A round-robin finite element analysis of human femur mechanics between seven participating laboratories with experimental validation

Abstract Finite element analysis is a common tool that has been used for the past few decades to predict the mechanical behavior of bone. However, to our knowledge, there are no round-robin finite element analyses of long human bones with more than two participating biomechanics laboratories published yet, where the results of the experimental tests were not known in advance. We prepared a fresh-frozen human femur for a compression test in a universal testing machine measuring the strains at 10 bone locations as well as the deformation of the bone in terms of the displacement of the loading point at a load of 2 kN. The computed tomography data of the bone with a calibration phantom as well as the orientation of the bone in the testing machine with the according boundary conditions were delivered to seven participating laboratories. These were asked to perform a finite element analysis simulating the experimental setup and deliver their results to the coordinator without knowing the experimental results. Resultantly, four laboratories had deviations from the experimentally measured strains of less than 40%, and three laboratories had deviations of their numerically determined values compared to the experimental data of more than 120%. These deviations are thought to be based on different material laws and material data, as well as different material mapping methods. Investigations will be conducted to clarify and assess the reasons for the large deviations in the numerical data. It was shown that the precision of finite element models of the human femur is not yet as developed as desired by the biomechanics community.

[1]  Leonard Steinborn,et al.  International Organization for Standardization ISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories , 2004 .

[2]  Zohar Yosibash,et al.  Pathological fracture risk assessment in patients with femoral metastases using CT-based finite element methods. A retrospective clinical study. , 2018, Bone.

[3]  Peter Augat,et al.  An investigation to determine if a single validated density-elasticity relationship can be used for subject specific finite element analyses of human long bones. , 2013, Medical engineering & physics.

[4]  M. Viceconti,et al.  Mathematical relationships between bone density and mechanical properties: a literature review. , 2008, Clinical biomechanics.

[5]  D. Dragomir-Daescu,et al.  QCT/FEA predictions of femoral stiffness are strongly affected by boundary condition modeling , 2016, Computer methods in biomechanics and biomedical engineering.

[6]  Peter Augat,et al.  Individual density-elasticity relationships improve accuracy of subject-specific finite element models of human femurs. , 2013, Journal of biomechanics.

[7]  K. Radermacher,et al.  Critical evaluation of known bone material properties to realize anisotropic FE-simulation of the proximal femur. , 2000, Journal of biomechanics.

[8]  A Rohlmann,et al.  Comparison of eight published static finite element models of the intact lumbar spine: predictive power of models improves when combined together. , 2014, Journal of biomechanics.

[9]  F. Kainberger,et al.  A nonlinear QCT-based finite element model validation study for the human femur tested in two configurations in vitro. , 2013, Bone.

[10]  Christian Schröder,et al.  Subject-specific finite element simulation of the human femur considering inhomogeneous material properties: A straightforward method and convergence study , 2013, Comput. Methods Programs Biomed..

[11]  M. Viceconti,et al.  The material mapping strategy influences the accuracy of CT-based finite element models of bones: an evaluation against experimental measurements. , 2007, Medical engineering & physics.

[12]  Wei Chen,et al.  Influence of Different Boundary Conditions in Finite Element Analysis on Pelvic Biomechanical Load Transmission , 2017, Orthopaedic surgery.

[13]  Ridha Hambli,et al.  Finite element prediction of proximal femur fracture pattern based on orthotropic behaviour law coupled to quasi-brittle damage. , 2012, Medical engineering & physics.

[14]  B Helgason,et al.  The influence of the modulus-density relationship and the material mapping method on the simulated mechanical response of the proximal femur in side-ways fall loading configuration. , 2016, Medical engineering & physics.

[15]  H. Genant,et al.  Comparison of proximal femur and vertebral body strength improvements in the FREEDOM trial using an alternative finite element methodology. , 2015, Bone.

[16]  Zhongmin Jin,et al.  Parametric study of patient-specific femoral locking plates based on a combined musculoskeletal multibody dynamics and finite element modeling , 2018, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[17]  Zohar Yosibash,et al.  Patient-specific finite element analysis of the human femur--a double-blinded biomechanical validation. , 2011, Journal of biomechanics.

[18]  Nico Verdonschot,et al.  Morphology based cohesive zone modeling of the cement-bone interface from postmortem retrievals. , 2011, Journal of the mechanical behavior of biomedical materials.

[19]  W. Kalender,et al.  A phantom for standardization and quality control in peripheral bone measurements by PQCT and DXA , 1993 .

[20]  C. Milgrom,et al.  Predicting the stiffness and strength of human femurs with real metastatic tumors. , 2014, Bone.

[21]  T. Keaveny,et al.  Trabecular bone modulus-density relationships depend on anatomic site. , 2003, Journal of biomechanics.

[22]  Zdenek Horak,et al.  Comparison of isotropic and orthotropic material property assignments on femoral finite element models under two loading conditions. , 2007, Medical engineering & physics.

[23]  H Weinans,et al.  Effects of fit and bonding characteristics of femoral stems on adaptive bone remodeling. , 1994, Journal of biomechanical engineering.

[24]  Marco Viceconti,et al.  Subject-specific finite element models can accurately predict strain levels in long bones. , 2007, Journal of biomechanics.

[25]  Daniel Kluess,et al.  Interlaboratory comparison of femur surface reconstruction from CT data compared to reference optical 3D scan , 2018, BioMedical Engineering OnLine.

[26]  Bernd-Arno Behrens,et al.  Numerical investigations on the strain-adaptive bone remodelling in the periprosthetic femur: Influence of the boundary conditions , 2009, Biomedical engineering online.

[27]  Rainer Bader,et al.  A convenient approach for finite-element-analyses of orthopaedic implants in bone contact: Modeling and experimental validation , 2009, Comput. Methods Programs Biomed..

[28]  E. Dall’Ara,et al.  Orthotropic HR-pQCT-based FE models improve strength predictions for stance but not for side-way fall loading compared to isotropic QCT-based FE models of human femurs. , 2014, Journal of the mechanical behavior of biomedical materials.

[29]  P. Zysset,et al.  Mechanical properties of cortical bone and their relationships with age, gender, composition and microindentation properties in the elderly. , 2016, Bone.

[30]  Mark Taylor,et al.  Four decades of finite element analysis of orthopaedic devices: where are we now and what are the opportunities? , 2015, Journal of biomechanics.

[31]  A. Cong,et al.  In situ parameter identification of optimal density-elastic modulus relationships in subject-specific finite element models of the proximal femur. , 2011, Medical engineering & physics.

[32]  Marcus G Pandy,et al.  Grand challenge competition to predict in vivo knee loads , 2012, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[33]  G Chen,et al.  Comparisons of node-based and element-based approaches of assigning bone material properties onto subject-specific finite element models. , 2015, Medical engineering & physics.