Diagnosing Fracture-Related Infection: Current Concepts and Recommendations

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.

High Rate of Undetected Infections in Failed Osteosynthesis of Pertrochanteric Fractures

OBJECTIVE

The objective of this study was to assess the incidence of infection in patients with cutout after proximal femur fracture (PFF) osteosynthesis.

METHODS

DESIGN

Retrospective cohort study.

SETTING

Third-level trauma center.

PATIENT SELECTION CRITERIA

Patients presenting with a cutout following PFF (OTA/AO 31A) osteosynthesis, between January 2007 and December 2020.

OUTCOME MEASUREMENTS AND COMPARISONS

The primary outcome was infection according to the European Bone and Joint Infection Society criteria.

RESULTS

Sixty-seven patients presenting with a cutout were included, with mean age of 83.3 years (range 63-96), and 51 (76.1%) were women. Of all cases, 16 (24.7%) presented a concomitant infection. The presence of concomitant infection was suspected preoperatively in only 3 of the cases. A subgroup analysis was performed between the cases with infection and those without infection, the groups being comparable in terms of demographic data and postoperative radiological criteria. Patients with underlying infection had a higher rate of surgical wound complication (56.3% vs. 22%, P = 0.014) and higher rates of leukocytosis (11.560 vs. 7.890, P = 0.023).

CONCLUSION

Faced with a cutout after osteosynthesis of a PFF, underlying infection should be considered as a possible etiological factor.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Prospects and challenges for the application of tissue engineering technologies in the treatment of bone infections

Osteomyelitis is a devastating disease caused by microbial infection in deep bone tissue. Its high recurrence rate and impaired restoration of bone deficiencies are major challenges in treatment. Microbes have evolved numerous mechanisms to effectively evade host intrinsic and adaptive immune attacks to persistently localize in the host, such as drug-resistant bacteria, biofilms, persister cells, intracellular bacteria, and small colony variants (SCVs). Moreover, microbial-mediated dysregulation of the bone immune microenvironment impedes the bone regeneration process, leading to impaired bone defect repair. Despite advances in surgical strategies and drug applications for the treatment of bone infections within the last decade, challenges remain in clinical management. The development and application of tissue engineering materials have provided new strategies for the treatment of bone infections, but a comprehensive review of their research progress is lacking. This review discusses the critical pathogenic mechanisms of microbes in the skeletal system and their immunomodulatory effects on bone regeneration, and highlights the prospects and challenges for the application of tissue engineering technologies in the treatment of bone infections. It will inform the development and translation of antimicrobial and bone repair tissue engineering materials for the management of bone infections.

Is there a role for suppression of infection in managing fracture-related infection following intra-medullary nailing?

BACKGROUND

The management of fracture-related infection has undergone radical progress following the development of international guidelines. However, there is limited consideration to the realities of healthcare in low-resource environments due to a lack of available evidence in the literature from these settings. Initial antimicrobial suppression to support fracture union is frequently used in low- and middle-income countries despite the lack of published clinical evidence to support its practice. This study aimed to evaluate the outcomes following initial antimicrobial suppression to support fracture union in the management of fracture-related infection.

METHODS

A retrospective review of consecutive patients treated with initial antimicrobial suppression to support fracture healing followed by definitive eradication surgery to manage fracture-related infections following intramedullary fixation was performed. Indications for this approach were; a soft tissue envelope not requiring reconstructive surgery, radiographic evidence of stable fixation with adequate alignment, and progression towards fracture union.

RESULTS

This approach was associated with successful treatment in 51/55 (93 %) patients. Fracture union was achieved in 52/55 (95 %) patients with antimicrobial suppression alone. Remission of infection was achieved in 54/55 (98 %) patients following definitive infection eradication surgery. Following antibiotic suppression, 6/46 (13 %) pathogens isolated from intra-operative samples demonstrated multi-drug resistance.

CONCLUSION

Initial antimicrobial suppression to support fracture healing followed by definitive infection eradication surgery was associated with successful treatment in 93 % of patients. The likelihood of remission of infection increases when eradication surgery is performed in a healed bone. This approach was not associated with an increased risk of developing multi-drug-resistant infections compared to contemporary bone infection cohorts in the published literature.

LEVEL OF EVIDENCE

IV.

3DFRINet: A Framework for the Detection and Diagnosis of Fracture Related Infection in Low Extremities Based on 18F-FDG PET/CT 3D Images

Fracture related infection (FRI) is one of the most devastating complications after fracture surgery in the lower extremities, which can lead to extremely high morbidity and medical costs. Therefore, early comprehensive evaluation and accurate diagnosis of patients are critical for appropriate treatment, prevention of complications, and good prognosis. 18Fluoro-deoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is one of the most commonly used medical imaging modalities for diagnosing FRI. With the development of deep learning, more neural networks have been proposed and become powerful computer-aided diagnosis tools in medical imaging. Therefore, a fully automated two-stage framework for FRI detection and diagnosis, 3DFRINet (Three Dimension FRI Network), is proposed for 18F-FDG PET/CT 3D imaging. The first stage can effectively extract and fuse the features of both modalities to accurately locate the lesion by the dual-branch design and attention module. The second stage reduces the dimensionality of the image by using the maximum intensity projection, which retains the effective features while reducing the computational effort and achieving excellent diagnostic performance. The diagnostic performance of lesions reached 91.55% accuracy, 0.9331 AUC, and 0.9250 F1 score. 3DFRINet has an advantage over six nuclear medicine experts in each classification metric. The statistical analysis shows that 3DFRINet is equivalent or superior to the primary nuclear medicine physicians and comparable to the senior nuclear medicine physicians. In conclusion, this study first proposed a method based on 18F-FDG PET/CT three-dimensional imaging for FRI location and diagnosis. This method shows superior lesion detection rate and diagnostic efficiency and therefore has good prospects for clinical application.

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.

Mismatch Rate of Empirical Antimicrobial Treatment in Fracture-Related Infections

OBJECTIVES

To evaluate the current standard of care regarding empirical antimicrobial therapy in fracture-related infections (FRIs).

METHODS

DESIGN

Retrospective cohort study.

SETTING

Level I Trauma Center.

PATIENT SELECTION CRITERIA

Adult patients treated for FRI with surgical debridement and empirical antibiotics between September 1, 2014, and August 31, 2022. Patients were excluded if less than 5 tissue samples for culture were taken, culture results were negative, or there was an antibiotic-free window of less than 3 days before debridement.

OUTCOME MEASURES AND COMPARISONS

FRI microbial etiology, antimicrobial resistance patterns (standardized antimicrobial panels were tested for each pathogen), the mismatch rate between empirical antimicrobial therapy and antibiotic resistance of causative microorganism(s), and mismatching risk factors.

RESULTS

In total, 75 patients were included [79% (59/75) men, mean age 51 years]. The most prevalent microorganisms were Staphylococcus aureus (52%, 39/75) and Staphylococcus epidermidis (41%, 31/75). The most frequently used empirical antibiotic was clindamycin (59%, 44/75), followed by combinations of gram-positive and gram-negative covering antibiotics (15%, 11/75). The overall mismatch rate was 51% (38/75) [95% confidence interval (CI), 0.39-0.62] and did not differ between extremities [upper: 31% (4/13) (95% CI, 0.09-0.61), lower: 55% (33/60) (95% CI, 0.42-0.68, P = 0.11)]. Mismatching empirical therapy occurred mostly in infections caused by S. epidermidis and gram-negative bacteria. Combination therapy of vancomycin with ceftazidime produced the lowest theoretical mismatch rate (8%, 6/71). Polymicrobial infections were an independent risk factor for mismatching (OR: 8.38, 95% CI, 2.53-27.75, P < 0.001).

CONCLUSIONS

In patients with FRI, a mismatching of empirical antibiotic therapy occurred in half of patients, mainly due to lack of coverage for S. epidermidis , gram-negative bacteria, and polymicrobial infections. Empirical therapy with vancomycin and ceftazidime produced the lowest theoretical mismatch rates. This study showed the need for the consideration of gram-negative coverage in addition to standard broad gram-positive coverage. Future studies should investigate the effect of the proposed empirical therapy on long-term outcomes.

LEVEL OF EVIDENCE

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

The Impact of Smoking on Hospital Course and Postoperative Outcomes in Patients With Fracture-Related Infections

OBJECTIVES

To assess the relationship between patient smoking status and fracture-related infection (FRI) characteristics including patient symptoms at FRI presentation, bacterial species of FRI, and rates of fracture union.

METHODS

DESIGN

Retrospective cohort study.

SETTING

Urban level 1 trauma center.

PATIENT SELECTION CRITERIA

All patients undergoing reoperation for FRI from January 2013 to April 2021 were identified through manual review of an institutional database.

OUTCOME MEASURES AND COMPARISONS

Data including patient demographics, fracture characteristics, infection presentation, and hospital course were collected through review of the electronic medical record. Patients were grouped based on current smoker versus nonsmoker status. Hospital course and postoperative outcomes of these groups were then compared. Risk factors of methicillin-resistant Staphylococcus aureus (MRSA) infection, Staphylococcus epidermidis infection, and sinus tract development were evaluated using multivariable logistic regression.

