The effects of density and test conditions on measured compression and shear strength of cancellous bone from the lumbar vertebrae of ewes

Abstract An animal model (the ewe) was used to study mechanical parameters of cancellous bone specimens. Compression and shear tests were conducted on ewe vertebral trabecular bone (L1–L5) from old ewes (mean age: 9 years) under two different conditions: first, at room temperature in air (“standard” test conditions); and secondly, in a physiological saline bath regulated at 37°C. The parameters obtained under “standard” test conditions with a uniaxial compression test were the mean value of the maximum strength ( e σ max =22.3 (7.06) MPa), Young's modulus ( E =1510 (784) MPa), the strain at maximum strength ( e σ max =3.21 (0.8) percent) and the energy absorbed during the test ( W =0.3 (0.12) MJ.m −3 ). No significant change was found when the test was carried out in a saline bath at 37°C ( p p p The non-destructive measurement of the Bone Mineral Density (BMD) accounted for up to 73.3 percent of the maximum compressive strength σ max and 61.5 percent of the maximum shear strength τ max determined in saline solution at 37°C. These results showed that other parameters influencing the mechanical properties of trabecular bone and its structure appeared to be essential.