Use of antibiotic-cement coated locking plates in the setting of periprosthetic infection and infected nonunion

Pathogens in FRI - Do bugs matter? - An analysis of FRI studies to assess your enemy

Fracture-related infection (FRI) is a devasting complication for both patients and their treating Orthopaedic surgeon that can lead to loss of limb function or even amputation. The unique and unpredictable features of FRI make its diagnosis and treatment a significant challenge. It has substantial morbidity and financial implications for patients, their families and healthcare providers. In this article, we perform an in-depth and comprehensive review of FRI through recent and seminal literature to highlight evolving definitions, diagnostic and treatment approaches, focusing on common pathogens such as Staphylococcus aureus, polymicrobial infections and multi-drug-resistant organisms (MDRO). Furthermore, multiple resistance mechanisms and adaptations for microbial survival are discussed, as well as modern evidence-based medical and surgical advancements in treatment strategies in combating FRI.

A technique for introducing broad-spectrum topical antibiotics during open reduction and internal fixation of acetabular fractures

Postoperative surgical site infections remain a significant and prevalent complication after open reduction and internal fixation of acetabular fractures. Local antibiotics have been shown to decrease risk of postoperative infection, although recent evidence is conflicting. We provide a consistent and replicable technique for delivering intraoperative broad-spectrum antibiotics in the form of a putty applied directly to surgical implants. With this technique, systemic levels of those antibiotics remain safe and stable.

Antibiotic bone cement accelerates diabetic foot wound healing: Elucidating the role of ROCK1 protein expression

Clinical studies indicate antibiotic bone cement with propeller flaps improves diabetic foot wound repair and reduces amputation rates, but the molecular mechanisms, particularly key proteins' role remain largely unexplored. This study assessed the efficacy of antibiotic bone cement for treating diabetic foot wounds, focusing on molecular impact on ROCK1. Sixty patients were randomized into experimental (EXP, n = 40) and control (CON, n = 20) groups, treated with antibiotic bone cement and negative pressure. Wound healing rate, amputation rate, wound secretion culture and C-reactive protein (CRP) changes, were monitored. Comprehensive molecular investigations were conducted and animal experiments were performed to further validate the findings. Statistical methods were employed to verify significant differences between the groups and treatment outcomes. The EXP group showed significant improvements in wound healing (χ 2 $$ {\chi}^2 $$ = 11.265, p = 0.004) and reduced amputation rates. Elevated levels of ROCK1, fibroblasts and VGF were observed in the trauma tissue post-treatment in the experimental group compared to pre-treatment and the control group (all p < 0.05). Improved trauma secretion culture and CRP were also noted in the EXP group (all p < 0.05). The study suggests that antibiotic bone cement enhances diabetic foot wound healing, possibly via upregulation of ROCK1. Further research is needed to elucidate the underlying molecular mechanisms and broader clinical implications.

Antibiotic-Coated Intramedullary Nailing Managing Long Bone Infected Non-Unions: A Meta-Analysis of Comparative Studies

Long bone infected non-unions are such an orthopedic challenge that antibiotic-coated intramedullary nailing (ACIN) has become a viable therapeutic option for their management. This study aims to provide a comprehensive assessment of the available data about the use of antibiotic-coated nailing in the treatment of long bone infected non-unions. Following the PRISMA guideline in this meta-analysis, a systematic literature search was conducted across major databases for studies evaluating ACIN in long bone infected non-unions. The primary outcome measures included union rates, infection control, complications and functional status. Five eligible studies encompassing 183 patients in total met the inclusion criteria. The meta-analysis revealed no difference in the union rate in the antibiotic-coated intramedullary nailing group compared to that of the control group (OR = 1.73 [0.75-4.02]). Antibiotic-coated intramedullary nailing demonstrated no association with higher infection eradication (OR = 2.10 [0.97-4.54]). Also, functional outcome measure was mostly not significantly different between ACIN and control interventions. According to this meta-analysis, compared to the management of controls, ACIN is neither linked to increased union rates nor decreased infection rates. The paucity of research on this topic emphasizes the continuous need for additional well-designed randomized controlled trials for the application of antibiotics-coated intramedullary nailing in long bone non-unions.

Open Reduction and Internal Fixation for Vancouver B1 and B2 Periprosthetic Femoral Fractures: A Proportional Meta-Analysis

Purpose

Periprosthetic femoral fracture (PFF) is a common complication after total hip arthroplasty, and open reduction and internal fixation (ORIF) is a common surgical treatment. We conducted a meta-analysis to compare the outcomes of ORIF in patients with different fracture patterns (Vancouver B1 and B2).

Materials and Methods

We conducted a systematic search of PubMed, Embase, Cochrane Library and KoreaMed from inception to August 2022. We conducted a pair-wise meta-analysis (with a fixed-effects model) on the 10 comparative studies and a proportional meta-analysis on the data from the 39 articles to determine a consensus. The outcomes were the incidence of reoperations that included osteosynthesis, irrigation/debridement and revision arthroplasty.

