Infection in Orthopaedics

Fracture-related infection blood-based biomarkers: Diagnostic strategies

Fracture-related infections are significant postoperative complications that carry substantial patient burden and additional healthcare costs. Despite their impact on outcome, early diagnosis of these infections remains challenging due to current available tests lacking acceptable diagnostic parameters. This review compiles existing information on blood-based biomarkers that have been evaluated as early diagnostic tools and highlights the challenges in their reliability. To begin to overcome these challenges new avenues of biomarker discovery utilizing "omics" technologies and novel analytical methods are being investigated in recent years. It appears that, despite their complexity, these newer approaches may be the future in biomarker discovery for fracture-related infection diagnosis.

Primary Closure of External Fixator Pin Sites Is Safe After Orthopaedic Trauma Surgery

OBJECTIVES

To determine if rates of pin site infection and surgical site infection among patients managed with primary closure after external fixator removal were similar to those allowed to heal secondarily.

METHODS

DESIGN

Retrospective cohort.

SETTING

Urban/Suburban Academic Level I Trauma Center.

PATIENT SELECTION CRITERIA

Patients who had received a lower extremity external fixator for provisional management before definitive fixation of lower extremity fractures were included with pin site wounds closed primarily or allowed to heal by secondary intention.

OUTCOME MEASURES AND COMPARISONS

The rate of pin tract infection and surgical site infection following primary closure of external fixator pin sites relative to patients whose pin sites were allowed to heal through secondary intention.

RESULTS

In total, 256 patients were evaluated: 143 patients (406 pin sites) in the primary closure group and 113 patients (340 in sites) in the secondary closure group. The average age was 49 ± 16 years. Sixty-five percent of included patients were male. There was no difference in pin tract infections between cohorts (primary = 0.5%, secondary = 1.5%, P = 0.26). External fixator duration in the primary closure group was 11.5 ± 8.4 days and 13.0 ± 8.1 days in the secondary closure group (P = 0.15). There was a greater rate of surgical site infections in the secondary intention cohort (15.9% vs. 7.7%, P = 0.047).

CONCLUSIONS

There was no difference in pin site infection rate after primary pin site closure relative to patients who were allowed to heal through secondary intention. Furthermore, there was a lower rate of surgical site infection after primary closure. These results challenge the dogma of secondary closure for ex fix pin sites, suggesting that debridement and primary closure is a safe option for management of external fixator pin sites and may impart benefit in decreasing infection risk.

LEVEL OF EVIDENCE

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

Time to consider blunt needles for implant surgery? A systematic review and meta-analysis shows that blunt suture needles reduce glove perforation

BACKGROUND

Despite a recent Cochrane Review demonstrating blunt suture needles are safer for surgeons, the use of blunt suture needles has not become widely adopted. In the 'Implant Era', with the value of medical implant companies to surpass $145 billion by 2027, should we re-examine the use of blunt suture needles, especially to reduce infection in implant surgery? We performed a systematic review and meta-analysis of randomised controlled trials (RCTs) assessing whether blunt suture needles reduce risks to surgeons and patients.

METHODS

A systematic review and meta-analysis was performed per PRISMA guidelines. PubMed, Cochrane and EMBASE databases were searched for RCTs. Dichotomous variables were pooled as risk ratios (RR) and associated 95% confidence intervals (CI) using the MH method. Random or fixed effects modelling use was based on statistical heterogeneity (I2).

RESULTS

14 RCTs were identified with 2488 patients. The RCTs included laparotomies, caesarean sections, episiotomies, and orthopaedic surgeries. Blunt suture needles when compared with sharp needles resulted in a significant reduction in glove perforation; RR: 0.47, 95% CI [0.37 to 0.60] and needlestick injuries, RR: 0.50, 95% CI [0.26 to 0.97]. Sharp needles caused more wound infections, but the result was not statistically significant; RR: 2.73, 95% CI [0.54 to 13.76], p 0.22. Surgeon's satisfaction decreased with blunt needles compared with sharp (RR: 1.22, 95% CI [1.09 to 1.37]).

CONCLUSION

Blunt suture needles are safer than sharp needles for surgeons and likely reduce risks to patients. This, however, comes at the cost of decreased ease of use. The authors recommend the routine use of blunt suture needles, especially in implant surgery.

Proteomic Analyses of Plasma From Patients With Fracture-Related Infection Reveals Systemic Activation of the Complement and Coagulation Cascades

OBJECTIVES

The objective of this study was to compare plasma proteomes of patients with confirmed fracture-related infections (FRIs) matched to noninfected controls using liquid chromatography-mass spectrometry.

METHODS

DESIGN

This was a prospective case-control study.

SETTING

The study was conducted at a single, academic, Level 1 trauma center.

PATIENT SELECTION CRITERIA

Patients meeting confirmatory FRI criteria were matched to controls without infection based on fracture region, age, and time after surgery from June 2019 to January 2022. Tandem mass tag liquid chromatography-mass spectrometry analysis of patient plasma samples was performed.

OUTCOME MEASURES AND COMPARISONS

Protein abundance ratios in plasma for patients with FRI compared with those for matched controls without infection were calculated.

RESULTS

Twenty-seven patients meeting confirmatory FRI criteria were matched to 27 controls. Abundance ratios for more than 1000 proteins were measured in the 54 plasma samples. Seventy-three proteins were found to be increased or decreased in patients with FRI compared with those in matched controls (unadjusted t test P < 0.05). Thirty-two of these proteins were found in all 54 patient samples and underwent subsequent principal component analysis to reduce the dimensionality of the large proteomics dataset. A 3-component principal component analysis accounted for 45.7% of the variation in the dataset and had 88.9% specificity for the diagnosis of FRI. STRING protein-protein interaction network analysis of these 3 PCs revealed activation of the complement and coagulation cascades through the Reactome pathway database (false discovery rates <0.05).

CONCLUSIONS

Proteomic analyses of plasma from patients with FRI demonstrate systemic activation of the complement and coagulation cascades. Further investigation along these lines may help to better understand the systemic response to FRI and improve diagnostic strategies using proteomics.

LEVEL OF EVIDENCE

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

Reuse of Orthopaedic Equipment: Barriers and Opportunities

» Reuse of orthopaedic equipment is one of many potential ways to minimize the negative impact of used equipment on the environment, rising healthcare costs and disparities in access to surgical care.» Barriers to widespread adoption of reuse include concerns for patient safety, exposure to unknown liability risks, negative public perceptions, and logistical barriers such as limited availability of infrastructure and quality control metrics.» Some low- and middle-income countries have existing models of equipment reuse that can be adapted through reverse innovation to high-income countries such as the United States.» Further research should be conducted to examine the safety and efficacy of reusing various orthopaedic equipment, so that standardized guidelines for reuse can be established.

