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Volume 99-B, Issue SUPP_22 December 2017 European Bone and Joint Infection Society (EBJIS), Nantes, France, September 2017

D. Vaznaisiene R. Sulcaite D. Jomantiene E. Beltrand A. Spucis A. Reingardas V. Kymantas A. Mickiene E. Senneville

Aim

To assess the spread of foot infection and its impact on the outcomes of major amputations of lower extremities in diabetic patients.

Method

In a multicentre retrospective and prospective cohort study, we included adult diabetic patients (≥ 18 years) who underwent a major amputation of a lower limb in 5 hospitals between 2000 and 2009, 2012 and 2014. A total of 51 patients were included (of which 27 (52.94%) were men and 24 (47.06%) were women) with the mean age of 65.51 years (SD=16.99). Concomitant section's osseous slice biopsy (BA) and percutaneous bone biopsy of the distal site (BD) were performed during limb amputation. A new surgical set-up and new instruments were used to try and reduce the likelihood of cross-contamination during surgery. A positive culture was defined as the identification of at least 1 species of bacteria not belonging to the skin flora or at least 2 bacteria belonging to the skin flora (CoNS (coagulase negative staphylococci), Corynebacterium spp, Propionibacterium acnes) with the same antibiotic susceptibility profiles. A doubtful culture was defined as the identification of 1 species of bacteria belonging to the skin flora. The patients were followed-up for 1 year. Stump outcomes were assessed on the delay of complete healing, equipment, need of re-intervention and antibiotics.


A. Loro G. Galiwango P. Muwa A. Hodges R. Ayella

Aim

Segmental bone defects following osteomyelitis in pediatric age group may require specifically designed surgical options. Clinical and radiographic elements dictate the option. Different elements play a role on the surgeon's choice. Among them, the size of the defect, the size and the quality of the bone stock available, the status of the skin envelope, the involvement of the adjacent joint. When conditions occur, vascularized fibula flap may represent a solution in managing defects of the long bones even during the early years of life.

Method

A retrospective study, covering the period between October 2013 and September 2015, was done. Fourteen patients, nine males, five females, aged 2–13 years, with mean skeletal defect of 8.6 cm (range, 5 to 14 cm), were treated; the mean graft length was of 8.3 cm. The bones involved were femur (4), radius (4), tibia (3) and humerus (3). In 5 cases fibula with its epiphysis was used, in 5 cases the flap was osteocutaneous and in the remaining 4 cases only fibula shaft was utilized. After an average time of 8 months from eradication of infection, the procedure was carried out and the flap was stabilized with external fixators, Kirschner's wires or mini-plate. No graft augmentation was used.


A. Ramsden J. Chan R. Millar M. McNally

Aim

Free tissue transfer is an important tool in successful reconstruction of chronic osteomyelitis but can be challenging due to extensive scarring. Our unit follows a multidisciplinary approach including excision of osteomyelitis and immediate microvascular soft-tissue reconstruction simultaneously with orthopaedic reconstruction. We aim to evaluate the success of free tissue transfer and disease recurrence in patients with chronic osteomyelitis.

Method

This is a retrospective consecutive cohort study between 2010–2015 inclusive by a single microvascular surgeon in a single centre. All patients had one stage excision of osteomyelitis, orthopaedic reconstruction and microvascular soft tissue reconstruction, with a minimum follow-up period of 1 year.


J. Ferguson M. McNally R. Kugan D. Stubbs

Aims

Ilizarov described four methods of treating non-unions but gave little information on the specific indications for each technique. He claimed, ‘infection burns in the fire of regeneration’ and suggested distraction osteogenesis could effectively treat infected non-unions.

This study investigated a treatment algorithm for described Ilizarov methods in managing infected tibial non-union, using non-union mobility and segmental defect size to govern treatment choice. Primary outcome measures were infection eradication, bone union and ASAMI bone and function scores.

Patients and Methods

A consecutive series of 79 patients with confirmed, infected tibial non-union, were treated with one of four Ilizarov protocols, consisting of; monofocal distraction (26 cases), monofocal compression (19), bifocal compression/distraction (16) and bone transport (18). Median non-union duration was 10 months (range 2–168). All patients had undergone at least one previous operation (mean 2.2; range 1–5), 38 had associated limb deformity and 49 had non-viable non-unions. Twenty-six cases (33%) had a new simultaneous muscle flap reconstruction at the time of Ilizarov surgery and 25 had pre-existing flaps reused.

Treatment algorithm based on assessment of bone gap and non-union stiffness, measured after resection of non-viable bone.


N. Jiang X. Zhao Y. Hou B. Yu

Aim

Previous studies have indicated that TNF-α and lymphotoxin-α (LTA) gene polymorphisms associate with the development of several different inflammatory diseases. However, potential associations of such gene polymorphisms with the susceptibility to extremity chronic osteomyelitis remain unknown. This study aimed to investigate potential links between TNF-α gene polymorphisms (rs1800629, rs361525, rs1799964, rs1800630, rs1799724 and rs1800750) and LTA gene polymorphism (rs909253) and the risk of developing extremity chronic osteomyelitis in Chinese population.

Method

A total of 233 patients with extremity chronic osteomyelitis and 200 healthy controls were genotyped for the above 7 polymorphisms of TNF-α and LTA genes using the genotyping method*.


A. Bouige C. Fourcade A. Bicart-Sée M.P. Félicé L. Gautié G. Krin P. Marlin G. Giordano E. Bonnet

Aim

Ceftobiprole, a broad-spectrum cephalosporin, could be used for post-operative treatment of bone implant-associated infections. The aim of the study is to evaluate the in vitro susceptibility of bacteria isolated from bone implant-associated infections to ceftobiprole.

Method

We conducted an in vitro, retrospective and comparative study between July 2013 to April 2017 including patients with bone implant-associated infections (prosthesis joint infection (PJI) and osteosynthesis material (OM)). To evaluate MIC distribution of ceftobiprole against Gram positive and Gram negative strains and to compare activity of ceftobiprole to vancomycin for Gram positive and ceftriaxone or ceftazidime for Gram negative strains, we tested all strains (stored in Cryobank storage system) for minimal inhibitory concentrations (MIC) determination by E-test bandelet for ceftobiprole and comparator antibiotics.


A. Vallejo M. Morgenstern J. Puetzler D. Arens T.F. Moriarty G. Richards

Aim

Antibiotic prophylaxis is critical for the prevention of fracture related infection (FRI) in trauma patients, particularly those with open wounds. Administration of prophylactic antibiotics prior to arrival at the hospital (e.g. by paramedics) may reduce intraoperative bacterial load and has been recommended; however scientific evidence for pre-hospital administration is scarce.

Methods

The contaminated rabbit humeral osteotomy model of Arens was modified to resemble the sequence of events in open fractures. In an initial surgery representing the “accident”, a 2mm mid-diaphyseal hole was created in the humerus and the wound was contaminated with a clinical Staphylococcus aureus strain (mean 1.6×106 Colony Forming Units, CFU). The animals were allowed recover for 4 hours mimicking the period from trauma to debridement. At this time, a second procedure was performed in order to debride and irrigate the wound, and to fix a complete osteotomy that was made through the initial defect. Three test groups were included (n=8 rabbits per group): 1) no antibiotic therapy; 2) standard “in-hospital” antibiotic prophylaxis (24 hours therapy starting 30 minutes before surgery); 3) “pre-hospital” antibiotics (single dose 15 minutes after the “accident”). The antibiotic used was cefuroxime and was administered in a weight-adjusted dosage.


T. Tkhilaishvili M. Di Luca A. Trampuz J. Gaudias

Aim

The increase of antimicrobial resistance reduces treatment options for implant-associated infections caused by methicillin-resistant Staphylococcus aureus (MRSA). Bacteriophages present a promising alternative to treat biofilm-related infections due to their rapid bactericidal activity and activity on multi-drug resistant bacteria. In this study, we investigated the synergistic activity of lytic bacteriophage Sb-1 with different antibiotics against MRSA biofilm, using a real-time highly sensitive assay measuring growth-related heat production (microcalorimetry).

