A major trauma centre experience with gentamicin-coated tibial intramedullary nails (ETN PROtect™) in acute primary open fracture fixation and complex revision surgery.

PURPOSE: Fracture-related infections (FRI) following intramedullary nailing for tibial shaft fractures remain challenging to treat with associated high patient morbidity and health care costs. Recently, antibiotic-coated nails have been introduced as a strategy to reduce implant related infection rates in high-risk patients. We present the largest single-centre case series on ETN PROtect® outcomes reporting on fracture union, infection rates and treatment complications. METHODS: Fifty-six adult patients underwent surgery with ETN PROtect® between 01/09/17 and 31/12/20. Indications consisted of acute open fractures and complex revision cases (previous FRI, non-union surgery and re-fracture) with a mean of three prior surgical interventions. We report on patient demographics, union rates and deep infection. Minimum follow-up was one year. RESULTS: One (1.8%) patient developed a deep surgical infection and associated non-union requiring further surgery. In addition, we identified three cases (5.4%) of aseptic non-union following facture treatment with ETN PROtect®. Of the five patients who underwent staged complex revision surgery for established FRI with ETN PROtect®, all had treatment failure with ongoing symptoms of deep infection requiring implant removal and further treatment. CONCLUSION: Use of the ETN PROtect® nail in high-risk patients (open fractures and those initially treated with external fixation) and in those patients with aseptic non-unions, demonstrates promising outcomes in the prevention of implant-related infection. In our limited series we have failed to observe any benefit over uncoated nails, when used in treating cases of previously established FRI/osteomyelitis and would therefore advise caution in their use, especially in view of the high cost.

Relevance of a bone and joint registry for fracture-related infections.

The UK Bone and Joint Infection Registry (BAJIR) is a national project established in 2018 with the aim of collecting information about demographics, co-morbidities, pathogens, treatment strategies and outcomes on all patients who are diagnosed with, and treated for, a bone or joint infection in the UK with the objective of providing an understanding of the burden of disease. In time these data will be used to inform best practice, direct research and provide information for commissioners of healthcare. In this fracture-related infection special edition article, we discuss the registry's development, relevance and how we see it directing our practice in the future. Equally, we have highlighted some potential limitations and lessons learned.

Microbiological Profile of Fracture Related Infection at a UK Major Trauma Centre.

Fracture Related Infection (FRI) represents one of the biggest challenges for Trauma and Orthopaedic surgery. A better understanding of the microbiological profile should assist with decision-making and optimising outcomes. Our primary aim was to report on the microbiological profile of FRI cases treated over a six-year period at one of Europe's busiest trauma centres. Secondarily, we sought to correlate our findings with existing anti-microbiological protocols and report on diagnostic techniques employed in our practice. All adult cases of FRI treated in our institution between 2016 and 2021 were identified, retrospectively. We recorded patient demographics, diagnostic strategies, causative organisms and antibiotic susceptibilities. There were 330 infection episodes in 294 patients. A total of 463 potentially pathogenic organisms (78 different species) were identified from cultures, of which 57.2% were gram-positive and 39.7% gram-negative. Polymicrobial cultures were found in 33.6% of cases and no causative organism was found in 17.5%. The most prevalent organisms were Staphylococcus aureus (24.4%), coagulase-negative Staphylococci (14%), Pseudomonas aeruginosa (8.2%), Enterobacter species (7.8%) and Escherichia coli (6.9%). Resistant gram-positive organisms (methicillin resistant Staphylococcus aureus or vancomycin-resistant Enterococci) were implicated in 3.3% of infection episodes and resistant gram-negatives (extended-spectrum beta-lactamase, ampC or carbapenemase-producing bacteria) in 13.6%. The organisms cultured in 96.3% of infection episodes would have been covered by our empirical systemic antibiotic choice of teicoplanin and meropenem. To our knowledge, this is the largest reported single-centre cohort of FRIs from a major trauma centre. Our results demonstrate patterns in microbiological profiles that should serve to inform the decision-making process regarding antibiotic choices for both prophylaxis and treatment.

Strategies and outcomes in severe open tibial shaft fractures at a major trauma center: A large retrospective case-series.

