Gentamicin in bone cement

Objectives

The objective of this study is to determine an optimal antibiotic-loaded bone cement (ALBC) for infection prophylaxis in total joint arthroplasty (TJA).

Methods

We evaluated the antibacterial effects of polymethylmethacrylate (PMMA) bone cements loaded with vancomycin, teicoplanin, ceftazidime, imipenem, piperacillin, gentamicin, and tobramycin against methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staph. aureus (MRSA), coagulase-negative staphylococci (CoNS), Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Standardised cement specimens made from 40 g PMMA loaded with 1 g antibiotics were tested for elution characteristics, antibacterial activities, and compressive strength in vitro.

Results

The ALBC containing gentamicin provided a much longer duration of antibiotic release than those containing other antibiotic. Imipenem-loading on the cement had a significant adverse effect on the compressive strength of the ALBC, which made it insufficient for use in prosthesis fixation. All of the tested antibiotics maintained their antibacterial properties after being mixed with PMMA. The gentamicin-loaded ALBC provided a broad antibacterial spectrum against all the test organisms and had the greatest duration of antibacterial activity against MSSA, CoNS, P. aeruginosa and E. coli.

Conclusion

When considering the use of ALBC as infection prophylaxis in TJA, gentamicin-loaded ALBC may be a very effective choice.