The rotator cuff as a bi-material interface

Abstract:

Joining of dissimilar materials is a fundamental challenge in engineering. Nature presents a highly effective solution at the attachment of tendon to bone ("enthesis") in the rotator cuff of the shoulder's humeral head. The natural enthesis does not regrow following healing or surgery, resulting in inferior tissue and in post-surgical tear recurrence rates as high as 94%. Pressing needs exist both to understand the mechanobiology of adhesion and toughening across hierarchical scales in the healthy enthesis, and to reconstitute these in healing.

Our results show the tendon to bone insertion to be a hierarchical, heterogeneous, disordered system that uses randomness to tailor strain fields, and to maximize the fraction of tissue involved in resisting injury-level stresses. Based upon this model, we are developing two new mechano-medicine products for clinical translation: a diagnostic technology to evaluate the degree to which an enthesis is succeeding in physiological strain redistribution, and a repair technology that mimics the mesoscale function of the healthy enthesis by maximizing the fraction of tissue involved in resisting injury-level stresses. This talk will summarize our understanding of the mechanics of tendon-to-bone attachment, and describe repair and imaging technologies under development that harness this with the goal of providing improved surgical outcomes.

Bio:

Guy M. Genin studies the mechanobiology of interfaces and adhesion. He is the Harold and Kathleen Faught Professor of Mechanical Engineering at Washington University in St. Louis, serving on the faculties of Mechanical Engineering & Materials Science, Biomedical Engineering, and Neurological Surgery. He is also Thousand Talents Plan Professor of Life Sciences at Xi'an Jiaotong University in Xi'an, China, and co-director of the Center for Engineering Mechanobiology, a joint NSF Science and Technology Center between Penn, Washington University, with several satellite sites. Prof. Genin serves as chief engineer for Washington University's Center for Innovation in Neuroscience and Technology and is active in several start-ups. He co-chairs the NIH/Interagency Modeling and Analysis Group's working group on integrated multiscale biomechanics experiment and modeling. Prof. Genin's training includes B.S.C.E. and M.S. degrees from Case Western Reserve University, S.M. and Ph.D. degrees in solid mechanics from Harvard, and post-doctoral training at Cambridge and Brown. Prof. Genin is the recipient of a number of awards for engineering design, teaching, and research, including a Research Career Award from the NIH, the ASME Skalak Medal, and the Changjiang Scholar Award from the Chinese Ministry of Education. He is a fellow of ASME and AIMBE.