title: Creep of trabecular bone from the human proximal tibia.
abstract: Creep is the deformation that occurs under a prolonged, sustained load and can lead to permanent damage in bone. Creep in bone is a complex phenomenon and varies with type of loading and local mechanical properties. Human trabecular bone samples from proximal tibia were harvested from a 71-year old female cadaver with osteoporosis. The samples were initially subjected to one cycle load up to 1% strain to determine the creep load. Samples were then loaded in compression under a constant stress for 2h and immediately unloaded. All tests were conducted with the specimens soaked in phosphate buffered saline with proteinase inhibitors at 37 °C. Steady state creep rate and final creep strain were estimated from mechanical testing and compared with published data. The steady state creep rate correlated well with values obtained from bovine tibial and human vertebral trabecular bone, and was higher for lower density samples. Tissue architecture was analyzed by micro-computed tomography (μCT) both before and after creep testing to assess creep deformation and damage accumulated. Quantitative morphometric analysis indicated that creep induced changes in trabecular separation and the structural model index. A main mode of deformation was bending of trabeculae.
authors.affiliation: Mechanical and Aerospace Engineering, UC, San Diego, La Jolla, CA 92093, USA; Materials Science and Engineering Program, UC, San Diego, La Jolla, CA 92093, USA. Electronic address: eevdokim@ucsd.edu.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Novitskaya
authors.affiliation: Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Zin
authors.affiliation: Departments of Bioengineering & Orthopaedic Surgery, UC, San Diego, La Jolla, CA 92093, USA.
authors.forename: Neil
authors.initials: N
authors.lastname: Chang
authors.affiliation: Departments of Bioengineering & Orthopaedic Surgery, UC, San Diego, La Jolla, CA 92093, USA.
authors.forename: Esther
authors.initials: E
authors.lastname: Cory
authors.affiliation: Departments of Bioengineering & Orthopaedic Surgery, UC, San Diego, La Jolla, CA 92093, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Chen
authors.affiliation: Shiley Center for Orthopaedic Research & Education, Scripps Health, La Jolla, CA 92037, USA.
authors.forename: Darryl
authors.initials: D
authors.lastname: D'Lima
authors.affiliation: Materials Science and Engineering Program, UC, San Diego, La Jolla, CA 92093, USA; Departments of Bioengineering & Orthopaedic Surgery, UC, San Diego, La Jolla, CA 92093, USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Sah
authors.affiliation: Mechanical and Aerospace Engineering, UC, San Diego, La Jolla, CA 92093, USA; Materials Science and Engineering Program, UC, San Diego, La Jolla, CA 92093, USA.
authors.forename: Joanna
authors.initials: J
authors.lastname: McKittrick
mesh_terms: D000368:Aged; D000465:Algorithms; D000818:Animals; D002417:Cattle; D019245:Compressive Strength; D004791:Enzyme Inhibitors / Q000737:chemistry; D005260:Female; D006801:Humans; D008954:Models, Biological; D013696:Temperature; D013977:Tibia / Q000000981:diagnostic imaging / Q000502:physiology*; D014057:Tomography, X-Ray Computed
chemical_list: D004791:Enzyme Inhibitors
keywords: Creep; Micro-computed tomography; Microscopy; Trabecular bone