RESULTS

A total of 301 patients, comprising 155 smokers (51%) and 146 nonsmokers (49%), undergoing FRI reoperation were included. Compared with nonsmokers, smokers were more likely male (69% vs. 56%, P = 0.024), were younger at the time of FRI reoperation (41.7 vs. 49.5 years, P < 0.001), and had lower mean body mass index (27.2 vs. 32.0, P < 0.001). Smokers also had lower prevalence of diabetes mellitus (13% vs. 25%, P = 0.008) and had higher Charlson Comorbidity Index 10-year estimated survival (93% vs. 81%, P < 0.001). Smokers had a lower proportion of S. epidermidis infections (11% vs. 20%, P = 0.037), higher risk of nonunion after index fracture surgery (74% vs. 61%, P = 0.018), and higher risk of sinus tracts at FRI presentation (38% vs. 23%, P = 0.004). On multivariable analysis, smoking was not found to be associated with increased odds of MRSA infection.

CONCLUSIONS

Among patients who develop a FRI, smokers seemed to have better baseline health regarding age, body mass index, diabetes mellitus, and Charlson Comorbidity Index 10-year estimated survival compared with nonsmokers. Smoking status was not significantly associated with odds of MRSA infection. However, smoking status was associated with increased risk of sinus tract development and nonunion and lower rates of S. epidermidis infection at the time of FRI reoperation.

LEVEL OF EVIDENCE

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

Examining the causal relationship between circulating immune cells and the susceptibility to osteomyelitis: A Mendelian randomization study

BACKGROUND

Osteomyelitis is considered as a deleterious inflammatory condition affecting the bone, primarily attributed to pathogenic infection. However, the underlying factors predisposing individuals to osteomyelitis remain incompletely elucidated. The immune system plays a multifaceted role in the progression of this condition, yet previous observational studies and randomized controlled trials investigating the association between circulating immune cell counts and osteomyelitis have been constrained. In order to address this knowledge gap, we conducted a Mendelian randomization (MR) analysis to evaluate the impact of diverse immune cell counts on the risk of developing osteomyelitis.

METHODS

In our study, we utilized single nucleotide polymorphisms (SNPs) that have been strongly linked to circulating immune cells or specific lymphocyte subtypes, as identified in large-scale genome-wide association studies (GWAS). These SNPs served as instrumental variables (IVs) for our MR analysis. We employed a more relaxed clumping threshold to conduct MR analysis on several related lymphocyte subtypes. To estimate causal effects, we utilized the Wald ratio, as well as the random-effects inverse variance weighted (IVW) and weighted median (WM) methods. To enhance the credibility of our results, we performed F-statistic calculations and a series of sensitivity analyses.

RESULTS

Our findings revealed a significant correlation between the absolute count of circulating lymphocytes and the risk of osteomyelitis [odds ratio(OR) 1.20；95 % confidence interval (CI), 1.08-1.32；P = 0.0005]. Furthermore, we identified a causal relationship between the absolute count of CD8+ T cells and susceptibility to osteomyelitis (OR 1.16; 95 % CI, 1.04-1.30; P = 0.0098). Importantly, these findings remained robust across a wide range of sensitivity analyses.

CONCLUSION

Through our MR analysis, we have provided evidence supporting a causal relationship between genetic predisposition to higher circulating immune cell counts and an increased risk of osteomyelitis. Specifically, our findings highlight the association between elevated CD8+ T cell counts and a heightened susceptibility to osteomyelitis. These results offer valuable insights for the future exploration of immunotherapy approaches in the management of osteomyelitis.

Low energy gunshot injuries: Does removal of retained bullet fragmentation at the time of internal fixation reduce the risk of fracture related infection?

OBJECTIVE

To examine the effects of RBF (Retained Bullet Fragment) removal at the time of long bone fixation on FRI (fracture related infection) rates in low energy GSI (Gunshot Injury) related fractures.

DESIGN

Retrospective Cohort Study SETTING: Level 1 Academic Trauma Center INTERVENTION: Retrospective review of the impact of RBFs on the risk of FRI when employing internal fixation in low energy GSI (Gunshot Injury) related fractures. In situations where the injury pattern requires surgical fixation, the question arises as to whether or not the RBFs need to be removed to prevent FRI.

MAIN OUTCOME MEASURES

Whether or not the RBFs removed in our patient population prevented short- and long-term fracture related infection after low-energy gunshot injury (FRI-LGI).

RESULTS

Of the 2,136 GSI related fractures, 131 patients met inclusion criteria, 81 patients underwent removal (R) of RBFs at the time of internal fixation while 50 patients did not undergo any removal (NR) at time of internal fixation. Among the patients who underwent surgical intervention, (Open Reduction Internal Fixation) ORIF was performed in 55 cases (R: 39; NR: 16), and (Intramedullary Nail) IMN was performed in 76 cases (R: 42; NR: 34). The overall rate of deep FRI-LGI was 6.9 % of the 131-patient cohort. We found that removal of RBFs had a statistically significant impact on the rate of deep FRI-LGI when compared to the NR group (p = 0.031). In the RBF removal group, only two patients (2.4 %) developed deep FRI-LGIs, whereas in the NR group, seven patients (14.0 %) developed deep FRI-LGIs. The incidence of early FRI-LGI was higher in the NR group (median 0.6 months) compared to the R group, which was associated with late FRI-LGIs (median 10.1 months) when they occurred.

DISCUSSION

In our study population, we found a statistically significantly increased incidence of deep and early FRI-LGI when RBFs are not removed at the time of extra-articular long bone internal fixation. The presence of retained bullet fragments following internal fixation may pose a risk factor for future development of deep FRI-LGI. We believe a surgeon should use their best judgment as to whether a RBF can safely be removed at the time of long bone fixation. Based on our findings, if safely permitted, RBF removal should be considered at the time of GSI long bone fixation resulting from low energy hand gun injuries.

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.

Approach to Tibial Shaft Nonunions: Diagnosis and Management

The tibia is the most common long bone at risk for nonunion with an annual incidence ranging from 12% to 19%. This topic continues to be an area of research as management techniques constantly evolve. A foundational knowledge of the fundamental concepts, etiology, and risk factors for nonunions is crucial for success. Treatment of tibial shaft nonunions often requires a multidisciplinary effort. This article provides guidance based on the most recent literature that can be used to aid the treating provider in the diagnosis, workup, and management of tibial shaft nonunions.

A retrospective cohort study of autogenous iliac strut bone grafting in large bone defects of the lower extremity

Autogenous iliac bone graft (AIBG) is the treatment of choice for managing bone defects, and favorable results have been reported for bone defects < 5 cm in length. In large bone defects ≥ 5 cm, it is difficult to obtain good results with simple bone grafting, and other management options have drawbacks, such as long immobilization periods and high complication rates. We hypothesized that AIBG in the strut form might show favorable results in large bone defects with minimal complications. This study aimed to investigate the outcomes of strut-type AIBG and evaluate its effectiveness compared to cancellous AIBG. This retrospective study included 50 patients who underwent AIBG for bone defects at a single institution between March 2011 and April 2020. We performed corticocancellous AIBG in a strut form to manage bone defects ≥ 5 cm in the lower extremities. The strut bone was harvested along the iliac crest and grafted slightly longer than the bone defect to apply a sufficient compressive force. Demographic information and radiographic and clinical results of patients who underwent strut AIBG (Group S) were analyzed. The outcomes of union, time to union, complications, and reoperation were compared with those of patients who underwent cancellous AIBG (Group C). The study population comprised 37 men (74%) and 13 women (26%), with a mean age of 50.0 (range: 19-78). The average follow-up period was 25.6 months (12-104 months). Group S included 16 patients with a mean bone defect length of 6.8 ± 1.2 cm. In Group S, union was achieved in all patients, with an average time to union of 6.7 months. Complications occurred in four cases, all related to wound problems. Group C comprised d 34 patients with a mean defect length of 2.8 ± 1.1 cm. Complications occurred in five patients in Group C, including four soft tissue problems and one implant failure. When comparing the outcomes of Groups S and C, no significant differences were observed. AIBG is an effective and safe technique for managing bone defects. Strut AIBG can be used effectively for bone defects ≥ 5 cm in the lower extremities.

Bones on fire: illuminating osteomyelitis through the radiant lens of 18F-FDG PET/CT

Osteomyelitis is an inflammatory process that is caused by an infecting microorganism and leads to progressive bone destruction and loss. Osteomyelitis can occur at any age and can involve any bone. The infection can be limited to a single portion of the bone or can involve several regions, such as marrow, cortex, periosteum, and the surrounding soft tissue. Early and accurate diagnosis plays a crucial role in reducing unnecessary treatment measures, improving the patient's prognosis, and minimizing time and financial costs. In recent years, the use of functional metabolic imaging has become increasingly widespread. Among them, 18F-FDG PET/CT has emerged as a cutting-edge imaging modality that combines anatomical and functional metabolic information. It has seen rapid development in the field of infectious diseases. 18F-FDG PET/CT has been demonstrated to yield acceptable diagnostic accuracy in a number of infectious and inflammatory diseases. This review aims to provide information about the 18F-FDGPET/CT in the use of chronic osteomyelitis,osteomyelitis secondary to a contiguous focus of infection and osteomyelitis associated with peripheral vascular disease.

