A Thesis entitled The Effects of Radial Core Decompression on Lunate and Scaphoid Kinematics by Andrew E. Smith Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science in Mechanical Engineering Dr. Mohamed Samir Hefzy, Committee Chair Dr. Vijay Goel, Committee Member Dr. Michael Dennis, Committee Member Dr. Abdul-Azim Mustapha, Committee Member Dr. Patricia R. Komuniecki, Dean College of Graduate Studies The University of Toledo May 2012 Copyright 2012, Andrew E. Smith This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. An Abstract of The Effects of Radial Core Decompression on Lunate and Scaphoid Kinematics by Andrew E. Smith Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science in Mechanical Engineering The University of Toledo May 2012 Kienbocks disease causes degeneration of the lunate bone in the wrist leading to pain and reduced function of the joint. Clinical studies have found a new technique, radial core decompression (RCD) to be clinically effective in improving early stage Kienbock's disease. However, there have been no biomechanical studies characterizing the changes in wrist kinematics following the RCD procedure. The purpose of this study is to determine the changes in lunate and scaphoid motions following the RCD procedure. This study employs an electromagnetic 3-dimensional tracking system, Polhemus 3-SPACE to measure the motions of the lunate, scaphoid, and third metacarpal in four cadaveric specimens. Specimens were partially dissected and sutures were attached to five major tendons used for wrist motion. Motion sensors were installed on the lunate, scaphoid, and third metacarpal, and a source was installed on the radius. CT scans were taken of the specimens and digitally reconstructed to determine the relationships between bony coordinate systems and sensor coordinate systems. Wrist specimens were installed in a custom test rig and weights were attached to the sutured tendons to simulate muscle tone. The wrists were passively moved through Flexion/Extension and Radial/Ulnar Deviation motion cycles with motion data collected at various positions through the cycles. iii After collecting motion data for intact wrist specimens, RCD procedures were performed and motion data was collected for the post-RCD wrists. Joint Coordinate Systems were developed for each specimen and test results were calculated as flexion, ulnar deviation, and pronation angles for each position of Flexion/Extension and Ra- dial/Ulnar Deviation motion. Results were normalized so that statistical comparisons could be performed. Results shows statistically significant differences in wrist motion following the RCD technique. However, most of these differences were less than 4 degrees. This suggests there are minimal clinically-relevant changes in wrist kinematics following the RCD technique. iv This work is dedicated to my late mother, Lynn Janet Fluster. Thank You Acknowledgments I extend my fullest gratitude to Dr. Mohamed Samir Hefzy. Thank you for your support, guidance, and patience throughout my master's program. Thank you for the opportunities you gave me, for pushing me, and for providing me with the learning experiences that exceeded my expectations for graduate school. This project would not have been possible without the help of many others. I would like to thank Dr. Philip Nowicki, Dr. Abdul-Azim Mustapha, Dr. Chad Smith, and the rest of the Department of Orthopaedic Surgery for coming forward with this project idea, and providing not only financial support, but the skilled hands and minds to complete the study. I would like to thank my fellow lab mate, Amey Kelkar for helping me with testing. I would like to Dan Ingraham, Zach Nielsen, and Vasanth Allampalli for broadening my MATLAB knowledge. I extend a great thank you to Dr. Michael Dennis and the CT Scanner technicians who found the time to provide me with their expertise and assistance in scanning and processing the data for many specimens. I would also like to thank Dr. Vijay Goel and Mr. David Dick for sharing their knowledge and the use of equipment necessary to the success of the project. Additionally, I would like to thank the faculty and staff of the College of Engineering for their assistance with my work. To my friends and family, thank you for you unending support and patience. Carrie Cochran, thank you for waiting. vi Contents Abstract iii Acknowledgments vi Contents vii List of Tables x List of Figures xx List of Abbreviations xxvi 1 Introduction 1 1.1 Wrist Anatomy . 1 1.1.1 Bony Anatomy . 2 1.1.1.1 Forearm . 2 1.1.1.2 Carpus and Metacarpals . 2 1.1.2 Ligamentous Anatomy . 3 1.1.3 Tendon Anatomy . 4 1.1.4 Wrist Motions . 4 1.2 Kienbocks Disease . 