Methods

Rifampin, fosfomycin, vancomycin and daptomycin were tested alone and in combination with S. aureus specific phage, Sb-1, against MRSA (Staphylococcus aureus*). MRSA biofilm was formed on porous glass beads (Φ 4 mm, pore size 60 µm) and incubated for 24 h at 37° C in BHI. After 3 times washing biofilms were exposed first to different titers of bacteriophages, ranging from 102 to104 plaque-forming unite (pfu)/ml and after 24h treated again with subinhibitory concentration of antibiotics (corresponding to 1/4, 1/8, 1/16, 1/32 × MHICbiofilm). After 24h antibiotic treatment, the presence of biofilm on glass beads was evaluated by isothermal microcalorimetry for 48h. Heat flow (µW) and total heat (J) were measured.


H. K. Li I. Rombach R. Zambellas S. Warren D. Mack S. Hopkins C. Hems-ley B. Atkins M. Rogers M. McNally M. Scarborough

Aim

Management of bone and joint infection can be technically complex and often requires a prolonged course of antibiotics. Traditionally, bone and joint infection management utilises nurse-led outpatient parenteral antibiotic therapy (OPAT) where adherence is unlikely to be an issue. However, with increasing evidence in favour of oral therapy, the question of adherence merits further consideration. We describe the adherence of both oral (PO) and self-administered intravenous (IV) antibiotics in the treatment of bone and joint infection using paper questionnaires (8-item Modified Morisky Adherence Score (MMAS)) and, in a subset of participants, electronic pill containers (Medication Event Monitoring Systems*).

Method

All eligible participants enrolled in the OVIVA trial (2010–2015) were randomised to six weeks of either PO or IV antibiotic treatment arms. Self-administering patients were followed up with questionnaires at day 14 and 42. A subset of PO participants was also given the medication event monitoring system* in order to validate the adherence questionnaires. The results were correlated with treatment failures at one-year follow-up.


A. J. Hotchen P. Garcia-Pulido A. Gojanur K. Stohr

Aims

This case series aims to describe the clinical consequences of juxta-physeal sub-acute osteomyelitis in children, specifically growth and limb deformity.

Methods

All children diagnosed with osteomyelitis between 2014 and 2016 at a single University Teaching Hospital in the UK were included. Juxta-physeal sub-acute osteomyelitis was identified using magnetic resonance imaging obtained within 48-hours of presentation. These cases were followed up prospectively on a regular basis in the outpatient clinic. Any clinical evidence of limb or growth deformity was evaluated using long-leg standing radiographs.


B. Kocjancic S. Jeverica A. Trampuz L. Simnic K. Avsec D. Dolinar

Aim

The aim of our study was to evaluate culture-negative prosthetic joint infections in patients who were pre-operatively evaluated as aseptic failure.

Method

For the purpose of the study we included patients planed for revision surgery for presumed aseptic failure. Intraoperatively acquired samples of periprosthetic tissue and explanted prosthesis were microbiologicaly evaluated using standard microbiologic methods and sonication. If prosthetic joint infection was discovered, additional therapy was introduced.


J. Jenny B. Adamczewski E. D. Thomasson J. Gaudias

Aim

The diagnosis of peri-prosthetic infection is sometimes difficult to assess, and there is no universal diagnostic test. The recommendations currently accepted include several diagnostic criteria, and are based mainly on the results of deep bacteriological samples, which only provide the diagnosis after surgery. A predictive score of the infection might improve the peri-operative management before repeat surgery after total hip arthroplasty (THA). The goal of this study was to attempt defining a composite score using conventional clinical, radiological and biological data that can be used to predict the positive and negative diagnosis of peri-prosthetic infection before repeat surgery after THA. The tested hypothesis was that the score thus defined allowed an accurate differentiation between infected and non-infected cases in more than 75% of the cases.

Method

104 cases of repeat surgery for any cause after THA were analyzed retrospectively: 61 cases of infection and 43 cases without infection. There were 54 men and 50 women, with a mean age of 70 ± 12 years (range, 30 to 90 years). A univariate analysis looked for individual discriminant factors between infected and uninfected case file records. A multivariate analysis integrated these factors concomitantly. A composite score was defined, and its diagnostic effectiveness was assessed by the percentage of correctly classified cases and by sensitivity and specificity.


J. Jenny V. Matter-Parrat C. Ronde-Oustau

Aim

Whether pre-operative microbiological sampling contributes to the management of chronic peri-prosthetic infection remains controversial. We assessed agreement between the results of pre-operative and intra-operative samples in patients undergoing single-stage prosthesis exchange to treat chronic peri-prosthetic infection. The tested hypothesis was that agreement between pre-operative and intra-operative samples exceeds 75% in patients undergoing single-stage exchange of a hip or knee prosthesis to treat chronic peri-prosthetic infection.

Method

This single-centre retrospective study included 85 single-stage prosthesis exchange procedures in 82 patients with chronic peri-prosthetic infection at the hip or knee. Agreement between pre-operative and intra-operative sample results was evaluated. Changes to the initial antibiotic regimen made based on the intra-operative sample results were recorded. Associations between sample agreement and infection-free survival were assessed.


M. Zeller M. Granier T. Auber W. Graff V. L. Strat L. Lhotellier M. Blandine S. Marmor V. Meyssonnier A. Mouton D. Passeron V. Zeller E. Klein B. Heym

Aim

Periprosthetic joint infection (PJI) is nowadays the most important problem leading to failure in primary and revision total knee (TKA) and total hip arthroplasty (THA), therefore accurate diagnosis of PJI is necessary. We evaluated a commercial multiplex PCR system1 for diagnosis of PJI in joint aspiration fluids prior to surgery.

Method

A total of 32 patients were included in the study. Twenty-four patients had TKA and eight had THA. Joint aspiration fluids were examined by standard bacteriological procedures. Excess material of joint aspirates was frozen at −20°C until testing by multiplex PCR1. Inclusion criteria were a minimum leucocyte count of 2.000 per ml and at least 60% of polymorphonucleaur neutrophils (PNN) in the joint aspiration fluid.


S. J. Gelderman P. C. Jutte R. Boellaard G. A. Kampinga J. J. Ploegmakers A. W. J. M. Glaudemans M. Wouthuyzen-Bakker

Aim

Diagnosing a prosthetic joint infection (PJI) can be difficult. Several imaging modalities are available, but the choice which technique to use is often based on local expertise, availability and costs. Some centers prefer to use 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) as first imaging modality of choice, but due to a lack of accurate interpretation criteria, FDG-PET is currently not routinely applied for diagnosing PJI. With FDG-PET it is difficult to differentiate between FDG uptake due to reactive inflammation and uptake due to an infection. Since the physiological uptake pattern around a joint prosthesis is not fully elucidated, the aim of this study was to determine: i) the FDG uptake pattern in non-infected total hip prostheses and, ii) to evaluate whether there is a difference in uptake between cemented and non-cemented prostheses.

Method

Patients with a primary total hip arthroplasty (1995–2016) without clinical signs of an infection that underwent a FDG-PET for another indication (mainly suspicion of malignancy) were included and retrospectively analysed. Patients in whom the prosthesis was implanted < 6 months prior to FDG-PET were excluded, to avoid post-surgical effects. Scans were visually and quantitatively analysed. Quantitative analysis was performed by calculating maximum and peak standardized uptake values (SUVmax and SUVpeak) by volume of interests (VOIs) at eight different locations around the prosthesis, from which the mean SUV was calculated. SUV was standardized by the liver SUV that was taken as background.


M. Loppini F. Traverso M. C. Ferrari R. Avigni R. Leone B. Bottazzi A. Mantovani G. Grappiolo

Aim

Diagnosis of periprosthetic joint infection (PJI) is still challenging due to limitations of available diagnostic tests. Many efforts are ongoing to find out novel methods for PJI diagnosis. Recently, several studies have shown a role of the long pentraxin PTX3 as a biomarker in inflammatory diseases and infections. This pilot diagnostic study evaluated the diagnostic ability of synovial fluid and serum PTX3 for the infection of total hip arthroplasty (THA) and total knee arthroplasty (TKA).

