Engineering Joint Implants for in vivo Longevity and Antibacterial ...06-11-2020

The “Applications of Engineering in Medicine and Biology” Seminar series


Arthritis affects a growing number of people both in the US and around the world; while regenerative therapies continue to be a focus of research, the clinical use of total joint replacement as an end-stage therapy is growing as well. Annually over 1 million patients in the US and over 3 million patients in the world receive total joint replacements in the hip, knee and shoulder, a majority of which include ultra-high molecular weight polyethylene (UHMWPE) as a load-bearing articular surface. For many years, the most significant problem limiting implant longevity was peri-prosthetic osteolysis caused mainly by UHMWPE wear particles. Engineering the properties of the polymeric bearing surface, pioneered by our laboratory has advanced this field of medicine significantly.

Radiation cross-linking of UHMWPE has contributed to an 87% reduction in the incidence of osteolysis and related revisions. Further, antioxidant stabilization methods using antioxidant diffusion and blending of this wear resistant semi-crystalline polymer is expected to result in improved longevity against in-vivo oxidation. Currently, one of the most important and dire problems facing total joint patients now is peri-prosthetic infection (PJI). The use of antibiotics locally as well as the delivery systems for these antibiotics are limited and the regulatory pathway for novel delivery devices is unclear. Our lab has designed antibiotic-loaded UHMWPE materials for drug delivery while maintaining their load-bearing ability to provide alternative and effective treatments for PJI prophylaxis and treatment. Preclinical animal models of infection using gait and function as endpoint measurements for orthopaedic recovery have been developed to evaluate the comparative efficacy of different local delivery regimens against relevant microorganisms. This talk will include examples of our work in engineering the structure-property relationship of this polymer to obtain clinically relevant properties and addressing orthopaedic problems.



Dr. Ebru Oral is an Associate Professor of Orthopaedics at Harvard Medical School and the Associate Director of Biomaterials at the Harris Orthopaedic Laboratory at Massachusetts General Hospital (MGH). She is an expert on polymeric bearing surfaces for joint replacement. Among other honors, she is a Fellow of the National Academy of Inventors, the highest national honor for inventors and a Fellow of the American Institute of Medical and Biological Engineers, an honor for the top 1-2% of biomedical scientists.

Dr. Oral received her BS degree from Boğaziçi University in Turkey and her PhD from Purdue University, both in Chemical Engineering. Her research is in the science, application, and relevant testing of implantable polymeric materials to address medical problems. Her work on joint implants resulted in the first clinical use of vitamin E-stabilized cross-linked UHMWPE joint implants. Her current work is in incorporating therapeutics for the controlled local release of antibiotics, anti-inflammatories and analgesics from implantable materials. She has over 60 peer-reviewed publications with an h-index of 32 and numerous book chapters and preprints.

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