Steady-State Piperacillin Concentrations in the Proximity of an Orthopedic Implant: A Microdialysis Porcine Study

Implant-associated osteomyelitis is one of the most feared complications following orthopedic surgery. Although the risk is low, sufficient antibiotic protection of the implant surface is important. The aim of this study was to assess steady-state piperacillin concentrations in the proximity of an orthopedic implant. Time above the minimal inhibitory concentration (fT>MIC) was evaluated for MIC of 8 (low target) and 16 μg/mL (high target). Six female pigs received an intravenous bolus infusion of 4 g/0.5 g piperacillin/tazobactam over 30 min every 6 h. Steady state was assumed achieved in the third dosing interval (12-18 h). Microdialysis catheters were placed in a cannulated screw in the proximal tibial cancellous bone, in cancellous bone next to the screw, and in cancellous bone on the contralateral tibia. Dialysates were collected from time 12 to 18 h and plasma samples were collected as reference. For the low piperacillin target (8 µg/mL), comparable mean fT>MIC across all the investigated compartments (mean range: 54-74%) was found. For the high target (16 µg/mL), fT>MIC was shorter inside the cannulated screw (mean: 16%) than in the cancellous bone next to the screw and plasma (mean range: 49-54%), and similar between the two cancellous bone compartments. To reach more aggressive piperacillin fT>MIC targets in relation to the implant, alternative dosing regimens such as continuous infusion may be considered.

Effect of Local Antibiotic Prophylaxis on Postoperative Deep Infection in Fracture Surgery: A Systematic Review and Meta-Analysis

OBJECTIVES

Despite the use of systemic antibiotic prophylaxis, postoperative infection after fracture surgery remains an issue. The purpose of this systematic review and meta-analysis was to evaluate the effect of locally applied antibiotics on deep infection in fracture surgery in both the open and closed fractures.

DATA SOURCES

A comprehensive search of MEDLINE, Embase, and PubMed was performed from the date of inception to April 15, 2021, and included studies in all languages.

STUDY SELECTION

Cohort studies were eligible if they investigated the effect on the infection rate of local antibiotic prophylaxis on deep infection after fracture surgery.

DATA EXTRACTION

This study was conducted according to the Cochrane Handbook for Systematic Reviews and reported as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Risk of bias was assessed using version 2 of the Cochrane risk-of-bias tool for randomized trials and the Methodological Index for Nonrandomized Studies tool where applicable.

DATA SYNTHESIS

An inverse variance random-effects model was the primary analysis model because of the anticipated diversity in the evaluated populations. Univariate models were used when a single outcome was of interest.

CONCLUSIONS

The risk of deep infection was significantly reduced when local antibiotics were applied compared with the control group receiving systemic prophylaxis only. This beneficial effect was observed in open fractures but failed to reach statistical significance in closed fractures. This meta-analysis suggests that there may be a significant risk reduction in deep infection rate after fracture surgery when local antibiotics are added to standard systemic prophylaxis, particularly in open fractures. Further high-powered Level I studies are needed to support these findings.

LEVEL OF EVIDENCE

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

Utility of Plasma Protein Biomarkers and Mid-infrared Spectroscopy for Diagnosing Fracture-related Infections: A Pilot Study

OBJECTIVES

To compare a large panel of plasma protein inflammatory biomarkers and mid-infrared (MIR) spectral patterns in patients with confirmed fracture-related infections (FRIs) with those in controls without infection.

DESIGN

Prospective case-control study.

SETTING

Academic, Level 1 trauma center.

PATIENTS

Thirteen patients meeting confirmatory FRI criteria were matched to 13 controls based on age, time after surgery, and fracture region.

INTERVENTION

Plasma levels of 49 proteins were measured using enzyme-linked immunosorbent assay techniques. Fourier transform infrared spectroscopy of dried films was used to obtain MIR spectra of plasma samples.

MAIN OUTCOME MEASUREMENTS

The main outcome measurements included plasma protein levels and MIR spectra of samples.

RESULTS

Multivariate analysis-based predictive model developed using enzyme-linked immunosorbent assay-based biomarkers had sensitivity, specificity, and accuracy of 69.2% ± 0.0%, 99.9% ± 1.0%, and 84.5% ± 0.6%, respectively, with platelet-derived growth factor-AB/BB, C-reactive protein, and MIG selected as the minimum number of variables explaining group differences ( P &lt; 0.05). Sensitivity, specificity, and accuracy of the predictive model based on MIR spectra were 69.9% ± 6.2%, 71.9% ± 5.9%, and 70.9% ± 4.8%, respectively, with 6 wavenumbers as explanatory variables ( P &lt; 0.05).

CONCLUSIONS

This pilot study demonstrates the feasibility of using a select panel of plasma proteins and Fourier transform infrared spectroscopy to diagnose FRIs. Preliminary data suggest that the measurement of these select proteins and MIR spectra may be potential clinical tools to detect FRIs. Further investigation of these biomarkers in a larger cohort of patients is warranted.

LEVEL OF EVIDENCE

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

Update on MRI findings of osteomyelitis of long bones in the adult population

OBJECTIVES

To evaluate the usefulness of new and established MRI signs of osteomyelitis in long bones in adults.

METHODS

All patient records over a 9-year period with clinical or MRI suspicion for osteomyelitis were retrospectively reviewed, using strict criteria for proof of infection. Two musculoskeletal radiologists independently reviewed the MRIs of proven osteomyelitis.

RESULTS

Out of 45 MRIs of confirmed osteomyelitis, 2 MRIs (4%) did not show confluent low-signal intensity on T1-weighted images, but all showed confluent high-signal intensity on T2-weighted images. Central hypoenhancing regions of marrow without abscess formation were found in 15-18/35 (43-51%) cases where gadolinium was given. We often found multiple foci of marrow replacement in the same bone. The areas of marrow involvement often had an irregular contour. Penumbra sign, marrow fat globules, and sequestra were uncommon.

CONCLUSION

Multiple foci of bone marrow signal abnormalities, an irregular contour of marrow abnormality, and central marrow hypoenhancement without abscess are common signs of osteomyelitis of long bones in adults. Confluent low T1-signal intensity is not always present.