Comparing outcomes of plate augmentation, nail exchange, and nail exchange with plate augmentation in the treatment of atrophic femoral shaft nonunion after intramedullary nailing: a multicenter retrospective study

INTRODUCTION

Intramedullary (IM) nailing is the treatment of choice for femoral shaft fractures, but nonunion rates have been reported to be as high as 12%. Surgical interventions for nonunion involve exchange nailing or plate augmentation. Recently, a combined treatment of exchange nailing and plate augmentation has demonstrated good results, but its comparative effectiveness remains unclear. This study aimed to compare the clinical and radiographic outcomes of three different surgical interventions for atrophic femoral shaft nonunion, and investigate the factors that affect bone healing after reoperation.

MATERIALS AND METHODS

A retrospective study was conducted at five university hospitals involving 149 patients with aseptic atrophic nonunion after IM nailing. These patients underwent reoperation with plate augmentation, exchange nailing, or combined treatment. Clinical and radiographic outcomes were assessed and compared according to reoperation procedure. Logistic regression analysis was performed to identify factors affecting persistent nonunion after reoperation.

RESULTS

Of the cohort, 57 patients underwent plate augmentation, 64 underwent exchange nailing, and 28 received combined treatment. There were no significant differences in patient demographics among the groups. Exchange nailing produced a significantly lower union rate than did the combined treatment (82.8% vs. 100%, p = 0.016), whereas no significant difference was observed in the union rate and time to the union between plate augmentation and the combined treatment. Combined treatment showed the longest operative time and the greatest transfusion requirements. The risk factors for persistent nonunion included age, absence of autogenous bone grafts, and use of an exchange nailing technique.

CONCLUSIONS

Exchange nailing as a treatment for atrophic femoral shaft nonunion after IM nailing resulted in a lower union rate. The efficacy of the combined treatment requires further study, and persistent nonunion may be influenced by age, bone grafting, and surgical techniques. A comprehensive approach targeting both biological environment and mechanical stability is crucial in the treatment of atrophic femoral shaft nonunion.

2023 International Consensus Meeting on musculoskeletal infection: Summary from the treatment workgroup and consensus on treatment in preclinical models

In vitro and in vivo studies are critical for the preclinical efficacy assessment of novel therapies targeting musculoskeletal infections (MSKI). Many preclinical models have been developed and applied as a prelude to evaluating safety and efficacy in human clinical trials. In performing these studies, there is both a requirement for a robust assessment of efficacy, as well as a parallel responsibility to consider the burden on experimental animals used in such studies. Since MSKI is a broad term encompassing infections varying in pathogen, anatomical location, and implants used, there are also a wide range of animal models described modeling these disparate infections. Although some of these variations are required to adequately evaluate specific interventions, there would be enormous value in creating a unified and standardized criteria to animal testing in the treatment of MSKI. The Treatment Workgroup of the 2023 International Consensus Meeting on Musculoskeletal Infection was responsible for questions related to preclinical models for treatment of MSKI. The main objective was to review the literature related to priority questions and estimate consensus opinion after voting. This document presents that process and results for preclinical models related to (1) animal model considerations, (2) outcome measurements, and (3) imaging.

Imaging in osteoarticular infection in adults

BACKGROUND

Osteoarticular infections are uncommon and required a multimodal approach for diagnosis. Imaging forms an important component of this multimodal approach.

OBJECTIVES

In this narrative review, we describe the different imaging modalities, features of osteoarticular infections present on these imaging approaches and recommendations for which imaging modality should be considered in different types of osteoarticular infections.

SOURCES

This narrative review was based on literature review from PubMed and was limited to bacterial infections in adult patients.

CONTENT

Imaging modalities include modalities that provide information on the anatomy or radionuclide imaging that provides information about the metabolic activity of the area of interest. Anatomical imaging includes plain radiographs (X-ray), computed tomography, and magnetic resonance imaging. Radionuclide approaches include three-phase bone scintigraphy, gallium scans, white blood cell scintigraphy, and 18F-fluorodeoxy-glucose positron emission tomography. The optimal radiological modality for diagnosis is influenced by multiple factors, including infection location, presence of metalware, timing of infection from any preceding surgery or fracture, antibiotic use, and patient comorbidities. Local availability of scanning modality, tracer supply, technical expertise, and patient access also influences choice.

IMPLICATIONS

A collaborative approach with imaging, pathology and clinical input in a multidisciplinary setting is paramount for the diagnosis of osteoarticular infections. Increasing research and improvements in technology will further improve the utility and accuracy of imaging approaches for imaging in osteoarticular infections.

Surprise positive culture rate in the treatment of presumed aseptic long-bone nonunion: a systematic review with meta-analysis of 2397 patients

INTRODUCTION

In pre-operatively presumed aseptic nonunions, the definitive diagnosis of infection relies on intraoperative cultures. Our primary objective was to determine (1) the rate of surprise positive intraoperative cultures in presumed aseptic long-bone nonunion (surprise positive culture nonunion), and (2) the rate of surprise positive cultures that represent infection vs. contamination. Secondary objectives were to determine the healing and secondary surgery rates and to identify cultured micro-organisms.

MATERIALS AND METHODS

We performed a systematic literature search of PubMed, Embase and Cochrane Libraries from 1980 until December 2021. We included studies reporting on ≥ 10 adult patients with a presumed aseptic long-bone nonunion, treated with a single-stage surgical protocol, of which intraoperative cultures were reported. We performed a meta-analysis for: (1) the rates of surprise positive culture nonunion, surprise infected nonunion, and contaminated culture nonunion, and (2) healing and (3) secondary surgery rates for each culture result. Risk of bias was assessed using the QUADAS-2 tool.

RESULTS

21 studies with 2,397 patients with a presumed aseptic nonunion were included. The rate of surprise positive culture nonunion was 16% (95%CI: 10-22%), of surprise infected nonunion 10% (95%CI: 5-16%), and of contaminated culture nonunion 3% (95%CI: 1-5%). The secondary surgery rate for surprise positive culture nonunion was 22% (95%CI: 9-38%), for surprise infected nonunion 14% (95%CI 6-22%), for contaminated culture nonunion 4% (95%CI: 0-19%), and for negative culture nonunion 6% (95CI: 1-13%). The final healing rate was 98% to 100% for all culture results. Coagulase-negative staphylococci accounted for 59% of cultured micro-organisms.

CONCLUSION

These results suggest that surprise positive cultures play a role in the clinical course of a nonunion and that culturing is important in determining the etiology of nonunion, even if the pre-operative suspicion for infection is low. High healing rates can be achieved in presumed aseptic nonunions, regardless of the definitive intraoperative culture result.

Diagnostic Performance of a telephone questionnaire for fracture-related infections (FRIs) in open tibia fracture patients in Tanzania

INTRODUCTION

Fracture-related infections (FRIs) are a major cause of trauma-associated morbidity worldwide. In 2018, an expert group supported by the AO Foundation, European Bone and Joint Infection Society developed a consensus definition of FRI. Still, there is limited knowledge on the applicability of this definition in low- and middle-income countries (LMICs). Given the unique barriers that cause low follow-up rates for orthopaedic trauma patients in LMICs, this study aims to evaluate the diagnostic performance of a telephone questionnaire in identifying patients with FRIs after open tibia fracture fixation in Tanzania.

MATERIALS AND METHODS

Patients from a randomized controlled trial investigating the infection prevention benefit of locally applied gentamycin for open tibial fractures were included. Patients completed FRI based telephone questionnaires 7-10 days prior to scheduled follow-ups at 6 weeks, 3 months, 6 months, 9 months, and 1 year. The questionnaire included two "confirmatory" criteria questions for FRI (i.e., open wound and purulent drainage) and three "suggestive" criteria questions (i.e., wound drainage, fever, and warmth). Contingency tests were performed to identify the sensitivity and specificity between answers and adjudicated FRI diagnoses at the corresponding in-person follow-up. Data was analysed using STATA version 15.0 and MedCalc's online diagnostic test calculator.

RESULTS

There were a total of 234 complete questionnaires and 85 unique patients included. The sensitivity and specificity of having any positive answer in the questionnaire was highest at 6 months (100 % and 92.5 %, respectively). For all time-points pooled, sensitivity was 71.4 % and specificity was 93.0 %. Drainage had the highest sensitivity (71.4 %) while fever had the highest specificity (99.6 %). For confirmatory criteria, sensitivity was 14.3 % and specificity was 96.0 %. Contrastingly, the sensitivity for suggestive criteria was higher (71.4 %), with a similar specificity (93.8 %).

CONCLUSION

Our study indicates that telephone questionnaires have adequate diagnostic performance when assessing FRIs. The presence of drainage identified the majority of patients with FRI, and specificities were high across confirmatory and suggestive criteria. Our study is one of the first to evaluate telephone questionnaires as a diagnostic tool for FRIs in patients with open tibia fractures in a LMIC hospital and validates the FRI consensus definition criteria.

Suprapatellar intramedullary nail combined with screw fixation has comparable surgical outcomes to minimally invasive locking plate fixation in ipsilateral tibial plateau and shaft fractures

PURPOSE

To compare union rate, union time, alignment, and complication rate in ipsilateral tibia plateau and shaft fractures treated via suprapatellar intramedullary nailing with screw fixation and minimally invasive locking plate fixation.

