title: Stochastic interdigitation as a toughening mechanism at the interface between tendon and bone.
abstract: Reattachment and healing of tendon to bone poses a persistent clinical challenge and often results in poor outcomes, in part because the mechanisms that imbue the uninjured tendon-to-bone attachment with toughness are not known. One feature of typical tendon-to-bone surgical repairs is direct attachment of tendon to smooth bone. The native tendon-to-bone attachment, however, presents a rough mineralized interface that might serve an important role in stress transfer between tendon and bone. In this study, we examined the effects of interfacial roughness and interdigital stochasticity on the strength and toughness of a bimaterial interface. Closed form linear approximations of the amplification of stresses at the rough interface were derived and applied in a two-dimensional unit-cell model. Results demonstrated that roughness may serve to increase the toughness of the tendon-to-bone insertion site at the expense of its strength. Results further suggested that the natural tendon-to-bone attachment presents roughness for which the gain in toughness outweighs the loss in strength. More generally, our results suggest a pathway for stochasticity to improve surgical reattachment strategies and structural engineering attachments.
authors.affiliation: Department of Biomedical Engineering, Washington University, St. Louis, Missouri; Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, Missouri.
authors.forename: Yizhong
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Engineering Education Center, Missouri Science & Technology, St. Louis, Missouri.
authors.forename: Victor
authors.initials: V
authors.lastname: Birman
authors.forename: A
authors.initials: A
authors.lastname: Deymier-Black
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Alix
authors.initials: A
authors.lastname: Demyier-Black
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Andrea G
authors.initials: AG
authors.lastname: Schwartz
authors.affiliation: Department of Biomedical Engineering, Washington University, St. Louis, Missouri; Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, Missouri; Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri. Electronic address: thomopouloss@wustl.edu.
authors.forename: Stavros
authors.initials: S
authors.lastname: Thomopoulos
authors.affiliation: Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, Missouri. Electronic address: genin@wustl.edu.
authors.forename: Guy M
authors.initials: GM
authors.lastname: Genin
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D006811:Humerus / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D051379:Mice; D008903:Minerals / Q000737:chemistry; D008954:Models, Biological; D011506:Proteins / Q000737:chemistry; D017006:Rotator Cuff / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D013269:Stochastic Processes
chemical_list: D008903:Minerals; D011506:Proteins