Biodegradable Bone Implants as a New Hope to Reduce Device-Associated Infections-A Systematic Review

Bone fractures often require fixation devices that frequently need to be surgically removed. These temporary implants and procedures leave the patient more prone to developing medical device-associated infections, and osteomyelitis associated with trauma is a challenging complication for orthopedists. In recent years, biodegradable materials have gained great importance as temporary medical implant devices, avoiding removal surgery. The purpose of this systematic review was to revise the literature regarding the use of biodegradable bone implants in fracture healing and its impact on the reduction of implant-associated infections. The systematic review followed the PRISMA guidelines and was conducted by searching published studies regarding the in vivo use of biodegradable bone fixation implants and its antibacterial activity. From a total of 667 references, 23 studies were included based on inclusion and exclusion criteria. Biodegradable orthopedic implants of Mg-Cu, Mg-Zn, and Zn-Ag have shown antibacterial activity, especially in reducing infection burden by MRSA strains in vivo osteomyelitis models. Their ability to prevent and tackle implant-associated infections and to gradually degrade inside the body reduces the need for a second surgery for implant removal, with expectable gains regarding patients’ comfort. Further in vivo studies are mandatory to evaluate the efficiency of these antibacterial biodegradable materials.

The Toxicity and Antibacterial Effects of Povidone-Iodine Irrigation in Fracture Surgery

Objective

Surgical site infection is a common complication of surgery, especially in orthopedics. Povidone‐Iodine (PI) is one of the oldest and most commonly used disinfectants in surgery. However, the toxicity and antimicrobial effect of PI have not been discussed. In addition, no study has explored the optimum PI concentration for sterilization and tissue healing. This study explores the germicidal efficacy of different concentrations PI, in addition, the toxicity and antibacterial effects of PI irrigation in fracture surgery are also discussed.

Methods

Methicillin‐resistant Staphylococcus aureus and Pseudomonas aeruginosa (P. aeruginosa) were used to evaluate the germicidal efficacy of PI in vitro and in vivo. In vitro, the effects of PI on bacterial growth were analyzed. 2.5%, 1.25%, 0.5%, 0.25%, 0.05%, 0.025%, 0.005%, 0.0025% and 0% PI was added into the bacterial suspension, besides, the bacterial algebra and growth rate were tested. Meanwhile, the fluorescence intensity of viable bacteria was also tested to evaluate the effects of PI on bacterial survival. In vivo, first, femoral fracture with wound infection rat models were established. Second, thyroid gland sections, blood thyroxine, urinary iodine, wound local skin, muscle and bone tissue sections, serum creatinine and alanine aminotransferase, serum and bone local tissue interleukin‐6 (IL‐6), interleukin‐10 (IL‐10), bone morphogenetic protein (BMP‐2), vascular endothelial growth factor (VEGF) and transforming growth factor (TGF‐β1) were detected in rat femoral shaft fracture model with 5%, 2.5%, 0.5%, 0.05%, and 0% PI irrigation. Third, tissue bacteria culture was tested in rat femoral fracture with wound infection model with different concentrations PI irrigation.

Results

In vitro, 2.5%, 1.25%, 0.5% PI inhibited the growth of bacteria. 1.25%, 0.5% PI killed all the bacteria, while 0.25%, 0.05% PI had not killed bacteria after about 10 min. The iodine absorption of 5%, 2.5%, 0.5% PI irrigation did not cause thyroid injury. The 5%, 2.5%, 0.5% PI irrigation did not make serum creatinine and alanine aminotransferase abnormal and can remove bacteria from wounds. The 0.5%, 2.5% PI irrigation can promote tissue healing and increase BMP‐2, VEGF, TGF‐β1, IL‐10, in addition, decrease IL‐6. 5% PI irrigation would inhibit tissue healing, and increase IL‐6, decrease BMP‐2, VEGF, TGF‐β1, IL‐10.

Conclusions

Povidone‐Iodine was a widely used disinfectant and 2.5%, 1.25% and 0.5% PI could effectively kill bacteria. Five percent and lower concentration PI irrigation was safe and could not cause thyroid, kidney and liver damage. The 0.5% PI irrigation was beneficial for tissue healing but 5% PI irrigation was the opposite.

The Suitability of Propolis as a Bioactive Component of Biomaterials

Propolis is a resinous product collected by bees from plant exudates to protect and maintain hive homeostasis. Propolis has been used therapeutically for centuries as folk medicine. Modern research investigating the diversity of the chemical composition and plant sources, biological activity, extraction processes, analytical methods, and therapeutic properties in clinical settings have been carried out extensively since the 1980s. Due to its antimicrobial, anti-inflammatory, and immuno-modulator properties, propolis appears to be a suitable bioactive component to be incorporated into biomaterials. This review article attempts to analyze the potential application of propolis as a biomaterial component from the available experimental evidence. The efficacy and compabitility of propolis depend upon factors, such as types of extracts and types of biomaterials. Generally, propolis appears to be compatible with hydroxyapatite/calcium phosphate-based biomaterials. Propolis enhances the antimicrobial properties of the resulting composite materials while improving the physicochemical properties. Furthermore, propolis is also compatible with wound/skin dressing biomaterials. Propolis improves the wound healing properties of the biomaterials with no negative effects on the physicochemical properties of the composite biomaterials. However, the effect of propolis on the glass-based biomaterials cannot be generalized. Depending on the concentration, types of extract, and geographical sources of the propolis, the effect on the glass biomaterials can either be an improvement or detrimental in terms of mechanical properties such as compressive strength and shear bond strength. In conclusion, two of the more consistent impacts of propolis across these different types of biomaterials are the enhancement of the antimicrobial and the immune-modulator/anti-inflammatory properties resulting from the combination of propolis and the biomaterials.

Establishment of a reliable in-vivo model of implant-associated infection to investigate innovative treatment options

The increasing number of implant-associated infections and of multiresistant pathogens is a major problem in the daily routine. In the field of osteomyelitis, it is difficult to manage a valid clinical study because of multiple influencing factors. Therefore, models of osteomyelitis with a simulation of the pathophysiology to evaluate treatment options for implant-associated infections are necessary. The aim of this study is to develop a standardized and reproducible osteomyelitis model in-vivo to improve treatment options. This study analyses the influence of a post-infectious implant exchange one week after infection and the infection progress afterward in combination with a systemic versus a local antibiotic treatment in-vivo. Therefore, the implant exchange, the exchange to a local drug-delivery system with gentamicin, and the implant removal are examined. Furthermore, the influence of an additional systemic antibiotic therapy is evaluated. An in-vivo model concerning the implant exchange is established that analyzes clinic, radiologic, microbiologic, histologic, and immunohistochemical diagnostics to obtain detailed evaluation and clinical reproducibility. Our study shows a clear advantage of the combined local and systemic antibiotic treatment in contrast to the implant removal and to a non-combined antibiotic therapy. Group genta/syst. showed the lowest infection rate with a percentage of 62.5% concerning microbiologic analysis, which is in accordance with the immunohistochemical, cytochemical, histologic, and radiologic analysis. Our in-vivo rat model has shown valid and reproducible results, which will lead to further investigations regarding treatment options and influencing factors concerning the therapy of osteomyelitis and implant-associated infections.

