Aim. As the number of performed total hip arthroplasties (THA) and total knee arthroplasties (TKA) has increased over the years, revision surgeries are expected to increase as well. Revision surgeries are associated with a longer operating room time, prolonged length of stay (LOS), and more frequent complications. Postoperative hematomas are a major reason for wound healing disturbances and periprosthetic joint infections (PJI). We aimed to systematically assess the use and safety of a microporous polysaccharide hemosphere (MPH) in revision THA and TKA. We focused on the risk reduction of further revision surgeries in case of wound healing disorders and hematoma, transfusion of packed red blood cells (PRBC), loss of hemoglobin (hb) and mean LOS following the use of MPH. Method. Our prospective study includes 89 patients who underwent revision surgery after THA and TKA with application of MPH and were compared to 102 patients who did not receive MPH and underwent revision surgery after THA and TKA. Five grams of MPH. 1. were applied periarticular before fascia closure and to the subcutaneous soft tissue. The follow-up was conducted in daily clinical visits during the inpatient stay and three months postoperatively in our outpatient clinic. Repeated revision surgery was performed in case of prolonged secretion (>10 days) or clinical suspicion of infection. After matching the cohorts the outcomes were statistically analyzed using paired methods. Results. A significantly lower odds ratio for repeat revisions was found for the MPH cohort (OR=0.312; 95%-CI 0.090, 0.893; p=0.027). Differences between pre- and postoperative hb levels, LOS and transfusions of PRBC did not reach significance. No intra- or postoperative complications to MPH occurred. Moreover, no infection relapse occurred after applying MPH. Conclusions. Routine use of MPH in revision arthroplasty management after TKA and THA appears to be safe and an effective way to support hemostasis, with no observed adverse events related to MPH use. There were noticeably less hematomas and revision surgeries in the MPH group. 1. Arista BD, Franklin Lakes, NJ, USA

The incidence of PJI in knee replacements is 2.8% and slightly lower with hip replacement surgery. PJI make up 15% (or even more) of knee revisions. To combat PJI, antibiotic laden bone cement has been used for many decades, but antibiotic stewardship dictates more prudent management of antimicrobials. Projected increase in infection rate, due to increased surgery and latent infection to be almost 5-fold up to 2035. Biofilm is a complex structure of bacteria and polysaccharide matrix and, is recognised as a major component in PJI and other orthopaedic infections. Biofilm is responsible for high incidence of resistance to antimicrobials and ineffective host immune response. Method. Stabilized hypochlorous acid has been reported to have a rapid kill rate on all pathogens, including MDR pathogens associated with chronic and acute wound infections. It destroys biofilm on contact, is not cytotoxic, reduces inflammation and stimulates wound healing. 0,038% of Hypochlorous acid was used as prophylaxis against infection and to treat PJI. We report on our experience with hypochlorous acid as a wound irrigation as prophylaxis against infection (more than 600 cases) and for PJI. We also report on a University study where a head to head analysis was done on the anti-biofilm efficacy between hypochlorous acid 0,038% (Trifectiv Surgical Wound Irrigation) and Product X (an industry-standard product for the prevention and treatment of biofilm infection. Hypochlorous acid offers a valuable addition to the armamentarium of wound antiseptics, with added anti-inflammatory value. An in vitro study demonstrated superior efficacy against biofilm when compared to Product X

The aim of the present study was to assess the antibiofilm activity of daptomycin- and vancomycin-loaded poly(methyl methacrylate) (PMMA) and PMMA-Eudragit RL100 (EUD) microparticles against mature biofilms of polysaccharide intercellular adhesin-positive S. epidermidis. The effect of plain, daptomycin- and vancomycin-loaded PMMA and PMMA-EUD microparticles on S. epidermidis biofilms was assessed by isothermal microcalorimetry (IMC) and fluorescence in situ hybridization (FISH). Biofilms were grown for 48h onto poly-urethane pieces of fixed dimensions. Each sample was washed with PBS in order to remove planktonic bacteria and incubated for 24h with different concentrations of acrylic microparticles (20–1.25 mg/mL). The minimal biofilm inhibitory concentration (MBIC) of the antibiotic-loaded particles was defined as the lowest concentration of particles that was able to prevent heat flow associated to the recovery of the biofilms. After incubation with the microparticles, sessile cocci were hybridized with the pan-bacterial EUB338-FITC and the staphylococci-specific STAPHY-FICT probes and stained with DAPI. Biofilm structure and metabolic state were characterized by fluorescence microscopy. According to the IMC results, plain PMMA-particles showed no effect on S. epidermidis biofilms, whereas PMMA-EUD-microparticles negatively influenced the recovery of the biofilm probably due to the highly positive charge of these particles. The MBIC of daptomycin-loaded PMMA-microparticles was 20 mg/mL, whereas vancomycin-loaded PMMA microparticles were not able to inhibit biofilm recovery. Adding EUD to the formulation reduced the MBIC of daptomycin-loaded microparticles to 1.25 mg/mL, corresponding to a 16-fold reduction. Regarding the vancomycin-loaded microparticles, EUD caused a further decrease of their antibiofilm activity. The FISH micrographs corroborated the IMC results and provided additional insights on the antibiofilm effect of these carriers. According to FISH, daptomycin-loaded PMMA-EUD microparticles were responsible for the most pronounced reduction in biofilm mass. In addition, FISH showed that both PMMA and PMMA-EUD microparticles were able to attach to the biofilms. Adding EUD to the formulations proved to be a powerful strategy to improve daptomycin-loaded microparticles antibiofilm activity. In addition, the combination of IMC and FISH was essential in order to fully assess the effect of polymeric microparticles on sessile S. epidermidis. Although the present study enabled gaining further insights on this subject, the nature of these interactions remains unclear. However, this may be a crucial aspect for the enhancement of antibiofilm activity of antibiotic-loaded polymeric microcarriers against mature biofilms. This work was supported by the Portuguese government (Fundação para a Ciência e a Tecnologia) and FEDER (grant SFRH/BD/69260/2010 and research project EXCL/CTM-NAN/0166/2012) and strategic project PEst-OE/SAU/UI4013/2011

The number of arthroplasties being undertaken is expected to grow year on year, and periprosthetic joint infections will be an increasing socioeconomic burden. The challenge to prevent and eradicate these infections has resulted in the emergence of several new strategies, which are discussed in this review.

Cite this article: Bone Joint J 2015;97-B:1162–9.