Method

Consecutive patients undergoing revision surgery for painful THA or TKA were enrolled. Patients with antibiotic therapy suspended for less than 2 weeks prior to surgery and patients eligible for spacer removal and prosthesis re-implantation were excluded. Quantitative assessment of synovial fluid and serum PTX3 was performed with ELISA method. Musculoskeletal Infection Society (MSIS) criteria were used as reference standard for diagnosis of PJI. Continuous data values were compared for statistical significance with univariate unpaired, 2-tailed Student's t-tests. Receiver operating characteristic (ROC) curve analyses was performed to assess the ability of serum and synovial fluid PTX3 concentration to determine the presence of PJI. Youden's J statistic was used to determine optimum threshold values for the diagnosis of infection. Sensitivity (Se), specificity (Sp), positive (PPV) and negative (NPV) predictive values, positive (LR+) and negative (LR-) likelihood ratio, area under the ROC curve (AUC) were calculated.


A. Zahar M. Citak C. Lausmann T. Gehrke

Aim

Alpha-defensin was recently introduced as a new biomarker having a very high accuracy to rule out periprosthetic joint infection (PJI). A new rapid lateral flow version of the Alpha-defensin test was developed and introduced to detect high levels of Alpha-defensin in synovial fluid quickly and with ease. We conducted a single-centre prospective clinical study to compare the results of the Alpha-defensin rapid test* against the conventional diagnostics according to MSIS criteria.

Method

A total of 223 consecutive patients with painful total hip or knee arthroplasty were enrolled into the study. In all patients, blood C-reactive protein was measured and joint aspirations were performed. From the synovial fluid a leukocyte cell count with granulocyte percentage, microbiology cultures and Leukocyte Esterase tests were carried out according to the recommendation of MSIS for diagnosing PJI. At the same time, the Lateral Flow Test* was performed from the aspirate. 191 subjects with 195 joint aspirations (96 hips, 99 knees) were included in final clinical and statistical evaluation. We had 119 joints with an aseptic revision and 76 joints with PJI.


I. K. Sigmund N. Renz K. Yermak A. Trampuz

Aim

Alpha-defensin is a new synovial fluid biomarker for the diagnosis of periprosthetic joint infections (PJI). We compared the performance of two different alpha-defensin assays: quantitative ELISA test and qualitative lateral flow test.

Method

In this prospective cohort study, consecutive patients with a painful prosthesis of the lower limb were eligible for inclusion. In addition to standard diagnostics of PJI, alpha-defensin was determined in the aspirated synovial fluid between October 2016 and April 2017. PJI was defined according to the modified Zimmerli criteria, the Musculoskeletal Infection Society (MSIS) criteria and the Infectious Disease Society of America (IDSA) criteria. A positive quantitative alpha-defensin test was defined at a cut-off value of 5.2 mg/L. The sensitivity, specificity, accuracy and area under the curve of each test were determined and the AUCs were compared among each other.


N. Renz K. Yermak C. Perka A. Trampuz

Aim

The aim of the study was to assess the accuracy of the alpha defensin lateral flow test for diagnosis of periprosthetic joint infection (PJI) using an optimized diagnostic algorithm and three classification systems. In addition, we compared the performance with synovial fluid leukocyte count, the most sensitive preoperative test.

Method

In this prospective multicenter study we included all consecutive patients with painful prosthetic hip and knee joints undergoing diagnostic joint aspiration. Alpha defensin lateral flow test was used according to manufacturer instructions. The following diagnostic criteria were used to confirm infection: Musculoskeletal Infection Society (MSIS), Infectious Diseases Society of America (IDSA) and Swiss orthopedics and Swiss Society of Infectious Diseases (SOSSID). In the latter, PJI was confirmed when at least one of following criteria applied: macroscopic purulence, sinus tract, positive cytology of joint aspirate (>2000 leukocytes/μl or >70% granulocytes), histological proof of acute inflammation in periprosthetic tissue, positive culture (from aspirate, tissue or sonication fluid). Infection was classified as chronic, if symptom duration was more than 3 weeks or if infection manifested after more than 1 month after surgery. The sensitivity and specificity of the alpha defensin lateral flow test and leukocyte count in synovial fluid were calculated and compared using McNemar Chi-square test.


R. Refaie K. Rankin C. Hilkens M. Reed

Aim

To evaluate a panel of peripheral blood and synovial fluid biomarkers for the identification of periprosthetic joint infection PJI.

Method

Peripheral blood and synovial fluid measurements of CD64, IL-1a, IL-1b, IL-6, IL-8, IL-10, IL-17, Alpha Defensin and CRP were made on samples collected from patients with suspected PJI using a combination of flow cytometry (CD64), ELISA (Alpha Defensin) and MSD Electrochemiluminescence (IL-1a, IL-1b, IL-6, IL-8, IL-10, IL-17). Receiver operating characteristic (ROC) curves which combine sensitivity and specificity were created for each marker using GraphPad PRISM statistical software. The diagnosis of infection was based on MSIS major criteria.


A. Semenistyy V. Obolenskiy A. Semenistyy A. Konnov

Aim

Chronic osteomyelitis of long bones is one of the most severe complications in orthopedics. Different options exist for treatment of this disease, however there is still no generally accepted comprehensive protocol that could potentially guide us in each particular step. There are many classifications that were designed to help us to make clinical decision, however even the most widely used Cierny-Mader classification does not count more a half of factors, assessment of which is essential for choosing the best treatment plan. This fact may be explained by the complexity of the disease process, diversity of treatment options and multistage approach to the management of these patients. Therefore, the purpose of this study was to work out a treatment protocol and clinical classification system, which will improve final outcomes in patients with chronic osteomyelitis of long bones.

Method

Three orthopedic surgeons and one general surgeon who specialize on bone and joint infection independently of each other made a review of literature dedicated to the topic of chronic osteomyelitis. Each surgeon created a list of factors that are essential to assess for successful treatment of chronic osteomyelitis. After four lists were thoroughly matched and discussed, 10 most important factors were defined. Each surgeon proposed his own protocol of treatment, based on existent data and own experience. All four protocols were discussed and analyzed to come up with new the most comprehensive one. Therefore, the new protocol was created. After the list of factors and protocol were created, surgeons independently of each other defined the most important factors for every stage in the new protocol. Thus new multi-stage classification of chronic osteomyelitis (MSC-CO) was proposed.


M. McNally J. Ferguson M. Dudareva A. Palmer D. Bose D. Stubbs

Aim

Bone infection can recur months or years after initially successful treatment. It is difficult to review patients for many years to determine the true incidence of recurrence. This study determined the minimum follow-up period which gives a good indication of the recurrence rate after surgery for chronic osteomyelitis and infected non-union.

Method

We studied five cohorts of patients who had surgery for long bone infection, over a 10 year period. We investigated the efficacy of various antibiotic carriers (PMMA and Collagen; n=185, Calcium Sulphate; n=195, Calcium Sulphate/Hydroxyapatite; n=233) and management of infected non-unions (n=146). Patients were reviewed and Kaplan-Meier Survivorship curves were constructed to show the incidence and timing of recurrence. The microbiology of the initial infection and the recurrent culture was also compared.


N. Jiang W. Hu Z. Yao B. Yu

Aim

Diagnosis of clavicle osteomyelitis (OM) is often difficult with delayed treatment due to the lower incidence of this disease. The present study aimed to summarize clinical experience with clinical features and treatment of clavicle OM.

Method

We systematically searched the Pubmed database to identify studies regarding clinical characteristics and management of clavicle OM from 1980 to 2016, with publication language limited to English. Effective data were collected and pooled for analysis.


T. Ferry A. Johan F. Boucher J. Chateau S. Hristo F. Daoud E. Braun C. Triffault-Fillit T. Perpoint F. Laurent M. Alain-Ali C. Chidiac F. Valour

Aim

A two-stage surgical strategy (debridement-negative pressure therapy (NPT) and flap coverage) with prolonged antimicrobial therapy is usually proposed in pressure ulcer-related pelvic osteomyelitis but has not been widely evaluated.

Method

Adult patients with pressure ulcer-related pelvic osteomyelitis treated by a two-stage surgical strategy were included in a retrospective cohort study. Determinants of superinfection (i.e., additional microbiological findings at reconstruction) and treatment failure were assessed using binary logistic regression and Kaplan-Meier curve analysis.


