Title: Development of a finite element model to study the torsional fracture strength of an analogue tibia with bicortical holes

Authors: Kimberly Reuter; Alexander Chong; Viswanathan Madhavan; Paul H. Wooley; Mark Virginia; Hamid M. Lankarani

Addresses: Center of Innovation for Biomaterials in Orthopaedic Research, National Institute for Aviation Research, Wichita State University, Wichita, Kansas, 67260-0093, USA ' Orthopaedic Research Institute, Via Christi Health, 929 N. St. Francis, Wichita, KS 67214, USA ' Industrial and Manufacturing Engineering Department, College of Engineering, Wichita State University, 1845 N. Fairmount Street, Wichita, Kanas, 67260-0035, USA ' Center of Innovation for Biomaterials in Orthopedic Research, Orthopaedic Research Institute, Via Christi Health, 929 N. St. Francis, Wichita, KS 67214, USA ' Altair Engineering, 3303 Monte Villa Parkway, Suite 320, Bothell, Washington 98021, USA ' Mechanical Engineering Department, College of Engineering, Wichita State University, 1845 N. Fairmount Street, Wichita, Kanas, 67260-0133, USA

Abstract: Fractured bones are often stabilised with orthopaedic fracture plates and screws until healed. If the plates and screws are removed, the vacant screw holes introduce a potential site for re-fracture. This study is aimed at simulating a laboratory torsional fracture test of a composite analogue tibia with vacant screw holes using a finite element (FE) model. This FE model is set up the same as the experimental torsion test, with a section from the distal portion of the tibia. The FE model contains over 35k second-order brick elements and nearly 165k nodes. It utilises an isotropic linear elastic material law with material properties obtained from the analogue tibia manufacturer. Comparisons between the experimental model and the FE model consider the fracture torque, fracture angle, and specific torsional stiffness. Stress contours of the FE model are compared to the fracture path of the experimental model. The FE model predicts the fracture location and a fracture torque within the standard deviation of that determined experimentally.

Keywords: finite element analysis; FEA; modelling; biomechanics; composites; human tibia; failure strength; torsion; screw holes; torsional fracture strength; analogue tibia; bicortical holes; bone fractures; bone refracturing; simulation; fracture torque; fracture angle; torsional stiffness; stress contours; fracture path; fracture location.

DOI: 10.1504/IJECB.2013.056528

International Journal of Experimental and Computational Biomechanics, 2013 Vol.2 No.2, pp.158 - 170

Received: 14 Sep 2012
Accepted: 03 Apr 2013
Published online: 12 Jul 2014 *

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