No-Observed-Effect Level of Silver Phosphate in Carbonate Apatite Artificial Bone on Initial Bone Regeneration

Fracture-related infections require both treatments for bacteria removal and bone reconstruction. The use of combined broad-spectrum antibacterial silver compounds and artificial bone with high osteogenic activity is considered to be an effective strategy for achieving these treatments in one surgery. However, silver compounds are toxic for living tissues even at low concentrations. Herein, we investigated the no-observed-effect level (NOEL) of silver phosphate (Ag₃PO₄) in a bone substitute composed of carbonate apatite (CO₃Ap), a bone mineral, using in vitro and in vivo experiments. In vitro experiments demonstrated that the CO₃Ap artificial bone containing ≥0.1 wt % Ag₃PO₄ exerted antibacterial effects against Staphylococcus epidermidis, while those containing ≤0.3 wt % Ag₃PO₄ did not affect cellular adhesion, proliferation, differentiation, and calcification of osteoblast-like MC3T3-E1 cells. In vivo experiments demonstrated that the CO₃Ap artificial bone containing ≤0.3 wt % Ag₃PO₄ replaced a new bone to the same levels as those without Ag₃PO₄ 4 weeks after implantation into the bone defect of the rabbit femur condyle. However, the CO₃Ap artificial bone containing 0.3 wt % Ag₃PO₄ caused an inflammatory reaction, whereas those containing ≤0.1 wt % Ag₃PO₄ did not. Thus, both bone regeneration and infection control without any adverse effects were achieved using the CO₃Ap artificial bone containing 0.1 wt % Ag₃PO₄, indicating that the NOEL of Ag₃PO₄ was 0.1 wt %. Our results provide an effective strategy for the treatments of fracture-related infections.

Epidemiology and microbiology of fracture-related infection: a multicenter study in Northeast China

Objective

This study aimed to explore the epidemiological and microbiological characteristics of fracture-related infection (FRI), analyze the drug resistance characteristics of major pathogens, and provide timely and relatively complete clinical and microbiological data for antimicrobial treatment of FRI.

Methods

The clinical and microbiological data of patients with FRI from January 1, 2011, to December 31, 2020, were collected from three tertiary hospitals in Northeast China. The automatic microbial analysis system was used for strain identification and drug susceptibility testing, and the drug susceptibility results were determined in accordance with the latest Clinical and Laboratory Standards Institute (CLSI) criteria (as applicable each year).

Results

A total of 744 patients with FRI were enrolled. The incidence of FRI was about 1.5%, and 81.7% were male patients, with an average age of 48.98 ± 16.01 years. Open fractures accounted for 64.8%. Motor crush (32.8%) and falling (29.8%) were the main causes of injuries. The common sites of infection were the tibia and fibula (47.6%), femur (11.8%), foot (11.8%), and hand (11.6%). A total of 566 pathogenic bacteria were cultured in 378 patients with positive bacterial cultures, of which 53.0% were Gram-positive bacteria and 47.0% were Gram-negative bacteria. The most common pathogen at all sites of infection is Staphylococcus aureus. Staphylococcus aureus had a high resistance rate to penicillin (PEN), erythromycin (ERY), and clindamycin (CLI), exceeding 50%. Methicillin-resistant Staphylococcus aureus (MRSA) was more than 80% resistant to CLI and ERY.

Conclusions

The incidence of FRI in Northeast China was at a low level among major medical centers nationwide. Staphylococcus aureus was still the main pathogen causing bone infections, and the proportion of MRSA was lower than reported abroad, but we have observed an increase in the proportion of infections. Enterobacteriaceae have a higher resistance rate to third-generation cephalosporins and quinolones. For Enterobacteriaceae, other sensitive treatment drugs should be selected clinically.

Clinical and microbiological features of anaerobic implant-related infection in 80 patients after orthopedic surgery

OBJECTIVES

Implant-related infection is a common complication after orthopedic surgery, but there is limited research focused on anaerobic infections. We retrospectively analyzed data from 80 patients with anaerobic implant-related infections in order to investigate the clinical features, bacterial distribution and antimicrobial resistant characteristics of this disease.

METHODS

80 patients who underwent implant-related infections with anaerobes were included. Pathogens were isolated and identified by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry with verification of 16s rRNA sequencing. Antimicrobial susceptibility testing (AST) was performed using Epsilometric test (E-test).

RESULTS

Among the 80 patients, 61.2% (49/80) were infected with anaerobes alone, while 38.8% (31/80) were co-infected with anaerobes and other bacteria. Early infection cases involving anaerobe-alone infections were significantly higher compared to the co-infection group (P < 0.001), also exhibiting lower levels of neutrophils (P = 0.033) and ESR (P = 0.046). Anaerobe-alone infections in the prosthetic joint infection group represented a higher proportion compared with other implant-related infections (P = 0.031). Among all species of anaerobes identified, the top 3 were Cutibacterium acnes, Finegoldia magna and Peptostreptococcus anaerobius. Low MIC values to vancomycin was recorded in C. acnes strains and for amoxicillin/clavulanic acid and piperacillin/tazobactam in most F. magna strains. One of the C. acnes and F. magna strains appeared multi-drug resistant except to vancomycin.

CONCLUSIONS

Anaerobe-alone infections have later first onset times and lower infection biomarker levels compared to co-infected patients. The first choice against C. acnes is vancomycin, while amoxicillin/clavulanic acid and piperacillin/tazobactam are recommended for F. magna.