Results

The pair-wise meta-analysis showed similar outcomes between two groups; the risk of reoperation (odds ratio [OR]=0.82, confidence interval [CI] 0.43-1.55, P=0.542), nonunion (OR=0.49; CI 0.22-1.10, P=0.085) and deep infection (OR=1.89, CI 0.48-7.46, P=0.361). In proportion meta-analysis, pooled prevalence of reoperation was 9% (95% CI, 6-12) in B1 and 8% (95% CI, 2-15) in B2 (heterogeneity between two groups (Q), P=0.772). The pooled prevalence of nonunion was same as of 4% in B1 and B2 (Q, P=0.678), and deep infection was 2% (95% CI, 1-3) in B1 and 4% (95% CI, 2-7) in B2 (Q, P=0.130).

Conclusion

ORIF is a feasible treatment for B1 and B2 periprosthetic femoral fractures, with acceptable outcomes in terms of, nonunion and infection. The results of this study would help clinicians and provide baseline data for further studies validating PFF.

Antimicrobial Mechanisms and Preparation of Antibiotic-impregnated Cement-coated Locking Plates in the Treatment of Infected Non-unions

Background

Antibiotic-impregnated cement-coated plates (ACPs) have been used successfully for temporary internal fixation between stages in the two-stage treatment of infected non-unions. We describe our approach of using an ACP in the staged treatment of a methicillin-resistant Staphylococcus aureus (MRSA)-infected distal femoral non-union below a total hip prosthesis. In addition, we present the results of an in vitro experiment to provide an in-depth insight into the capacity of ACPs in (i) treating residual biofilm and (ii) preventing bacterial recolonisation.

Materials and methods

In the first stage, we used a titanium LISS plate coated with hand-mixed PALACOS with vancomycin (PAL-V) for temporary internal fixation combined with commercially prepared COPAL with gentamicin and vancomycin (COP-GV) to fill the segmental defect. In the second stage, the non-union was treated with double-plate fixation and bone grafting.A Kirby-Bauer agar disc diffusion assay was performed to determine the antimicrobial activity of both ACPs and a drug-release assay to measure antibiotic release over time. A biofilm killing assay was also carried out to determine if the antibiotic released was able to reduce or eradicate biofilm of the patient's MRSA strain.

Results

At one-year follow-up, there was complete bone-bridging across the previous non-union. The patient was pain-free and ambulatory without need for further surgery. Both ACPs with COP-GV and PAL-V exerted an antimicrobial effect against the MRSA strain with peak concentrations of antibiotic released within the first 24 hours. Concentrations released from COP-GV in the first 24 hours in vitro caused a 7.7-fold log reduction of colony-forming units (CFU) in the biofilm. At day 50, both COP-GV and PAL-V still released concentrations of antibiotic above the respective minimal inhibitory concentrations (MIC), likely contributing to the positive clinical outcome.

Conclusion

The use of an ACP provides stability and infection control in the clinical scenario of an infected non-union. This is confirmed in vitro where the release of antibiotics from ACPs is characterised by an early burst followed by a prolonged sustained release above the MIC until 50 days. The burst release from COP-GV reduces CFU in the biofilm and prevents early recolonisation through synergistic activity of the released vancomycin and gentamicin.

Clinical significance

An antibiotic-impregnated cement-coated plate is a useful addition to the surgeon's armamentarium to provide temporary internal fixation without the disadvantages of external fixation and contribute to infection control in an infected non-union.

How to cite this article

Wagner RK, Guarch-Pérez C, van Dam AP, et al. Antimicrobial Mechanisms and Preparation of Antibiotic-impregnated Cement-coated Locking Plates in the Treatment of Infected Non-unions. Strategies Trauma Limb Reconstr 2023;18(2):73-81.

Does the use of antibiotic spacer disrupt induced membrane function?

Treatment of large segmental bone defects has been a challenging and long process for both physicians and patients. At present, the induced membrane technique is one of the reconstruction techniques commonly utilized in treating large segmental bone defects. It consists of a two-step procedure. In the first one, after bone debridement, the defect is filled with bone cement. The aim at this stage is to support and protect the defective area with cement. A membrane is formed around the area where cement was inserted 4-6 weeks after the first surgical stage. This membrane secretes vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), as shown in the earliest studies. In the second step, the bone cement is removed, and the defect is filled with cancellous bone autograft. In the first stage, antibiotics can be added to the applied bone cement, depending on the infection. Still, the histological and micromolecular effects of the added antibiotic on the membrane are unknown.This study investigates the molecular and histological effects of antibiotics addition into bone cement on the induced membrane.In this study, conducted on 27 male New Zealand rabbits, the 2 cm long defects of a bone were created in the rabbit femurs. Three groups were formed by placing antibiotic-free, gentamicin, and vancomycin-containing cement in the defect area.These groups were followed for six weeks, and the membrane formed at the end of 6 weeks was examined histologically. As a result of this study, it found that the membrane quality markers (Von Willebrand factor (vwf), Interleukin 6-8 (IL), Transforming growth factor beta (TGF-β), Vascular endothelial growth factor (VEGF) were significantly higher in the antibiotic-free bone cement group. Our study has shown that antibiotics added to the cement have negative effects on the membrane. Based on the results we obtained, it would be a better choice to use antibiotic-free cement in aseptic nonunions. However, more data is needed to understand the effects of these changes on the cement on the membrane.