R. Mahieu V. Dubee S. Ansart L. Bernard L. M. Gwenael N. Asseray C. Arvieux C. Ramanantsoa E. Legrand P. Abgueguen

Aim

The optimal treatment of streptococcal prosthetic joint infections (PJIs) is unclear. Poorer outcome has been associated with Streptococcus agalactiae species, comorbidities and polyethylene exchange for conservative approach. Rifampicin use may be associated with higher remission rate but results are sparse.

Method

A cohort of streptococcal PJI (including total hip arthroplasty –THA- or total knee arthroplasty –TKA-) was prospectively created and retrospectively reviewed in 7 reference centers for management of complex PJI between January 1, 2010 and December 31, 2012.


E. Vacha H. Deppe N. Wantia A. Trampuz

Aim

The risk of haematogenic periprosthetic joint infection (PJI) after dental procedures is discussed controversially. To our knowledge, no study has evaluated infections according to the origin of infection based on the natural habitat of the bacteria. We investigated the frequency of positive monomicrobial cultures involving bacteria from oral cavity in patients with suspected PJI compared to bone and joint infections without joint prosthesis.

Method

In this retrospective study we included all patients with suspected PJI or bone and joint infection without endoprosthesis, hospitalized at our orthopaedic clinic from January 2009 through March 2014. Excluded were patients with superficial surgical site infections or missing data. Demographic, clinical and microbiological data were collected using a standardized case report form. Groups were compared regarding infections caused by oral bacteria. χ2 test or Fisher's exact test was employed for categorical variables and t-test for continuous variables.


A. Stefánsdóttir O. Thompson M. Sundberg A. W-Dahl L. Lidgren O. Robertsson

Aim

Patients reporting penicillin allergy do often receive clindamycin as systemic antibiotic prophylaxis. The effect of clindamycin has however not been compared to antibiotics with proven effect in joint arthroplasty surgery. The aim of the study was to reveal if there were differences in the rate of revision due to infection after total knee arthroplasty (TKA) depending on which antibiotic was used as systemic prophylaxis.

Method

Patients reported to the Swedish Knee Arthroplasty Register having a TKA performed due to osteoarthritis (OA) during the years 2009 – 2015 were included in the study. The type of prophylactic antibiotic is individually registered. For 80,018 operations survival statistics were used to calculate the rate of revision due to infection until the end of 2015, comparing the group of patients receiving the beta-lactam cloxacillin with those receiving clindamycin as systemic prophylaxis.


M. Bortolin A. Bidossi M. Toscano E. De Vecchi C. L. Romanò R. Mattina L. Drago

Aim

Biofilm-related infections represent a recurrent problem in the orthopaedic setting. In recent years, great interest was directed towards the identification of novel molecules capable to interfere with pathogens adhesion and biofilm formation on implant surfaces. In this study, two stable forms of α-tocopherol, the hydrophobic acetate ester and the water-soluble phosphate ester, were tested in vitro as coating for titanium prostheses.

Method

Antimicrobial activity against microorganisms responsible of prosthetic and joints infections was assessed by broth microdilution method. In addition, α-tocopherol esters were evaluated for both their ability to hamper bacterial adhesion and biofilm formation on sandblasted titanium surfaces.


R. Anderson J. Bates-Powell C. Cole S. Kulkarni E. Moore A. Norrish E. Nickerson

Aim

This study aimed to evaluate the impact on length of hospital stay from dedicated infectious diseases input for orthopaedic infection patients compared to sporadic infection specialist input.

Method

We conducted an observational cohort study of 157 adults with orthopaedic infections at a teaching hospital in the UK. The orthopaedic infections included were: osteomyelitis, septic arthritis, infected metalwork and prosthetic joint infections, and adults were aged 18 years or more. Prior to August 2016, advice on orthopaedic infection patients was adhoc with input principally from the on-call infectious diseases registrar and phone calls to microbiology whereas after August 2016 these patients received regular input from dedicated infectious diseases doctor(s). The dedicated input involved bedside reviews, medical management, correct antimicrobial prescribing, managing adverse drug reactions, increased use of outpatient parenteral antimicrobial therapy (OPAT) services especially self-administration of intravenous antibiotics and shared decision-making for treatment failure, whilst remaining under orthopaedic team care. Orthopaedic patients operated on for management of their infection between 29/8/16 and 15/3/17 were prospectively identified and orthopaedic operation records were used to retrospectively identified patients between 29/8/15 and 15/3/16. The length of stay was compared between the 2 groups.


T. Kramer

Aim

Periprosthetic joint infections (PJI) are a rare, but devastating complication. Diagnostic approaches to PJI vary greatly between different centers. Most commonly tissue biopsies and synovial fluid sampling are recommended for identification pathogens causing PJI. However, sensitivity and specificity of those techniques have been shown to be highly dependent on preanalytical factors like time and conditions of transportation, location of sampling, as well as analytical approaches and prolonged incubation for up to 14days. Sonication of explanted orthopedic devices has been shown to be more than only an addition in the diagnosis of PJI. The goal of this study was to evaluate the diagnostic value of sonication in PJI.

Method

Retrospective cohort analysis of orthopedic samples sent for sonication from 29 surgical centers between 06/2014–04/2017. Until 07/2015 samples were plated on Columbia-, MacConkey-, Chocolate- and Schaedler agar*, incubated aerobically and anaerobically for up to 14 days.

In 07/2015 an additional enrichment of 10ml per aerobic and anaerobic blood culture bottles* was introduced. The bottles were also incubated up to 14days and plated immediately if growth was detected.


K. Uchiyama H. Kanda T. Yamaguchi S. Ibe K. Sakurai S. Nihonyanagi Y. Minegishi S. Ikeda Y. Kanou K. Fukushima N. Takahira M. Takaso

Aim

We used a polymerase chain reaction (PCR) lateral flow assay1) to rapidly diagnose joint infection. We evaluated the usefulness of multiplex-PCR (PCR lateral flow assay: PCR-LF) using detailed clinical data.

Method

A total of 35 synovial fluid samples were collected from 26 patients in whom bacterial infection was suspected, including 22 from knee joints, 11 from hip joints, and 2 from other joints. After purifying the DNA from the samples, multiplex PCR targeting two MRSA-associated genes (femA and mecA) and the bacterial 16S rRNA gene was performed. Amplified gene fragments were specifically detected with DNA probes immobilized on stick devices through DNA-DNA hybridization and visualization, enabling diagnosis of MRSA, MSSA, MRCNS, gram-positive, and/or gram-negative bacterial infection. Genetic identification of bacteria by determining the 16S rRNA gene sequence was also performed using multiplex PCR-positive samples. Finally, the usefulness of our PCR-LF method was evaluated using detailed clinical data.


A. Bicart-Sée A. Bouige C. Fourcade G. Krin S. Arnaud P. Conte M.P. Félicé E. Bonnet G. Giordano M. Rottman

Aim

Pre-operative distinction between prosthetic joint infections (PJI) and non-infectious causes of joint failure is particularly challenging, especially in chronic situations. Guidelines propose different algorithms using numerous preoperative tests. We evaluated place of serology.

Method

During a 9 month period, we included consecutive patients undergoing arthroplasty revision for a suspected chronic hip or knee infection. Serologies were sampled at the same day than the other blood tests. Results were compared with the final diagnosis, determined with peroperative bacteriological and histological results.

Serology was performed using a multiplex antibody detection*. This multiplex antibody detection assay detects antibodies against Staphylococcus species, Propionibacterium acnes and Streptococcus agalactiae.


A. Siddiqi C. Restrepo J. Parvizi

Aim

Diagnosis of periprosthetic joint infection (PJI) presents a real challenge in some patients. Batteries of tests are available to reach this diagnosis. It is unknown if blood cultures have any role in diagnosis of PJI. The objective of this study was to evaluate whether blood cultures, taken in a group of patients with PJI, was useful in identifying the infecting pathogen.

Methods

The institutional database was used to identify all patients treated at our institution between 2000 – 2015 for PJI according to the latest MSIS criteria. There were a total of 864 patients with mean age of 68 years. Synovial fluid sample and/or deep tissue samples were analyzed and cultured in all of these patients. In 371 (42.9%) patients with PJI, blood cultures were also taken. Statistical analyses were performed for correlation purposes.


