1. ` Printing: This poster is 48” wide by 36” high. It’s designed to be printed on a large- format printer. Customizing the Content: The placeholders in this poster are formatted for you. Type in the placeholders to add text, or click an icon to add a table, chart, SmartArt graphic, picture or multimedia file. To add or remove bullet points from text, just click the Bullets button on the Home tab. If you need more placeholders for titles, content or body text, just make a copy of what you need and drag it into place. PowerPoint’s Smart Guides will help you align it with everything else. Want to use your own pictures instead of ours? No problem! Just right-click a picture and choose Change Picture. Maintain the proportion of pictures as you resize by dragging a corner. Developing a Dynamic Biomechanical Model of the Knee Using 3D Printing Luai S. MustafaJuan Carlos Batlle, MD Lab Director: Ranu Jung, PhDLab Mentor : Andres E. Pena Purpose Develop a patient-specific, dynamic model of the knee Ensure the model is accurate in demonstrating patellar tracking. Devise a procedure which is consist in reproducing accurate models for any patient. Background Diagnosing patellofemoral disorders can be challenging. Failure to diagnose in early stages may lead to far more serious complications in the knee joint. Limited patellar mobility, hypermobility, subluxation and dislocation, soft tissue damage from trauma, arthritis, and clicking in the joint (Dixit, 2007, pp. 194- 202). Failure to diagnose in early stages can diminish the effectiveness of noninvasive treatments, making surgery the only viable option for pain relief. CT imaging is limited since it can only image stationary objects. CT images produce DICOM data however 3D printers require STL files. Mimics software used to convert the DICOM data into a 3D printable mesh. Post processing done with Meshlab Reattachments of prints must be accurate in demonstrating patellar tracking. Objectives Convert DICOM data into an STL file. Separate the bones of the knee joint without disturbing the surface of the trochlea or tibial plateau. Remesh the bones to ensure a printable surface. Print each bone to scale and separately on the Z18 MakerBot and 5 th gen. MakerBot Replicator. Accurately reattach the ligaments and tendons using braided nylon and other flexible materials with similar tensile strengths. Demonstrate accurate patellafemoral tracking with the model. Develop a consist measuring procedure to recreate a dynamic model for any patient. Survey the usefulness of the design by distributing the model to Orthopedic Surgeons and Radiologists. Enhance the model for future applications in the medical field. Methods Image two anonymous patients knees’ bilaterally using Computerized Tomography (CT). Convert the DICOM data obtained from CT imaging into 3D printable STL files. Separate the bones of the knee joint using the STL software Mimics by Materialise. Use Meshlab to re-mesh the models and fill holes in the designs so that they become printable. 3D print the bones using a Z18 MakerBot and a 5 th gen. MakerBot Replicator. Print time will take over 15 hours total. Bones printed with white/transparent PLA. Reattach the knee joint using braided nylon and other flexible materials to substitute the role of ligaments and tendons. Compare patellar tracking in the model to actual patient’s patellar tracking measured on CT images. Readjust the model (tendons/ligaments) to ensure accurate patellar tracking. Advancing the Model Have an experienced Orthopedic Surgeon mark the origins and insertions of the tendons and ligaments on incorporated in the knee joint. Cruciate ligaments and the patellar tendon will likely be represented with nylon threads. Quadriceps tendon will be fashioned from a sleeve of nylon. Drill holes in the model to implant flexible threads, substituting soft tissue. Various materials will be tested as surrogate for ligaments/tendons. The material which provides the most accurate patellar tracking will be used. Biomechanical motion of the knee will be tested by flexing/extending the model with the materials attached as tendons/ligaments. Motion of patella can be correlated with original CT scans of the knee; taken in varying degrees. Main focus will be on the accuracy of patellofemoral tracking in the model. Other focuses include the length of the patellar tendon and using the model to diagnose obscure pathologies of the joint which are not clear in static CT images. Progress to Date Future Applications Dixit, S., & Difiori, J. (2007). Management of Patellofemoral Pain Syndrome. American Family Physician, 75(2), 194-202. O'Connor, F., & Mulvaney, S. (2014, July 22). Patellofemoral pain syndrome. Retrieved March 7, 2015, from http://www.uptodate.com/contents/patellofemoral-pain-syndrome "Patellofemoral Instability|Primary,Secondary,Causes,Symptoms,Treatment." Pain Assist. EPainAssist, 2015. Web. 16 Mar. 2015.. Shubin Stein, B. (2013, June 18). Patellofemoral Disorders: An Overview. Retrieved March 7, 2015, from http://www.hss.edu/conditions_patellofemoral-disorders-overview.asp#.VJR9xsAAA Patient specific bones printed separately. Femur Tibia/Fibula Patella Sources Preoperative planning and surgical simulations. Reducing radiation exposure by only performing CT scans at a single degree of flexion rather than multiple. Patient education. Color-code triangles of the mesh to indicate footprints for drills. Multi-material printing process to tendons/ligaments directly onto model. Reapply similar methods to develop models for different joints in the body (elbow, hip, etc.). The Department of Biomedical Engineering Printing Process Femur and the tibia/fibula printed on 5 th gen. Patella printed on z18.