Tissue viscoelasticity is related to tissue composition but may not fully predict the apparent-level viscoelasticity in human trabecular bone – An experimental and finite element study

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

Trabecular bone is viscoelastic under dynamic loading. However, it is unclear how tissue viscoelasticity controls viscoelasticity at the apparent-level. In this study, viscoelasticity of cylindrical human trabecular bone samples (n = 11, male, age 18–78 years) from 11 proximal femurs were characterized using dynamic and stress-relaxation testing at the apparent-level and with creep nanoindentation at the tissue-level. In addition, bone tissue elasticity was determined using scanning acoustic microscope (SAM). Tissue composition and collagen crosslinks were assessed using Raman micro-spectroscopy and high performance liquid chromatography (HPLC), respectively. Values of material parameters were obtained from finite element (FE) models by optimizing tissue-level creep and apparent-level stress-relaxation to experimental nanoindentation and unconfined compression testing values, respectively, utilizing the second order Prony series to depict viscoelasticity. FE simulations showed that tissue-level equilibrium elastic modulus (Eeq) increased with increasing crystallinity (r = 0.730, p =.011) while at the apparent-level it increased with increasing hydroxylysyl pyridinoline content (r = 0.718, p =.019). In addition, the normalized shear modulus g1 (r = −0.780, p =.005) decreased with increasing collagen ratio (amide III/CH2) at the tissue-level, but increased (r = 0.696, p =.025) with increasing collagen ratio at the apparent-level. No significant relations were found between the measured or simulated viscoelastic parameters at the tissue- and apparent-levels nor were the parameters related to tissue elasticity determined with SAM. However, only Eeq, g2 and relaxation time τ1 from simulated viscoelastic values were statistically different between tissue- and apparent-levels (p <.01). These findings indicate that bone tissue viscoelasticity is affected by tissue composition but may not fully predict the macroscale viscoelasticity in human trabecular bone.

Detaljer

Författare
  • X. Ojanen
  • P. Tanska
  • M. K.H. Malo
  • H. Isaksson
  • S. P. Väänänen
  • A. P. Koistinen
  • L. Grassi
  • S. P. Magnusson
  • S. M. Ribel-Madsen
  • R. K. Korhonen
  • J. S. Jurvelin
  • J. Töyräs
Enheter & grupper
Externa organisationer
  • University of Eastern Finland
  • Kuopio University Hospital
  • Bispebjerg Hospital
  • University of Copenhagen
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Fysiologi
  • Ortopedi

Nyckelord

Originalspråkengelska
Sidor (från-till)96-105
Antal sidor10
TidskriftJournal of Biomechanics
Volym65
StatusPublished - 2017 dec 8
PublikationskategoriForskning
Peer review utfördJa