Is Gentamicin Elution Influenced by the Timing of Antibiotic Addition to the Bone Cement? An In Vitro Study on Articulating Hip Spacers

Abstract

Periprosthetic Joint Infection (PJI) is a challenging complication after joint replacements, and cement spacers are standard treatment in two-stage revision surgery. This experimental in vitro study aimed to evaluate the elution properties of different gentamicin formulations from commercially available intraoperative molded hip cement spacers. The study compared spacers prepared with premixed antibiotic bone cement, spacers with antibiotic powder added during preparation, spacers stored for two months, and spacers with an additional antibiotic. The results showed that the timing of antibiotic addition influenced gentamicin elution, with immediate elution resulting in higher levels than stored spacers. Spacers with antibiotic powder added during preparation exhibited higher elution than premixed antibiotic spacers. Furthermore, adding vancomycin to the bone cement significantly increased gentamicin elution. These findings suggest that optimizing the timing and method of antibiotic addition in cement spacers may enhance the effectiveness of antibiotic treatment in PJI. However, further research is needed to validate these findings and explore their clinical implications.