Gentamicin in bone cement: A potentially more effective prophylactic measure of infectionin joint arthroplasty

Abstract

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. Cite this article: Bone Joint Res 2013;2:220-6.

Keywords: Arthroplasty; Bone cement; Gentamicin; Infection; Peri-prosthetic joint infection.

Figs. 1a - 1c

Micro-tube dilution bioassays showing the antibacterial activities against gram-positive bacteria in broth elution samples from the low-dose antibiotic loaded cements (1 g antibiotic in 40 g polymethylmethacrylate) over a 14-day elution period for a) methicillin-sensitive Staphylococcus aureus (MSSA), b) methicillin-resistant Staph. aureus (MRSA) and c) coagulase-negative staphylococci (CoNS).

Figs. 1a - 1c

Micro-tube dilution bioassays showing the antibacterial activities against gram-positive bacteria in broth elution samples from the low-dose antibiotic loaded cements (1 g antibiotic in 40 g polymethylmethacrylate) over a 14-day elution period for a) methicillin-sensitive Staphylococcus aureus (MSSA), b) methicillin-resistant Staph. aureus (MRSA) and c) coagulase-negative staphylococci (CoNS).

Figs. 1a - 1c

Micro-tube dilution bioassays showing the antibacterial activities against gram-positive bacteria in broth elution samples from the low-dose antibiotic loaded cements (1 g antibiotic in 40 g polymethylmethacrylate) over a 14-day elution period for a) methicillin-sensitive Staphylococcus aureus (MSSA), b) methicillin-resistant Staph. aureus (MRSA) and c) coagulase-negative staphylococci (CoNS).

Figs. 2a - 2c

Micro-tube dilution bioassays showing the antibacterial activities against gram-negative bacteria in broth elution samples from the low-dose antibiotic loaded cements (1 g antibiotic in 40 g polymethylmethacrylate) over a 14-day elution period for a) Pseudomonas aeruginosa, b) Escherichia coli and c) Klebsiella pneumoniae.

Figs. 2a - 2c

Micro-tube dilution bioassays showing the antibacterial activities against gram-negative bacteria in broth elution samples from the low-dose antibiotic loaded cements (1 g antibiotic in 40 g polymethylmethacrylate) over a 14-day elution period for a) Pseudomonas aeruginosa, b) Escherichia coli and c) Klebsiella pneumoniae.

Figs. 2a - 2c

Micro-tube dilution bioassays showing the antibacterial activities against gram-negative bacteria in broth elution samples from the low-dose antibiotic loaded cements (1 g antibiotic in 40 g polymethylmethacrylate) over a 14-day elution period for a) Pseudomonas aeruginosa, b) Escherichia coli and c) Klebsiella pneumoniae.

Fig. 3

Bar chart showing the mean ultimate compressive strength of the cement samples before and after the 14-day broth elution assay compared with cement without antibiotics (control). The bars denote the mean of three tests for each antibiotic with the standard error of the mean. Asterisks denote a significant difference (p < 0.01) when compared with the control.