MATERIALS AND METHODS

A retrospective study was conducted on 48 patients who underwent minimally invasive plate fixation (n = 35) or suprapatellar intramedullary nailing with screw fixation (n = 13), for the treatment of ipsilateral tibial plateau and shaft fractures with at least 1-year follow-up. Union rate, union time, radiologic alignment, and complication rate such as malalignment, nonunion, and fracture-related infection (FRI) were investigated.

RESULTS

Demographic data were not different between the two groups. Coronal plane alignment was 0.17 ± 4.23 in the plate group and -0.48 ± 4.17 in the intramedullary nail group (p = 0.637). Sagittal plane alignment was -0.13 ± 5.20 in the plate group and -1.50 ± 4.01 in the suprapatellar intramedullary nail group (p = 0.313). Coronal and sagittal malalignment recorded equal results: (p > 0.99), FRI (p = 0.602), nonunion and union times recorded (p = 0.656) and (p = 0.683, 0.829), respectively, and showed no significant difference between the two groups.

CONCLUSION

Suprapatellar intramedullary nailing with screw fixation had similar surgical outcomes with minimally invasive locking plate fixation in ipsilateral tibial plateau and shaft fractures in terms of union rate, union time, alignment, and complication rate. Thus, frequent use of intramedullary nailing combined with screw fixation is anticipated in patients with ipsilateral tibial plateau and shaft fractures when the soft tissue condition is not desirable.

LEVEL OF EVIDENCE

Level III.

Intraoperative tissue sampling for histology in chronic osteomyelitis shows high neutrophil infiltration centrally and low remains in debrided presumed infection-free regions

INTRODUCTION

Histology of debrided bone tissue is a confirmatory diagnostic criterion for fracture related infection (FRI) and prosthetic joint infection (PJI). The aim of the present study was to describe the histopathology of the first and last debrided bone tissue in chronic osteomyelitis (CO) according to the international diagnostic guidelines for FRI and PJI.

METHODS

15 patients with CO were allocated to surgical treatment using a one-stage protocol including extensive debridement. Suspected infected bone tissue eradicated early in the debridement procedure was collected as a clearly infected sample (S1). Likewise, the last eradicated bone tissue was collected as a suspected non-infected sample (S2). The samples were processed for histology. HE-stained sections were patho-morphologically examinated. Immunohistochemistry with MAC-387 antibodies towards calprotectin was used for estimation of neutrophil granulocyte (NP) score (0, 1, 2 or 3).

RESULTS

S1 samples showed a mean NP score of 2.6 (3 is confirmatory for infection). Following debridement, the NP score was significantly (p = 0.005) reduced to a mean NP score of 1.6. The S1 samples showed a mix of fibrovascular tissue, dense fibrosis, viable bone, bone necrosis and bone debris. S2 samples contained mostly viable bone tissue, however, often small fragments of necrotic bone or bone debris were present.

CONCLUSION

The inflammatory response of CO still exists after debridement, although the response fades from the center. Therefore, sampling of debrided bone tissue for histology must be performed initially during surgery, otherwise there is a risk for underestimation of NP infiltration. The present results might also be highly relevant for FRI and PJI.

[Translated article] Risk factors for infection of tibial plateau fractures

INTRODUCTION

Tibial plateau fractures are injuries prone to postoperative infection, with its reported incidence being higher than that of other fractures, between 5% and 12%. The primary objectives of this study were to quantify the postoperative infection rate of internal fixation of tibial plateau fractures (TPFs) and to identify the risk factors for this.

MATERIAL AND METHODS

Retrospective cohort study including patients who underwent TPF osteosynthesis between 2015 and 2020, in the same center. The study population was divided into two groups, according to the presence or absence of postoperative infection. Demographic variables related to the fracture, surgical parameters, as well as the need for reoperation were collected. Finally, in the case of debridement, the number of positive cultures and the pathogen responsible for the infection were collected, as well as the treatment applied.

RESULTS

One hundred and twenty-four patients were included, with a total of 14 infections (global infection rate of 11.3%). Risk factors for developing infection were open fractures (p=.002), Schatzker V and VI type fractures (p=.002) and the use of external fixation (p<.001). Regarding the surgical variables, only the longest ischemia time (p=.032) was identified as a risk factor. Staphylococcus aureus was the most frequently identified microorganism (43%), followed by Enterobacter cloacae (35.7%).

CONCLUSION

The overall infection rate after osteosynthesis of tibial plateau fractures was 11.3%. Different factors are associated with a higher risk of infection, including diabetes mellitus, open fractures, the use of external fixation, a higher grade in the Schatzker classification or a longer intraoperative ischemia time.

Risk factors for infection of tibial plateau fractures

INTRODUCTION

Tibial plateau fractures are injuries prone to postoperative infection, with its reported incidence being higher than that of other fractures, between 5% and 12%. The primary objectives of this study were to quantify the postoperative infection rate of internal fixation of tibial plateau fractures (TPF) and to identify the risk factors for this.

MATERIAL AND METHODS

Retrospective cohort study including patients who underwent TPF osteosynthesis between 2015 and 2020, in the same center. The study population was divided into two groups, according to the presence or absence of postoperative infection. Demographic variables related to the fracture, surgical parameters, as well as the need for reoperation were collected. Finally, in the case of debridement, the number of positive cultures and the pathogen responsible for the infection were collected, as well as the treatment applied.

RESULTS

One hundred and twenty-four patients were included, with a total of 14 infections (global infection rate of 11.3%). Risk factors for developing infection were open fractures (P=.002), Schatzker V and VI type fractures (P=.002) and the use of external fixation (P<.001). Regarding the surgical variables, only the longest ischemia time (P=.032) was identified as a risk factor. S. aureus was the most frequently identified microorganism (43%), followed by E. cloacae (35.7%).

CONCLUSION

The overall infection rate after osteosynthesis of tibial plateau fractures was 11.3%. Different factors are associated with a higher risk of infection, including diabetes mellitus, open fractures, the use of external fixation, a higher grade in the Schatzker classification or a longer intraoperative ischemia time.

Analysis of fracture-related infections from Swedish insurance claims between 2011 and 2021

Fracture-related infections (FRI) pose a serious complication with an incidence of 1-2%. This study aimed to analyze compensation claims submitted to The Swedish National Patient Insurance Company (LÖF) because of FRI after closed/open reduction and internal fixation (C/ORIF) in the four most common fracture sites (proximal humerus, distal radius, hip, ankle). Patients registered in the LÖF database with a suspected FRI between 2011 and 2021 were identified by matching International Classification of Diseases and procedural codes indicative of a combination of fractures to the proximal humerus, distal radius, hip and ankle, C/ORIF and infection. Medical records were reviewed for fracture sites, pathogens and complications. Data from the Swedish Fracture Register (SFR) were extracted to estimate the proportion of reported claims to the presumed number of FRI. Of 122 FRI identified in the LÖF database, 34 were after C/ORIF in the proximal humerus, 12 in the distal radius, 28 in the hip and 48 in the ankle. LÖF compensated 111 patients (91%). Median time from C/ORIF to an FRI was 3 weeks (interquartile range 2-6), and 95% of all FRI occurred within 1 year after C/ORIF. Staphylococcus aureus was the most common pathogen in patients with a distal radius, hip and ankle FRI. In contrast, Cutibacterium spp. were the most common aetiology in FRI of the proximal humerus. The total number of fractures treated with C/ORIF in the four fracture sites registered in the SFR during 2021 was 18,711. Most of the FRI patients were diagnosed within the first year after C/ORIF, and 91% of the patients received compensation. Given an expected FRI incidence of 1-2%, our estimates with extrapolated data from the SFR indicate that < 10% of affected patients applied for compensation.

The global burden of fracture-related infection: can we do better?

Fracture-related infection is a major complication related to musculoskeletal injuries that not only has important clinical consequences, but also a substantial socioeconomic impact. Although fracture-related infection is one of the oldest disease entities known to mankind, it has only recently been defined and, therefore, its global burden is still largely unknown. In this Personal View, we describe the origin of the term fracture-related infection, present the available data on its global impact, and discuss important aspects regarding its prevention and management that could lead to improved outcomes in both high-resource and low-resource settings. We also highlight the need for health-care systems to be adequately compensated for the high cost of human resources (trained staff) and well-equipped facilities required to adequately care for these complex patients. Our aim is to increase awareness among clinicians and policy makers that fracture-related infection is a disease entity that deserves prioritisation in terms of research, with the goal to standardise treatment and improve patient outcomes on a global scale.

