Microencapsulation of rifampicin: a technique to preserve the mechanical properties of bone cement

Two-stage exchange with antibiotic-loaded bone cement spacers remains the gold standard for chronic periprosthetic joint infection (PJI). Rifampicin is highly efficient on stationary-phase staphylococci in biofilm; however, its addition to PMMA to manufacture spacers prevents polymerization and reduces mechanical properties. Isolation of rifampicin during polymerization by microencapsulation could allow manufacturing rifampicin-loaded bone cement maintaining elution and mechanical properties. Microcapsules of rifampicin with alginate, polyhydroxybutyratehydroxyvalerate (PHBV), ethylcellulose and stearic acid (SA) were synthesized. Alginate and PHBV microcapsules were added to bone cement and elution, compression, bending, hardness, setting time and microbiological tests were performed. Repeated measures ANOVA and Bonferroni post-hoc test were performed, considering a p