F. El Sayed A. Gruber G. Sapriel N. Fawal T. Bauer B. Heym C. Dupont S. L. Hello J. Gaillard M. Rottman

Aim

According to Tsukuyama classification, late acute hematogenous prosthesis joint infections (PJI) should be treated with debridement and implant retention (DAIR). We report here a recurrent Salmonella Dublin hip prosthesis infection. Through this case, we show how a recurrence of chronic PJI may have an acute clinical presentation leading to an inadequate surgical treatment.

Method

Case report. On May 2011, a 74-year-old woman with bilateral hip prostheses (implanted in 1998 (right) and 2001 (left)), was admitted to intensive care for sepsis and pain of her left hip. Blood cultures and a joint aspiration of the left hip yielded pure cultures of S.Dublin. The patient had a recent history of febrile diarrhea after consuming dubious meat. The patient underwent DAIR followed by a six-week antibiotherapy. Three years later, she presented to the emergency room for an acute onset febrile PJI of the right hip. The patient underwent DAIR of the right hip. Blood cultures, joint aspiration fluid, and all intraoperative periprosthetic tissue samples yielded S.Dublin. Colonoscopy and abdomen ultrasound were negative. The patient received two weeks of intravenous combined antibiotherapy followed by oral antibiotics for further 10 weeks. Six weeks post operatively, the surgical wound was healed and the patient walked normally. One year later, the patient was referred by her primary care practitioner for night fevers without local signs or dysfunction of her prostheses. Radioleucoscintigraphy showed right hip inflammation. Bilateral hip biopsies were nevertheless performed, yet S. Dublin was recovered solely from the right hip biopsy. A one-stage exchange of the right hip was performed. All intraoperative periprosthetic tissue samples yielded S.Dublin. A six-week-combined antibiotherapy was undertaken. One year later, the patient appeared free of infection and walked normally.


A. Dublanchet O. Patey

Aim

Many bone and joint infections, in spite of appropriated antibiotics therapy and surgery, lead to a therapeutic dead end. We are then faced with a chronic infection with or without continuous antibiotic treatment, with daily local care, and an exhorbitant economic and social cost. Pami the incriminated factors: the presence of foreign implant material, the poor diffusion of antibiotics at the infectious site, the presence of biofilm.

The bacteriophages, biological drug, natural environmental viruses possess the properties to meet these difficulties: well diffusion to the infectious focus with possibilities of local use, destruction of the biofilm allowing a release of the bacteria and a synergistic effect with the antibiotics, antibiofilm effect for the restoration of osteoblastosis.

Method and results

We report a cohort of phage - treated patients with or without antibiotics in bone and joint infections in a therapeutic dead end. Without disponibility of therapeutic phages available in the European Union, commercial cocktails of phages, antistaphylococcal or polyvalent, of Russian* or Georgian** origin were used.

Ten patients have benefited since 2008 from phages, alone or in combination with an adapted antibiotic therapy. Patients were 40 to 89 years old and had chronic bone and joint infections except for one case with acute MRSA infection on femoral implant. Bacteria were Staphylococcus aureus 7 times, Pseudomonas aeruginosa 3 times, Klebsiella 2 times. In 4 cases implant was left in place (knee prosthesis, femoral screw plate) or introduced (1 screw in 1 case) during the procedure. In all cases except 1 patient, the phages were applied in per-operative.

With a follow-up of up to 9 years for some patients, the initial bacteria were eradicated and in 2 cases replaced by another bacterium (Pseudomonas in place of S. aureus in one case and Enterococcus in place of P. aeruginosa for an elderly patient with a knee prosthesis without possible surgery.


A. Trampuz A. Klatt M. D. Luca

Aim

Phage therapy has attracted attention as a promising alternative treatment option for biofilm infections.

To establish a successful phage therapy, a comprehensive stock of different phages covering a broad bacterial spectrum is crucial. We screened human and environmental sources for presence of lytic phages against selected bacteria.

Methods

Saliva collected from 10 volunteers and 500 ml of sewage water were screened for the presence of lytic phages active against 20 clinical strains of Staphylococcus aureus and 10 of Escherichia coli, both isolated from patients with prosthetic joint infection. Laboratory strains of methicillin-resistant S. aureus (MRSA)*1 and E. coli*2 were also tested. Screening was performed plaque-assay to detect phages for different strains. Isolated plaques were collected and phages were enriched to determine their activity against their bacterial host strains. The activity of bacteriophages against adherent E. coli and MRSA was evaluated by crystal violet, staining bacterial biofilms grown on glass beads.


C. Fourcade B. Aurelie A. B. See G. Giordano E. Bonnet

Aim

European population is ageing concurrently with an increase number of arthroplasties. Prosthetic joint infection (PJI) in the elderly is considered more severe. The aim of this study is to describe PJI's management of patients over 79 years of age.

Methods

We conducted a retrospective study including all patients aged over 79 years old consulting for a suspected hip or knee PJI in our community hospital where a complex bone and joint unit is present.


M. Amara T. Bauer B. Bercot B. Heym H. Jacquier V. Joste S. Marmor E. Salomon S. C. I. de France

Aim

The frequency of arthroplasty among older people is increasing. Taking care of Prosthetic Joint infection (PJI) in this specific population is a challenge. The purpose of this multicentric retrospective study was to evaluate the bacterial epidemiology of hip and knee PJI in octogenarians and nonagenarians over ten years.

Method

Data were collected using two softwares* in each of the 4 Centers participating.

Inclusion criteria:

age ≥ 80 years PJI (knee or hip)

between January 2007 and December 2016

microbiological data available (strains isolated from osteo-articular samples)

Bacterial identification: biochemical methods, followed by Malditof since 2009. For Staphylococcus aureus, Pseudomonas aeruginosa and Enterobacteriaceae, resistance profiles to antibiotics frequently used in PJI were collected. Antimicrobial susceptibility testing: disk diffusion (recommendations: French Society of Microbiology yearly updated).


P. H. Gundtoft A. B. Pedersen C. Varnum S. Overgaard

Aim

To study whether revision for prosthetic joint infection (PJI) after early PJI in primary Total Hip Arthroplasty (THA) is associated with a high mortality, when compared with:

Patients, who did not undergo revision for any reason and Patients who underwent an aseptic revision.

Method

This population-based cohort study was based on the Danish Hip Arthroplasty Register on primary THA performed in Denmark from 2005 to 2014. Data from the Danish Hip Arthroplasty Register were linked to microbiology databases, the National Register of Patients, and the Civil Registration System to obtain data on microbiology, comorbidity, and vital status on all patients. The mortality risk for the patients who underwent revision for PJI within 1 year from implantation of primary THA was compared with (1) the mortality risk for patients who did not undergo revision for any reason within 1 year of primary THA; and (2) the mortality risk for patients who underwent an aseptic revision.


A. Fischbacher O. Borens

Aim

There is a constant increase of joint arthroplasties to improve the quality of life of an aging population. Prosthetic-joint infections are rare, with an incidence of 1–2%, but they represent serious complications in terms of morbidity and mortality. The mortality was known to be approaching 8% in the elderly. The aim of this retrospective study is to reassess the two-year mortality rate over the last ten years.

Method

Patients having a prosthetic joint infection at Lausanne University Hospital (Switzerland) between 2006 and 2016 were included. The two-year mortality rate depending on sex, age, type of infection and type of surgical therapy was measured.


E. Senneville A. Coelho

Aim

Prosthetic joint infection (PJI) concerns up to 20% of all prosthesis revision procedures. The IDSA recommends at least 2 weeks of intravenous antimicrobial therapy while most of the appropriate antibiotics in these settings have very high oral bioavailability (e.g., rifampicin, cotrimoxazole, fluoroquinolone, clindamycin, fusidic acid, linezolid and doxycycline).

Method

AVAPOM is a monocentric retrospective non-inferiority study which included patients who received at least one of the highly bioavailable antibiotics listed above as a documented treatment (i.e., following the intravenous empirical post-operative antibiotic treatment) for PJIs in order to compare the remission rate of infection and the length of hospital stay (LOS). Patients were split between intravenous group (IV, from 1st January 2013 to 31st December 2014) and complete oral group (PO; since 1st January 2015) and were compared on both the PJI outcome regarding the last news available and the length of stay (LOS).


