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Gentamicin release from commercially-available gentamicin-loaded PMMA bone cements in a prosthesis-related interfacial gap model and their antibacterial efficacy.

Neut D, Kluin OS, Thompson J, van der Mei HC, Busscher HJ - BMC Musculoskelet Disord (2010)

Bottom Line: All three Palacos variants showed equal burst releases but each of the successor Palacos cements showed significantly higher sustained releases.Although marketed as the original gentamicin-loaded Palacos cement, orthopaedic surgeons should be aware that the successor cements do not appear to have the same release characteristics as the original one.These concentrations may be expected to effectively decontaminate the prosthesis-related interfacial gap directly after implantation, provided that these bacteria are sensitive for gentamicin.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands. d.neut@med.umcg.nl

ABSTRACT

Background: Around about 1970, a gentamicin-loaded poly (methylmethacrylate) (PMMA) bone cement brand (Refobacin Palacos R) was introduced to control infection in joint arthroplasties. In 2005, this brand was replaced by two gentamicin-loaded follow-up brands, Refobacin Bone Cement R and Palacos R + G. In addition, another gentamicin-loaded cement brand, SmartSet GHV, was introduced in Europe in 2003. In the present study, we investigated differences in gentamicin release and the antibacterial efficacy of the eluent between these four cement brands.

Methods: 200 μm-wide gaps were made in samples of each cement and filled with buffer in order to measure the gentamicin release. Release kinetics were related to bone cement powder particle characteristics and wettabilities of the cement surfaces. Gaps were also inoculated with bacteria isolated from infected prostheses for 24 h and their survival determined. Gentamicin release and bacterial survival were statistically analysed using the Student's t-test.

Results: All three Palacos variants showed equal burst releases but each of the successor Palacos cements showed significantly higher sustained releases. SmartSet GHV showed a significantly higher burst release, while its sustained release was comparable with original Palacos. A gentamicin-sensitive bacterium did not survive in the high gentamicin concentrations in the interfacial gaps, while a gentamicin-resistant strain did, regardless of the type of cement used. Survival was independent of the level of burst release by the bone cement.

Conclusions: Although marketed as the original gentamicin-loaded Palacos cement, orthopaedic surgeons should be aware that the successor cements do not appear to have the same release characteristics as the original one. Overall, high gentamicin concentrations were reached inside our prosthesis-related interfacial gap model. These concentrations may be expected to effectively decontaminate the prosthesis-related interfacial gap directly after implantation, provided that these bacteria are sensitive for gentamicin.

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SEM micrographs of the Refobacin Palacos R, Refobacin Bone Cement R, Palacos R + G, and SmartSet GHV powder. The arrow indicates agglomerates of the smaller radiopacifier particles. Bar denotes 100 μm.
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Figure 2: SEM micrographs of the Refobacin Palacos R, Refobacin Bone Cement R, Palacos R + G, and SmartSet GHV powder. The arrow indicates agglomerates of the smaller radiopacifier particles. Bar denotes 100 μm.

Mentions: Each cement powder consists of a mixture of different components (Figure 2). The larger and prevailing structures observed in all cement powders are spherical granules corresponding to pre-polymerized PMMA and the size of these beads varies between 10 μm and 100 μm. The remainder of the structures observed are much smaller and correspond with radio-pacifiers (about 15 w/w% zirconium dioxide) and 2-4 wt% gentamicin particles. Zirconium dioxide particles are more or less polyhedral with a size range between 1 μm to 5 μm, are added to facilitate X-ray contrast. A problem associated with the use of 1-5 μm diameter radio-pacifier particles is that incomplete dispersion of the particles may result in the formation of particle agglomerates of 50 μm - 200 μm in diameter (Figure 2). The gentamicin particles (with diameter of 5 μm - 40 μm) in cured SmartSet GHV clearly appear as spherical particles (Figure 3), while the Palacos variants include much larger antibiotic particles with a more crystalline structure (Figure 3). The particle distributions of the cement powders are shown in Figure 4. Two features are noted: (a) the proportion of small-sized PMMA beads (mean diameter, d, between 5 μm and 40 μm) in the powder, and (b) the proportion of large-sized PMMA beads (d ≥ 75 μm) in the powder (Table 1). All Palacos variants contain large-sized PMMA beads (portion between 10-15 wt%), while SmartSet GHV only contained small-sized particles.