Establishment and application of TSDPSO-SVM model combined with multi-dimensional feature fusion method in the identification of fracture-related infection

Fracture-related infection (FRI) is one of the most common and intractable complications in orthopedic trauma surgery. This complication can impose severe psychological burdens and socio-economic impacts on patients. Although the definition of FRI has been proposed recently by an expert group, the diagnostic criteria for FRI are not yet standardized. A total of 4761 FRI patients and 4761 fracture patients (Non-FRI) were included in the study. The feature set of patients included imaging characteristics, demographic information, clinical symptoms, microbiological findings, and serum inflammatory markers, which were reduced by the Principal Component Analysis. To optimize the Support Vector Machine (SVM) model, the Traction Switching Delay Particle Swarm Optimization (TSDPSO) algorithm, a recognition method was proposed. Moreover, five machine learning models, including TSDPSO-SVM, were employed to distinguish FRI from Non-FRI. The Area under the Curve of TSDPSO-SVM was 0.91, at least 5% higher than that of other models. Compared with the Random Forest, Backpropagation Neural Network (BP), SVM and eXtreme Gradient Boosting (XGBoost), TSDPSO-SVM demonstrated remarkable accuracy in the test set ([Formula: see text]). The recall of TSDPSO-SVM was 98.32%, indicating a significant improvement ([Formula: see text]). Compared with BP and SVM, TSDPSO-SVM exhibited significantly superior specificity, false positive rate and precision ([Formula: see text]. The five models yielded consistent results in the training and testing of FRI patients across different age groups. TSDPSO-SVM is validated to have the maximum overall prediction ability and can effectively distinguish between FRI and Non-FRI. For the early diagnosis of FRI, TSDPSO-SVM may provide a reference basis for clinicians, especially those with insufficient experience. These results also lay a foundation for the intelligent diagnosis of FRI. Furthermore, these findings exhibit the application potential of this model in the diagnosis and classification of other diseases.

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.

Open tibial plateau fractures: Infection rate and functional outcomes

INTRODUCTION

Open tibial plateau fractures are complex injuries that require specialized management to prevent complications. The objective of this study was to compare the infection risk and functional outcomes between open and closed tibial plateau fractures.

MATERIALS AND METHODS

In this multicenter cohort study the propensity score matching was used to pair participants according to age, sex, and Schatzker classification. 190 patients were followed for 1 year postoperatively. The Fracture-Related Infection (FRI) Consensus Group criteria was used to diagnose infection. Knee functionality was measured using the Oxford Knee Score scale (OKS).

RESULTS

The proportion of open fractures was 5.1%, and the overall incidence rate of FRI was 8% with 14% of them represented by open fractures and 4% for closed fractures (p = 0.014). Open fractures were found to be a risk factor associated with FRI, with a 5.48 times higher probability of FRI than closed fractures (odds ratio 5.41, 95% confidence interval [CI] 1.55-18.85). Among the study population, 50% had satisfactory functional outcomes of the knee (median OKS 45, IQR = 3). The median OKS was 44 (IQR = 11) in open fractures and 46 (IQR = 7) in closed ones (p = 0.03). Multivariate analysis showed that the OKS was 3 points lower for open fractures (95% CI -5.530--0.478) than closed ones, and the score was 9.7 points lower for FRI.

CONCLUSION

Open TPF is a risk factor that increases the probability of fracture related infections. Functional outcomes were excellent for both open and closed TPF, with a slight difference numerical that was under the minimal clinical difference (MCID). The presence of FRI significantly decreases the functional outcome.

Open Fixation After Preperitoneal Pelvic Packing Is Associated With a High Surgical Site Infection Rate

OBJECTIVES

To evaluate the incidence of pelvic space surgical site infection (SSI) after preperitoneal pelvic packing (PPP) for persistent hemodynamic instability.

DESIGN

Retrospective comparative study.

SETTING

Urban Level 1 trauma center.

PATIENTS/PARTICIPANTS

83 patients who received PPP and 55 patients who had open reduction and internal fixation (ORIF) of the anterior pelvic ring without PPP.

INTERVENTION

Operative fixation.

MAIN OUTCOME MEASUREMENTS

Pelvic space SSI.

RESULTS

The SSI rate in the PPP group was 31.3% (26/83) compared with 10.9% (6/55) in the control group (proportional difference 20.4%, confidence interval (CI) 6.4-32.5, P = 0.007). Patients in the PPP group (n = 43) were 1:1 propensity score matched with patients in the control group to account for differences in Injury Severity Score and American Society of Anesthesiologists score. In this matched cohort, the rate of pelvic space SSI remained higher in the PPP group compared with that in the control group (30.2% vs. 9.3%; proportional difference 20.9%, CI, 3.7-36.3; P = 0.02). On multivariate analysis of the PPP group, anterior ORIF (odds ratio 6.56, CI, 2.00-21.47, P = 0.002) was found to be independently associated with SSI.

CONCLUSIONS

PPP is an independent risk factor of space SSI. The likelihood of SSI after PPP is increased with anterior ORIF. The morbidity of SSI after PPP must be weighed against the risk of exsanguination.

LEVEL OF EVIDENCE

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

Inguinal draining-lymph node in 18F-FDG PET/CT images could be a new indicator for the diagnosis of fracture-related infection in the lower extremities

Purpose

The imaging diagnosis of fracture-related infection is often challenging. The aim of this study was to evaluate the value of 18F-FDG PET/CT for the diagnosis of fracture-related infection (FRI) with internal fixation after orthopedic surgery in lower extremities.

Methods

A total of 254 consecutive patients who underwent 18F-FDG PET/CT scans with suspected FRI with internal fixation in lower extremities were retrospectively investigated 18F-FDG PET/CT images were semiquantitatively evaluated with multiple metabolic parameters. Additionally, morphological information of the inguinal draining lymph nodes (DLN) with the highest SUV value was also collected and analyzed.

Results

Patients were divided into two groups according to final diagnosis: the infected (N=197) and the non-infected group (N=57). The differences in the inguinal DLN-related parameters, including the long diameter, short diameter, maximum cross-sectional area, maximum standardized uptake value (SUVmax), metabolic volume (MV) 60%, MV70%, MV80%, total lesional glycolysis (TLG) 60%, TLG70%, TLG80%, and the infection suspected area related parameters, including SUVmax, MV25%, MV30%, MV35%, MV40%, MV50%, and TLG70%, between the two groups were statistically significant. We then compared the highest area under the curves (AUCs) among the morphological parameters of DLN, metabolic parameters of DLN, and metabolic parameters of the suspected infection area. The result demonstrated that SUVmax of the inguinal DLN showed the best diagnostic performance with an AUC of 0.939 (P<0.05).

Conclusion

Semiquantitative analysis (especially SUVmax) of the inguinal DLN in 18F-FDG PET/CT images could be a promising method for the diagnosis of suspected FRI with internal fixation after orthopedic surgery in lower extremities.

The effect and mechanism of iodophors on the adhesion and virulence of Staphylococcus aureus biofilms attached to artificial joint materials

BACKGROUND

Iodophors are known to be a treatment for biofilm-related periprosthetic joint infection. However, the efficacy and mechanism of eradicating biofilms from different artificial joint materials after iodophor treatment are unknown. This study was conducted to understand the effect and mechanism of iodophors with respect to the adhesion and virulence of Staphylococcus aureus biofilms attached to artificial joint materials.

METHODS

Biofilms of Staphylococcus aureus strains were grown on titanium alloy, cobalt chromium molybdenum and polyethylene coupons, which are commonly used materials for artificial joints, for 24 h. Afterward, all coupons were divided into experimental and control groups: (1) exposed to a 0.5 ± 0.05% iodophor for 5 min and (2) exposed to phosphate-buffered saline for 5 min. To gauge the level of biofilm, colony forming units (CFU), live/dead staining confocal microscopy and crystal violet staining were used. Meanwhile, the expression of icaACDR and clfA, which are related to virulence and adhesion, was examined in both the experimental and control groups.

RESULTS

A roughly three-log decrease in CFU/cm2 was seen in the viable plate count compared to the control group. Confocal imaging and crystal violet staining verified the CFU data. Moreover, the expression of icaACDR was reduced on three different orthopaedic implant materials, and the expression of clfA was also inhibited on titanium alloy coupons exposed to the iodophor.

CONCLUSIONS

Our results indicated that exposure to an iodophor for 5 min could significantly eliminate biofilms. When Staphylococcus aureus that had adhered to these three materials, which were used for artificial joints, was treated with an iodophor for 5 min, the expression of icaACDR was significantly reduced. This provides strong evidence for clinically clearing periprosthetic joint infections without removing the artificial joints.

Mechanism of regulating macrophages/osteoclasts in attenuating wear particle-induced aseptic osteolysis

Joint replacement surgery is the most effective treatment for end-stage arthritis. Aseptic loosening caused by periprosthetic osteolysis is a common complication after joint replacement. Inflammation induced by wear particles derived from prosthetic biomaterials is a major cause of osteolysis. We emphasize that bone marrow-derived macrophages and their fusion-derived osteoclasts play a key role in this pathological process. Researchers have developed multiple intervention approaches to regulate macrophage/osteoclast activation. Aiming at wear particle-induced periprosthetic aseptic osteolysis, this review separately discusses the molecular mechanism of regulation of ROS formation and inflammatory response through intervention of macrophage/osteoclast RANKL-MAPKs-NF-κB pathway. These molecular mechanisms regulate osteoclast activation in different ways, but they are not isolated from each other. There is also a lot of crosstalk among the different mechanisms. In addition, other bone and joint diseases related to osteoclast activation are also briefly introduced. Therefore, we discuss these new findings in the context of existing work with a view to developing new strategies for wear particle-associated osteolysis based on the regulation of macrophages/osteoclasts.