M. Scarborough H. K. Li I. Rombach R. Zambellas S. Walker M. Kumin B. A. Lipsky H. Hughes D. Bose S. Warren C. Geue N. McMeekin A. Woodhouse B. Atkins M. McNally T. Berendt B. Angus I. Byren G. Thwaites P. Bejon

Aim

Current standard of care in the management of bone and joint infection commonly includes a 4–6 week course of intravenous (IV) antibiotics but there is little evidence to suggest that oral antibiotic therapy results in worse outcomes. The primary objective was to determine whether oral antibiotics are non-inferior to IV antibiotics in this setting.

Method

This was a parallel group, randomised (1:1), open label, non-inferiority trial across twenty-six NHS hospitals in the United Kingdom. Eligible patients were adults with a clinical diagnosis of bone, joint or orthopaedic metalware-associated infection who would ordinarily receive at least six weeks of antibiotics and who had received ≤7 days of IV therapy from the date of definitive surgery (or the start of planned curative treatment in patients managed non-operatively). Participants were randomised to receive either oral or IV antibiotics for the first 6 weeks of therapy. Follow-on oral therapy was permitted in either arm. The primary outcome was the proportion of participants experiencing definitive treatment failure within one year of randomisation. The non-inferiority margin was set at 7.5%.


A. Alvand H. K. Li I. Rombach R. Zambellas B. Kendrick A. Taylor B. Atkins P. Bejon M. McNally M. Scarborough

Aim

To assess the influence of route of antibiotic administration on patient-reported outcome measures (PROMS) of individuals treated for hip and knee infections in the OVIVA multi-centre randomised controlled trial.

Method

This study was designed to determine whether oral antibiotic therapy is non-inferior to intravenous (IV) therapy when given for the first six weeks of treatment for bone and joint infections. Of the 1054 participants recruited from 26 centres, 462 were treated for periprosthetic or native joint infections of the hip or knee. There were 243 participants in the IV antibiotic cohort and 219 in the oral cohort. Functional outcome was determined at baseline through to one year using the Oxford Hip/Knee Score (OHS/OKS) as joint-specific measures (0 the worse and 48 the best). An adjusted quantile regression model was used to compare functional outcome scores.


I. K. Sigmund J. Gamper C. Weber J. Holinka P. Funovics R. Windhager

Aim

Periprosthetic joint infections are a devastating complication after modular endoprosthetic reconstruction following resection of a musculoskeletal tumour. Due to long operating times, soft tissue dissection and immunosuppression, the infection rate after limb salvage is high and ranges between 8% and 15%. The aim of this retrospective single centre study was to assess the reinfection and re-reinfection rate after septic complications of megaprostheses.

Method

In this retrospective study, 627 patients with a primary replacement of a musculoskeletal tumour of the lower limb and reconstruction by a megaprosthesis were recorded from 1983 – 2016. 83 out of 621 patients available for follow-up experienced an infection (13.4%). Two patients were treated with debridement and removal of the mobile parts, 61 patients with a one-stage revision, 16 patients with a two-stage revision, and 4 patients with an amputation. The mean follow up was 133 months (range: 2 – 423 months).


M. Glehr S. Klim P. Sadoghi G. Bernhardt A. Leithner R. Radl F. Amerstorfer

Aim

One of the most challenging problems in total knee arthroplasty (TKA) is periprosthetic infection. A major problem that arises in septic revision TKA (RTKA) are extended bone defects. In case of extended bone defects revision prostheses with metaphyseal sleeves are used. Only a few studies have been published on the use of metaphyseal sleeves in RTKA - none were septic exclusive. The aim of our study was to determine the implant survival, achieved osseointegration as well as the radiological mid-term outcomes of metaphyseal sleeve fixation in septic two-stage knee revision surgery.

Method

Clinical and radiological follow-up examinations were performed in 49 patients (25 male and 24 female). All patients were treated with a two-stage procedure, using a temporary non-articulating bone cement spacer.

The spacer was explanted after a median of 12 weeks (SD 5, min. 1 – max. 31) and reimplantation was performed, using metaphyseal sleeves in combination with stem fixation. Bone defects were classified on preoperative radiographs using the Anderson Orthopaedic Research Institute (AORI) classification. During follow-up postoperative range of motion (ROM) was measured and radiographs were performed to analyse: (i) osseointegration (radiolucent lines and spot welds), (ii) leg alignment, (iii) patella tilt and shift.


G. Burastero L. Cavagnaro F. Chiarlone G. Riccio L. Felli

Aim

Femoral or tibial massive bone defects (AORI F2B-F3 / T2B-T3) are common in septic total knee replacement. Different surgical techniques are described in literature. In our study we show clinical and radiological results associated with the use of tantalum metaphyseal cones in the management of cavitary bone defects in two-stage complex knee revision.

Method

Since 2010 we have implanted 70 tantalum metaphyseal cones associated with constrained or semiconstrained knee prostheses in 47 patients. The indication for revision was periprosthetic knee infection (43 cases, 91.5%) or septic knee arthritis (4 patients, 8.5%) with massive bone defect. All cases underwent a two-stage procedure. Patients were screened for main demographic and surgical data. Clinical and radiological analysis was performed in the preoperative and at 3,6 months, 1 years and each year thereafter in the postoperative. The mean follow-up was 31.1 months ± 18.8. No dropout was observed.


K. Yamada T. Miyazaki T. Shinozaki H. Oka F. Tokimura Y. Tajiri H. Okazaki

Aim

Surgical site infection (SSI) is associated with substantial morbidity, mortality and economic burden. Management of spinal SSI is becoming more challenging especially in instrumented cases, but is not well recognized as high risk procedure. The objective of this study was to determine the impact of procedure type comparing SSI risk with arthroplasties among all orthopaedic procedures.

Method

Using prospectively collected data of consecutive samples in multi-center orthopedic SSI surveillance, we explored the differences in SSI rates within 30 days after surgery by procedure types. Patients who underwent surgery of single site between November 2013 and May 2016 were enrolled. SSI was our primary outcome. Urinary tract infection (UTI), and respiratory tract infection (RTI) were also evaluated. The definition of SSI was based on the CDC definition with slight modifications. All patients were followed for 30 days postoperatively. Multivariate logistic regression analyses were done, and variables were carefully selected for adjustments.


O. Demay S. Renaud S. Bredin S. Diallo X. Ohl

Aim

Chronic osteomyelitis of the calcaneus is a frequent problem in a population of diabetic patients, patients with neurologic disorders or bedridden patients with ulcers. Partial calcanectomy is an alternative option which avoid major amputation. The aim of this retrospective study was to determine the effectiveness of partial calcanectomy for treating chronic osteomyelitis of the calcaneux.

Method

We conducted a retrospective review of patients who underwent in our department a partial calcanectomy between 2006 and 2015. All patients with a complete set of radiographs and adequate follow-up (minimum 2 years) were included. We reviewed these cases to determine healing rate, microbiological analysis, risk factors of failure (comorbidities), limb salvage rate and survival rate. We analyzed specifically the footwear and the functional subjective evaluation according to the LEFS score (Lower Extremity Functional Scale).


A. Becker F. Valour T. Perpoint L. Boussel A. Ruffion F. Laurent E. Senneville C. Chidiac T. Ferry

Aim

Pubic osteomyelitis (PO) is one of less frequent Bone and Joint Infections forms (BJI). Its management is still poorly codified as far as nosological framework is still unclear in medical literature. We aim to describe PO epidemiology and to look for factors associated with management failure.

Method

We performed a retrospective cohort study, carried out in two Reference Centres, including patients with PO in 2010–2016. Treatment failure was defined by: (i) persistence of clinical signs despite treatment; (ii) clinical relapse with same microorganisms; (iii) infection recurrence with one or more different microorganism(s);

(iv) new signs of infection (abscess, sinus tract) in same area, without recourse to get microbiological documentation. Factors associated with management failure were determined by univariate Cox analysis (hazard ratio [HR] and 95% confidence interval calculation). Kaplan-Meier curve were compared between groups by log-rank test.


