Background: The number of periprosthetic joint infections caused by vancomycin-resistant pathogens is increasing. Currently, no PMMA cement is commercially available to cover VRE. Daptomycin shows promising results in treating infection, offering a good safety profile and a reduced risk of developing resistance. The purpose of this in vitro study was to investigate the mechanical stability, handling properties, elution behavior, and antimicrobial effectiveness of PMMA cement loaded with three different daptomycin concentrations in comparison to commercially available antibiotic-loaded bone cement (ALBC). Methods: Mechanical properties and handling characteristics (ISO 5833, DIN 53435), HPLC elution, antimicrobial effectiveness with proliferation assay (DIN 17025), and inhibition zone testing were investigated. Results: All tested daptomycin concentrations met the ISO and DIN standards for mechanical strength. Loading of 40 g of PMMA cement with 0.5 g of daptomycin did not show any antimicrobial effectiveness, in contrast to 1.0 g and 1.5 g. PMMA cement with 1.5 g of daptomycin was the best in terms of elution and effectiveness, and it showed good ISO mechanical strength; ISO doughing was sticky for a little longer and setting was faster compared to the vancomycin-containing reference cement. Conclusion: PMMA cement containing 0.5 g of gentamicin and 1.5 g of daptomycin could be a good alternative to the already established COPAL^® (Wehrheim, Germany) G+V for the treatment of PJIs caused by VRE.

Background: Hip and knee implants can either be fixed without cement, press-fit, or with bone cement. Real-world data from arthroplasty registers, as well as studies provide a broad database for the discussion of cemented versus uncemented arthroplasty procedures. Objective: What does current evidence from international arthroplasty registries and meta-analyses recommend regarding cemented or cementless fixation of hip and knee implants? Methods: A recommendation is generated by means of direct data comparison from the arthroplasty registries of eight countries (USA, Germany, Australia, UK, Sweden, Norway, New Zealand, Netherlands), the comparison of 22 review studies and meta-analyses based on registry data, as well as an evaluation of recommendations of healthcare systems from different nations. For this purpose, reviews and meta-analyses were selected where the results were statistically significant, as were the annual reports of the arthroplasty registries that were current at the time of writing. Results: For knee arthroplasties, long survival time as well as lower risk of revision can be achieved with the support of cemented fixation with antibiotic-loaded bone cement. In patients aged 70 years and older, cemented fixation of hip stem implants significantly reduces risk of intraoperative or postoperative periprosthetic fracture (quadruple). This applies both to elective total hip arthroplasties and to hemiarthroplasty after femoral neck fractures. Antibiotic-loaded bone cement significantly (p = 0.041) reduces the risk of periprosthetic infection, especially in patients with femoral neck fractures. Conclusion: Total knee replacement with antibiotic-loaded bone cement is well established internationally and is evidence-based. Registry data and meta-analyses recommend cemented fixation of the hip stem in older patients. In Germany, USA and Australia these evidence-based recommendations still must be transferred to daily practice. Graphic

Antibiotic-loaded bone cements (ALBCs) are used to prevent and treat periprosthetic joint infections (PJI). This study compares the in vitro release and antibacterial effectiveness of gentamicin from Palacos^® R+G and tobramycin from Simplex^® T. Standardized cylindrical specimens of Palacos^® R+G and Simplex^® T were incubated in phosphate-buffered saline. Antibiotic release was quantified using high-performance liquid chromatography (HPLC) over 14 and 42 days. Antibacterial efficacy was assessed using inhibition zone tests (IZT) against Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli over 42 days. Palacos^® R+G exhibited a significantly higher and more sustained antibiotic release of gentamicin compared to tobramycin from Simplex^® T. The cumulative release of gentamicin from Palacos^® R+G was 1.148 µg/cm², while Simplex^® T released 198.87 µg/cm² tobramycin over 14 days. Inhibition zone tests showed that Palacos^® R+G maintained antibacterial activity for 42 days, while Simplex^® T’s activity diminished after 14 days. Statistical analysis confirmed significant differences in antibacterial efficacy between the two cements. Palacos^® R+G demonstrated superior gentamicin release and sustained antibacterial activity compared to tobramycin from Simplex^® T. These findings suggest that Palacos^® R+G may offer better clinical outcomes in preventing and treating PJIs.