Novel dental implant modifications with two-staged double benefits for preventing infection and promoting osseointegration in vivo and in vitro

Peri-implantitis are a major problem causing implant failure these days. Accordingly, anti-infection during the early stage and subsequent promotion of osseointegration are two main key factors to solve this issue. Micro-arc oxidation (MAO) treatment is a way to form an oxidation film on the surface of metallic materials. The method shows good osteogenic properties but weak antibacterial effect. Therefore, we developed combined strategies to combat severe peri-implantitis, which included the use of a novel compound, PD, comprising dendrimers poly(amidoamine) (PAMAM) loading dimethylaminododecyl methacrylate (DMADDM) as well as MAO treatment. Here, we explored the chemical properties of the novel compound PD, and proved that this compound was successfully synthesized, with the loading efficiency and encapsulation efficiency of 23.91% and 31.42%, respectively. We further report the two-stage double benefits capability of PD + MAO: (1) in the first stage, PD + MAO could decrease the adherence and development of biofilms by releasing DMADDM in the highly infected first stage after implant surgery both in vitro and in vivo; (2) in the second stage, PD + MAO indicated mighty anti-infection and osteoconductive characteristics in a rat model of peri-implantitis in vivo. This study first reports the two-staged, double benefits of PD + MAO, and demonstrates its potential in clinical applications for inhibiting peri-implantitis, especially in patients with severe infection risk.

ReGeneraTing Agents (rgta®) technology combined with antibiotics improves outcomes for infections in the upper limb

A matrix therapy agent marketed as CACIPLIQ20® showed marked improvement in the healing rate of hand infections, including functional recovery. It can be used at both earlier and later stages to promote faster healing and prevent an adverse outcome.

Do Antibiotic Beads Need to be Removed?

Background

Polymethylmethacrylate antibiotic impregnated beads can be an effective treatment for chronic osteomyelitis or an adjuvant in the treatment of open fractures. It remains unclear however whether the beads cause long-term adverse events if not removed. The purpose of this study was to determine if removal of antibiotic beads was required in order to avoid long term complications.

Methods

A retrospective chart review was conducted on patients with an extremity or pelvis fracture that had implantation of polymethylmethacrylate (PMMA) antibiotic beads over a five-year period.

Results

Fifty-one patients met inclusion criteria for this study; thirty-seven patients (73%) did not have complications after surgical debridement and placement of PMMA antibiotic beads necessitating removal.

Conclusion

Our findings suggest that polymethylmethacrylate antibiotic beads can be utilized as a means of delivering high-dose concentrations of local antibiotics and do not have to be removed in all patients.

Modified algorithm for managing postoperative osteomyelitis following fracture fixation with Cierny-Mader type

Background

No standardized protocol has been suggested in the treatment of postoperative osteomyelitis following fracture fixation. Our team evaluates the clinical efficacy of the modified algorithm for managing postoperative osteomyelitis following fracture fixation with Cierny–Mader type.

Methods

Ninety-five wounds were reviewed from March 2009 to February 2016 in our hospital. Sixty-one wounds were treated by the modified algorithm as follows: stable hardware + bone not healed Cierny–Mader 1 type = remove hardware, temporary stabilize; stable hardware + bone not healed Cierny–Mader 2 type = retain hardware ; stable hardware + bone not healed Cierny–Mader for type 3 and type 4 = remove hardware, temporary stabilize/Ilizarov technique; unstable hardware + bone not healed = remove hardware, temporary stabilize/Ilizarov technique; and stable hardware + bone healed = remove hardware. Thirty-four wounds were treated by the conventional algorithm. Autodermoplasty, flap transfer, myocutaneous flap, and other methods including antibiotic irrigation and drug delivery system were used in wound repair.

Results

The patients treated with modified algorithm had a significantly reduced recurrence (P < 0.01) and increased results of negative bacterial cultures (P < 0.01); however, a decrease in the number of retained hardware cases was observed (P < 0.05). For those treated with tissue reconstruction, there was no significance (P > 0.05) compared with the conventional group.

Conclusions

The modified algorithm for the postoperative osteomyelitis following fracture fixation according to the stability of the hardware and Cierny–Mader type represents a good clinical efficacy in the management of postoperative osteomyelitis. This procedure is simple and shows promising results; more clinical evidence is needed to confirm the existing findings and optimize the treatment of postoperative osteomyelitis following fracture fixation.

Adjuvant Local Antibiotic Hydroxyapatite Bio-Composite in the management of open Gustilo Anderson IIIB fractures

Background

This study aims to evaluate outcomes of using Adjuvant Local Antibiotic Hydroxyapatite Bio-Composite in management of Open Gustilo-Anderson IIIB Fractures.

Methods and results

80 patients were managed with single-stage "Fix and Flap" along with intra-operative Adjuvant Local Antibiotic Bio-Composite. Successful fracture union was achieved in 96.1% of patients, with a limb salvage rate of 96.25%. Infection rate was only 1.25%.

Conclusion

High union rate and very low deep infection rate can be predictably achieved in complex Open Gustilo-Anderson IIIB fractures by meticulous technique, use of local adjunctive antibiotics bio-composite and a combined ortho-plastic approach.

Does the induced membrane have antibacterial properties? An experimental rat model of a chronic infected nonunion

INTRODUCTION

The Masquelet procedure proved its efficiency in treating infected nonunion filling bony gaps up to 25 cm. Yet the use of local antibiotics is still questionable in the daily practice with lack of evidence regarding its usefulness in controlling infection. An experimental rat model is put in place to study the antibacterial properties of the induced membrane produced during the first stage of Masquelet.

METHOD

Twenty-three-month-old wistar male rats are inoculated with a 0.5 mL solution of 10^8 CFU/mL MRSA over a critical fracture done on the right femur. Six weeks later, remaining 11 rats exhibiting signs of a chronic infection with a sinus tract and oozing pus along with radiological nonunion are used for a first stage Masquelet procedure. They are randomly divided into two groups with six rats having no local antibiotic in the cement mixture and five rats having 3 g of vancomycin mixed with gentamycin loaded cement. Six weeks later (twelve weeks from baseline), all eleven rats are euthanized and blood samples for C-reactive protein are withdrawn. The induced membrane is identified and resected along with bone fragments and sent for cultures and pathology.

RESULTS

MRSA is isolated in the cultures of all six rats in the first group where no local antibiotic was added. Altered polymorphonuclears with abscess and pus are noted on four of six pathology samples. However in the second group where local antibiotics were added, three out of five rats exhibited eradication of MRSA (p = 0.034) and all samples did not exhibit clear infection signs on pathology. A pyo-epithelioid over a foreign body reaction is seen predominantly in this group demonstrating a regenerative process.

DISCUSSION

The induced membrane does not have antimicrobial properties capable of overcoming an infected nonunion on its own. When local antibiotics were added during the first stage of the Masquelet procedure, new bone formation occurred indicating the need to control an infection in order for bone union to occur.

CONCLUSION

Local antibiotics use in adjunction to extensive debridement is advisable during the first stage of a Masquelet procedure for an infected nonunion.

