Assessing bone quality through mechanical properties in postmenopausal trabecular bone

Injury. 2018 Sep:49 Suppl 2:S3-S10. doi: 10.1016/j.injury.2018.07.035.

Abstract

Background: The inner structure of trabecular bone is a result of structural optimization provided by remodeling processes. Changes in hormonal status related to menopause cause bone tissue loss and micro-architectural deterioration with a consequent susceptibility to fracture. Accumulation of micro-damage in bone, as a function of the rate of production and rate of repair, underlies the development of stress fractures, increasing fragility associated to age and osteoporosis, especially in transmenopausal women.

Patients and methods: Quasi-static and nano-dynamic mechanical characterization were undertaken in trabecular bone from femoral neck biopsies of postmenopausal women. AFM (Atomic Force Microscopy) complementary studies were performed to determine nano-roughness (SRa) and the fibrils width of collagen. Nanoindentations were used to quantify transmenopausal changes in intrinsic mechanical properties of trabecular bone: hardness (Hi), modulus of Young (Ei), complex modulus (E*), tan delta (δ), storage modulus (E') and loss modulus (E").

Results: As result of the quasi-static measurements, 0.149 (0.036) GPa and 2.95 (0.73) GPa of Hi and Ei were obtained, respectively. As result of the nano-dynamic measurements, 17.94 (3.15), 0.62 (0.10), 13.79 (3.21 and 6.39 (1.28) GPa of E*, tan (δ), E' and E" were achieved, respectively. 101.07 SRa and 831.28 nm of fibrils width were additionally obtained.

Conclusions: This study poses a first approach to the measurement of bone quality in postmenopausal trabecular bone by combining quasi-static, nano-DMA analysis and tribology of dentin surface through AFM characterization.

Keywords: Dynamic; Mechanic; Menopause; Static; Trabecular bone.

MeSH terms

  • Biomechanical Phenomena
  • Bone Density
  • Cancellous Bone / diagnostic imaging*
  • Cancellous Bone / pathology
  • Cancellous Bone / ultrastructure
  • Elasticity
  • Female
  • Femur Neck / diagnostic imaging*
  • Femur Neck / pathology
  • Femur Neck / ultrastructure
  • Hardness
  • Humans
  • Microscopy, Atomic Force*
  • Middle Aged
  • Osteoporosis, Postmenopausal / diagnostic imaging*
  • Osteoporosis, Postmenopausal / pathology
  • Postmenopause / physiology*