Effect of alendronate amount on the static mechanical properties of bone cement

Abstract

To determine the effect of alendronate amount on the static mechanical properties of bone cement before elution and 4 weeks after elution, and determine suitable amount of alendronate in cement from the perspective of biomechanics. Samples of compression strength and bending strength (modulus) were prepared with bone cement adding 0, 10, 50, 100, 500 and 1000 mg alendronate in 50 g Cemex®XL bone cement powders respectively (named as G0-G5 groups). The compression strength, bending strength, and bending modulus of bone cement were examinated by INSTRON 8032 tester before the elution and 4 weeks after the elution. Some broken samples of 4-point bending test were examinated by scanning electronic microscopy (SEM), and some other samples of bending strength (modulus) tests by micro-CT. No significant difference was found in the compression strength before the elution,4 weeks after elution in the 6 groups, and before and after the elution in the respective groups (P>0.05). Compared with G0 group, G1-G4 groups had no obvious difference in the bending strength before the elution and 4 weeks after the elution (P>0.05), while G5 group had difference (P<0.05). There was no significant difference in the bending strength before and after the elution in the respective groups (P>0.05). Taken G0 group as the control group, G1-G4 groups had no visible effects on the bending modulus 4 weeks after the elution (P>0.05), while G5 group decreased it significantly (P<0.05). Bending modulus before the elution in the 6 groups didn't show obvious difference (P>0.05), while bending modulus before and after the elution in the respective groups displayed a marked difference (P<0.05). Less than 500 mg alendronate added in Cemex?XL 50 g bone cement powder does not decrease the compressive strength, flexural strength and flexural modulus before the elution and 4 weeks after the elution.