Selenium nanoparticles as anti-infective implant coatings for trauma orthopedics against methicillin-resistant Staphylococcus aureus and epidermidis: in vitro and in vivo assessment

Background: Bacterial infection is a common and serious complication in orthopedic implants following traumatic injury, which is often associated with extensive soft tissue damage and contaminated wounds. Multidrug-resistant bacteria have been found in these infected wounds, especially in patients who have multi trauma and prolonged stay in intensive care units.Purpose: The objective of this study was to develop a coating on orthopedic implants that is effective against drug-resistant bacteria.

Methods and results: We applied nanoparticles (30-70nm) of the trace element selenium (Se) as a coating through surface-induced nucleation-deposition on titanium implants and investigated the antimicrobial activity against drug resistant bacteria including Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-resistant Staphylococcus epidermidis (MRSE) in vitro and in an infected femur model in rats.The nanoparticles were shown in vitro to have antimicrobial activity at concentrations as low as 0.5ppm. The nanoparticle coatings strongly inhibited biofilm formation on the implants and reduced the number of viable bacteria in the surrounding tissue following inoculation of implants with biofilm forming doses of bacteria.

Conclusion: This study shows a proof of concept for a selenium nanoparticle coatings as a potential anti-infective barrier for orthopedic medical devices in the setting of contamination with multi-resistant bacteria. It also represents one of the few (if only) in vivo assessment of selenium nanoparticle coatings on reducing antibiotic-resistant orthopedic implant infections.

Multiflora and Gram-Negative Microorganisms Predominate in Infections Affecting Pelvic Endoprostheses Following Tumor Resection

BACKGROUND

Periprosthetic infections after pelvic reconstruction are common, with reported rates ranging from 11% to 53%. Management of these infections is troublesome, as they commonly necessitate multiple surgical interventions and implant removal. The epidemiology and outcomes of these infections are largely unknown. The aim of this study was to analyze the causative microorganisms and the clinical outcome of treatment in a series of patients with pelvic endoprostheses affected by infection following tumor resection.

METHODS

In this retrospective, multicenter cohort study, we identified all patients who developed an infection after endoprosthetic reconstruction in periacetabular tumor resection, between 2003 and 2017. The microorganisms that were isolated during the first debridement were recorded, as were the number of reoperations for ongoing infection, the antimicrobial treatment strategy, and the outcome of treatment.

RESULTS

In a series of 70 patients who underwent pelvic endoprosthetic reconstruction, 18 (26%) developed an infection. The type of pelvic resection according to the Enneking-Dunham classification was type P2-3 in 14 (78%) of these patients and type P2 in 4 (22%). Median follow-up was 66 months. Fourteen (78%) of the 18 patients with infection had a polymicrobial infection. Enterobacteriaceae were identified on culture for 12 (67%). Of a total 42 times that a microorganism was isolated, the identified pathogen was gram-negative in 26 instances (62%). Microorganisms associated with intestinal flora were identified 32 times (76%). At the time of latest follow-up, 9 (50%) of the patients had the original implant in situ. Of these, 2 had a fistula and another 2 were receiving suppressive antibiotic therapy. In the remaining 9 (50%) of the patients, the original implant had been removed. At the time of final follow-up, 3 of these had a second implant in situ. The remaining 6 patients had undergone no secondary reconstruction.

CONCLUSIONS

Infections that affect pelvic endoprostheses are predominantly polymicrobial and caused by gram-negative microorganisms, and may be associated with intestinal flora. This differs fundamentally from mono-bacterial gram-positive causes of conventional periprosthetic joint infections and may indicate a different pathogenesis. Our results suggest that prophylaxis and empiric treatment may need to be re-evaluated.

LEVEL OF EVIDENCE

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

Top 100 cited articles on infection in orthopaedics: A bibliometric analysis

PURPOSE

The infection is an essential problem in the clinical practice in orthopedics. The bibliometric analysis was conducted to evaluate the top 100 cited articles on infection in orthopaedics.

METHODS

The Web of Science (WoS) Core Database was comprehensively searched from 1975 to 2017, and the literature search was limited in Science Citation Index Expanded (SCI-E). The subject terms included "infection", "infectious", and "infect*". All retrieved articles were filtrated by selecting the subspecialty of "Orthopedics". The searching results were listed by citation times to identify the top 100 cited articles. Significant information was elicited, including the authors, journals, countries, institutions, published year, and types of publication.

RESULTS

A significant increase was observed in the number of annual publications focusing on infection in orthopedics worldwide. Each of the top 100 cited articles was cited more than 150 times. Total citation times was positively associated with citation times in 2016 (P <.01) and mean citation times per year (P <.01). Conversely, age of the article was negatively associated with citation times in 2016 (P <.01) and mean citation times per year (P <.01). Besides, citation times in 2016 was positively related to mean citation times per year (P <.01). The United States was the most productive country, surgery was the most popular subspecialty and Journal of Bone and Joint Surgery American Volume was the most popular journal.

CONCLUSION

Infection in orthopaedics has attracted more and more researchers' concern. As for the top 100 cited articles, there were significant relationships among total citation times, citation times in 2016 and mean citation times per year as well as age of the article. The United States was the most productive country, surgery was the most popular subspecialty and Journal of Bone and Joint Surgery American Volume was the most popular journal.

Coatings as the useful drug delivery system for the prevention of implant-related infections

Implant-related infections (IRIs) which led to a large amount of medical expenditure were caused by bacteria and fungi that involve the implants in the operation or in ward. Traditional treatments of IRIs were comprised of repeated radical debridement, replacement of internal fixators, and intravenous antibiotics. It needed a long time and numbers of surgeries to cure, which meant a catastrophe to patients. So how to prevent it was more important than to cure it. As an excellent local release system, coating is a good idea by its local drug infusion and barrier effect on resisting biofilms which were the main cause of IRIs. So in this review, materials used for coatings and evidences of prevention were elaborated.

The effect of local antibiotic prophylaxis when treating open limb fractures: A systematic review and meta-analysis

Objectives

As well as debridement and irrigation, soft-tissue coverage, and osseous stabilization, systemic antibiotic prophylaxis is considered the benchmark in the management of open fractures and considerably reduces the risk of subsequent fracture-related infections (FRI). The direct application of antibiotics in the surgical field (local antibiotics) has been used for decades as additional prophylaxis in open fractures, although definitive evidence confirming a beneficial effect is scarce. The purpose of the present study was to review the clinical evidence regarding the effect of prophylactic application of local antibiotics in open limb fractures.

Methods

A comprehensive literature search was performed in PubMed, Web of Science, and Embase. Cohort studies investigating the effect of additional local antibiotic prophylaxis compared with systemic prophylaxis alone in the management of open fractures were included and the data were pooled in a meta-analysis.