Zusammenfassung: Hintergrund: In der Endoprothetik gibt es Hüft- und Knieimplantate, die zementfrei, „press-fit“ oder mit Knochenzement verankert werden. Real-World-Evidenz aus Endoprothesenregistern sowie Studien bieten eine breite Datenbasis zur Diskussion von zementierten im Vergleich zu zementfreien Endoprothesen. Fragestellung: Wie lautet die Empfehlung zur zementierten oder zementfreien Verankerung von Hüft- und Knieimplantaten, basierend auf der aktuellen Evidenzlage internationaler Endoprothesenregister und Metaanalysen? Material und Methode: Mittels des direkten Vergleichs von Daten aus den Endoprothesenregistern acht verschiedener Länder (USA, Deutschland, Australien, UK, Schweden, Norwegen, Neuseeland, Niederlande), dem Vergleich von 22 Review-Studien und Metaanalysen basierend auf Registerdaten, sowie der Auswertung der Empfehlung von Gesundheitssystemen unterschiedlicher Nationen wird eine Empfehlung generiert. Dazu wurden Reviews und Metaanalysen ausgewählt, deren Ergebnisse statistisch signifikant sind, ebenso wie die zum Zeitpunkt der Erstellung des Artikels aktuellen Jahresberichte der Endoprothesenregister. Ergebnisse: Für Knieendoprothesen kann eine lange Überlebensdauer sowie ein geringeres Revisionsrisiko mithilfe einer zementierten Verankerung mit antibiotikabeladenem Knochenzement erreicht werden. Bei Patienten ab einem Alter von 70 Jahren reduziert eine zementierte Verankerung des Hüftschaftimplantats das Risiko einer intra- oder postoperativen periprothetischen Fraktur um das Vierfache, dies gilt sowohl für elektive Hüfttotalendoprothesen (Hüft-TEP), als auch für Hemiendoprothesen nach Schenkelhalsfrakturen. Ein antibiotikabeladener Knochenzement reduziert signifikant (p = 0,041) das Risiko für das Auftreten einer periprothetischen Infektion, insbesondere bei Patienten mit Schenkelhalsfrakturen. Schlussfolgerungen: Die mit antibiotikabeladenem Knochenzement versorgte Knieendoprothese ist in Deutschland etabliert und wird durch die Evidenzlage bestätigt. Registerdaten und Metaanalysen empfehlen eine zementierte Verankerung des Hüftschaftimplantats beim älteren Patienten – hier sollte die Praxis in Deutschland der aktuellen Evidenz folgen.

Periprosthetic joint infection (PJI) is an infrequent yet severe complication. A fundamental aspect of PJI treatment involves the use of polymethylmethacrylate (PMMA) cement augmented with antibiotics. For therapeutic application, it is often necessary to manually mix antibiotics with commercially produced PMMA cements. However, the potential issues arising from this manual admixing have not been thoroughly documented. This study aims to elucidate the impact of additional homogenization through dry mixing of a polymer‐active substance blend on the quality of manually mixed PMMA cement. In this laboratory‐based investigation, four cement samples were prepared using various methods for the manual incorporation and homogenization of the antibiotic vancomycin. The reference controls were Copal G + V and Copal G + C pro (Heraeus Medical GmbH, Wehrheim, Germany), representing commercially available PMMA cements and a closed mixing system. The samples were analyzed for mechanical, microbiological, and microscopic properties. The mechanical and microbiological analyses revealed no statistically significant differences between the manually mixed samples and the references. However, microscopic examination of the mixing cartridges' inner surfaces indicated scratching and signs of abrasion during the mixing process. The manual incorporation of antibiotics into PMMA cement should be limited to specific indications, with a preference for using commercially available mixtures whenever possible.