Getting it right first time: The importance of a structured tissue sampling protocol for diagnosing fracture-related infections

Fracture related infection in open tibial fractures

Open tibia fractures frequently occur following high-energy trauma. Contamination of the fracture site combined with limited soft tissue coverage and blood supply means that these open fractures are associated with a high rate of complications, including fracture related infection (FRI). FRI is associated with lowered patient outcomes and requires early recognition and appropriate surgical and medical management. The current evidence on FRI after open tibial fractures largely is limited to case series, small retrospective cohort studies and expert opinion. Recent expert consensus has produced guidelines with the aim of standardising care for these patients. This review summarises the current management strategies employed in treating FRI following open tibial fractures and where possible the evidence behind them.

Ortho-plastic approaches to fracture related infection (FRI)

When a plastic surgery opinion is sought to support orthopaedic colleagues, invaluable contributions to decision-making in fracture-related infection (FRI) can be made. We summarise the plastic surgeon's perspective on the most pertinent questions which are relevant when assessing infections as a sequelae of fractures: 1.) How to define the soft tissues involved. 2.) Local & free tissue cover: options & outcomes. 3.) What to do when flaps fail. 4.) When simple dressings are an option.

The surgical management of fracture-related infection. Surgical strategy selection and the need for early surgical intervention

The aim of this narrative review is to describe the various surgical management strategies employed in fracture-related infection (FRI), to explore how they are selected and discuss the rationale for early surgical intervention. Surgical treatment options in patients with FRI include debridement, antibiotics and implant retention (DAIR), revision (exchange) or removal. In selecting a treatment strategy, a variety of factors need to be considered, including the condition of the bone, soft tissues, host and causative microorganism. Irrespective of the selected treatment strategy, prompt surgical intervention should be considered in order to confirm the diagnosis of an FRI, to identify the causative organism, remove necrotic or non-viable tissue that can serve as a nidus for ongoing infection, ensure a healthy soft tissue envelope and to prevent the vicious cycle of infection associated with skeletal and/or implant instability. Ultimately, the objective is to prevent the establishment of a persistent infection. Urgent surgery may be indicated in case of active, progressive disease with systemic deterioration, local progression of infection, deterioration of soft tissues, or progressive fracture instability. In case of static disease, the patient should be monitored closely and surgery can be performed on an elective basis, allowing adequate time for optimisation of the host through risk factor modification, optimisation of the soft tissues and careful planning of the surgery.

Fracture-related infection in revision proximal femoral intramedullary nails

BACKGROUND

The proximal femoral nail is a commonly used fixation device for extra-capsular neck of femur fractures at our UK NHS Trust. Fracture-related infection (FRI) is a catastrophic complication that can be associated with internal fixation. FRI is often diagnosed late, and causes significant impact on the patient and healthcare system, leading to extended hospital stays, reduced quality of life, high healthcare costs and increased mortality and morbidity.

AIM

This study aims to evaluate whether failed proximal femoral nails treated at a major trauma centre in the United Kingdom are undergoing routine intraoperative microbiology sampling, as outlined by the FRI Consensus Group in 2020, and also to establish how often fracture-related infection is present in failed proximal femoral nails.

METHOD

Electronic patient record systems were reviewed over a 4-year period between 2018-2022 to identify patients who had a proximal femoral nailing, and those who required revision surgery. From this cohort, we then identified whether sampling had taken place during revision surgery, and the number of samples taken.

RESULTS

1041 proximal femoral nails were performed at our trust during the 4-year period. 60 of these implants failed, with 52 of these undergoing revision surgery at our hospital.  Only 56% cases had intra-operative samples taken for microbiology testing, with an average of 9 samples sent per case. Intra-operative sampling confirmed infection in 25% of cases with samples sent.  Of the cases requiring ≥ 3 operations, 75% of cases had confirmed infection.

DISCUSSION

The data shows that more can be done to ensure earlier diagnosis of fracture-related infection in failed proximal femoral nails. We should have a high suspicion of FRI in this cohort of patients. This study highlights the importance of a standardised protocol to ensure routine intra-operative sampling during proximal femoral nail revision surgery.

The role of implant retention and conservative management in the management of fracture-related infection

Fracture-related infection (FRI) management has advanced considerably in recent years, offering new possibilities for predictable rates of infection eradication. Debridement, antibiotics, and implant retention (DAIR) procedures have shown promise in the treatment of early FRI. This article provides an overview of the principles and indications of DAIR, including the importance of meticulous debridement and the management of dead space. The outcomes of DAIR are discussed, highlighting the range of fracture union rates reported in the literature. The role of antimicrobial suppression in optimizing host biology and facilitating surgical intervention is also explored. While further research is needed to establish optimal treatment strategies, DAIR offers a valuable treatment approach for FRI when specific criteria are met.

LEVEL OF EVIDENCE

IV.

Developing an antibiogram for empiric antibiotic prescribing for adult non-spinal orthopaedic infections in a developing world setting

PURPOSE

Empiric antibiotic strategies in the treatment of fracture-related infections, chronic osteomyelitis, prosthetic joint infection, and septic arthritis should be based on local microbiological antibiograms. This study aims to describe the microbiology and review the antibiogram profiles of bacterial isolates from patients undergoing surgical treatment for non-spinal orthopaedic infections, to identify the most appropriate empiric antibiotic strategy.

METHODS

A retrospective review was performed of all cases of non-spinal orthopaedic infections treated surgically from 1 January 2018 to 31 December 2018. The National Health Laboratory Service microbiology database was used to identify all intra-operative microbiological specimens obtained from orthopaedic patients, and data were correlated with the orthopaedic surgical database. Cases were divided into fracture-related infections, chronic osteomyelitis, prosthetic joint infection, and septic arthritis. Antibiotic susceptibility data were used to predict the efficacy of different empiric antibiotic regimens.

RESULTS

A total of 107 cases were included in the study; 184 organisms were cultured. Overall, the most common organism cultured was Staphylococcus aureus (25%) followed by Acinetobacter baumannii (9%), Enterococcus faecalis (7%) and Enterobacter cloacae (5%). Across all categories the oral antibiotic combination with the highest effectiveness (81%) would have been a combination of co-trimoxazole, ciprofloxacin and amoxicillin. The most effective intravenous antibiotic combination would have been either piperacillin-tazobactam, amikacin and vancomycin or meropenem and vancomycin; 90% of tested isolates were susceptible to either of these combinations.

