In vitro elution and mechanical properties of antibiotic-loaded SmartSet HV and Palacos R acrylic bone cements

Background. The continuing emergence of new bone cements with additional antibiotics makes it important to establish which one will provide the most favourable antibiotic elution. An in vitro antibiotic elution and mechanical study was therefore carried out to compare a newer bone cement, SmartSet, with the established Palacos R cement. Methods. Samples were prepared with each cement adding I g gentamicin, 1 g of vancomycin, or 1 g of gentamicin and vancomycin. The samples were analysed using fluorescence polarisation immunoassay. Mechanical tests were performed to determine whether any significant degradation in the cement strength occurred following addition of the antibiotic. Results. With regards to gentamicin release Palacos R eluted significantly more antibiotic over the study period than SmartSet (p < 0.001). Both cements eluted significantly more gentamicin when two antibiotics were added. With respect to vancomycin release there was no significant difference. Palacos R was significantly stronger than SmartSet in the 4-point bending test when the gentamicin + vancomycin antibiotic groups were compared (p=0.01). Palacos R also demonstrated a higher elastic modulus than SmartSet when the gentamicin and gentannicin + vancomycin groups were compared (p=0.03, p=0.005). Conclusions. Gentamcin shows better release characteristics from Palacos R. Both cements exhibited synergistic release of combined antibiotics.