Results

In total, eight studies which included 2738 patients were eligible for quantitative synthesis. The effect of antibiotic-loaded poly(methyl methacrylate) beads was investigated by six of these studies, and two studies evaluated the effect of local antibiotics applied without a carrier. Meta-analysis showed a significantly lower infection rate when local antibiotics were applied (4.6%; 91/1986) than in the control group receiving standard systemic prophylaxis alone (16.5%; 124/752) (p < 0.001) (odds ratio 0.30; 95% confidence interval 0.22 to 0.40).

Conclusion

This meta-analysis suggests a risk reduction in FRI of 11.9% if additional local antibiotics are given prophylactically for open limb fractures. However, due to limited quality, heterogeneity, and considerable risk of bias, the pooling of data from primary studies has to be interpreted with caution.

Cite this article: M. Morgenstern, A. Vallejo, M. A. McNally, T. F. Moriarty, J. Y. Ferguson, S. Nijs, WJ. Metsemakers. Bone Joint Res 2018;7:447–456. The effect of local antibiotic prophylaxis when treating open limb fractures: A systematic review and meta-analysis. DOI: 10.1302/2046-3758.77.BJR-2018-0043.R1

The value of quantitative histology in the diagnosis of fracture-related infection

Aims

This study aimed to investigate the role of quantitative histological analysis in the diagnosis of fracture-related infection (FRI).

Patients and Methods

The clinical features, microbiology culture results, and histological analysis in 156 surgically treated nonunions were used to stratify the likelihood of associated infection. There were 64 confirmed infected nonunions (one or more confirmatory criteria: pus, sinus, and bacterial growth in two or more samples), 66 aseptic nonunions (no confirmatory criteria), and 26 possibly infected nonunions (pathogen identified from a single specimen and no confirmatory criteria). The histological inflammatory response was assessed by average neutrophil polymorph (NPs) counts per high-power field (HPF) and compared with the established diagnosis.

Results

Assuming a cut-off of over five neutrophils per high-power field to diagnose septic nonunion, there was 80% sensitivity and 100% specificity (accuracy 90%). Using a cut-off of no neutrophils seen in any high-power field to diagnose aseptic nonunion, there was a sensitivity of 85% and a specificity of 98% (accuracy 92%).

Conclusion

Histology can be used in a bimodal fashion as a diagnostic test for FRI. The presence of more than five NPs/HPF had a positive predictive value for infected nonunion of 100%, while the complete absence of any NPs is almost always indicative of an aseptic nonunion (positive predictive value of 98%). Cite this article: Bone Joint J 2018;100-B:966–72.

Diagnostic challenges and future perspectives in fracture-related infection

Fracture-related infection (FRI) is one of the most challenging complications in orthopaedic trauma surgery. It has severe consequences for patients and an important socio-economic impact. FRI has distinct properties and needs to be addressed interdisciplinary. Since criteria for the diagnosis of FRI are not standardized, an expert panel recently proposed a definition for FRI. In this review the current diagnostic modalities and an interdisciplinary diagnostic algorithm based on this recently published definition, are presented and future diagnostic techniques discussed. Since to date, there is no single universal diagnostic test available that gives the clinician the definitive diagnosis of FRI, it is mandatory to follow a standardized diagnostic algorithm to correctly diagnose FRI.

Treatment Approach for Infection of Healed Fractures After Internal Fixation

OBJECTIVE

To review the efficacy of a treatment approach for patients with infection and colonized implants after open reduction and internal fixation of fractures.

DESIGN

Retrospective case series.

SETTING

Level one trauma center.

PATIENTS

Twenty patients were treated for wound infection with colonized implants after open reduction and internal fixation.

INTERVENTION

Surgical debridement, removal of implants, and a short postoperative oral antibiotic course.

MAIN OUTCOME MEASUREMENT

The course of patients after surgical debridement and removal of implants, including culture results, antibiotic administration, and presence of recurrent clinical infection and radiographic union.

RESULTS

Twenty patients had clinical presentations, including skin breakdown, serous drainage, purulent drainage and/or exposed implants, most commonly of the tibia (15 of 20). Mean time from index procedure to debridement with implant removal was 19.7 months. At the time of debridement and implant removal, 18 of 20 (90%) patients had a positive intraoperative culture (16 routine cultures and 2 broth cultures). The most common bacteria were Enterobacter cloacae (5/17) and methicillin-sensitive Staphylococcus aureus (4/17). All patients had soft tissue healing without signs of recurrent infection after mean follow up of 40 months after implant removal.

CONCLUSIONS

Surgical debridement with implant removal plus a short oral antibiotic course is effective to resolve wound infection with a colonized implant in the setting of healed fracture after internal fixation.

LEVEL OF EVIDENCE

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

Determining potential of PMMA as a depot for rifampin to treat recalcitrant orthopaedic infections

BACKGROUND

Open fractures are often complicated by infection. In cases of severe soft tissue and vascular injury, systemic antibiotics may be ineffective due to their inability to reach and provide direct antimicrobial activity to the zone of injury. High antibiotic concentrations within the wound can be achieved with reduced systemic toxicity by using local antibiotic delivery. As bacteria associated with musculoskeletal injuries frequently form biofilms, antibiotic selection is important. Herein, the use of rifampin, an antibiotic with activity against biofilms, delivered via polymethylmethacrylate (PMMA) beads is evaluated for use in a traumatic musculoskeletal wound model.

METHODS

PMMA beads loaded with rifampin, or combinations of rifampin and vancomycin, were prepared and evaluated for time to curing, drug release kinetics in vitro, and infection prevention in vivo using a well-established rat model of musculoskeletal infection. A segmental bone defect was created and contaminated with methicillin susceptible Staphylococcus aureus (UAMS-1). Wounds were debrided, irrigated, and treated with PMMA beads, containing rifampin or combinations of rifampin plus vancomycin, following a 6-h (early) or 24-h (delayed) treatment. After 14days, tissue, implants, and beads were removed for bacterial quantification and assessed for rifampin resistance.

RESULTS

There was a direct association between loaded concentration and release kinetics of the rifampin and vancomycin from PMMA beads. Higher rifampin concentrations delayed PMMA curing times. The addition of vancomycin to PMMA resulted in more rapid release of rifampin from beads. However, the highest concentration of rifampin loaded PMMA beads (10% wt/wt) was the only treatment to significantly reduce bacterial counts. No rifampin resistance was observed.

