Antibiotic elution from acrylic bone cement loaded with high doses of tobramycin and vancomycin

Abstract

Two-stage revision treatment of prosthetic joint infection (PJI) frequently employs the use of a temporary bone cement spacer loaded with multiple antibiotic types. Tobramycin and vancomycin are commonly used antibiotics in cement spacers, however, there is no consensus on the relative concentrations and combinations that should be used. Therefore, the purpose of this study was to investigate the influence of dual antibiotic loading on the total antibiotic elution and compressive mechanical properties of acrylic bone cement. Varying concentrations of tobramycin (0-3 g) and vancomycin (0-3 g) were added either alone or in combination to acrylic cement (Palacos R), resulting in 12 experimental groups. Samples were submerged in 37°C saline for 28 d and sampled at specific time points. The collected eluent was analyzed to determine the cumulative antibiotic release. In addition, the cement's compressive mechanical properties and porosity were characterized. Interestingly, the cement with the highest concentration of antibiotics did not possess the best elution properties. Cement samples containing both 3 g of tobramycin and 2 g vancomycin demonstrated the highest cumulative antibiotic release after 28 d, which was coupled with a significant decrease in the mechanical properties and an increased porosity. The collected data also suggests that tobramycin elutes more effectively than vancomycin from cement. In conclusion, this study demonstrates that high antibiotic loading in cement does not necessarily lead to enhanced antibiotic elution. Clinically this information may be used to optimize cement spacer antibiotic loading so that both duration and amount of antibiotics eluted are optimized. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1078-1085, 2018.

Antibiotic Choice: The Synergistic Effect of Single vs Dual Antibiotics

“…Penner et al [8] tested vancomycin and tobramycin release, finding that elution of vancomycin and tobramycin was 103% greater and 68% greater in dual combinations, respectively. Similar results were presented by Slane et al [9], who found that mixing tobramycin with vancomycin resulted in significantly higher elution of both antibiotics (P < .001), additionally observing a synergistic effect on tobramycin elution with the addition of vancomycin. A study by Klekamp et al [20] discovered that vancomycin decreased the elution of tobramycin, while tobramycin did not have a reciprocal effect.…”

“…Vancomycin is the most common antibiotic added to aminoglycoside ALCs and improves the spectrum of coverage to include methicillin-resistant Gram positive organisms [7]. A secondary effect of these combinations is a higher and longer lasting elution of both drugs [8,9]. This synergism between vancomycin and aminoglycosides has been recognized and extensively studied for decades.…”

Does the Effectiveness and Mechanical Strength of Kanamycin-Loaded Bone Cement in Musculoskeletal Tuberculosis Compare to Vancomycin-Loaded Bone Cement

“…The dose of antibiotics contained in the bone cement had been regarded as an important factor affecting the elution or mechanical strength of antibiotics in experimental setting [22]. In in vitro experiments, greater amount of antibiotics loaded bone cement usually showed higher concentration of eluate in early phase; however, the gap of concentration between different doses of contained antibiotics has been narrowed toward late phase [9,10,19,22,23]. In most of the experimental studies, a similar pattern of elution was observed, initially released in large amounts and then sharply decreased [19,22e25].…”

“…There were several experiments to assess whether the addition of antibiotics to bone cement reduces the mechanical properties depending on doses of antibiotics [32,34e36]. Related to eluting capacity of antibiotics and mechanical strength of ALBC, superficial characteristics and porosity of bone cement is considered as important factors controlling the release kinetics of antibiotics and supporting the microstructures of ALBC [22,37,38]. Therefore, a number of variables that influence the porosity of bone cement during production of ALBC had been investigated [22,33,38e40].…”

“…Therefore, a number of variables that influence the porosity of bone cement during production of ALBC had been investigated [22,33,38e40]. Generally, decrease in the mechanical properties with the addition of antibiotics supported by the finding that greater porosity of bone cement causes a loss in load-bearing structural area and concentrate mechanical stress on specific areas [22]. However, significant increase of the mechanical properties has been also reported because of superior stiffness of antibiotics than that of the polymer matrix [41].…”