Aims. Fracture-related infection (FRI) is commonly classified based on the time of onset of symptoms. Early infections (< two weeks) are treated with debridement, antibiotics, and implant retention (DAIR). For late infections (> ten weeks), guidelines recommend implant removal due to tolerant biofilms. For delayed infections (two to ten weeks), recommendations are unclear. In this study we compared infection clearance and bone healing in early and delayed FRI treated with DAIR in a rabbit model. Methods. Staphylococcus aureus was inoculated into a humeral osteotomy in 17 rabbits after plate osteosynthesis. Infection developed for one week (early group, n = 6) or four weeks (delayed group, n = 6) before DAIR (systemic antibiotics: two weeks, nafcillin + rifampin; four weeks, levofloxacin + rifampin). A control group (n = 5) received revision surgery after four weeks without antibiotics. Bacteriology of humerus, soft-tissue, and implants was performed seven weeks after revision surgery. Bone healing was assessed using a modified radiological union scale in tibial fractures (mRUST). Results. Greater bacterial burden in the early group compared to the delayed and control groups at revision surgery indicates a retraction of the infection from one to four weeks. Infection was cleared in all animals in the early and delayed groups at euthanasia, but not in the control group. Osteotomies healed in the early group, but bone healing was significantly compromised in the delayed and control groups. Conclusion. The duration of the infection from one to four weeks does not impact the success of infection clearance in this model. Bone healing, however, is impaired as the duration of the infection increases. Cite this article: Bone Joint Res 2024;13(3):127–135

Aims. Although low-intensity pulsed ultrasound (LIPUS) combined with disinfectants has been shown to effectively eliminate portions of biofilm in vitro, its efficacy in vivo remains uncertain. Our objective was to assess the antibiofilm potential and safety of LIPUS combined with 0.35% povidone-iodine (PI) in a rat debridement, antibiotics, and implant retention (DAIR) model of periprosthetic joint infection (PJI). Methods. A total of 56 male Sprague-Dawley rats were established in acute PJI models by intra-articular injection of bacteria. The rats were divided into four groups: a Control group, a 0.35% PI group, a LIPUS and saline group, and a LIPUS and 0.35% PI group. All rats underwent DAIR, except for Control, which underwent a sham procedure. General status, serum biochemical markers, weightbearing analysis, radiographs, micro-CT analysis, scanning electron microscopy of the prostheses, microbiological analysis, macroscope, and histopathology evaluation were performed 14 days after DAIR. Results. The group with LIPUS and 0.35% PI exhibited decreased levels of serum biochemical markers, improved weightbearing scores, reduced reactive bone changes, absence of viable bacteria, and decreased inflammation compared to the Control group. Despite the greater antibiofilm activity observed in the PI group compared to the LIPUS and saline group, none of the monotherapies were successful in preventing reactive bone changes or eliminating the infection. Conclusion. In the rat model of PJI treated with DAIR, LIPUS combined with 0.35% PI demonstrated stronger antibiofilm potential than monotherapy, without impairing any local soft-tissue. Cite this article: Bone Joint Res 2024;13(7):332–341

Aims. Arthroplasty surgery of the knee and hip is performed in two to three million patients annually. Periprosthetic joint infections occur in 4% of these patients. Debridement, antibiotics, and implant retention (DAIR) surgery aimed at cleaning the infected prosthesis often fails, subsequently requiring invasive revision of the complete prosthetic reconstruction. Infection-specific imaging may help to guide DAIR. In this study, we evaluated a bacteria-specific hybrid tracer (. 99m. Tc-UBI. 29-41. -Cy5) and its ability to visualize the bacterial load on femoral implants using clinical-grade image guidance methods. Methods. 99m. Tc-UBI. 29-41. -Cy5 specificity for Stapylococcus aureus was assessed in vitro using fluorescence confocal imaging. Topical administration was used to highlight the location of S. aureus cultured on femoral prostheses using fluorescence imaging and freehand single photon emission CT (fhSPECT) scans. Gamma counting and fhSPECT were used to quantify the bacterial load and monitor cleaning with chlorhexidine. Microbiological culturing helped to relate the imaging findings with the number of (remaining) bacteria. Results. Bacteria could be effectively stained in vitro and on prostheses, irrespective of the presence of biofilm. Infected prostheses revealed bacterial presence on the transition zone between the head and neck, and in the screw hole. Qualitative 2D fluorescence images could be complemented with quantitative 3D fhSPECT scans. Despite thorough chlorhexidine treatments, 28% to 44% of the signal remained present in the locations of the infection that were identified using imaging, which included 500 to 2,000 viable bacteria. Conclusion. The hybrid tracer . 99m. Tc-UBI. 29-41. -Cy5 allowed effective bacterial staining. Qualitative real-time fluorescence guidance could be effectively combined with nuclear imaging that enables quantitative monitoring of the effectiveness of cleaning strategies. Cite this article: Bone Joint Res 2023;12(1):72–79

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This study aimed to assess the risk of acute kidney injury (AKI) associated with combined intravenous (IV) and topical antibiotic therapy in patients undergoing treatment for periprosthetic joint infections (PJIs) following total knee arthroplasty (TKA), utilizing the Kidney Disease: Improving Global Outcomes (KDIGO) criteria for classification.

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There is a considerable challenge in treating bone infections and orthopaedic device-associated infection (ODAI), partly due to impaired penetration of systemically administrated antibiotics at the site of infection. This may be circumvented by local drug administration. Knowledge of the release kinetics from any carrier material is essential for proper application. Ceftriaxone shows a particular constant release from calcium sulphate (CaSO₄) in vitro, and is particularly effective against streptococci and a large portion of Gram-negative bacteria. We present the clinical release kinetics of ceftriaxone-loaded CaSO₄ applied locally to treat ODAI.

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Here we used a mature seven-day biofilm model of Staphylococcus aureus, exposed to antibiotics up to an additional seven days, to establish the effectiveness of either mechanical cleaning or antibiotics or non-contact induction heating, and which combinations could eradicate S. aureus in mature biofilms.

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Electromagnetic induction heating has demonstrated in vitro antibacterial efficacy over biofilms on metallic biomaterials, although no in vivo studies have been published. Assessment of side effects, including thermal necrosis of adjacent tissue, would determine transferability into clinical practice. Our goal was to assess bone necrosis and antibacterial efficacy of induction heating on biofilm-infected implants in an in vivo setting.

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Bacteriophages infect, replicate inside bacteria, and are released from the host through lysis. Here, we evaluate the effects of repetitive doses of the Staphylococcus aureus phage 191219 and gentamicin against haematogenous and early-stage biofilm implant-related infections in Galleria mellonella.

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This study aimed to explore the role of small colony variants (SCVs) of Staphylococcus aureus in intraosseous invasion and colonization in patients with periprosthetic joint infection (PJI).

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We compared the risks of re-revision and mortality between two-stage and single-stage revision surgeries among patients with infected primary hip arthroplasty.

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We aimed to determine the concentrations of synovial vancomycin and meropenem in patients treated by single-stage revision combined with intra-articular infusion following periprosthetic joint infection (PJI), thereby validating this drug delivery approach.

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We compared the risks of re-revision and mortality between two-stage revision surgery and single-stage revision surgery among patients with infected primary knee arthroplasty.