CONCLUSION

Although higher concentrations of rifampin resulted in significant reductions of bacteria, these levels extended PMMA curing times and transformed PMMA material characteristics. While these characteristics make the material unsuitable for weight-bearing applications, such as total joint arthroplasty, the use of rifampin-loaded PMMA beads may be an effective intervention in a contaminated traumatic extremity wound due to its ability to eradicate biofilms.

Efficacy and safety of clindamycin-based treatment for bone and joint infections: a cohort study

Clindamycin has high bioavailability together with good diffusion in bone tissue and could represent an alternative antibiotic compound for the treatment of bone and joint infections (BJIs). However, data regarding the efficacy and safety of clindamycin for BJIs are limited. A monocentric cohort study based on our medical dashboard, which prospectively recorded 28 characteristics for all hospitalized patients since July 2005, was performed. BJIs were selected, and then, all mono-microbial BJI managed with clindamycin-based therapy were included. Remission was defined as the absence of clinical and/or microbiological relapse after treatment. The duration of follow-up without relapse was determined retrospectively using computerized medical records. For 10 years, 196 BJIs, of which 80 (41%) were device-associated infections, were treated with clindamycin-based therapy. The bacterial causative agent was Staphylococcus aureus in 130 cases (66%), coagulase-negative staphylococci in 29 cases (15%), streptococci in 31 cases (16%) and other bacteria in 6 cases (3%). When used in combination therapy, clindamycin was mainly paired with fluoroquinolones (31%) or rifampin (27%). The mean duration of clindamycin treatment was 7.4 ± 3.2 weeks (range, 1-24). An AE was recorded for 9 (4.5%) patients. Remission was recorded for 111 (57%) patients, with a mean duration of clinical follow-up of 28 ± 24 months. Treatment failure occurred in 22 (11%) patients, 50 patients (25%) were lost to follow-up, and 8 (4%) required long-term suppressive therapy. Among the assessable patients, clindamycin-based therapy was efficient in 111/133 cases (83%) and thus represents a reliable and safe alternative treatment option.

Outcomes of post-traumatic tibial osteomyelitis treated with an Orthofix LRS versus an Ilizarov external fixator

OBJECTIVE

To compare the therapeutic effects of the Orthofix limb reconstruction system (LRS) versus the Ilizarov external fixator on osteomyelitis of a tibial bone defect.

MATERIALS AND METHODS

Among 153 patients hospitalized for bone lengthening therapy from January 1, 1996 to January 1, 2015, 129 patients were selected for a retrospective analysis. Forty-three of the candidate patients were treated using the Orthofix LRS and the other 86 were treated using an Ilizarov external fixator. The average follow-up was 96 months. We evaluated the patients at follow-up visits, and compared the length of time the patients wore the fixation devices. We also examined the scores of Activities of Daily Living (ADL) tests and a Self-rated Anxiety Scale (SAS), the range of motion, and the incidence of pin track infections.

RESULTS

The results indicated that both approaches were effective for treating the bone defect. Compared with the patients who wore an Ilizarov fixator for the treatment of post-traumatic osteomyelitis, those who wore an Orthofix LRS tended to be more satisfied with their quality of life and the outcome after the operation.

CONCLUSION

Although both approaches were effective for treating the bone defect, the overall patient outcomes were superior for the Orthofix LRS, suggesting that it should be considered as the first option in the treatment of traumatic osteomyelitis of the tibial diaphysis.

Antimicrobial and bone-forming activity of a copper coated implant in a rabbit model

Current strategies in implant technology are directed to generate bioactive implants that are capable to activate the regenerative potential of the surrounding tissue. On the other hand, implant-related infections are a common problem in orthopaedic trauma patients. To meet both challenges, i.e. to generate a bone implant with regenerative and antimicrobial characteristics, we tested the use of copper coated nails for surgical fixation in a rabbit model. Copper acetate was galvanically deposited with a copper load of 1 µg/mm² onto a porous oxide layer of Ti6Al4V nails, which were used for the fixation of a tibia fracture, inoculated with bacteria. After implantation of the nail the concentration of copper ions did not increase in blood which indicates that copper released from the implant was locally restricted to the fracture site. After four weeks, analyses of the extracted implants revealed a distinct antimicrobial effect of copper, because copper completely prevented both a weak adhesion and firm attachment of biofilm-forming bacteria on the titanium implant. To evaluate fracture healing, radiographic examination demonstrated an increased callus index in animals with copper coated nails. This result indicates a stimulated bone formation by releasing copper ions. We conclude that the use of implants with a defined load of copper ions enables both prevention of bacterial infection and the stimulation of regenerative processes.

Posttraumatic Reconstruction of the Foot and Ankle in the Face of Active Infection

Posttraumatic infection of the foot and ankle is a challenging issue for orthopedic surgeons. Making the diagnosis often requires combining laboratory and radiologic testing, patient examination, and history. Patient comorbidities should be identified and optimized whenever possible. Treatment must combine effective antibiotic therapy with thorough debridement of the infected zone. Reconstruction often requires a 2-staged approach using antibiotic spacers and temporary external fixation, with the goal of obtaining a functional, pain-free limb that is free of infection.

Microflora of Retained Intracochlear Electrodes from Infected Cochlear Implants

Objectives Cochlear implant infections may be refractory to medical management and require device removal with subsequent reimplantation. During device removal, the intracochlear electrode array is commonly left in place to prevent obliteration of the cochlear lumen. If the electrode is colonized with pathogens, this risks contaminating the replacement implant. In this study, we compare the microorganisms detected on infected cochlear implants against those on the retained electrode using culture and microbial gene-sequencing techniques. Study Design Prospective single-cohort study. Setting Tertiary medical center. Subjects and Methods Six patients with refractory cochlear implant infections had the receiver-stimulator and extracochlear electrode removed to facilitate treatment of the infection. The intracochlear electrode was removed at (delayed) reimplantation. Implant specimens were analyzed by microbial culture and 16S DNA gene sequencing. Results Staphylococcus aureus was the organism most commonly identified. None of the 6 patients' intracochlear electrodes yielded microbes by culture. Two intracochlear electrodes revealed bacterial species, and 1 revealed fungal species by gene sequencing. There was no correlation between the microbes on the infected extracochlear implants and the retained intracochlear electrodes. All subjects underwent reimplantation after resolution of their infections. One of 6 subjects developed a second infection after reimplantation, with S aureus in the primary and secondary infections. Conclusions The intracochlear electrodes of infected cochlear implants carry a low microbial burden. Preserving intracochlear electrodes upon removal of infected cochlear implants appears to carry a low risk of contaminating a replacement cochlear implant.