[Effect of alendronate amount on the static mechanical properties of bone cement].

ABSTRACT

OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.