CONCLUSION

Antibiogram profiles can serve to guide to empiric antibiotic choice in the management of different categories of non-spinal orthopaedic infections.

The Role of Combined Inflammatory Biomarkers in the Diagnosis of High- and Low-Virulence FRI Among High-Risk Lower Extremity Fractures

Objective

The aim of this study is to evaluate the diagnostic accuracy of infection-related biomarkers in high-risk lower limb injury patients with fracture-related infection (FRI) caused by high-/low-virulence microorganisms.

Methods

This study was a retrospective analysis of patients with high-risk lower extremity fractures (including tibial plateau, calcaneus, and Pilon fractures) who underwent open reduction internal fixation (ORIF) surgery from January 2017 to February 2022. Peripheral blood samples were collected within 24 hours of admission, and the following information was evaluated: gender, age, BMI, smoking, comorbidities, injury information, surgical details, values for serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), as well as neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR).

Results

A total of 576 patients receiving lower extremity fracture surgery were included in this study. Fifty-one patients (8.85%) were identified as FRI, and 28 (54.9%) of these 51 cases were further classified as high-virulence group. The median levels of CRP, ESR, NLR, and MLR were significantly higher in the FRI group than in the non-FRI group (p < 0.01). Similarly, the marginally significantly higher levels of CRP and NLR presented in the high-virulence group, compared to the low-virulence group (p < 0.1). The AUC areas of CRP, NLR, and CRP+NLR were 0.826, 0.650, and 0.873, respectively. We calculated the optimal cut-off points for CRP+NLR as diagnostic markers of high-virulent infection was 0.377.

Conclusion

This study showed the incidence of FRI in high-risk lower extremity fractures was 8.9%, and identified preoperative serum biomarkers, including CRP, ESR, NLR, and PLR, as useful tools for assisting in the diagnosis of infection. Additionally, the combination of CRP with NLR played a discriminating clinical role in postoperative infections caused by different virulence.

Level of Evidence

Clinical study.

Fracture-related infection: Prevalence and application of the new consensus definition in a cohort of 1004 surgically treated ankle fractures

BACKGROUND

Surgical treatment of ankle fractures comes with a substantial risk of complications, including infection. An unambiguously definition of fracture-related infections (FRI) has been missing. Recently, FRI has been defined by a consensus group with a diagnostic algorithm containing suggestive and confirmatory criteria. The aim of the current study was to report the prevalence of FRI in patients operated for ankle fractures and to assess the applicability of the diagnostic algorithm from the consensus group.

PATIENTS AND METHODS

Records of all patients with surgically treated ankle fractures from 2015 to 2019 were retrospectively reviewed for signs of postoperative infections. Patients with suspected infection were stratified according to confirmatory or suggestive criteria of FRI. Rate of FRI among patients with confirmatory and suggestive criteria were calculated.

RESULTS

Suspected infection was found in 104 (10%) out of 1004 patients. Among those patients, confirmatory criteria were met in 76/104 (73%) patients and suggestive criteria were met in 28/104 (27%) at first evaluation. Patients with clinical confirmatory criteria (N = 76) were diagnosed with FRI. Patients with suggestive criteria were further examined with either bacterial sampling at the outpatient clinic, revision surgery including bacterial sampling, or a wait-and-see approach. Eleven (39%) of the 28 patients had positive cultures and were therefore diagnosed as having FRI at second evaluation. In total 87 (9%) patients were diagnosed with FRI according to the consensus definition. Only 73 (70%) of the 104 patients with suspected FRI had adequate bacterial sampling.

CONCLUSION

The prevalence of FRI, applying the FRI-consensus criteria, for patients with surgically treated ankle fractures was 9%. Twenty-two percent of patients who met the confirmatory criteria had negative bacterial cultures. The current study shows that we did not have a systematic approach to patients with suspected FRI as recommended by the consensus group. A systematic approach to adequate bacterial sampling when FRI is suspected is paramount. The consensus definition of FRI and its diagnostic algorithm facilitates such an approach.

LEVEL OF EVIDENCE

Level III - retrospective cohort study.

Clinical and Radiological Outcomes of Gustilo-Anderson Type IIIB Open Fractures in 125 Patients

INTRODUCTION

This study describes single-centre outcomes of Gustilo-Anderson type IIIB open fractures in relation to the current standards in the United Kingdom, which aim at performing skeletal fixation and soft tissue coverage at an early stage to salvage the limb and achieve bone union with a minimum infection rate.

METHODS

A total of 125 patients with 134 Gustilo-Anderson type IIIB open fractures, who had definitive skeletal fixation with soft tissue coverage between June 2013 and October 2021, were prospectively followed up and included in this study.

RESULTS

Initial debridement was performed within 12 hours from the time of injury for 62 (49.6%) patients and within 24 hours for 119 (95.2%) patients (mean= 12.4 hours). Definitive skeletal fixation and soft tissue coverage were achieved within 72 hours for 25 (20%) patients and within seven days for 71 (57%) patients (mean= 8.5 days). The mean follow-up duration was 43.3 (6-100) months, and the limb salvage rate was 97.1%. The occurrence of deep infections was associated with time from injury to initial debridement (p=0.049). Three patients (2.4%) developed deep (metalwork) infections, all three had their initial debridement performed within 12 hours from the time of injury. There was no association between time to definitive surgery and the development of deep infection (p=0.340). Bone union was achieved in 84.3% of patients following their primary surgery. Time to union was associated with fixation modality (p=0.002) and type of soft tissue coverage (p=0.028), and was negatively correlated with time to initial debridement (p=0.002, correlation coefficient -0.321). There was a 0.27-month decrease in time to union for every hour delay in time to debridement (p=0.021).

CONCLUSION

Delaying initial debridement or definitive fixation and soft tissue coverage didn't increase the rate of deep (metalwork) infections. The time to achieve bone union was negatively correlated with the time from injury to initial debridement. We advise prioritising surgical technique and availability of expertise over strict adherence to time thresholds of surgeries.