Prophylactic Intrawound Antibiotics Significantly Reduce the Risk of Deep Infections in Fracture Fixation: Subgroup Meta-analyses of the Type of Fracture, Antibiotics, and Organism

OBJECTIVES

To analyze the efficacy of subgroups of various intrawound local antibiotics in reducing the rate of fracture-related infections.

DATA SOURCES AND STUDY SELECTION

PubMed, MEDLINE via Ovid, Web of Science, Cochrane database, and Science Direct were searched for articles in English on July 5, 2022, and December 15, 2022.

STUDY SELECTION

All clinical studies comparing the incidence of fracture-related infection between the administration of prophylactic systemic and topical antibiotics in fracture repair were analyzed.

DATA EXTRACTION

Cochrane collaboration's assessment tool and the methodological bias and the methodological index for nonrandomized studies were used to detect bias and evaluate the quality of included studies, respectively.

DATA SYNTHESIS

RevMan 5.3 software (Nordic Cochrane Centre, Denmark) was used to conduct the meta-analyses and generate forest plots.

CONCLUSIONS

From 1990 to 2021, 13 studies included 5309 patients. Nonstratified meta-analysis showed that intrawound administration of antibiotics significantly decreased the overall incidence of infection in both open and closed fractures, regardless of the severity of open fracture and antibiotics class [OR = 0.58, ( P = 0.007)] [OR = 0.33, ( P < 0.00001)], respectively. The stratified analysis revealed that prophylactic intrawound antibiotics significantly lowered infection rate in open fracture patients with Gustilo-Anderson type I (OR = 0.13, P = 0.004), type II (OR = 0.29, P = 0.0002), type III (OR = 0.21, P < 0.00001), when either tobramycin PMMA beads (OR = 0.29, P < 0.00001) or vancomycin powder (OR = 0.51, P = 0.03) was applied. This study demonstrates prophylactic administration of intrawound antibiotics significantly decreases the overall incidence of infection in all subgroups of surgically fixated fractures but does not affect the patient's length of hospital stay.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Risk factors for fracture-related infection after ankle fracture surgery

INTRODUCTION

Ankle fracture surgery comes with a risk of fracture-related infection (FRI). Identifying risk factors are important in preoperative planning, in management of patients, and for information to the individual patient about their risk of complications. In addition, modifiable factors can be addressed prior to surgery. The aim of the current paper was to identify risk factors for FRI in patients operated for ankle fractures.

METHODS

A cohort of 1004 patients surgically treated for ankle fractures at Haukeland University Hospital in the period of 2015-2019 was studied retrospectively. Patient charts and radiographs were assessed for the diagnosis of FRI. Binary logistic regression was used in analyses of risk factors. Regression coefficients were used to calculate the probability for FRI based on the patients' age and presence of one or more risk factors.

RESULTS

FRI was confirmed in 87 (9%) of 1004 patients. Higher age at operation (p < .001), congestive heart failure (CHF), p = 0.006), peripheral artery disease (PAD, p = 0.001), and current smoking (p = .006) were identified as risk factors for FRI. PAD and CHF were the risk factors displaying the strongest association with FRI with an adjusted odds ratio of 4.2 (95% CI 1.8-10.1) and 4.7 (95% CI 1.6-14.1) respectively.

CONCLUSION

The prevalence of FRI was 9% after surgical treatment of ankle fractures. The combination of risk factors found in this study demonstrate the need for a thorough, multidisciplinary, and careful approach when faced with an elderly or frail patient with an ankle fracture. The results of this study help the treating surgeons to inform their patients of the risk of FRI prior to ankle fracture surgery.

LEVEL OF EVIDENCE

Level III retrospective case-control study.

Acute Fixation Protocol for High-Energy Tibial Pilon Fractures Decreases Time to Fixation and Lowers Operative Costs Without Affecting Wound Complications and Reoperations

OBJECTIVES

To determine whether an acute fixation protocol for high-energy tibial pilon fractures increases the rate of wound complications.

DESIGN

Retrospective comparative study.

SETTING

Urban level 1 trauma center.

PATIENTS/PARTICIPANTS

One hundred forty-seven patients with OTA/AO 43B and 43C high-energy tibial pilon fractures treated with open reduction and internal fixation (ORIF).

INTERVENTION

Acute (<48 hours) versus delayed ORIF protocols.

MAIN OUTCOME MEASUREMENT

Wound complications, reoperations, time to fixation, operative costs, and hospital length of stay (LOS). Patients were compared by protocol, regardless of ORIF timing, for an intention-to-treat analysis.

RESULTS

Thirty-five and 112 high-energy pilon fractures were treated under the acute and delayed ORIF protocols, respectively. In the acute ORIF protocol group, 82.9% of patients received acute ORIF versus 15.2% of patients in the standard delayed protocol group. The 2 groups had no observed difference (OD) in the rate of wound complications (OD -5.7%, confidence interval (95% CI) -16.1% to 7.8%; P = 0.56) or reoperations (OD -3.9%, 95% CI, -14.1% to 9.4%; P = 0.76). The acute ORIF protocol group had a shorter LOS (OD -2.0, 95% CI, -4.0 to 0.0; P = 0.02) and lower operative costs (OD $-2709.27, 95% CI, -3582.02 to -1601.16; P < 0.01). On multivariate analysis, wound complications were associated with open fractures (odds ratio 3.36, 95% CI, 1.06-10.69; P = 0.04) and an American Society of Anesthesiologists score >2 (odds ratio 3.68, 95% CI, 1.07-12.67; P = 0.04).

CONCLUSION

This study suggests that an acute fixation protocol for high-energy pilon fractures decreases time to definitive fixation, lowers operative costs, and shortens hospital LOS without affecting wound complications or reoperations.

LEVEL OF EVIDENCE

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

Treatment of Fracture-Related Infection after Pelvic Fracture

BACKGROUND

The management of pelvic fractures is a significant challenge. Surgical site infection can result in the need for revision surgery, cause functional impairment, and lead to a prolonged length of stay and increased treatment costs. Although reports on fracture-related infection (FRI) after pelvic fracture fixation are sparsely reported in the literature, it is a serious complication. This study analysed patients with FRIs after pelvic fracture regarding patient characteristics, treatment strategies, and an evaluation of risk factors for FRI.

METHODS

In this retrospective single-centre study, FRI was diagnosed based on clinical symptoms of infection and a positive culture of a bacterial infection. Depending on the severity and acuteness of the infection, osseous stabilization was restored either via implant retention (stable implant, no osteolysis), exchange (loose implant or bony defect), or external fixation (recurrence of infection after prior implant retaining revision). Healing of infection was defined as no sign of recurring infection upon clinical, radiological, and laboratory examination in the last follow-up visit.

RESULTS

The FRI rate in our patient population was 7.5% (24/316). In 8/24 patients, the FRI occurred within the first three weeks after initial surgery (early) and 16/24 presented with a late onset of symptoms of FRI. A strategy of debridement, antibiotics, and implant retention (DAIR) was successful in 9/24 patients with FRI after pelvic fracture. A total of 10 patients required an exchange of osteo-synthetic implants, whereof three were exchanged to an external fixator. In five patients, we removed the implant because the fracture had already consolidated at the time of revision for infection. A total of 17/24 patients had a poly-microbial infection after a pelvic fracture and 3/24 patients died from post-traumatic multi-organ failure within the first 6 months after trauma. There were no cases of persistent infection within the remaining 21 patients.

CONCLUSIONS

Although poly-microbial infection is common in FRI after pelvic fracture, the recurrence rate of infection is relatively low. A complex pelvic trauma with significant soft tissue injury is a risk factor for recurrent infection and multiple revisions. A strategy of DAIR can be successful in patients with a stable implant. In cases with recurrent infection or an unstable fracture site, the exchange of implants should be considered.

Epidemiological updates of post-traumatic related limb osteomyelitis in china: a 10 years multicentre cohort study

BACKGROUND

Post-traumatic related limb osteomyelitis (PTRLO) is a complex bone infection. Currently, there are no available microbial data on a national scale that can guide appropriate antibiotic selection, and explore the dynamic changes in dominant pathogens over time. This study aimed to conduct a comprehensive epidemiological analysis of PTRLO in China.

METHODS

The study was approved by the Institutional Research Board (IRB), and 3526 PTRLO patients were identified from 212 394 traumatic limb fracture patients at 21 hospitals between 1 January 2008 and 31 December 2017. A retrospective analysis was conducted to investigate the epidemiology of PTRLO, including changes in infection rate (IR), pathogens, infection risk factors and antibiotic resistance and sensitivity.

RESULTS

The IR of PTRLO increased gradually from 0.93 to 2.16% (Z=14.392, P <0.001). Monomicrobial infection (82.6%) was significantly higher than polymicrobial infection (17.4%) ( P <0.001). The IR of Gram-positive (GP) and Gram-negative (GN) pathogens showed a significant increase from the lowest 0.41% to the highest 1.15% (GP) or 1.62% (GN), respectively. However, the longitudinal trend of GP vs. GN's composition did not show any significance (Z=±1.1918, P >0.05). The most prevalent GP strains were Methicillin-sensitive Staphylococcus aureus (MSSA) (17.03%), Methicillin-resistant Staphylococcus aureus (MRSA) (10.46%), E. faecalis (5.19%) and S. epidermidis (4.87%). In contrast, the dominant strains GN strains were Pseudomonas Aeruginosa (10.92%), E. cloacae (10.34%), E. coli (9.47%), Acinetobacter Baumannii (7.92%) and Klebsiella Pneumoniae (3.33%). In general, the high-risk factors for polymicrobial infection include opened-fracture (odds ratio, 2.223), hypoproteinemia (odds ratio, 2.328), and multiple fractures (odds ratio, 1.465). It is important to note that the antibiotics resistance and sensitivity analysis of the pathogens may be influenced by complications or comorbidities.

