Effects of the addition of vancomycin on the physical and handling properties of calcium sulfate bone cement

Intra-operative applications of bone graft substitutes into bone voids support mechanical stability, and accelerate fracture healing. Calcium sulfate bone cement, an injectable substitute, is used widely in non-loading bones with favorable results. In addition, calcium sulfate also serves as a vehicle for antibiotics that treat osteomyelitis or prevent contaminations. However, the effects of the addition of antibiotics on the physical properties of calcium sulfate are rarely addressed. In this study, calcium sulfates mixed with vancomycin at different weight ratios (4:0, 4:0.025, 4:0.05, 4:0.075, and 4:0.1) were evaluated in vitro. No obvious temperature increase or pH change was observed during setting and immersion in the simulated body fluid. The added vancomycin did not influence the mechanical strength, crystalline phase, or microstructure of the calcium sulfate cement. However, the addition of vancomycin extended the initial and final setting time (4:0.075, and 4:0.1). A higher amount of vancomycin resulted in a higher initial boosting release, but did not lead to faster degradation. The vancomycin-impregnated cement exhibited inhibitory effects against Staphylococcus aureus. These data indicate that the extended initial and final setting time of the calcium sulfate bone cement with the addition of vancomycin should be considered during operation.