Outcome and risk factors for recurrence of early onset fracture-related infections treated with debridement, antibiotics and implant retention: Results of a large retrospective multicentre cohort study

INTRODUCTION

Early Fracture-Related Infections (FRIs) are a common entity in hospitals treating trauma patients and are often treated with a Debridement, Antibiotics and Implant Retention (DAIR) procedure. Aims of this study were to 1) evaluate the recurrence rate after DAIR procedures for early onset FRI, 2) establish the number of surgical procedures to gain control of the initial infection and 3) identify independent predictors for recurrence in this cohort.

METHODS

A retrospective multicentre cohort study was conducted in two level 1 trauma centres. Consecutive patients who underwent a DAIR procedure between January 1st 2015 and July 1st 2020 for confirmed FRI with an onset of <6 weeks after the latest osseous operation were included. Recorded data included patient demographics, treatment characteristics and follow-up. Univariate and multivariate logistic regression analyses were performed to assess predictors for recurrent FRI.

RESULTS

A total of 141 patients with early FRI were included in this study with a median age of 54.0 years (interquartile range (IQR) 34.5-64.0). The recurrence rate of FRI was 13% (n = 19) at one year follow-up and 18% (n = 25) at 23.1 months (IQR 15.3-36.4) follow-up. Infection control was achieved in 94% (n = 127/135) of cases. In total, 73 patients (52%) underwent at least two surgical procedures to treat the ongoing initial episode of FRI, of whom 54 patients (74%) required two to three procedures and 17 patients (23%) four to five procedures. Predictors for recurrent FRI were use of an intramedullary nail during index operation (odds ratio (OR) 4.0 (95% confidence interval (CI) 1.1-13.8)), need for additional surgical procedures to treat ongoing infection during the treatment period following the first presentation of early FRI (OR 1.9 (95% CI 1.1-3.5)) and a decreased Injury Severity Score (ISS) (inverted OR 1.1 (95% CI 1.0-1.1)).

CONCLUSION

The recurrence rate after treatment of early onset FRI in patients treated with a DAIR procedure was 18% at 23.1 months follow-up. At least two surgical procedures to gain control of the initial infection were needed in 52% of patients. Independent predictors for recurrent FRI were the use of an intramedullary nail during index operation, need for additional surgical procedures and a decreased ISS.

Implant surface culture may be a useful adjunct to standard tissue sampling culture for identification of pathogens accounting for fracture-device-related infection: a within-person randomized agreement study of 42 patients

BACKGROUND AND PURPOSE

Identification of pathogens causing fracture-device-related infection (FDRI) is always a challenge as the positive rate of standard tissue sampling culture (TSC) remains unsatisfactory. This study evaluates the efficiency of implant surface culture (ISC) as an adjunct to standard TSC for identification of FDRI-associated microorganisms.

PATIENTS AND METHODS

Between November 2020 and March 2022, patients diagnosed with FDRI defined by the International Fracture-Related Infection (FRI) Consensus Group, and indicated for implant removal, underwent both methods for bacteria detection. The test order of ISC and TSC was randomly selected for each patient included, as a within-person randomized design. For ISC, the recovered implants were gently covered with tryptic soy agar after rinsing with normal saline twice, and then incubated at 37℃ 5% CO2 for up to 14 days. For TSC, 5 specimens were sampled and sent to the Clinical Laboratory of Southern Medical University Nanfang Hospital, Guangzhou, for culture and identification.

RESULTS

42 consecutive patients were included, with a mean age of 46 years. The most frequent infection site and implant type were the tibia (21 cases) and plates with screws (30 cases), respectively. Altogether 21 patients were found with positive outcomes by both methods, and the identified pathogens were consistent. ISC found an additional 15 patients showing positive results, which were negative by TSC. Furthermore, the mean culture time of ISC was shorter than that of TSC (1.5 days vs. 3.2 days).

INTERPRETATION

ISC may be a useful adjunct to TSC for detection of bacteria causing FDRI, with a relatively higher positive rate and a shorter culture time.

Causative Pathogens Do Not Differ between Early, Delayed or Late Fracture-Related Infections

Fracture-related infections (FRIs) are classically considered to be early (0−2 weeks), delayed (3−10 weeks) or late (>10 weeks) based on hypothesized differences in causative pathogens and biofilm formation. Treatment strategies often reflect this classification, with debridement, antimicrobial therapy and implant retention (DAIR) preferentially reserved for early FRI. This study examined pathogens isolated from FRI to confirm or refute these hypothesized differences in causative pathogens over time. Cases of FRI managed surgically at three centres between 2015−2019 and followed up for at least one year were included. Data were analysed regarding patient demographics, time from injury and pathogens isolated. Patients who underwent DAIR were also analysed separately. In total, 433 FRIs were studied, including 51 early cases (median time from injury of 2 weeks, interquartile range (IQR) of 1−2 weeks), 82 delayed cases (median time from injury of 5 weeks, IQR of 4−8 weeks) and 300 late cases (median time from injury of 112 weeks, IQR of 40−737 weeks). The type of infection was associated with time since injury; early or delayed FRI are most likely to be polymicrobial, whereas late FRIs are more likely to be culture-negative, or monomicrobial. Staphylococcus aureus was the most commonly isolated pathogen at all time points; however, we found no evidence that the type of pathogens isolated in early, delayed or late infections were different (p = 0.2). More specifically, we found no evidence for more virulent pathogens (S. aureus, Gram-negative aerobic bacilli) in early infections and less virulent pathogens (such as coagulase negative staphylococci) in late infections. In summary, decisions on FRI treatment should not assume microbiological differences related to time since injury. From a microbiological perspective, the relevance of classifying FRI by time since injury remains unclear.

Risk factors for fracture-related infection after open reduction and internal fixation of proximal humerus fractures: A multicenter retrospective study of 496 fractures (TRON group study)

INTRODUCTION

One of the complications of the surgical therapy for proximal humerus fractures is fracture-related infection (FRI). This multicenter study aimed to investigate the incidence of FRI and clarify the risk factors associated with FRI in patients receiving open reduction and internal fixation for proximal humerus fracture.

