High dose of vancomycin plus gentamicin incorporated acrylic bone cement decreased the elution of vancomycin Tao Li,1,*, Lilan Fu,2,* Jian Wang,1 Zhanjun Shi11Department of Orthopedics, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China; 2Nanfang PET Center, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China*These authors contributed equally to this workPurpose: Low doses of vancomycin and gentamicin were commonly incorporated into acrylic bone cement (antibiotic-impregnated bone cement, AIBC) during revision arthroplasty. Previous studies showed that only a very small amount of antibiotics could be eluted from AIBC. Given the fact that a high dose of antibiotic would elute high concentration of antibiotic, this study investigated the influence of a high dose of dual-antibiotic loading on the properties of cement.Methods: A total of 8 groups of AIBC containing either gentamicin or vancomycin or both with different amounts of antibiotics (1 g, 2 g and 4 g) were tested on material properties, elution profiles, antibacterial activity and cytological toxicity.Results: A high dose of gentamicin and vancomycin AIBC (with 2 g gentamicin and 2 g vancomycin loaded) regiment showed acceptable compressive strength of 74.25±0.72 MPa. No cytotoxicity or antibacterial activity reduction was observed in any group tested in this study. The elution profiles indicated that incorporating 2 g vancomycin resulted in 4.77% (1049.57±3.74 μg) released after 28 days. However, after 2 g gentamicin was added, the vancomycin released was significantly reduced to 2.42% (532.24±1.77 μg) (p