Economic advantage of 'self-made' antibiotic-loaded spacer compared to prefabricated antibiotic-loaded spacer and spacer molds in two-staged revision arthroplasty.

Infection after total hip or total knee arthroplasty is a serious complication implying great costs for the health care system. Amongst the different treatment options, the two-step exchange using a spacer in the interval is a valid option. We evaluate the economic impact of our self-made antibiotic-loaded hip and knee cement spacers compared with prefabricated spacers and spacer molds. Costs to prepare self-made cement spacers are detailed for each spacer type. We also assess the intraoperative time spent for fabricating our self-made hip and knee spacers. The price of these self-made knee spacer is 514 CHF (450 EUR / 505 USD) if non-articulated and 535 CHF (470 EUR / 525 USD) if articulated ; the price for the self-made hip spacer is 749 CHF (760 EUR / 735 USD). Our average preparation time is 14 minutes for our self-made knee spacers and 16 minutes for our self-made hip spacers. While the senior surgeon is fabricating the self-spacers, another surgeon of the team continues intensive irrigation and debridement. Thus, no time is lost waiting for the self-spacer to be fabricated. In our hands, self-made hip and knee spacers are at least 40-50% cheaper than prefabricated spacers and spacer-molds. This is a serious economic advantage in this already expensive surgery. When done in teamwork, self-spacer fabrication does not increase the surgery time. The economic advantage is added to the main and most important advantage of self- made spacers, which remains the possibility of patient adapted anatomical reconstruction of the joint.

Bactericidal efficacy of molybdenum oxide nanoparticles against antimicrobial-resistant pathogens.

Multidrug-resistant bacteria pose a major threat to effective antibiotics and alternatives to fight multidrug-resistant pathogens are needed. We synthetized molybdenum oxide (MoO3) nanoparticles (NP) and determined their antibacterial activity against 39 isolates: (i) eight Staphylococcus aureus, including representatives of methicillin-resistant S. aureus epidemic clones; (ii) six enterococci, including vancomycin-resistant isolates; and (iii) 25 Gram-negative isolates (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterobacter cloacae), including extended spectrum beta-lactamases and carbapenemases producers. All isolates showed a MoO3 NP MIC of 700-800 mg l-1. MoO3 NP produced a clear inhibition zone for S. aureus and all Gram-negative isolates at concentrations ≥25 mg ml-1 and ≥50 mg ml-1 for enterococci. When the NP solutions were adjusted to pH ~7, the biocidal activity was completely abolished. MoO3 NP create an acidic pH and show a universal antimicrobial activity against susceptible and resistant isolates belonging to the most relevant bacterial species responsible for hospital-acquired infections.

The influence of nanoparticle architecture on latex film formation and healing properties.

We present a study of chain interdiffusion in films formed by specially architectured PBMA nanoparticles by Förster Resonance Energy Transfer -FRET. Polymer nanoparticles contained linear chains with narrower molecular weight distributions than other previous reports, allowing a more detailed study. Apparent fractions of mixing and diffusion coefficients, determined from the quantum efficiency of energy transfer, were used to characterize the interdiffusion mechanism in the different films. The resistance of the films to dissolution by a good solvent was finally correlated with the interdiffusion results, in order to get information about film healing. We concluded that whenever interdiffusion occurs between nanoparticles containing linear chains and fully cross-linked nanoparticles, healing becomes more effective in spite of showing slower interdiffusion. We also observed that particles with longer chains are more effective for film healing. Finally, we concluded that interdiffusion occurs both ways across interfaces in blends formed by particles swollen with linear chains of different molecular weights.