The Relationship between Trabecular Bone Structure Modeling Methods and the Elastic Modulus as Calculated by FEM

• Published in: TheScientificWorld Vol. 2012; no. 2012; pp. 1 - 9
• Main Authors: Cichański, Artur, Topoliński, Tomasz, Mazurkiewicz, Adam, Nowicki, Krzysztof
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Puplishing Corporation 01.01.2012; The Scientific World Journal; John Wiley & Sons, Inc; Wiley
• Subjects: Absorptiometry, Photon; Arthroplasty (hip); Biocompatibility; Biomechanics; Biomedical materials; Bone Density; Bones; Cancellous bone; Clinical medicine; Computed tomography; Computer Simulation; Cores; Elastic deformation; Elastic Modulus; Elastic properties; Femur; Femur - diagnostic imaging; Femur - physiopathology; Finite Element Analysis; Finite element method; Fractures; Hip; Humans; Mathematical models; Mechanical properties; Medical imaging; Methods; Microtomography; Models, Biological; Modulus of elasticity; NMR; Nuclear magnetic resonance; Osteoarthritis, Hip - diagnostic imaging; Osteoarthritis, Hip - physiopathology; Osteoporosis; Osteoporosis - diagnostic imaging; Osteoporosis - physiopathology; Spatial discrimination; Spatial resolution; Surgery; Surgical implants; Tomography, X-Ray Computed
• ISSN: 2356-6140; 1537-744X; 1537-744X
• DOI: 10.1100/2012/827196

Trabecular bone cores were collected from the femoral head at the time of surgery (hip arthroplasty). Investigated were 42 specimens, from patients with osteoporosis and coxarthrosis. The cores were scanned used computer microtomography (microCT) system at an isotropic spatial resolution of 36 microns. Image stacks were converted to finite element models via a bone voxel-to-element algorithm. The apparent modulus was calculated based on the assumptions that for the elastic properties, E=10 MPa and ν=0.3. The compressive deformation as calculated by finite elements (FE) analysis was 0.8%. The models were coarsened to effectively change the resolution or voxel size (from 72 microns to 288 microns or from 72 microns to 1080 microns). The aim of our study is to determine how an increase in the distance between scans changes the elastic properties as calculated by FE models. We tried to find a border value voxel size at which the module values were possible to calculate. As the voxel size increased, the mean voxel volume increased and the FEA-derived apparent modulus decreased. The slope of voxel size versus modulus relationship correlated with several architectural indices of trabecular bone.