MATERIAL AND METHODS

Among 684 patients diagnosed as having proximal humerus fracture and who were treated by surgical therapy in 13 institutions (named TRON group) from 2015 through 2020, 496 patients (men, n = 134, women, n = 362; mean [SD] age, 68.5 [14.5] years; mean [SD] body mass index [BMI], 23.0 [4.4] kg/m²) were included as subjects. Excluded were 188 patients due to less than 12 month's follow-up, patients who underwent osteosynthesis using neither plate nor nail and those with open fracture. We extracted the following as risk factors of FRI: sex, BMI, smoking status, diabetes, glenohumeral fracture dislocation, fracture classification, approach, implant, waiting period, type of anesthesia, operative time and blood loss during surgery. We conducted logistic regression analysis to investigate the risk factors of FRI using these extracted items as explanatory variables and the presence or absence of FRI as the response variable.

RESULT

FRI occurred after surgery for proximal humerus fracture in 9 of the 496 patients (1.8%). The causative organism was methicillin-susceptible Staphylococcus aureus in 4 patients, Pseudomonas aeruginosa in one patient and Enterococcus faecalis in one patient. In the other 3 patients, causative organisms were not detected. The univariate analysis showed significant differences for present of glenohumeral fracture dislocation (p = 0.004). Logistic regression analysis showed glenohumeral fracture dislocation to be the significant explanatory factor for FRI (odds ratio 12.3, p = 0.0375).

CONCLUSION

This study revealed an infection rate following open reduction and internal fixation of proximal humerus fracture of 1.8% (9 patients) and that Staphylococcus was the most frequent causative organism. Glenohumeral fracture dislocation is a significant risk for postoperative FRI.

Validation of the diagnostic criteria of the consensus definition of fracture-related infection

BACKGROUND

The recently developed fracture-related infection (FRI) consensus definition, which is based on specific diagnostic criteria, has not been fully validated in clinical studies. We aimed to determine the diagnostic performance of the criteria of the FRI consensus definition and evaluated the effect of the combination of certain suggestive and confirmatory criteria on the diagnostic performance.

METHODS

A multicenter, multi-national, retrospective cohort study was performed. Patients were subdivided into an FRI or a control group, according to the treatment they received and the recommendations from a multidisciplinary team ('intention to treat'). Exclusion criteria were patients with an FRI diagnosed outside the study period, patients younger than 18 years of age, patients with pathological fractures or patients with fractures of the skull, cervical, thoracic and lumbar spine. Minimum follow up for all patients was 18 months.

RESULTS

Overall, 637 patients underwent revision surgery for suspicion of FRI. Of these, 480 patients were diagnosed with FRI, treated accordingly, and included in the FRI group. The other 157 patients were included in the control group. The presence of at least one confirmatory sign was associated with a sensitivity of 97.5%, a specificity of 100% and a high discriminatory value (AUROC 0.99, p < 0.001). The presence of a clinical confirmatory criterion or, if not present, at least one positive culture was associated with the highest diagnostic performance (sensitivity: 98.6%, specificity: 100%, AUROC: 0.99 (p < 0.001)). In the subgroup of patients without clinical confirmatory signs at presentation, specificities of at least 95% were found for the clinical suggestive signs of fever, wound drainage, local warmth and redness.

CONCLUSIONS

The presence of at least one confirmatory criterion identifies the vast majority of patients with an FRI and was associated with an excellent diagnostic discriminatory value. Therefore, our study validates the confirmatory criteria of the FRI consensus definition. Infection is highly likely in case of the presence of a single positive culture with a virulent pathogen. When certain clinical suggestive signs (e.g., wound drainage) are observed (individually or in combination and even without a confirmatory criterion), it is more likely than not, that an infection is present.

Tissue sampling is non-inferior in comparison to sonication in orthopedic revision surgery

BACKGROUND

The aim of this study was to assess the role of sonication fluid cultures in detecting musculoskeletal infections in orthopedic revision surgery in patients suspected of having peri-prosthetic joint infection (PJI), fracture-related infections (FRI), or postoperative spinal implant infections (PSII).

METHODS

Between 2016 and 2019, 149 cases with a data set including sonication fluid cultures and tissue specimen and histological analysis were included. Accuracy of each diagnostic tool as well as the influence of antibiotic therapy was analyzed. Pathogens identified in the sonication cultures and in the associated tissue samples were compared based on the matching of the antibiograms. Therapeutic benefits were then assessed.

RESULTS

Of 149 cases, 43.6% (n = 65) were identified as PJI, 2.7% (n = 4) as FRI, 12.8% (n = 19) as PSII, 6.7% (n = 10) as aseptic non-union, and 34.2% (n = 51) as aseptic implant loosening. The sensitivity and specificity of tissue and synovial specimens showed no significant difference with respect to sonication fluid cultures (sensitivity/specificity: tissue: 68.2%/96.7%; sonication fluid cultures: 60.2%/98.4%). The administration of antibiotics over 14 days prior to microbiological sampling (n = 40) resulted in a lower sensitivity of 42.9% each. Histological analysis showed a sensitivity 86.3% and specificity of 97.4%. In 83.9% (n = 125) of the cases, the results of sonication fluid cultures and tissue specimens were identical. Different microorganisms were found in only four cases. In 17 cases, tissue samples (n = 5) or sonication (n = 12) were false-negatives.

CONCLUSION

Sonication fluid culture showed no additional benefit compared to conventional microbiological diagnostics of tissue and synovial fluid cultures. Preoperative administration of antibiotics had a clearly negative effect on microbiologic test accuracy. In over 83.9% of the cases, sonication fluid and tissue cultures showed identical results. In the other cases, sonication fluid culture did not further contribute to the therapy decision, whereas other factors, such as fistulas, cell counts, or histological analysis, were decisive in determining therapy.

One-stage combined "fix and flap" approach for complex open Gustilo-Anderson IIIB lower limbs fractures: a prospective review of 102 cases

BACKGROUND

Management of open fractures is challenging and requires a multidisciplinary team approach. This study aims to evaluate outcomes of open Gustilo-Anderson IIIB fractures managed at a single Ortho-Plastic centre following One-stage "Fix and Flap" approach.