A. Shahi R. Boe S. Oliashirazi J. Salava A. Oliashirazi

Aim

Persistent wound drainage has been recognized as one of the major risk factors of periprosthetic joint infection (PJI). Currently, there is no consensus on the management protocol for patients who develop wound drainage after total joint arthroplasty (TJA). The objective of our study was to describe a multimodal protocol for managing draining wounds after TJA and assess the outcomes.

Methods

We conducted a retrospective study of 4,873 primary TJAs performed between 2008 and 2015. Using an institutional database, patients with persistent wound drainage (>48 hours) were identified. A review of the medical records was then performed to confirm persistent drainage. Draining wounds were first managed by instituting local wound care measures. In patients that drainage persisted over 7 days, a superficial irrigation and debridement (I&D) was performed if the fascia was intact, and if the fascia was not intact modular parts were exchanged. TJAs that underwent subsequent I&D, revision surgery, or developed PJI within one year were identified.


E. McPherson M. Chowdhry M. Dipane S. Kenney

Aim

Infection rates after revision THA vary widely, up to 12%. In countries that use antibiotic-loaded cemented stems in combination with perioperative IV antibiotics, infection rates in registry studies are lower. In many countries, however, cementless revision implants are preferred. Our aim was to apply an antibiotic-loaded calcium sulfate coating to cementless revision stems to reduce periprosthetic joint infection (PJI). This study sought to answer two questions: 1) Does the coating of cementless revision stems with calcium sulfate inhibit osteointegration in THA? 2) Does the antibiotic-loaded calcium sulfate coating of revision stems reduce the incidence of PJI?

Method

From Dec. 2010 to Dec. 2015, 111 consecutive revision femoral stems were coated with commercially pure calcium sulfate. 10cc of calcium sulfate was mixed with 1g of vancomycin powder and 240mg of tobramycin liquid and applied to the stem in a semi-firm liquid state immediately prior to stem insertion. The results are compared to a designated control cohort (N=104) performed across the previous 5 years. The surgical methods were comparable, but for the stem coating. All patients were staged preoperatively using the Musculoskeletal Infection Society Staging System and followed for at least 1 year.


A. Sousa P. Gouveia L. Coutinho C. Rodrigues H. Fonte A. Cipriano A. C. Santos M. Abreu I. Amorim R. Sousa

Aim

Autologous-labeled leukocytes combined with sulfur colloid bone marrow scan is the current imaging modality of choice for diagnosing prosthetic joint infection (PJI). Although this technique is reliable, in-vitro leukocyte labeling raises technical difficulties that limit its widespread use and sulfur colloid is increasingly difficult to obtain. Therefore, valid alternatives are needed. The purpose of our study was to determine the clinical value of 99mTc-sulesomab combined with 99mTc-colloidal rhenium sulphide (nanocolloid) bone marrow imaging in the diagnosis of infection in painful total joint arthroplasties.

Materials and methods

A retrospective study was conducted on a cohort of 53 patients with painful hip or knee prostheses that underwent 99mTc-sulesomab and 99mTc-nanocolloids sequentially, between January 2008 and December 2016. The combined images were interpreted as positive for infection when there was activity on the sulesomab scan without corresponding activity on the bone marrow scan. The final diagnosis was made with microbiological findings or by clinical follow up of at least 12 months.


D. Akgün A. Rakow C. Perka A. Trampuz N. Renz

Background

Periprosthetic joint infections (PJI), caused by pathogens, for which no biofilm-active antibiotics are available, are often referred to as difficult-to-treat (DTT). It is unclear whether DTT PJI has worse outcome due to unavailability of biofilm-active antibiotics. We evaluated the outcome of DTT and non-DTT PJI managed according to a standardized treatment regimen.

Methods

Patients with hip and knee PJI from 2013 to 2015 were prospectively included and followed-up for ≥2 years. DTT PJI was defined as growth of microorganism(s) resistant to biofilm-active antibiotics. The Kaplan-Meier survival analysis was used to compare the probability of infection-free survival between DTT and non-DTT PJI.


M. Cindy M. Caseris C. Doit M. Maesani K. Mazda S. Bonacorsi B. Ilharreborde

Aim

Nasal colonization with S.aureus (SA) is a risk factor for developing nosocomial infections in cardiac surgery. However, the risk in orthopedic surgery remains unclear, especially in adolescent idiopathic scoliosis (AIS) surgery were data are missing. This study aims to evaluate the efficacy of a preoperative nasal decontamination program in SA healthy carriers on early surgical site infections (SSI) after AIS posterior surgery in a pediatric universitary Parisian hospital.

Method

Between 01-01-2014 and 03-31-2017, all AIS patients were screened preoperatively with nasal swabs and decontaminated with mupirocine if positive during the 5 days before surgery. Early SSI were prospectively identified and microorganisms' findings were compared to a previous serie published before the beginning of the decontamination program (2007–2011).


A.J. Hotchen P. Sendi M.A. McNally

Aims

We have reviewed the published classifications of long-bone osteomyelitis. This review demonstrated the limitations and poor recognition of existing classifications. We have designed a new system which includes four easily identifiable variables which are Bone involvement, Antimicrobial availability, Soft tissue coverage and Host status. This is called the B.A.C.H. classification system. In this study, we aim to retrospectively validate this classification in a cohort of osteomyelitis cases.

Methods

We identified 100 patients who had received surgery for osteomyelitis between 2013–2015 in a single specialist centre. Each patient was classified retrospectively by two assessors who were not involved in the initial patient care. Osteomyelitis was confirmed in each patient by a validated composite protocol.


C. L. Romanò D. Romanò S. Scarponi N. Logoluso

Aim

The treatment of osteomyelitis often requires extensive surgical debridement and removal of all infected tissues and foreign bodies. Resulting bone loss can then eventually be managed with antibacterial bone substitutes, that may also serve as a regenerative scaffold. Aim of the present study is to report the clinical results of a continuous series of patients, treated at our centre with an antibacterial bioglass*.

Method

From November 2010 to May 2016, a total of 106 patients, affected by osteomyelitis, were included in this prospective, single centre, observational study. Inclusion criteria were the presence of osteomyelitis with a contained bone defect or segmental defects < 10 mm, with adequate soft tissue coverage. All patients underwent a one-stage procedure, including surgical debridement and bone void filling with the bioactive glass*, with systemic antibiotic therapy and no local antibiotics. Clinical, radiographic and laboratory examinations were performed at 3, 6 and 12 months and yearly thereafter.


D. Papadia L. Bertoldi

Aim

Open fractures with bone defects and skin lesions carry a high risk of infection potentially leading to prolonged hospitalization and complication requiring revision procedures. Treatment options for diaphyseal fractures with soft tissue lesions are one- or two-stage approaches using external fixation or intramedullary nailing. We describe a surgical technique combining intramedullary nailing with an antibiotic-eluting biphasic bone substitute (BBS) applied both at the fracture site, for dead-space management and infection prevention, and on the nail surface for the prophylaxis of implant-related infection.

Method

Adult patients with an increased risk of bony infection (severe soft tissue damage and open fractures of Gustilo-Anderson grades I and II) were treated with debridement followed by application on the intramedullary nail surface, in the canal and at the fracture site of a BBS with prolonged elution (to 28 days) of either gentamicin or vancomycin. All patients also received systemic antibiotic prophylaxis following surgery. Data on infections and other adverse events were collected throughout the follow-up period. Bone union was determined by radiographic assessment of 4 cortices in radiographs obtained 1 year after surgery.


M. Schröder H. Windhagen T. Calliess N. Angrisani J. Reifenrath

Aim

The aim of this study was to establish an implant-associated osteomyelitis model in rats with the ability to quantify biofilm formation on implants for prospective evaluation of antibacterial effects on micro-structured implant surfaces.

Method

Staphylococcus aureus (strain 36/07) suspension with infection concentrations of 106, 105, 104 and 103 CFU/10µl, respectively was injected in the tibia of 32 rats (n=8 per group). Afterwards a titanium implant (0.8×0.8×12 mm) was inserted. 8 rats were implanted with a preincubated implant (107 CFU/ml, 12 h) and 8 rats served as a control (injection of 0.9% NaCl). During the follow up, clinical, radiographic and µ-CT examinations were conducted. On day 21 post op, all rats were sacrificed. Implant and tibia were explanted under sterile conditions. The implant was stained with green and red fluorescent nucleic acid dye (live/ dead) and analyzed by confocal microscopy. The amount of vivid and dead biomass as well as vivid bacteria on the implant surface was calculated with an image software*.


