Patellofemoral Unloader Knee Brace A Major Qualifying Project Submitted to the Faculty of WORCESTER POLYTECHNIC INSTITUTE in partial fulfilment of the requirements for the Degree of Bachelor of Science Submitted By: James Junker Matthew Liberacki Brianna Owen Olivia Wisniewski Advisors Ambady, Sakthikumar Department of Biomedical Engineering Sabuncu, Ahmet C Department of Mechanical Engineering 1 Table of Contents Table of Contents Table of Contents .....................................................................................................................................2 Table of Figures .......................................................................................................................................4 Table of Tables .........................................................................................................................................6 Authorship .................................................................................................................................................7 Acknowledgements .................................................................................................................................8 Abstract ......................................................................................................................................................9 1. Introduction ................................................................................................................................... 10 2. Literature Review ........................................................................................................................ 11 2.1. Anatomy and Biomechanics of the Knee ........................................................................... 11 2.1.1. Bones .................................................................................................................................................................................. 11 2.1.2. Tendons and Ligaments ............................................................................................................................................. 13 2.1.3. Cartilage and Synovial Fluid..................................................................................................................................... 14 2.1.4. Contact Angle, Degree of Flexion, and Forces .................................................................................................. 15 2.1.5. Q-Angle .............................................................................................................................................................................. 16 2.2. Complications of the Patella and Injuries ................................................................... 17 2.2.1. Subluxation and Dislocation .................................................................................................................................... 18 2.2.2. Patella Tendonitis and Patellofemoral Pain Syndrome ............................................................................... 19 2.3 Patellofemoral Arthritis ................................................................................................... 20 2.3.1 Pathophysiology .............................................................................................................. 20 2.3. Current Treatments............................................................................................................ 21 2.4. Benefits and Limitations ................................................................................................... 24 3. Project Strategy ............................................................................................................................ 26 3.1. Initial Client Statement ..................................................................................................... 26 3.2. Revised Client Statement .................................................................................................. 26 3.3. Objectives & Constraints .................................................................................................. 27 3.4. Project Approach ................................................................................................................. 27 4. Design Process .............................................................................................................................. 28 4.1. Needs Analysis ...................................................................................................................... 28 4.1.1. Stakeholder Groups ..................................................................................................................................................... 28 4.1.2. Stakeholder Interviews .............................................................................................................................................. 29 4.1.3. Needs Statement ........................................................................................................................................................... 31 4.2. Design Requirements, Functions (Specifications) ................................................... 32 4.3. Important Industry Standards ....................................................................................... 34 2 4.4. Additional Considerations ............................................................................................... 35 4.4.1. Economics .......................................................................................................................... 35 4.4.2. Environmental Impact ................................................................................................... 35 4.4.3. Societal Influence ............................................................................................................ 35 4.4.4. Political Ramifications .................................................................................................. 35 4.4.5. Ethical Concerns .............................................................................................................. 36 4.4.6. Health and Safety Issues ............................................................................................... 36 4.4.7. Manufacturability ........................................................................................................... 36 4.4.8. Sustainability .................................................................................................................... 36 4.5. Conceptual Designs............................................................................................................. 36 4.6. Design Selection ................................................................................................................... 39 4.7. Modeling ................................................................................................................................. 42 4.7.1. Conceptual Design Selection and Rationale ...................................................................................................... 42 4.7.2. CAD History ..................................................................................................................................................................... 44 4.7.3. Design Rationale ............................................................................................................................................................ 48 4.7.4. Final Design Function ................................................................................................................................................. 49 4.8. Test Methods and Traceability ....................................................................................... 52 4.8.1. Test Methods ................................................................................................................................................................... 52 4.8.2. Traceability ...................................................................................................................................................................... 54 5. Verification and Validation ....................................................................................................... 55 5.1. Tensile Wire Test................................................................................................................................................................ 55 5.2. Dimension Test.................................................................................................................................................................... 57 5.3. Flexion Test ........................................................................................................................................................................... 58 5.4. CT Test .................................................................................................................................................................................... 58 5.5. Kinematic Motion Tracking ........................................................................................................................................... 61 5.6. FujiFilm ................................................................................................................................................................................... 67 5.7. C-Clamp Test .......................................................................................................................................................................