METHODS

Prospective data review for patients presenting with Gustilo-Anderson IIIB Fractures to our centre and managed with one-stage "Fix and Flap" approach. Postoperative outcomes are presented only for the patients who had a minimum of 12 months postoperative follow-up.

RESULTS

120 patients were included (83 males and 37 females). Mean age was 43 years (10-96). Tibia diaphysis was the most common site of injury (60%). 55.9% of injuries were road traffic accidents (RTA). 102 out of 120 patients had a minimum of 12 months follow-up (mean follow-up duration 25 months). Meantime from injury until definitive surgery was 7.71 days. Primary union achieved in 86.73%. Delayed union was encountered in 10.20%. 3.06% of patients had non-union. Limb salvage rate was 97.05% and Deep infection rate was only 0.98%.

CONCLUSION

Our results showed that low infection rate, high limb salvage rate, and high union rate can be achieved in these complex injuries with meticulous technique, combined Ortho-Plastic (Fix and Flap) approach, and MDT input.

[Fracture-related infections after intramedullary nailing : Diagnostics and treatment]

Intramedullary nailing is the treatment of choice for a large number of fractures requiring surgery. In cases of fracture-related infections (FRI) the treatment of nail infections requires special attention due to the closed situation of the osteosynthesis material in the intramedullary canal. This article gives an overview of the general principles and diagnostic criteria for FRI after nail fixation and discusses the treatment recommendations based on three case examples. In cases of acute implant infections, an implant-retaining procedure is principally possible for both periprosthetic joint infections and FRI; however, after intramedullary nailing the nail should also be exchanged in cases of acute nail infections as a sufficient debridement of the nail is impossible due to its intramedullary location. In chronic FRI after intramedullary nailing a one-stage or two-stage procedure can be followed. In cases of adequate soft tissue coverage, good fracture reduction and an expected bone healing without critical bony substance defects, a one-stage procedure with nail exchange should be preferred. If a chronic infection with soft tissue and bone defects develops after intramedullary nailing, a two-stage procedure analogous to the treatment of osteomyelitis should be considered. In this case a multidisciplinary team approach with specialists in plastic surgery, microbiology and infectious diseases is necessary. The use of local antibiotics and antimicrobial-coated implants is deemed to be advantageous.

The Role of Negative-Pressure Wound Therapy in Patients with Fracture-Related Infection: A Systematic Review and Critical Appraisal

INTRODUCTION

Fracture-related infection (FRI) is a severe musculoskeletal complication in orthopedic trauma surgery, causing challenges in bony and soft tissue management. Currently, negative-pressure wound therapy (NPWT) is often used as temporary coverage for traumatic and surgical wounds, also in cases of FRI. However, controversy exists about the impact of NPWT on the outcome in FRI, specifically on infection recurrence. Therefore, this systematic review qualitatively assesses the literature on the role of NPWT in the management of FRI.

METHODS

A literature search of the PubMed, Embase, and Web of Science database was performed. Studies that reported on infection recurrence related to FRI management combined with NPWT were eligible for inclusion. Quality assessment was done using the PRISMA statement and the Newcastle-Ottawa Quality Assessment Scale.

RESULTS

After screening and quality assessment of 775 unique identified records, eight articles could be included for qualitative synthesis. All eight studies reported on infection recurrence, which ranged from 2.8% to 34.9%. Six studies described wound healing time, varying from two to seven weeks. Four studies took repeated microbial swabs during subsequent vacuum dressing changes. One study reported newly detected pathogens in 23% of the included patients, and three studies did not find new pathogens.

CONCLUSION

This review provides an assessment of current literature on the role of NPWT in the management of soft tissue defects in patients with FRI. Due to the lack of uniformity in included studies, conclusions should be drawn with caution. Currently, there is no clear scientific evidence to support the use of NPWT as definitive treatment in FRI. At this stage, we can only recommend early soft tissue coverage (within days) with a local or free flap. NPWT may be safe for a few days as temporarily soft tissue coverage until definitive soft tissue management could be performed. However, comparative studies between NPWT and early wound closure in FRI patients are needed.

What is the diagnostic value of the Centers for Disease Control and Prevention criteria for surgical site infection in fracture-related infection?

BACKGROUND

Fracture-related infection (FRI) remains one of the most challenging complications in orthopaedic trauma surgery. An early diagnosis is of paramount importance to guide treatment. The primary aim of this study was to compare the Centers for Disease Control and Prevention (CDC) criteria for the diagnosis of organ/space surgical site infection (SSI) to the recently developed diagnostic criteria of the FRI consensus definition in operatively treated fracture patients.

METHODS

This international multicenter retrospective cohort study evaluated 257 patients with 261 infections after operative fracture treatment. All patients included in this study were considered to have an FRI and treated accordingly ('intention to treat'). The minimum follow-up was one year. Infections were scored according to the CDC criteria for organ/space SSI and the diagnostic criteria of the FRI consensus definition.

RESULTS

Overall, 130 (49.8%) FRIs were captured when applying the CDC criteria for organ/space SSI, whereas 258 (98.9%) FRIs were captured when applying the FRI consensus criteria. Patients could not be classified as having an infection according to the CDC criteria mainly due to a lack of symptoms within 90 days after the surgical procedure (n = 96; 36.8%) and due to the fact that the surgery was performed at an anatomical localization not listed in the National Healthcare Safety Network (NHSN) operative procedure code mapping (n = 37; 14.2%).

CONCLUSION

This study confirms the importance of standardization with respect to the diagnosis of FRI. The results endorse the recently developed FRI consensus definition. When applying these diagnostic criteria, 98.9% of the infections that occured after operative fracture treatment could be captured. The CDC criteria for organ/space SSI captured less than half of the patients with an FRI requiring treatment, and seemed to have less diagnostic value in this patient population.

