The addition of tobramycin to contrast bone cement. Effect on flexural strength.

Samples of polymethylmethacrylate (PMMA) bone cement were polymerized in vitro with no additives and with the following additives: methylene blue dye, tobramycin, methylene blue plus tobramycin. After storage for 7 days in saline, samples were tested to failure in three-point bending. Addition of the antibiotic significantly weakened the cement (to 87% of control). However, the combination of tobramycin plus methylene blue was no weaker than tobramycin alone, suggesting that addition of both dye and antibiotic to bone cement is probably a reasonable clinical practice.