A Finite Element Model of a Realistic Foot and Ankle for Flatfoot Analysis Item Type text; Electronic Thesis Authors Williams, Lindsey Leigh Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 27/09/2021 13:32:56 Link to Item http://hdl.handle.net/10150/626145 A FINITE ELEMENT MODEL OF A REALISTIC FOOT AND ANKLE FOR FLATFOOT ANALYSIS by Lindsey Leigh Williams ___________________________ Copyright © Lindsey Leigh Williams 2017 A Thesis Submitted to the Faculty of the DEPARTMENT OF AEROSPACE AND MECHANICAL ENGINEERING In Partial Fulfillment of the Requirements For the Degree of MASTER OF SCIENCE WITH A MAJOR IN MECHANICAL ENGINEERING In the Graduate College THE UNIVERSITY OF ARIZONA 2017 STATEMENT BY AUTHOR The thesis titled A Finite Element Model of a Realistic Foot and Ankle for Flatfoot Analysis prepared by Lindsey Williams has been submitted in partial fulfillment of requirements for a master’s degree at the University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this thesis are allowable without special permission, provided that an accurate acknowledgement of the source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author. SIGNED: Lindsey Williams APPROVAL BY THESIS DIRECTOR This thesis has been approved on the date shown below: _________________________________________ ________ L. Daniel Latt, MD PhD Date Associate Professor Orthopaedic Surgery and Biomedical Engineering 2 ACKNOWLEDGEMENTS I would like to thank: Dr. Daniel Latt and Dr. Erdogan Madenci for their generous help and support. I appreciate their valuable time, guidance, and recommendations. Committee member Dr. John Szivek for his time and insightful suggestions. Eric Lintula from Paragon 28 for his time and recommendations to advance the project. Cody Mitts and Evan Willmarth for helping create the geometry and giving valuable advice. Rafael Bernal, Mehmet Dorduncu, Yile Hu, and Scott Harrison for their support. Dr. Samy Missoum for his thoughtful comments and suggestions. Joe Shaffer, Dustin Boesch, Jeremy Gustin, and Taylor Wender from Quartus Engineering for their valuable time and support for troubleshooting the model. Hari Subramanium from ANSYS for his time and suggestions. Foot & Ankle Orthopaedics for publishing the model on their journal cover. Paragon 28 and the University of Arizona for the financial support. My parents Don and Peggy Conklin, my sister Megan Clarke, and my husband Jacob Williams for their continuous love, patience, and support. 3 TABLE OF CONTENTS LIST OF FIGURES ............................................................................................................................... 6 LIST OF TABLES ................................................................................................................................. 9 1. ABSTRACT ................................................................................................................................... 10 2. BACKGROUND ............................................................................................................................ 11 2.1. Foot Anatomy ..................................................................................................................... 11 2.1.1. Anatomical Coordinates ............................................................................................... 11 2.1.2. Foot Tissues .................................................................................................................. 13 2.2. Adult Acquired Flatfoot ....................................................................................................... 18 2.2.1. Definition ..................................................................................................................... 18 2.2.2. Treatment .................................................................................................................... 21 2.3. Finite Element Method ....................................................................................................... 25 2.4. Literature Review ................................................................................................................ 28 3. FINITE ELEMENT METHOD ......................................................................................................... 30 3.1. Geometry ............................................................................................................................ 30 3.1.1. Bone Assembly ............................................................................................................. 30 3.1.2. Cartilage Assembly ....................................................................................................... 37 3.1.3. Ligament and Tendon Assembly .................................................................................. 38 3.1.4. Ground Surface ............................................................................................................ 40 3.1.5. Geometry Summary ..................................................................................................... 40 3.2. Mesh (Finite elements) ....................................................................................................... 41 3.2.1. Solid Elements .............................................................................................................. 41 3.2.2. Contact Elements ......................................................................................................... 43 3.2.3. Mesh Summary ............................................................................................................ 45 3.3. Material Properties ............................................................................................................. 46 3.4. Boundary Conditions ........................................................................................................... 46 3.5. Loading ................................................................................................................................ 49 4. RESULTS...................................................................................................................................... 52 5. DISCUSSION AND FUTURE WORK .............................................................................................. 54 5.1 Finite Element Model Discussion ......................................................................................... 54 5.1.1 Finite Element Model Benefits ..................................................................................... 54 5.1.2. Finite Element Model Drawbacks ................................................................................ 54 4 5.3. Future Work ........................................................................................................................ 55 5.2.1. Model Adjustments for Convergence .......................................................................... 55 5.2.2. Compare Results .......................................................................................................... 60 5.2.3. Simulate Flatfoot .......................................................................................................... 60 5.2.4. Simulate Osteotomies .................................................................................................. 61 6. CONCLUSION .............................................................................................................................. 62 7. APPENDICES ............................................................................................................................... 63 7.1. APPENDIX A – List of Modeled Bones ................................................................................. 63 7.2. APPENDIX B – List of Modeled Ligaments .......................................................................... 64 7.3. APPENDIX C – List of Modeled Tendons ............................................................................. 66 7.4. APPENDIX D – Model Images courtesy of ANSYS, Inc. Version 17.0 ................................... 67 REFERENCES ................................................................................................................................... 70 5 LIST OF FIGURES Figure 1: Medial, lateral, proximal and distal directional terminology explained using a diagram of the foot (Northcoast Footcare, 2017) ....................................................................................... 12 Figure 2: Three anatomical body planes (coronal, sagittal, and axial) explained using a diagram of the human body (Explaining Spinal Anatomy, 2017) ..................................................................... 13 Figure 3: Foot bones categorized into hindfoot (talus, calcaneus), midfoot (cuneiforms, cuboid, and navicular), and forefoot (metatarsals