Abstract:
Total joint replacements (TJR) restore pain-free mobility and function to damaged or diseased cartilage in the articular joints using engineering materials. These load-bearing implant systems typically comprise metal-on-polymer couplings. There are nearly one million total joint replacement surgeries performed annually in the United States with CoCr alloys articulating against ultra-high molecular weight polyethylene (UHMWPE) comprising the majority of hip, knee and shoulder replacements (American Academy of Orthopedic Surgeons, 2022). These medical devices must offer extraordinary resistance to wear, corrosion and fatigue loading. Approximately 12% of these devices require revision due to loosening, wear-mediated osteolysis (bone loss around the implant), fracture of components or failure of the bearing surfaces within their first decade of use.

Professor Pruitt and her lab have devoted nearly 30 years of research toward the understanding of the complex material behavior in total joint replacement designs. Her work has elucidated many of the primary failure mechanisms found in the bearing systems as well as the inherent trade-offs that exist in the fatigue, fracture, wear and oxidation resistance in orthopedic polymers, and most notably in UHMWPE. These failure schemes are complicated by stress concentrations required for locking mechanisms, joint articulation, fixation to surrounding tissues and features in the implants that facilitate retrieval of the device. Well-functioning implants offer 10-20 years of service but generally require at least one revision in the lifetime of a patient. Hence implants must enable a retrieval scheme that minimizes damage to surrounding tissues upon replacement of an implant - such challenges are ever-increasing as demographics shift to younger and more active patients.

Professor Pruitt’s ongoing research focuses on the characterization of structure-property relationships in orthopedic biomaterials in order to optimize systems for resistance to in-vivo fatigue, wear and oxidation in TJR. Professor Pruitt will also discuss how such research provides a pathway for inclusive excellence in teaching, research and mentoring.

Bio:
Lisa Pruitt, Ph.D., is Professor of Mechanical Engineering and Bioengineering at the University of California at Berkeley. Dr. Pruitt also is the Director of the Medical Polymer Group at the school. She received her Ph.D. from Brown University and joined the faculty of Mechanical Engineering at UC Berkeley in 1993.

Dr. Pruitt has authored more than 300 publications in her research field of failure analysis, biomaterials and medical devices. The recipient of numerous awards and honors, her research has been recognized with a Congressional citation; a National Science Foundation CAREER award; an Office of Naval Research Young Investigator Award; and election to the American Institute of Medical and Biological Engineering. Professor Pruitt has also been honored for her commitment to excellence in mentoring, teaching and outreach. She has received the American Association of Advancement of Sciences Mentoring Award; the Presidential Award for Excellence in Science, Mathematics and Engineering Mentoring; the UC Berkeley Distinguished Teaching Award as well as the Brown Engineering Alumni Medal.

Professor Pruitt teaches undergraduate and graduate courses in Mechanical Behavior of Engineering Materials, Failure Analysis, Polymer Engineering, Medical Device Design and Personal Leadership. Lisa Pruitt is the author of four books including Soul of a Professor: Memoir of an Un-engineered Life (Merry Dissonance Press, 2022); Mechanics of Biomaterials: Fundamentals for Implant Design (Cambridge University Press, 2011); Horse of Fire: The story of an extraordinary and Knowing Horse as told by JJ Luck (Authorhouse, 2008; Amazon, 2019); as well as a children’s book, Savanna and the Magic Boots (Authorhouse, 2011).