Is There a Difference in Microbiological Epidemiology and Effective Empiric Antimicrobial Therapy Comparing Fracture-Related Infection and Periprosthetic Joint Infection? A Retrospective Comparative Study

This study aims to investigate (1) microbial patterns in fracture-related infections (FRIs) in comparison to microbiological patterns of periprosthetic joint infections (PJIs), (2) the identification of effective empiric antibiotic therapy for FRIs and PJIs and (3) analysis of difficult-to-treat (DTT) pathogens. Patients treated for FRIs or PJIs from 2017 to 2020 were evaluated for pathogens detected during treatment. Antibiotic susceptibility profiles were examined with respect to broadly used antibiotics and antibiotic combinations. Resistance rates to rifampicin or fluoroquinolone were determined. A total of 81 patients with PJI and 86 with FRI were included in the study. For FRIs Staphylococcus aureus was the most common infection-causing pathogen (37.4% vs. 27.9% for PJI). Overall, there was no statistical difference in pathogen distribution (p = 0.254). For FRIs, combinations of gentamicin + vancomycin (93.2%), co-amoxiclav + glycopeptide and meropenem + vancomycin (91.9% each) would have been effective for empiric therapy, similar to PJIs. Difficult to treat pathogens were more frequently detectable in PJIs (11.6% vs. 2.3%). Empiric therapy combinations such as gentamicin + vancomycin, co-amoxiclav + glycopeptide or meropenem + vancomycin, are effective antibiotic strategies for both FRI and PJI patients. More DTT pathogens were detectable in PJIs compared to FRIs.

Optimal microbiological sampling for the diagnosis of osteoarticular infection

Infection is a dire complication afflicting every field of orthopaedics and traumatology. If specific clinical, laboratory and imaging parameters are present, infection is often assumed even in the absence of microbiological confirmation. However, apart from confirming infection, knowing the exact infecting pathogen(s) and their antimicrobial susceptibility patterns is paramount to help guide treatment. Every effort should therefore be undertaken with that goal in mind.Not all microbiological findings carry the same relevance, and knowing exactly how and where a sample was collected is key. Several different sampling techniques are available, and one must be aware of both advantages and limitations. Microbiological sampling alternatives in some of the most common clinical scenarios such as native and prosthetic joint infections, osteomyelitis and fracture-related infections, spinal and diabetic foot infections will be discussed.Orthopaedic surgeons should also be aware of basic laboratory sample processing techniques as they have a direct impact on the way specimens should be dealt with and transported to the laboratory. Only by knowing these basic principles will surgeons be able to participate in the multidisciplinary discussion and decision making around how to interpret microbiological findings in each specific patient. Cite this article: EFORT Open Rev 2021;6:390-398. DOI: 10.1302/2058-5241.6.210011.

Diagnosing fracture related infections: Where are we now?

Accurate diagnosis of fracture related infection (FRI) is critical for preventing poor outcomes such as loss of function or amputation. Due to the multiple variables associated with FRI, however, accurate diagnosis is challenging and complicated by a lack of standardized diagnostic criteria. Limitations with the current gold standard for diagnosis, which is routine microbiology culture, further complicate the diagnostic and management process. Efforts to optimize the process rely on a foundation of data derived from prosthetic joint infections (PJI), but differences in PJI and FRI make it clear that unique approaches for these distinct infections are required. A more concerted effort focusing on FRI has dominated more recent investigations and publications leading to a consensus definition by the American Orthopedics (AO) Foundation and the European Bone and Joint Infection Society (EBJIS). This has the potential to better standardize the diagnostic process, which will not only improve patient care but also facilitate more robust and reproducible research related to the diagnosis and management of FRI. The purpose of this review is to explore the consensus definition, describe the foundation of data supporting current FRI diagnostic techniques, and identify pathways for optimization of clinical microbiology-based strategies and data.

Providing an Evidence Base for Tissue Sampling and Culture Interpretation in Suspected Fracture-Related Infection

BACKGROUND

The recent consensus definition for the diagnosis of fracture-related infection (FRI) includes the identification of indistinguishable microorganisms in at least 2 surgical deep-tissue specimens as a confirmatory criterion. However, this cut-off, and the total number of specimens from a patient with suspected FRI that should be sent for microbiological testing, have not been validated. We endeavored to estimate the accuracy of different numbers of specimens and diagnostic cut-offs for microbiological testing of deep-tissue specimens in patients undergoing surgical treatment for possible FRI.

METHODS

A total of 513 surgical procedures in 385 patients with suspected FRI were included. A minimum of 2 surgical deep-tissue specimens were submitted for microbiological testing; 5 or more specimens were analyzed in 345 procedures (67%). FRI was defined by the presence of any confirmatory criteria other than microbiology. Resampling was utilized to model the sensitivity and specificity of diagnostic cut-offs for the number of surgical specimens yielding indistinguishable microorganisms and for the total number of specimens. The likelihood of detecting all clinically relevant microorganisms was also assessed.

RESULTS

A diagnostic cut-off of at least 2 of 5 specimens with indistinguishable microorganisms identified by culture was 68% sensitive (95% confidence interval [CI], 62% to 74%) and 87% specific (95% CI, 81% to 94%) for the diagnosis of FRI. Two out of 3 specimens were 60% sensitive (95% CI, 55% to 66%) and 92% specific (95% CI, 88% to 96%). Submitting only 3 deep-tissue specimens risked missing clinically relevant microorganisms in at least 1 in 10 cases.

CONCLUSIONS

The present study was the first to validate microbiological criteria for the diagnosis of FRI, supporting the current confirmatory diagnostic criteria for FRI. Analysis of at least 5 deep-tissue specimens in patients with possible FRI is recommended.

LEVEL OF EVIDENCE

Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

[Infections of the spine : Pyogenic spondylodiscitis and implant-associated vertebral osteomyelitis]

Pyogenic (unspecific) spondylodiscitis and implant-associated vertebral osteomyelitis (IAVO) are important diseases with the risk of neurological and septic complications. An early diagnosis is essential in which magnetic resonance imaging (MRI), histopathology and microbiological identification of the pathogen play key roles. The goals of conservative treatment in uncomplicated spondylodiscitis are antibiotic infection control and pain management. In the case of sepsis, neurological deficits, segmental instability or epidural abscesses surgical treatment of the infection with stabilization of the spine should be considered. In IAVO the formation of a mature biofilm represents the transition from acute to chronic infection. Acute infections can be treated by extensive debridement in combination with biofilm-active antibiotic treatment while retaining the implant. In chronic infections implant removal or exchange in combination with several weeks of antibiotic treatment is often necessary.