BACKGROUND: Severe open tibia fractures are challenging to treat with a lack of published clear management strategies. Our aim was to provide an overview of the largest single-center experience in the literature, with minimum 1-year follow-up, of adult type 3 open tibial shaft fractures at Cambridge University Hospitals (a United Kingdom major trauma center). We sought to define patient characteristics and our main outcome measures were infection, union and re-fracture. AIM: To retrospectively define patient and injury characteristics, present our surgical methods and analyze our outcomes-namely infection, union and re-fracture rates. METHODS: Consecutive series of 74 patients with 75 open tibial fractures treated between 2014 and 2020 (26 classified as Gustilo-Anderson 3A, 47 were 3B and two were 3C). Nine patients underwent intramedullary nailing (IMN), 61 underwent Taylor spatial frame (TSF) fixation and 5 were treated with Masquelet technique (IMN and subsequent bone grafting). RESULTS: Mean follow-up was 16 mo (IMN) and 25 mo (TSF). We had an infection rate of 6.7% (5), non-union rate of 4% (3) and re-fracture rate of 2.7% (2). Average time to union was 22 wk for IMN and 38.6 wk for TSF. Thirty-three cases had a bone defect with a mean of 5.4 cm (2-11). Patient age, sex, diabetes, smoking status or injury severity did not have a significant effect on union time with either fixation method. Our limb salvage rate was 98.7%. CONCLUSION: Grade 1 to 3A injuries can effectively be treated with reamed or unreamed IMN. Grade 3B/C injuries are best treated by circular external fixators as they provide good, reproducible outcomes and allow large bone defects to be addressed via distraction osteogenesis.

Chondrogenic potential of bone marrow-derived mesenchymal stem cells on a novel, auricular-shaped, nanocomposite scaffold.

Reconstruction of the human auricle remains a challenge to plastic surgeons, and current approaches are not ideal. Tissue engineering provides a promising alternative. This study aims to evaluate the chondrogenic potential of bone marrow-derived mesenchymal stem cells on a novel, auricular-shaped polymer. The proposed polyhedral oligomeric silsesquioxane-modified poly(hexanolactone/carbonate)urethane/urea nanocomposite polymer has already been transplanted in patients as the world's first synthetic trachea, tear duct and vascular bypass graft. The nanocomposite scaffold was fabricated via a coagulation/salt-leaching method and shaped into an auricle. Adult bone marrow-derived mesenchymal stem cells were isolated, cultured and seeded onto the scaffold. On day 21, samples were sent for scanning electron microscopy, histology and immunofluorescence to assess for neocartilage formation. Cell viability assay confirmed cytocompatability and normal patterns of cellular growth at 7, 14 and 21 days after culture. This study demonstrates the potential of a novel polyhedral oligomeric silsesquioxane-modified poly(hexanolactone/carbonate)urethane/urea scaffold for culturing bone marrow-derived mesenchymal stem cells in chondrogenic medium to produce an auricular-shaped construct. This is supported by scanning electron microscopy, histological and immunofluorescence analysis revealing markers of chondrogenesis including collagen type II, SOX-9, glycosaminoglycan and elastin. To the best of our knowledge, this is the first report of stem cell application on an auricular-shaped scaffold for tissue engineering purposes. Although many obstacles remain in producing a functional auricle, this is a promising step forward.

Tissue engineering: revolution and challenge in auricular cartilage reconstruction.

External ear reconstruction for congenital deformity such as microtia or following trauma remains one of the greatest challenges for reconstructive plastic surgeons. The problems faced in reconstructing the intricate ear framework are highly complex. A durable, inert material that is resistant to scar contracture is required. To date, no material, autologous or prosthetic, is available that perfectly mimics the shapely elastic cartilage found in the ear. Current procedure involves autologous costal cartilage that is sculpted to create a framework for the overlying soft tissues. However, this is associated with donor-site morbidity, and few surgeons worldwide are skilled in the techniques required to obtain excellent results. Various alloplastic materials have therefore been used as a framework. However, a degree of immunogenicity and infection and extrusion are inevitable, and results are often disappointing. Tissue-engineered cartilage is an alternative approach but, despite significant progress in this area, many problems remain. These need to be addressed before routine clinical application will become possible. The current tissue-engineered options are fragile and inflexible. The next generation of auricular cartilage engineering is promising, with smart materials to enhance cell growth and integration, and the application of stem cells in a clinical setting. More recently, the authors' team designed the world's first entirely synthetic trachea composed of a novel nanocomposite material seeded with the patient's own stem cells. This was successfully transplanted in a patient at the Karolinska Hospital in Sweden and may translate into a tissue-engineered auricle in the future.