Does the Use of Local Antibiotics Affect Clinical Outcome of Patients with Fracture-Related Infection?

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.

Fracture-Related Infection-Epidemiology, Etiology, Diagnosis, Prevention, and Treatment

BACKGROUND

Fracture-related infection (FRI) is a challenge to physicians and other workers in health care. In 2018, there were 7253 listed cases of FRI in Germany, corresponding to an incidence of 10.7 cases per 100 000 persons per year.

METHODS

This review is based on pertinent publications retrieved from a search in PubMed with the search terms "fracture," "infection," "guideline," and "consensus." Aside from the primary literature, international guidelines and consensus recommendations were evaluated as well.

RESULTS

FRI arise mainly from bacterial contamination of the fracture site. Staphylococcus aureus is the most commonly detected pathogen. The treatment is based on surgery and antibiotics and should be agreed upon by an interdisciplinary team; it is often difficult because of biofilm formation. Treatment options include implant-preserving procedures and single-stage, two-stage, or multi-stage implant replacement. Treatment failure occurs in 10.3% to 21.4% of cases. The available evidence on the efficacy of various treatment approaches is derived mainly from retrospective cohort studies (level III evidence). Therefore, periprosthetic joint infections and FRI are often discussed together.

CONCLUSION

FRI presents an increasing challenge. Preventive measures should be optimized, and the treatment should always be decided upon by an interdisciplinary team. Only low-level evidence is available to date to guide diagnostic and treatment decisions. High-quality studies are therefore needed to help us meet this challenge more effectively.

[Bone cement as a local antibiotic carrier]

BACKGROUND

There is widespread consensus that adjuvant local use of antimicrobial agents in combination with their systemic administration can better prevent and treat implant-associated musculoskeletal infections. The advantage of local antibiotics lies in their particular pharmacokinetics with initially high antibiotic concentrations at the implant site with only low systemic uptake.

AIM OF TREATMENT

The aim of local application is to protect the foreign bodies directly at the implantation site from bacterial colonization and biofilm formation (prophylaxis) and to support the eradication of an already established infection after surgical debridement (treatment). Since the observations of Prof. Buchholz, bone cement has been the most frequently used local carrier system.

APPLICATION

In cases of infection, surgeons should ideally work together with microbiologists, infectiologists or clinical pharmacists to determine which anti-infective agents are indicated systemically for the patient and which ones are indicated locally with PMMA cement, based on the pathogen(s) and antibiograms. However, for the anti-infective agents administered with bone cement, there is still uncertainty about which agents can be added to this carrier material and at what concentrations. Accordingly, the authors of this review article not only summarize the rationale and evidence for local antibiotic use but also elaborate on the points that must be considered for admixing these agents to the cement.

Multidisciplinary Treatment of Fracture-Related Infection Has a Positive Impact on Clinical Outcome-A Retrospective Case Control Study at a Tertiary Referral Center

OBJECTIVES

Fracture-related infection (FRI) is a major complication in orthopedic and trauma surgery. The management and choice of treatment can be difficult depending on multiple factors. Therefore, we implemented a weekly multidisciplinary team discussion to determine diagnostic and treatment strategies in FRI patients and aimed to analyze its effect on clinical outcomes.

METHODS

Clinical outcomes of FRI patients treated before and after implementation of a structured multidisciplinary treatment (MDT) approach with a weekly case discussion were compared at a follow-up of 12 months.

RESULTS

In total, n = 117 were eligible for enrolment, whereby n = 58 patients (72.4% male, mean age 56.7 ± 16.8 years) constituted the MDT group and n = 59 patients (72.9% male, mean age 55.0 ± 16.5 years) the control group. In the MDT group more cases were treated with local antibiotics (67.2% vs. 27.1%, p < 0.001) and significant less amputations (3.4% vs. 6.8%, p = 0.014), as well as less revision surgeries (1.5 ± 1.2 (0-5) vs. 2.2 ± 1.2 (0-7), p = 0.048) were performed. A trend towards less debridement, antibiotics and implant retention (DAIR) procedures, lower rates of recurrence of infection and less treatment failures in the MDT group was observable, even though not statistically significant.

CONCLUSION

An MDT approach providing a patient tailored treatment concept in the treatment of FRI patients appears to be beneficial for the affected patients. Quality and efficacy of implemented MDT meetings should further be evaluated to provide sufficient evidence to further implement this valuable tool in clinical practice and decision making.

Pre-Referral Microbiology in Long Bone Infection: What Can It Tell Us?

Background: It remains unclear how accurately patients’ previous microbiology correlates with that ascertained from deep sampling in long bone infection. This study assessed the quality of microbiology referral information and compared it to the gold standard of intra-operative deep tissue sampling. Methods: All patients referred to a single specialist centre within the UK between January 2019 and March 2020 who received surgery for long bone infection were eligible for inclusion. Data on microbiological testing that was performed prior to referral was collected prospectively at the time of clinic appointment and prior to surgery. Pre-referral microbiology was compared to microbiology from deep tissue samples taken during surgery. Results: 141 patients met the diagnostic criteria for long bone infection and were included for analysis. Of these, 72 patients had microbiological information available at referral from 88 samples, obtained from either sinus swab (n = 40), previous surgical sampling (n = 25), biopsy (n = 19) or blood cultures (n = 4). In 65.9% of samples, pre-referral microbiology was deemed to be a non-match when compared to intra-operative samples. Factors that increased risk of a non-match included presence of a sinus (odd’s ratio (OR) 11.3 [95% CI 2.84−56.6], p = 0.001), increased duration of time from sampling (OR 2.29, [95% CI 1.23−5.90], p = 0.030) and results from prior surgical sampling (OR 23.0 [95% CI 2.80−525.6], p = 0.011). Furthermore, previous surgical debridement gave an increased risk of multi-, extensively or pan-resistant isolates cultured from intra-operative sampling (OR 3.6 [95% CI 1.5−8.7], p < 0.01). Conclusions: We have demonstrated that presence of a sinus, a long time from the sample being taken and results from prior surgical sampling are more likely to give inaccurate representation of current microbiology. Importantly, in cases with previous debridement surgery, there was an increased risk of multi drug resistant isolates which should be planned for in future treatments.