cadaveric validation in a standardized manner (Anderson et al, 2004;Bodzay et al, 2014;Bruna-Rosso et al, 2016;García et al, 2000;Hammer et al, 2013;Hao et al, 2011;Hu et al, 2017). The remaining majority performs validation based on literature, qualitative description, plastic models or none.…”

“…Regarding material properties, a majority of models were stated as being linear elastic (Tables 1a,1b,1c), and only three models were nonlinear (Anderson et al, 2004;Eichenseer et al, 2011;Lee et al, 2017). Isotropic material properties form the majority of the existing modeling approaches, whereas only four studies used non-isotropic material parameters (Anderson et al, 2004;Hao et al, 2011;Hu et al, 2017;Shi et al, 2014). No material model was given in the remaining models.…”

“…The underlying data for the material models was primarily obtained from literature with few exceptions. To date, only seven studies have assessed their models parametrically to investigate the influence of alternating material properties and boundary conditions on pelvis and SIJ deformation (Eichenseer et al, 2011;Hammer et al, 2013;Hao et al, 2011;Hu et al, 2017;Ma et al, 2015;Phillips et al, 2007b;Watson et al, 2017).…”

“…Primary objectives in the field of (basic science) biomechanical research of the human pelvis were primarily to refine models, resulting in realistic load deformations (Anderson et al, 2004;Ma et al, 2015;Volinski et al, 2018) or to compare the effects of boundary conditions on pelvic motion (Hu et al, 2017;Phillips et al, 2007a;Shi et al, 2014;Watson et al, 2017). Further research in the field addressed the influence of the altered ligament strain in relation to pelvic motion (Buford et al, 2010;Eichenseer et al, 2011;Hammer et al, 2013;Hao et al, 2011), or the reciprocal influence of the SIJ-hip joint complex.…”

Computational Biomechanical Analysis of Postoperative Calcaneal Fractures with Different Placement of the Sustentaculum Screw

“…Compared with the limitation of source shortage of specimens, and the inability to perform the research with different load conditions on cadaver specimens or physical models, the three‐dimensional (3‐D) finite element analysis (FEA) method has become one of the most effective approaches for biomechanical studies due to the rapid development of computer technology. As a reliable and effective computational biomechanical tool, FEA could be used to calculate the stress distribution, the contact area, and the displacement of the specific model. Ni et al .…”