In vitro release of antibiotics from commercial PMMA beads and articulating hip spacers

The efficacy and benefits of high-dose antibiotic cement spacers compared with beads in the treatment of an infected prosthesis have been shown. However, in clinical practice, commercial, low-dose antibiotic bone cement is often used. This study investigated the in vitro antibiotic release of hip spacers made from Refobacin-Palacos-R or Antibiotic-Simplex-P cement compared with Septopal beads. Antibiotic concentrations were measured during 6 weeks. All carriers showed a burst release, but spacers showed little additional release after the first week. Cumulative release was 27.5 +/- 2.3 mg for Palacos, 23.8 +/- 0.2 mg for Simplex, and 188.3 +/- 9.3 mg for Septopal (P < .001). Despite the efficacy of high-dose antibiotic bone cement spacers, we believe one should be cautious toward using low-dose antibiotic bone cement for spacers because this could result in an unsuccessful eradication of infection.