5 1.2.1 Core Decompression Surgery . 6 1.3 Previous Biomechanical Studies . 7 1.4 Scope of Study . 13 vii 2 Experimental Set-up 24 2.1 Motion Tracking . 24 2.2 Specimen Preparation . 25 2.3 Laser Tracker Attachment . 27 2.4 Test Apparatus . 27 2.5 Testing . 28 2.6 RCD Procedure . 29 3 Data Analysis 38 3.1 CT Reconstruction . 39 3.2 Coordinate Systems . 40 3.2.1 Radius . 40 3.2.2 Carpal Bones . 40 3.2.3 Third Metacarpal . 41 3.2.4 Source and Sensors . 41 3.3 Radial Bony Coordinate System Derivation . 41 3.4 Source Coordinate System Derivation . 43 3.5 Carpal (Lunate and Scaphoid) Bony Coordinate System Derivation . 45 3.6 Third Metacarpal Bony Coordinate System Derivation . 47 3.7 Sensor Coordinate System Derivation . 48 3.8 Source-Sensor Transformation Derivation . 50 3.9 Joint Coordinate Systems . 52 3.10 Data Processing . 55 4 Results 69 4.1 Flexion/Extension Results . 69 4.1.1 Intact Specimen Results . 70 4.1.2 Post-RCD Specimen Results . 72 viii 4.2 Radial/Ulnar Deviation Results . 73 4.2.1 Intact Specimen Results . 73 4.2.2 Post-RCD Specimen Results . 75 5 Discussion and Conclusions 131 5.1 In-plane motions during FEM testing . 132 5.2 Out-of-plane motions during FEM testing . 133 5.2.1 Pronation/Supination . 133 5.2.2 Radial/Ulnar Deviation . 135 5.3 In-plane motions during RUD testing . 136 5.4 Out-of-plane motions during RUD testing . 136 5.4.1 Flexion . 136 5.4.2 Pronation . 137 5.5 Effects of RCD on Scaphoid and Lunate Kinematics . 138 5.5.1 FEM Testing . 139 5.5.2 RUD Testing . 142 5.6 Influence of Experimental Setup Factors . 144 5.7 Previous Biomechanical Studies on RCD . 146 5.8 Conclusions . 147 5.9 Limitations and Future Work . 147 References 178 A Normalized Specimen Data 183 B Transformation Matrix Program 240 C Data Normalization Program 253 D Results Comparison Program 267 ix List of Tables 2.1 Attributes of Tested Specimens . 25 4.1 Tendon Loads at Neutral Wrist Position . 76 4.2 Wrist Position during FEM Testing for Specimen 1 . 76 4.3 Wrist Position during FEM Testing for Specimen 2 . 77 4.4 Wrist Position during FEM Testing for Specimen 3 . 78 4.5 Wrist Position during FEM Testing for Specimen 4 . 79 4.6 Comparison of FEM ranges for Test Specimens . 79 4.7 Wrist Position during RUD Testing for Specimen 1 . 80 4.8 Wrist Position during RUD Testing for Specimen 2 . 80 4.9 Wrist Position during RUD Testing for Specimen 3 . 81 4.10 Wrist Position during RUD Testing for Specimen 4 . 82 4.11 Comparison of RUD ranges for Test Specimens . 82 5.1 Multiple study comparison of in-plane carpal motion during wrist FEM movement. * Wrist motions measured by radiocapitate joint motions. 150 5.2 Multiple study comparison of in-plane carpal motion during wrist RUD movement . 150 5.3 Kinematic Effects of RCD during FEM cycle for Specimen 1 Metacarpal 151 5.4 Kinematic Effects of RCD during FEM cycle for Specimen 2 Metacarpal 151 5.5 Kinematic Effects of RCD during FEM cycle for Specimen 3 Metacarpal 151 5.6 Kinematic Effects of RCD during FEM cycle for Specimen 4 Metacarpal 152 x 5.7 Kinematic Effects of RCD during FEM cycle for Specimen 1 Lunate . 152 5.8 Kinematic Effects of RCD during FEM cycle for Specimen 2 Lunate . 152 5.9 Kinematic Effects of RCD during FEM cycle for Specimen 3 Lunate . 153 5.10 Kinematic Effects of RCD during FEM cycle for Specimen 4 Lunate . 153 5.11 Kinematic Effects of RCD during FEM cycle for Specimen 1 Scaphoid . 153 5.12 Kinematic Effects of RCD during FEM cycle for Specimen 2 Scaphoid . 154 5.13 Kinematic Effects of RCD during FEM cycle for Specimen 3 Scaphoid . 154 5.14 Kinematic Effects of RCD during FEM cycle for Specimen 4 Scaphoid . 154 5.15 Comparison of Effects of RCD during FEM cycle for Lunate Flexion . 155 5.16 Comparison of Effects of RCD during FEM cycle for Lunate Ulnar Deviation155 5.17 Comparison of Effects of RCD during FEM cycle for Lunate Pronation . 155 5.18 Comparison of Effects of RCD during FEM cycle for Scaphoid Flexion . 156 5.19 Comparison of Effects of RCD during FEM cycle for Scaphoid Ulnar De- viation . 156 5.20 Comparison of Effects of RCD during FEM cycle for Scaphoid Pronation 157 5.21 Comparison of Effects of RCD on Metacarpal Flexion . 158 5.22 Comparison of Effects of RCD on Metacarpal Ulnar Deviation . 159 5.23 Comparison of Effects of RCD on Metacarpal Pronation . 160 5.24 Kinematic Effects of RCD during RUD cycle for Specimen 1 Metacarpal 161 5.25 Kinematic Effects of RCD during RUD cycle for Specimen 2 Metacarpal 161 5.26 Kinematic Effects of RCD during RUD cycle for Specimen 3 Metacarpal 162 5.27 Kinematic Effects of RCD during RUD cycle for Specimen 4 Metacarpal 162 5.28 Kinematic Effects of RCD during RUD cycle for Specimen 1 Lunate .