Current concepts in the prevention, diagnosis and treatment of fracture-related infection (FRI)

Fracture-related infection (FRI) is one of the most challenging complications following operative management of fractures. It can have profound implications for the patient, can be associated with considerable morbidity and often lead to impaired outcomes. There are significant healthcare-related costs. In recent years, there has been significant progress towards developing preventative strategies. Furthermore, diagnostic algorithms and management protocols have recently been reported. Lack of a strong evidence base has previously hindered efforts to implement these and develop established standards of care. There are multiple aspects of care that need to be considered and a multi-disciplinary approach is recommended. In this narrative review, we present the most up-to-date recommendations in the prevention, diagnosis and management of FRI.

Intramedullary tissue cultures from the Reamer-Irrigator-Aspirator system for diagnosing fracture-related infection

Fracture-related infection (FRI) is a serious complication following musculoskeletal trauma. Accurate diagnosis and appropriate treatment depend on retrieving adequate deep tissue biopsies for bacterial culture. The aim of this cohort study was to compare intraoperative tissue cultures obtained by the Reamer-Irrigator-Aspirator system (RIA)-system against standard tissue cultures obtained during the same surgical procedure. All patients had long bone fractures of the lower limbs and were assigned to the FRI or Control group based on the FRI consensus definition. The FRI group consisted of 24 patients with confirmed FRI and the Control group consisted of 21 patients with aseptic nonunion or chronic pain (in the absence of other suggestive/confirmatory criteria). Standard tissue cultures and cultures harvested by the RIA-system showed similar results. In the FRI group, standard tissue cultures and RIA cultures revealed relevant pathogens in 67% and 71% of patients, respectively. Furthermore, in four FRI patients, cultures obtained by the RIA-system revealed additional relevant pathogens that were not found by standard tissue culturing, which contributed to the optimization of the treatment plan. In the Control group, there were no false-positive RIA culture results. As a proof-of-concept, this cohort study showed that the RIA-system could have a role in the diagnosis of FRI as an adjunct to standard tissue cultures. Since scientific evidence on the added value of the RIA-system in the management of FRI is currently limited, further research on this topic is required before its routine application in clinical practice.

Simultaneous debridement, Ilizarov reconstruction and free muscle flaps in the management of complex tibial infection

Chronic bone infections often present with complex bone and soft tissue loss. Management is difficult and commonly delivered in multiple stages over many months. This study investigated the feasibility and clinical outcomes of reconstruction in one stage.

Fifty-seven consecutive patients with chronic osteomyelitis (n=27) or infected non-union (n=30) were treated with simultaneous debridement, Ilizarov method and free muscle flap transfer. 41 patients (71.9 %) had systemic co-morbidities (Cierny-Mader group Bs hosts). Infection was confirmed with strict criteria. 48 patients (84.2 %) had segmental defects.

The primary outcome was eradication of infection at final follow-up. Secondary outcomes included bone union, flap survival and complications or re-operation related to the reconstruction.

Infection was eradicated in 55/57 cases (96.5 %) at a mean follow-up of 36 months (range 12–146). No flap failures occurred during distraction but 6 required early anastomotic revision and 3 were not salvageable (flap failure rate 5.3 %).

Bony union was achieved in 52/57 (91.2 %) with the initial surgery alone. After treatment of the five un-united docking sites, all cases achieved bony union at final follow-up.

Simultaneous reconstruction with Ilizarov method and free tissue transfer is safe but requires careful planning and logistic considerations. The outcomes from this study are equivalent or better than those reported after staged surgery.

Definition and diagnosis of fracture-related infection

Fracture-related infection (FRI) is common and often diagnosed late.Accurate diagnosis is the beginning of effective treatment.Diagnosis can be difficult, particularly when there are no outward signs of infection.The new FRI definition, together with clear protocols for nuclear imaging, microbiological culture and histological analysis, should allow much better study design and a clearer understanding of infected fractures.In recent years, there has been a new focus on defining FRI and avoiding non-specific, poorly targeted treatment. Previous studies on FRI have often failed to define infection precisely and so are of limited value. This review highlights the essential principles of making the diagnosis and how clinical signs, serum tests, imaging, microbiology, molecular biology and histology all contribute to the diagnostic pathway. Cite this article: EFORT Open Rev 2020;5:614-619. DOI: 10.1302/2058-5241.5.190072.

Polymicrobial infections and microbial patterns in infected nonunions - a descriptive analysis of 42 cases

BACKGROUND

Frequencies of polymicrobial infection and pathogens evidenced in course of infected nonunion treatment are largely unknown. Therefore, this study aims at investigating microbial patterns in infected nonunions.

METHODS

Surgically treated patients with long bone infected nonunion admitted between January 2010 and March 2018 were included in the study. Microbiological culture and polymerase-chain-reaction results of tissue samples of initial and follow-up revision surgeries were assessed and compared with patient and treatment characteristics.

RESULTS

Forty two patients with a mean age of 53.9 ± 17.7 years were included. In six patients (14.3%) polymicrobial infection was evident. A change of pathogens evidenced in course of the treatment occurred in 21 patients (50%). In 16 patients (38.1%) previously detected bacteria could be determined by microbial testing after further revision surgery. Staphylococcus aureus was most often detected (n = 34, 30.6%), followed by Enterococcus spp. (n = 25, 22.5%) and Staphylococcus epidermidis (n = 18, 16.2%). Five Staphylococcus aureus were resistant to methicillin (MRSA). In patients without polymicrobial infection or further germ detection in course of the treatment, 86.4% of the infections were due to Staphylococcus spp.. Infections due to Streptococcus spp. and gram-negative bacteria were only present in patients with polymicrobial infection and germ-change in course of the treatment.

CONCLUSION

A low rate of polymicrobial infections was evidenced in the present study. Germ-change often occurs in course of revision surgeries. Prospective studies with more sensitive diagnostic tools are necessary to elucidate the therapeutical relevance of microbiological testing results for surgical as well as medical treatment in infected nonunions.

