Objective: To evaluate the effect of strain rate (̇ε), apparent density (ρa) and tissue density (ρt) on Young's modulus (E), strength (σu) and ultimate strain (εu) on intervertebral bone from a Chinese population.
Methods: Testing was performed by uniaxial compression at five strain rates on 36 human trabecular bone specimens from three male T₁₂~L₄ vertebrae.
Results: Apparent density ranged between 0.46 and 0.71 g/cm³. Tissue density ranged between 1.02 and 1.54 g/cm³. Non-linear regression analyses using strength, Young's modulus or ultimate strain as dependent variables (Y) and strain rate and apparent density or tissue density as independent variables were performed using the following equation: Y=aρḃεc. The exponent of apparent density and strain rate to Young's modulus were 1.88 and 0.07, separately (P = 0.0007). The variation of strength was explained only by apparent density with an exponent of 1.29 (P = 0.0107). The variation of Young's modulus was explained equally by the quadratic and cubic relationship to apparent density or tissue density (P < 0.01). Ultimate strain varied independently of apparent density or tissue density and strain rate.
Relevance: An understanding of the biomechanical characteristics of human trabecular bone can help us to understand the mechanism of spine compressive fracture.