Gentamicin release from commercially-available gentamicin-loaded PMMA bone cements in a prosthesis-related interfacial gap model and their antibacterial efficacy.

Neut D, Kluin OS, Thompson J, van der Mei HC, Busscher HJ - BMC Musculoskelet Disord (2010)

SEM micrographs of the Refobacin Palacos R, Refobacin Bone Cement R, Palacos R + G, and SmartSet GHV powder. The arrow indicates agglomerates of the smaller radiopacifier particles. Bar denotes 100 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2992479&req=5

Figure 2: SEM micrographs of the Refobacin Palacos R, Refobacin Bone Cement R, Palacos R + G, and SmartSet GHV powder. The arrow indicates agglomerates of the smaller radiopacifier particles. Bar denotes 100 μm.
Mentions: Each cement powder consists of a mixture of different components (Figure 2). The larger and prevailing structures observed in all cement powders are spherical granules corresponding to pre-polymerized PMMA and the size of these beads varies between 10 μm and 100 μm. The remainder of the structures observed are much smaller and correspond with radio-pacifiers (about 15 w/w% zirconium dioxide) and 2-4 wt% gentamicin particles. Zirconium dioxide particles are more or less polyhedral with a size range between 1 μm to 5 μm, are added to facilitate X-ray contrast. A problem associated with the use of 1-5 μm diameter radio-pacifier particles is that incomplete dispersion of the particles may result in the formation of particle agglomerates of 50 μm - 200 μm in diameter (Figure 2). The gentamicin particles (with diameter of 5 μm - 40 μm) in cured SmartSet GHV clearly appear as spherical particles (Figure 3), while the Palacos variants include much larger antibiotic particles with a more crystalline structure (Figure 3). The particle distributions of the cement powders are shown in Figure 4. Two features are noted: (a) the proportion of small-sized PMMA beads (mean diameter, d, between 5 μm and 40 μm) in the powder, and (b) the proportion of large-sized PMMA beads (d ≥ 75 μm) in the powder (Table 1). All Palacos variants contain large-sized PMMA beads (portion between 10-15 wt%), while SmartSet GHV only contained small-sized particles.

Bottom Line: All three Palacos variants showed equal burst releases but each of the successor Palacos cements showed significantly higher sustained releases.Although marketed as the original gentamicin-loaded Palacos cement, orthopaedic surgeons should be aware that the successor cements do not appear to have the same release characteristics as the original one.These concentrations may be expected to effectively decontaminate the prosthesis-related interfacial gap directly after implantation, provided that these bacteria are sensitive for gentamicin.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands. d.neut@med.umcg.nl

ABSTRACT

Background: Around about 1970, a gentamicin-loaded poly (methylmethacrylate) (PMMA) bone cement brand (Refobacin Palacos R) was introduced to control infection in joint arthroplasties. In 2005, this brand was replaced by two gentamicin-loaded follow-up brands, Refobacin Bone Cement R and Palacos R + G. In addition, another gentamicin-loaded cement brand, SmartSet GHV, was introduced in Europe in 2003. In the present study, we investigated differences in gentamicin release and the antibacterial efficacy of the eluent between these four cement brands.

Methods: 200 μm-wide gaps were made in samples of each cement and filled with buffer in order to measure the gentamicin release. Release kinetics were related to bone cement powder particle characteristics and wettabilities of the cement surfaces. Gaps were also inoculated with bacteria isolated from infected prostheses for 24 h and their survival determined. Gentamicin release and bacterial survival were statistically analysed using the Student's t-test.

Results: All three Palacos variants showed equal burst releases but each of the successor Palacos cements showed significantly higher sustained releases. SmartSet GHV showed a significantly higher burst release, while its sustained release was comparable with original Palacos. A gentamicin-sensitive bacterium did not survive in the high gentamicin concentrations in the interfacial gaps, while a gentamicin-resistant strain did, regardless of the type of cement used. Survival was independent of the level of burst release by the bone cement.

Conclusions: Although marketed as the original gentamicin-loaded Palacos cement, orthopaedic surgeons should be aware that the successor cements do not appear to have the same release characteristics as the original one. Overall, high gentamicin concentrations were reached inside our prosthesis-related interfacial gap model. These concentrations may be expected to effectively decontaminate the prosthesis-related interfacial gap directly after implantation, provided that these bacteria are sensitive for gentamicin.

Show MeSH
Related in: MedlinePlus