General treatment principles for fracture-related infection: recommendations from an international expert group

Fracture-related infection (FRI) remains a challenging complication that creates a heavy burden for orthopaedic trauma patients, their families and treating physicians, as well as for healthcare systems. Standardization of the diagnosis of FRI has been poor, which made the undertaking and comparison of studies difficult. Recently, a consensus definition based on diagnostic criteria for FRI was published. As a well-established diagnosis is the first step in the treatment process of FRI, such a definition should not only improve the quality of published reports but also daily clinical practice. The FRI consensus group recently developed guidelines to standardize treatment pathways and outcome measures. At the center of these recommendations was the implementation of a multidisciplinary team (MDT) approach. If such a team is not available, it is recommended to refer complex cases to specialized centers where a MDT is available and physicians are experienced with the treatment of FRI. This should lead to appropriate use of antimicrobials and standardization of surgical strategies. Furthermore, an MDT could play an important role in host optimization. Overall two main surgical concepts are considered, based on the fact that fracture fixation devices primarily target fracture consolidation and can be removed after healing, in contrast to periprosthetic joint infection were the implant is permanent. The first concept consists of implant retention and the second consists of implant removal (healed fracture) or implant exchange (unhealed fracture). In both cases, deep tissue sampling for microbiological examination is mandatory. Key aspects of the surgical management of FRI are a thorough debridement, irrigation with normal saline, fracture stability, dead space management and adequate soft tissue coverage. The use of local antimicrobials needs to be strongly considered. In case of FRI, empiric broad-spectrum antibiotic therapy should be started after tissue sampling. Thereafter, this needs to be adapted according to culture results as soon as possible. Finally, a minimum follow-up of 12 months after cessation of therapy is recommended. Standardized patient outcome measures purely focusing on FRI are currently not available but the patient-reported outcomes measurement information system (PROMIS) seems to be the preferred tool to assess the patients' short and long-term outcome. This review summarizes the current general principles which should be considered during the whole treatment process of patients with FRI based on recommendations from the FRI Consensus Group.Level of evidence: Level V.

[Fracture-related infections in traumatology : Current standards and new developments in diagnostics and treatment]

BACKGROUND

The high demands that fracture-related infections put on patients, physicians and the healthcare system have led to the establishment of a international group of experts called the Fracture-Related Infection (FRI) Consensus Group, whose aim is to develop evidence-based treatment recommendations.

DIAGNOSIS

Fracture-related infections are classified according to the time of occurrence, extent and treatment options. The diagnostic algorithm distinguishes between confirmatory and suggestive diagnostic criteria. If there are indications of an infection, tissue biopsy with microbiological and histological workup is recommended to confirm the diagnosis.

THERAPY

The primary objective of FRI treatment is to achieve fracture consolidation, while avoiding osteomyelitis. Therapeutic options are removal of the implant, eradication of the infection with implant retention or suppression of FRI. A multidisciplinary team is recommended to develop a patient-specific, optimized surgical and antimicrobial therapy.

Complete ejection of a ring sequestrum 8 years after external fixation of the tibia

On the day of scheduled debridement for a persistent pin tract infection, a 23-year old man presented himself carrying a small bony ring sequestrum that had spontaneously ejected from his tibial wound 1 week earlier. Eight years prior to presentation, he was treated for an open crural fracture which was stabilised with an external fixator. Revision of the operation notes revealed that the placement of this external fixator was performed without predrilling.

Diagnosing Fracture-Related Infection: Current Concepts and Recommendations

Fracture-related infection (FRI) is a severe complication after bone injury and can pose a serious diagnostic challenge. Overall, there is a limited amount of scientific evidence regarding diagnostic criteria for FRI. For this reason, the AO Foundation and the European Bone and Joint Infection Society proposed a consensus definition for FRI to standardize the diagnostic criteria and improve the quality of patient care and applicability of future studies regarding this condition. The aim of this article was to summarize the available evidence and provide recommendations for the diagnosis of FRI. For this purpose, the FRI consensus definition will be discussed together with a proposal for an update based on the available evidence relating to the diagnostic value of clinical parameters, serum inflammatory markers, imaging modalities, tissue and sonication fluid sampling, molecular biology techniques, and histopathological examination. Second, recommendations on microbiology specimen sampling and laboratory operating procedures relevant to FRI will be provided. LEVEL OF EVIDENCE:: Diagnostic Level V. See Instructions for Authors for a complete description of levels of evidence.

The accuracy of diagnostic Imaging techniques in patients with a suspected Fracture-related Infection (IFI) trial: study protocol for a prospective multicenter cohort study

INTRODUCTION

The optimal diagnostic imaging strategy for fracture-related infection (FRI) remains to be established. In this prospective study, the three commonly used advanced imaging techniques for diagnosing FRI will be compared. Primary endpoints are (1) determining the overall diagnostic performances of white blood cell (WBC) scintigraphy, fluorodeoxyglucose positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) in patients with suspected FRI and (2) establishing the most accurate imaging strategy for diagnosing FRI.

METHODS AND ANALYSIS

This study is a non-randomised, partially blinded, prospective cohort study involving two level 1 trauma centres in The Netherlands. All adult patients who require advanced medical imaging for suspected FRI are eligible for inclusion. Patients will undergo all three investigational imaging procedures (WBC scintigraphy, FDG-PET and MRI) within a time frame of 14 days after inclusion. The reference standard will be the result of at least five intraoperative sampled microbiology cultures, or, in case of no surgery, the clinical presence or absence of infection at 1 year follow-up. Initially, the results of all three imaging modalities will be available to the treating team as per local protocol. At a later time point, all scans will be centrally reassessed by nuclear medicine physicians and radiologists who are blinded for the identity of the patients and their clinical outcome. The discriminative ability of the imaging modalities will be quantified by several measures of diagnostic accuracy.

ETHICS AND DISSEMINATION

Approval of the study by the Institutional Review Board has been obtained prior to the start of this study. The results of this trial will be disseminated by publication of peer-reviewed manuscripts, presentation in abstract form at scientific meetings and data sharing with other investigators through academically established means.

TRIAL REGISTRATION NUMBER

The IFI trial is registered in the Netherlands Trial Register (NTR7490).