CONCLUSIONS

This study provides the latest data of PTRLO in China and offers trustworthy guidelines for clinical practice. (China Clinical Trials.gov number, ChiCTR1800017597).

Safety of terminally gamma-ray-sterilized screws coated with fibroblast growth factor 2-calcium phosphate composite layers in non-human primates

Screws coated with fibroblast growth factor 2 (FGF-2)-calcium phosphate (CP) composite layers exhibit enhanced soft tissue and bone formation and angiogenesis because of the biological activity of FGF-2. Furthermore, the mitogenic activity of the FGF-2 within the composite layers remains unchanged after gamma-ray sterilization, which may improve the storage stability prior to clinical use. However, the in vivo safeties of these screws as spinal implants remain unknown. Here, a randomized controlled trial, involving non-human primates, investigated the safety of using FGF-2-CP composite layer-coated screws after either gamma-ray sterilization or aseptic processing. Titanium alloy screws coated with FGF-2-CP composite layers and subjected to either gamma-ray sterilization at 25 kGy (GS group) or aseptic storage (AS group) were implanted into the vertebral bodies of two cynomolgus monkeys exceeding 12 weeks (day 99). Physiological, histological, and radiographic investigations were performed to evaluate the safeties of the screws. There were no serious adverse events, such as surgical site infection, significant loss of body weight, or abnormal blood test results. No radiolucent areas were observed around the screws from the GS or AS group throughout the study. In the intraosseous region, no significant differences were observed in bone and fibrous tissue apposition rates and rate of bone formation between the two groups (p = 0.49, 0.77, and 0.11, respectively). Neither tumor lesions nor accumulation of lymphocytes and neutrophils were observed in either group. Our data suggest that FGF-2-CP composite layer-coated screws subjected to terminal gamma-ray sterilization are as safe as those fabricated in aseptic processing.

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.

Fracture-related infections

Fracture-related infection is a serious complication which can occur following musculoskeletal injury and is associated with significant morbidity. These complications can be challenging to recognise, and experts have provided a clearer definition of fracture-related infection to help with the diagnosis and detection of these infections. This system includes clinical, radiological and laboratory-based diagnostic features which are either confirmatory or suggestive of fracture-related infection. Treatment requires a multifaceted approach with multidisciplinary involvement, and generally a combination of surgical techniques and prolonged antibiotics, the timing and choice of which should be optimised. This article provides an evidence-based review of the British Orthopaedic Association Standards for Trauma for the diagnosis and management of fracture-related infections.

Medial augmentation plating of aseptic distal femoral nonunions

BACKGROUND

Distal femur nonunions are well-recognized contributors to persistent functional disability, with limited data regarding their treatment options. In the current study, we asked whether additional medial augmentation plating is a feasible treatment option for patients with aseptic distal femoral nonunion and intact lateral implants.

METHODS

We conducted a single-center, retrospective study including 20 patients treated for aseptic distal femoral nonunion between 2002 and 2017. The treatment procedure included a medial approach to the distal femur, debridement of the nonunion site, bone grafting and medial augmentation plating utilizing a large-fragment titanium plate. Outcome measures were bone-related and functional results, measured by the Hospital for Special Surgery Knee Rating Scale (HSS) and the German Short Musculoskeletal Function Assessment questionnaire (SMFA-D).

RESULTS

Eighteen of 20 nonunions showed osseous healing at 8.16 ± 5.23 (range: 3-21) months after augmentation plating. Regarding functional results, the mean HSS score was 74.17 ± 11.12 (range: 57-87). The mean SMFA-D functional index was 47.38 ± 16.78 (range 25.74-71.32) at the last follow-up. Index procedure-associated complications included two cases of persistent nonunion and one case of infection.

CONCLUSIONS

According to the assessed outcome measures, augmentation plating is a feasible treatment option, with a high proportion of patients achieving bony union and good functional outcomes and a few patients experiencing complications.

Nitric oxide synthase 2 genetic variation rs2297514 associates with a decreased susceptibility to extremity post-traumatic osteomyelitis in a Chinese Han population

Background

Previous studies have indicated that nitric oxide synthase 2 (NOS2) genetic variations are involved in delayed fracture healing and fracture non-union. Whether these genetic variants associate with the development of osteomyelitis (OM) remains unclear. Here, we analyzed the potential relationships between NOS2 genetic variations and the risk of developing post-traumatic OM (PTOM) in a Chinese Han population.

Methods

Altogether 704 participants, including 336 PTOM patients and 368 healthy controls, were genotyped of rs2297514 and rs2248814 of the NOS2 gene using the SNaPshot genotyping method.

Results

Outcomes showed that the frequency of allele C of rs2297514 in the patient group was significantly lower than that in the control group (48.7% vs. 54.5%, P = 0.029, OR = 0.792, 95% CI 0.642 - 0.976). In addition, significant associations were found between rs2297514 and susceptibility to PTOM by the recessive model (P = 0.007, OR = 0.633, 95% CI 0.453 - 0.884), and the homozygous model (P = 0.039, OR = 0.648, 95% CI 0.429 - 0.979). Moreover, patients with the CC genotype of rs2297514 had lower inflammatory biomarkers levels than the TT genotype, especially for the C-reactive protein (CRP) level (median: 4.1 mg/L vs. 8.9 mg/L, P = 0.027). However, no significant relationship was noted between rs2248814 and the risk of developing PTOM.

Conclusion

In this Chinese cohort, rs2297514 is correlated with a decreased risk of PTOM development, with genotype CC as a protective factor.

Treatment and outcome of fracture-related infection of the clavicle

INTRODUCTION

The number of operatively treated clavicle fractures has increased over the past decades. Consequently, this has led to an increase in secondary procedures required to treat complications such as fracture-related infection (FRI). The primary objective of this study was to assess the clinical and functional outcome of patients treated for FRI of the clavicle. The secondary objectives were to evaluate the healthcare costs and propose a standardized protocol for the surgical management of this complication.

METHODS

All patients with a clavicle fracture who underwent open reduction and internal fixation (ORIF) between 1 January 2015 and 1 March 2022 were retrospectively evaluated. This study included patients with an FRI who were diagnosed and treated according to the recommendations of a multidisciplinary team at the University Hospitals Leuven, Belgium.

RESULTS

We evaluated 626 patients with 630 clavicle fractures who underwent ORIF. In total, 28 patients were diagnosed with an FRI. Of these, eight (29%) underwent definitive implant removal, five (18%) underwent debridement, antimicrobial treatment and implant retention, and fourteen patients (50%) had their implant exchanged in either a single-stage procedure, a two-stage procedure or after multiple revisions. One patient (3.6%) underwent resection of the clavicle. Twelve patients (43%) underwent autologous bone grafting (tricortical iliac crest bone graft (n = 6), free vascularized fibular graft (n = 5), cancellous bone graft (n = 1)) to reconstruct the bone defect. The median follow-up was 32.3 (P₂₅-P₇₅: 23.9-51.1) months. Two patients (7.1%) experienced a recurrence of infection. The functional outcome was satisfactory, with 26 out of 28 patients (93%) having full range of motion. The median healthcare cost was € 11.506 (P₂₅-P₇₅: € 7.953-23.798) per patient.

CONCLUSION

FRI is a serious complication that can occur after the surgical treatment of clavicle fractures. In our opinion, when treated adequately using a multidisciplinary patient-specific approach, the outcome of patients with an FRI of the clavicle is good. The median healthcare costs of these patients are up to 3.5 times higher compared to non-infected operatively treated clavicle fractures. Although not studied individually, we consider factors such as the size of the bone defect, condition of the soft tissue, and patient demand important when it comes to guiding our surgical decision making in cases of osseous defects.

The value of sonication in the differential diagnosis of septic and aseptic femoral and tibial shaft nonunion in comparison to conventional tissue culture and histopathology: a prospective multicenter clinical study

BACKGROUND

Septic and aseptic nonunion require different therapeutic strategies. However, differential diagnosis is challenging, as low-grade infections and biofilm-bound bacteria often remain undetected. Therefore, the examination of biofilm on implants by sonication and the evaluation of its value for differentiating between femoral or tibial shaft septic and aseptic nonunion in comparison to tissue culture and histopathology was the focus of this study.

MATERIALS AND METHODS

Osteosynthesis material for sonication and tissue samples for long-term culture and histopathologic examination from 53 patients with aseptic nonunion, 42 with septic nonunion and 32 with regular healed fractures were obtained during surgery. Sonication fluid was concentrated by membrane filtration and colony-forming units (CFU) were quantified after aerobic and anaerobic incubation. CFU cut-off values for differentiating between septic and aseptic nonunion or regular healers were determined by receiver operating characteristic analysis. The performances of the different diagnostic methods were calculated using cross-tabulation.

