1188 Management of Prosthetic Joint Infections and Fracture Related Infections at A District General Hospital

Aim The aim of our study was to determine if there was cohesion in management of orthopaedic infections between the surgical and microbiology team to ensure optimal patient outcome in accordance with BOA standards for management of Orthopaedic infections. Surgical sampling intraoperatively of orthopaedic infections was evaluated. Method We retrospectively reviewed 19 patients that had suspected PJI or fracture related infections between July 2019 to December 2019 at a District General Hospital. Patient information was collated from patient notes, fusion, bone infection database and MDT notes. Analyses were performed using R (R Foundation for Statistical computing, Vienna, Austria). Results 19/19 patients had a preoperative antibiotic plan prior to index surgery. 0% of discharge summaries contained information for patients or primary care staff regarding management of a suspected orthopaedic infection. 100% of patients who were septic were reviewed by a consultant within 24hours of admission. 72% of patients that had operative intervention had 5 microbiology + 2 histology samples. 0% of patients had surgical recording of process of sampling. All patients were discussed at the newly formed Bone infection MDT with a microbiology consultant, radiologist, and allied health professionals. Conclusions For optimal management of orthopaedic infections an MDT approach is vital. Early microbiological input and appropriate surgical sampling and debridement are key to providing a diagnosis of deep infection. The newly created PJI pathway will aid future management of orthopaedic infections and standardise care.

Systematic review of risk prediction studies in bone and joint infection: are modifiable prognostic factors useful in predicting recurrence?

Background: Classification systems for orthopaedic infection include patient health status, but there is no consensus about which comorbidities affect prognosis. Modifiable factors including substance use, glycaemic control, malnutrition and obesity may predict post-operative recovery from infection. Aim: This systematic review aimed (1) to critically appraise clinical prediction models for individual prognosis following surgical treatment for orthopaedic infection where an implant is not retained; (2) to understand the usefulness of modifiable prognostic factors for predicting treatment success. Methods: EMBASE and MEDLINE databases were searched for clinical prediction and prognostic studies in adults with orthopaedic infections. Infection recurrence or re-infection after at least 6 months was the primary outcome. The estimated odds ratios for the primary outcome in participants with modifiable prognostic factors were extracted and the direction of the effect reported. Results: Thirty-five retrospective prognostic cohort studies of 92 693 patients were included, of which two reported clinical prediction models. No studies were at low risk of bias, and no externally validated prediction models were identified. Most focused on prosthetic joint infection. A positive association was reported between body mass index and infection recurrence in 19 of 22 studies, similarly in 8 of 14 studies reporting smoking history and 3 of 4 studies reporting alcohol intake. Glycaemic control and malnutrition were rarely considered. Conclusion: Modifiable aspects of patient health appear to predict outcomes after surgery for orthopaedic infection. There is a need to understand which factors may have a causal effect. Development and validation of clinical prediction models that include participant health status will facilitate treatment decisions for orthopaedic infections.

Bacteriophage therapy for bone and joint infections

Antibiotic resistance represents a threat to human health. It has been suggested that by 2050, antibiotic-resistant infections could cause ten million deaths each year. In orthopaedics, many patients undergoing surgery suffer from complications resulting from implant-associated infection. In these circumstances secondary surgery is usually required and chronic and/or relapsing disease may ensue. The development of effective treatments for antibiotic-resistant infections is needed. Recent evidence shows that bacteriophage (phages; viruses that infect bacteria) therapy may represent a viable and successful solution. In this review, a brief description of bone and joint infection and the nature of bacteriophages is presented, as well as a summary of our current knowledge on the use of bacteriophages in the treatment of bacterial infections. We present contemporary published in vitro and in vivo data as well as data from clinical trials, as they relate to bone and joint infections. We discuss the potential use of bacteriophage therapy in orthopaedic infections. This area of research is beginning to reveal successful results, but mostly in nonorthopaedic fields. We believe that bacteriophage therapy has potential therapeutic value for implant-associated infections in orthopaedics. Cite this article: Bone Joint J 2021;103-B(2):234–244.

Antibiotic loaded β-tricalcium phosphate/calcium sulfate for antimicrobial potency, prevention and killing efficacy of Pseudomonas aeruginosa and Staphylococcus aureus biofilms

This study investigated the efficacy of a biphasic synthetic β-tricalcium phosphate/calcium sulfate (β-TCP/CS) bone graft substitute for compatibility with vancomycin (V) in combination with tobramycin (T) or gentamicin (G) evidenced by the duration of potency and the prevention and killing efficacies of P. aeruginosa (PAO1) and S. aureus (SAP231) biofilms in in vitro assays. Antibiotic loaded β-TCP/CS beads were compared with antibiotic loaded beads formed from a well characterized synthetic calcium sulfate (CS) bone void filler. β-TCP/CS antibiotic loaded showed antimicrobial potency against PAO1 in a repeated Kirby-Bauer like zone of inhibition assay for 6 days compared to 8 days for CS. However, both bead types showed potency against SAP231 for 40 days. Both formulations loaded with V + T completely prevented biofilm formation (CFU below detection limits) for the 3 days of the experiment with daily fresh inoculum challenges (P < 0.001). In addition, both antibiotic loaded materials and antibiotic combinations significantly reduced the bioburden of pre-grown biofilms by between 3 and 5 logs (P < 0.001) with V + G performing slightly better against PAO1 than V + T. Our data, combined with previous data on osteogenesis suggest that antibiotic loaded β-TCP/CS may have potential to stimulate osteogenesis through acting as a scaffold as well as simultaneously protecting against biofilm infection. Future in vivo experiments and clinical investigations are warranted to more comprehensively evaluate the use of β-TCP/CS in the management of orthopaedic infections.

1 Detection of Microbes in Orthopaedic Infections

A very broad range of microorganisms cause orthopaedic infections. Modern diagnosis depends on traditional culture techniques, which remain in common use, and on molecular testing, which is advancing rapidly as a field. Advances in culture-based techniques include modifications in specimen collection, incubation, and identification. Identification of pathogens through detection and analysis of microbial nucleic acids, without culturing the organism, is the focus of molecular microbiologic diagnostics. A variety of polymerase chain reaction (PCR) tests can identify single or multiple pathogens in a single PCR reaction. 16S PCR uses conserved DNA sequences to identify a very broad array of pathogens. Newer techniques (next-generation sequencing) avoid the limitations of PCR and can detect an even broader, theoretically unlimited range of pathogens by sequencing all of the nucleic acids in entire samples. The place for these technologies in orthopaedics is evolving. While anecdotal reports and some studies show molecular diagnostics’ advantages over culture, traditional cultures still remain the most accessible, affordable, and reliable in most clinical scenarios. However, further improvements are likely to alter the landscape of microbial diagnosis of orthopaedic infections.

2 Antibiotics for Orthopaedic Infections

Antibiotics play a critical role in the treatment of bone and joint infections. In clinical practice, antibiotics may be delivered intravenously, orally, or topically, alone or as part of a delivery mechanism. This chapter will discuss the most commonly used oral and intravenous antibiotics in orthopaedic infections, their efficacy and bioavailability, and important considerations when using these antibiotics for patient care. This chapter will additionally focus on the use of topical antibiotics and nondegradable/biodegradable carriers for antibiotic delivery, such as the use of heat-stable antibiotics in cement spacers. The information presented here is designed for use as a clinical reference to provide guidance on the care of patients with orthopaedic infections including osteomyelitis, septic joints, and periprosthetic joint infections.