The Journal of arthroplasty
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This study investigated the use of liquid gentamicin, a much less costly antibiotic (<1/20 the price of tobramycin) with a broad antimicrobial spectrum, alone and in combination with vancomycin in bone cement. Standardized cement specimens loaded with 480 mg of liquid gentamicin, 4 g of powdered vancomycin, or both antibiotics were tested for elution characteristics, bioactivity, compressive strength, and porosity. Vancomycin elution was enhanced by 146% with the addition of gentamicin liquid, and gentamicin elution was enhanced by 45% when combined with vancomycin. ⋯ Adding liquid gentamicin increased porosity, whereas adding vancomycin did not. Compressive strength decreased by 13%, 37%, and 45% in specimens containing vancomycin, liquid gentamicin, and both antibiotics, respectively. Despite inferior mechanical properties, the temporary nature of cement beads and spacers makes the liquid gentamicin-vancomycin mixture a potentially more cost-effective regimen in bone cement to treat musculoskeletal infections.