RESULTS

The cut-off value for differentiating between septic and aseptic nonunion was ≥ 13.6 CFU/10 ml sonication fluid. With a sensitivity of 52% and a specificity of 93%, the diagnostic performance of membrane filtration was lower than that of tissue culture (69%, 96%) but higher than that of histopathology (14%, 87%). Considering two criteria for infection diagnosis, the sensitivity was similar for one tissue culture with the same pathogen in broth-cultured sonication fluid and two positive tissue cultures (55%). The combination of tissue culture and membrane-filtrated sonication fluid had a sensitivity of 50%, which increased up to 62% when using a lower CFU cut-off determined from regular healers. Furthermore, membrane filtration demonstrated a significantly higher polymicrobial detection rate compared to tissue culture and sonication fluid broth culture.

CONCLUSIONS

Our findings support a multimodal approach for the differential diagnosis of nonunion, with sonication demonstrating substantial usefulness.

LEVEL OF EVIDENCE

Level 2 Trial registration DRKS00014657 (date of registration: 2018/04/26).

Septic Tibial Nonunions on Proximal and Distal Metaphysis-A Systematic Narrative Review

BACKGROUND

Infected nonunion of the tibia represents a challenging complication for orthopedic surgeons and poses a major financial burden to healthcare systems. The situation is even more compounded when the nonunion involves the metaphyseal region of long bones, a rare yet demanding complication due to the poor healing potential of infected cancellous bone; this is in addition to the increased likelihood of contamination of adjacent joints. The purpose of this study was to determine the extent and level of evidence in relation to (1) available treatment options for the management of septic tibial metaphyseal nonunions; (2) success rates and bone healing following treatment application; and (3) functional results after intervention.

METHODS

We searched the MEDLINE, Embase, and CENTRAL databases for prospective and retrospective studies through to 25 January 2021. Human-only studies exploring the efficacy of various treatment options and their results in the setting of septic, quiescent, and metaphyseal (distal or proximal) tibia nonunions in the adult population were included. For infection diagnosis, we accepted definitions provided by the authors of source studies. Of note, clinical heterogeneity rendered data pooling inappropriate.

RESULTS

In terms of the species implicated in septic tibial nonunions, staphylococcus aureus was found to be the most commonly isolated microorganism. Many authors implemented the Ilizarov external fixation device with a mean duration of treatment greater than one year. Exceptional or good bone and functional results were recorded in over 80% of patients, although the literature is scarce and possible losses of the follow-up were not recorded.

CONCLUSION

A demanding orthopedic condition that is scarcely studied is infected metaphyseal tibial nonunion. External fixation seems promising, but further research is needed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO No. CRD42020205781.

Fluorescence In Situ Hybridization as Diagnostic Tool for Implant-associated Infections: A Pilot Study on Added Value

Implant-associated infections are a devastating complication in surgery. Especially in infections with biofilm-forming microorganisms, the identification of the causing microorganism remains a challenge. However, the classification as biofilm is not possible with conventional polymerase chain reaction or culture-based diagnostics. The aim of this study was to evaluate the additional value of fluorescence in situ hybridization (FISH) and nucleic acid amplification technique (FISHseq) to discuss a diagnostic benefit of the culture-independent methods and to map spatial organization of pathogens and microbial biofilms in wounds.

Methods

In total, 118 tissue samples from 60 patients with clinically suspected implant-associated infections (n = 32 joint replacements, n = 24 open reduction and internal fixation, n = 4 projectiles) were analyzed using classic microbiological culture and culture-independent FISH in combination with polymerase chain reaction and sequencing (FISHseq).

Results

In 56 of 60 wounds, FISHseq achieved an added value. FISHseq confirmed the result of cultural microbiological examinations in 41 of the 60 wounds. In 12 wounds, one or more additional pathogens were detected by FISHseq. FISHseq could show that the bacteria initially detected by culture corresponded to a contamination in three wounds and could exclude that the identified commensal pathogens were a contamination in four other wounds. In five wounds, a nonplanktonic bacterial life form was detected.

Conclusions

The study revealed that FISHseq gives additional diagnostic information, including therapy-relevant findings that were missed by culture. In addition, nonplanktonic bacterial life forms could also be detected with FISHseq, albeit less frequently than previously indicated.

The Routine Use of Running Subcuticular Closures in Orthopaedic Trauma Patients Does Not Increase Wound Complications

OBJECTIVE

To investigate whether the routine use of running subcuticular closures (RSC) in orthopaedic trauma patients increases the rate of wound complications and reoperations.

DESIGN

Retrospective comparative study.

SETTING

Urban Level 1 trauma center.

PATIENTS/PARTICIPANTS

Two hundred sixty-six patients undergoing orthopaedic trauma procedures between June 2020 and March 2022.

INTERVENTION

Adoption of an RSC protocol where any incision/wound that could be approximated with interrupted subcuticular 2-0 monofilament sutures was closed with a running subcuticular 3-0 monofilament suture.

MAIN OUTCOME MEASUREMENTS

Wound complications and subsequent reoperations.

RESULTS

With adoption of the RSC protocol, 91.0% of all orthopaedic trauma procedures were closed with RSC compared with 7.5% of the historical control group. There were no observed differences in the rate of wound complications (proportional difference (PD) 6.0%, confidence interval (CI) -2.3% to 14.1%; P = 0.15) or reoperations (PD 5.2%, CI -1.9% to 12.2%; P = 0.14) between the RSC and the control group. Wound complications were not associated with RSC on univariate analysis (PD 7.2%, CI -10.0% to 24.0%; P = 0.41). On multivariate analysis, an ASA>2 (odds ratio (OR) 2.4, CI 1.0 to 5.7; P = 0.03), lower extremity injuries (OR 4.9, CI 1.3 to 17.8; P = 0.01), and open reduction internal fixation procedures (OR 2.8, CI 1.1 to 7.2; P = 0.02) were found to be independently associated with wound complications.

CONCLUSION

RSC for orthopaedic trauma procedures was not associated with increased wound complications when compared a historical cohort.

LEVEL OF EVIDENCE

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

Ultrastructural Evidence of Mitochondrial Dysfunction in Osteomyelitis Patients

Osteomyelitis is a difficult-to-treat disease with high chronification rates. First studies suggest increases in mitochondrial fission and mitochondrial dysfunction as possible contributors to the accumulation of intracellular reactive oxygen species and thereby to the cell death of infected bone cells. The aim of the present study is to analyze the ultrastructural impact of bacterial infection on osteocytic and osteoblastic mitochondria. Human infected bone tissue samples were visualized via light microscopy and transmission electron microscopy. Osteoblasts, osteocytes and their mitochondria were analyzed histomorphometrically and compared with the control group of noninfectious human bone tissue samples. The results depicted swollen hydropic mitochondria including depleted cristae and a decrease in matrix density in the infected samples. Furthermore, perinuclear clustering of mitochondria could also be observed regularly. Additionally, increases in relative mitochondrial area and number were found as a correlate for increased mitochondrial fission. In conclusion, mitochondrial morphology is altered during osteomyelitis in a comparable way to mitochondria from hypoxic tissues. This gives new perspectives on the treatment strategies since the manipulation of mitochondrial dynamics may improve bone cell survival as a potential new target for the therapy of osteomyelitis.

Analyzing risk factors for treatment failure in fracture-related infection

INTRODUCTION

Fracture-related infection (FRI) represents a challenging clinical scenario. Limited evidence exists regarding treatment failure after initial management of FRI. The objective of our investigation was to determine incidence and risk factors for treatment failure in FRI.

MATERIALS AND METHODS

We conducted a retrospective review of patients treated for FRI between 2011 and 2015 at three level 1 trauma centers. One hundred and thirty-four patients treated for FRI were identified. Demographic and clinical variables were extracted from the medical record. Treatment failure was defined as the need for repeat debridement or surgical revision seven or more days after the presumed final procedure for infection treatment. Univariate comparisons were conducted between patients who experienced treatment failure and those who did not. Multivariable logistic regression was conducted to identify independent associations with treatment failure.

RESULTS

Of the 134 FRI patients, 51 (38.1%) experienced treatment failure. Patients who failed were more likely to have had an open injury (31% versus 17%; p = 0.05), to have undergone implant removal (p = 0.03), and additional index I&D procedures (3.3 versus 1.6; p < 0.001). Most culture results identified a single organism (62%), while 15% were culture negative. Treatment failure was more common in culture-negative infections (p = 0.08). Methicillin-resistant Staphylococcus aureus (MRSA) was the most common organism associated with treatment failure (29%; p = 0.08). Multivariate regression demonstrated a statistically significant association between treatment failure and two or more irrigation and debridement (I&D) procedures (OR 13.22, 95% CI 4.77-36.62, p < 0.001) and culture-negative infection (OR 4.74, 95% CI 1.26-17.83, p = 0.02).

CONCLUSIONS

The rate of treatment failure following FRI continues to be high. Important risk factors associated with treatment failure include open fracture, implant removal, and multiple I&D procedures. While MRSA remains common, culture-negative infection represents a novel risk factor for failure, suggesting aggressive treatment of clinically diagnosed cases remains critical even without positive culture data.

LEVEL OF EVIDENCE

Retrospective cohort study; Level III.