C. Frapwell C. Duignan J. Webb S. Aiken J. Cooper P. Stoodley R. Howlin

Aim

Bacterial biofilms play a key role in prosthetic infection (PI) pathogenesis. Establishment of the biofilm phenotype confers the bacteria with significant tolerance to systemic antibiotics and the host immune system meaning thorough debridement and prosthesis removal often remain the only possible course of treatment. Protection of the prosthesis and dead-space management may be achieved through the use of antibiotic loaded cements and beads to release high concentrations of antibiotics at the surgical site. The antibacterial and antibiofilm efficacy of these materials is poorly understood in the context of mixed species models, such as are often encountered clinically.

Methods

A P. aeruginosa and S. aureus in vitro co-culture biofilm model was grown using 1/5th BHI supplemented with 20 µM hemin. The ability of beads made from a synthetic calcium sulfate (CaSO4) loaded with vancomycin, tobramycin and vancomycin & tobramycin in combination to prevent biofilm formation and kill established co-culture biofilms were assessed using viable cell counts and confocal scanning laser microscopy (CSLM) over a 7 day time course. To assay for genetic changes to the individual species as a result of their presence together within a biofilm, mutation rates were measured using fluctuation analysis following growth as planktonic and biofilm cultures, alone or in co-culture. Mutants were determined based on their ability to grow on agar plates containing an inhibitory concentration of rifampicin. Mutation rates were calculated using the Ma-Sandri-Sarkar Maximum Likelihood Estimator and 94% confidence intervals compared for significance.


L. K. Jensen N. L. Henriksen H. E. Jensen

Aim

Despite the expanding research focusing on bacterial biofilm formation, specific histochemical biofilm stains have not been developed for light microscopy. Therefore, pathologists are often not aware of the presence of biofilm formation when examining slides for diagnosing bacterial infections, including orthopaedic infections. The aim of the present study was to develop a combined histochemical and immunohistochemical biofilm stain for simultaneous visualization of Staphylococcus aureus bacteria and extracellular matrix in different colours using light microscopy.

Methods

Infected bone tissue was collected from two different porcine models of osteomyelitis inoculated with the biofilm forming S. aureus strain S54F9. The infection time was 5 and 15 days, respectively. First, 25 common histochemical protocols were used in order to find stains that could identify extracellular biofilm matrix. Hereafter, the histochemical protocols for Alcian Blue pH3, Luna and Methyl-pyronin green were combined with an immunohistochemical protocol based on a specific antibody against S. aureus. Finally, the three new combined protocols were applied to infected bone tissue from a child suffering from chronic staphylococcal osteomyelitis for more than a year. For all combined protocols applied on all types of tissue (porcine and human) the number of double stained bacterial aggregates were counted. On the same sections the percentage of extracellular matrix of representative bacterial aggregates was calculated by image analysis.


G. Davies N. Bradford R. Oliver R. Verheul W. Bruce W. Walsh

Aim

The prevention of surgical-site infection (SSI) is of great importance. Airborne particulate correlates with microbial load and SSI. There are many potential sources of airborne particulates in theatre and from an experimental point of view impossible to control. We evaluated the effectiveness of a novel air decontamination-recirculation system (ADRS) in reducing airborne particles in a laboratory environment and controlled the introduction of particulate using diathermy.

Methods

Airborne particles were measured with and without activation of the ADRS in PC2 laboratory to provide a baseline. Particles were generated in a controlled manner utilising electrocautery ablation of porcine skin tissue. Ablation was performed at 50W power (Cut) for 60 seconds at a constant rate with and without the ADRS operating in the PC2 laboratory. Particles were measured continuously in 30s intervals at two sites 0.5m and 3m from the site of diathermy. Adequate time was allowed for return to baseline between each repetition. Each experiment was repeated 10 times.


P. E. Hanberg M. Bue H. B. Sørensen K. Søballe M. Tøttrup

Aim

Pyogenic spondylodiscitis is associated with prolonged antimicrobial therapy and high relapse rates. Nevertheless, tissue pharmacokinetic studies of relevant antimicrobials in both prophylactic and therapeutic situations are still sparse. Previous approaches based on bone biopsy and discectomy exhibit important methodological limitations. The objective of this study was therefore to assess the concentration of cefuroxime in intervertebral disc (IVD), vertebral body cancellous bone, subcutaneous adipose tissue (SCT) and plasma pharmacokinetics after single dose administration by use of microdialysis (MD) in a large animal model.

Method

Ten female pigs were assigned to receive 1,500 mg of cefuroxime intravenously over 15 min. Measurements of cefuroxime were obtained from plasma, SCT, the vertebral cancellous bone and the IVD for 8 hours thereafter. MD was applied for sampling in solid tissues. The cefuroxime concentration in both the MD and plasma samples was determined using ultra-high performance liquid chromatography.


J. Pützler D. Arens W. Metsemakers S. Zeiter K. Richard G. Richards M. Raschke F. Moriarty

Aim

Open fractures still have a high risk for fracture-related Infection (FRI). The optimal duration of perioperative antibiotic prophylaxis (PAP) for open fractures remains controversial due to heterogeneous guidelines and highly variable prophylactic regimens in clinical practice. In order to provide further evidence with which to support the selection of antibiotic duration for open fracture care, we performed a preclinical evaluation in a contaminated rabbit fracture model.

Method

A complete humeral osteotomy in 18 rabbits was fixed with a 7-hole-LCP and inoculated with Staphylococcus aureus (2×106 colony forming units, CFU per inoculum). This inoculum was previously shown to result in a 100% infection rate in the absence of any antibiotic prophylaxis. Cefuroxime was administered intravenously in a weight adjusted dosage equivalent to human medicine (18.75 mg/kg) as a single shot only, for 24 hours (every 8 hours) and for 72 hours (every 8 hours) in separate groups of rabbits (n=6 per group). Infection rate per group was assessed after two weeks by quantitative bacteriological evaluation of soft tissue, bone and implants. Blood samples were taken from rabbits preoperatively and on days 3, 7 and 14 after surgery to measure white blood cell count (WBC) and C-reactive protein (CRP) levels.


C. Ravn I. S. Ferreira E. Maiolo S. Overgaard A. Trampuz

Aim

The primary aim of this in vitro study was to test the efficacy of daptomycin to eradicate staphylococcal biofilms on various orthopedic implant surfaces and materials. The secondary aim was to quantitatively estimate the formation of staphylococcal biofilm on various implant materials with different surface properties.

Method

We tested six clinically important biomaterials: cobalt chrome alloy, pure titanium, grid-blasted titanium, porous plasma-coated titanium with/without hydroxyapatite, and polyethylene. Two laboratory strains of bacteria commonly causing PJI were used, namely Staphylococcus aureus* and Staphylococcus epidermidis*. After overnight incubation with biofilm formation, the test samples were washed and individually exposed to increasing daptomycin concentrations (4–256 mg/l) during 24-hours. Samples were subsequently sonicated in order to detect dislodged biofilm bacteria on blood agar plates by viable growth and transferred to a microcalorimeter*** for real-time measurement of growth related heat flow during 24-h incubation. Minimal biofilm eradication concentration (MBEC) was determined as the lowest concentration of antibiotic required to eradicate the biofilm bacteria on the sample.

The time to detection expressed as the heat flow >50 µW (TTD-50) indirectly quantifies the initial amount of biofilm bacteria, with a shorter TTD-50 representing a larger amount of bacteria.


V. Post M. Morgenstern L. Harris L. Mageiros M. D. Hitchings G. Méric B. Pascoe S. K. Sheppard G. Richards F. Moriarty

Aim

Staphylococcus epidermidis has emerged as an important opportunistic pathogen causing orthopedic device-related infections (ODRIs). In this prospective clinical and laboratory study, we have investigated the association of genome variation and phenotypic features of the infecting S. epidermidis isolate with the clinical outcome of the infected patient.

Method

One hundred and four invasive S. epidermidis isolates were prospectively collected from patients with ODRI. Upon patient entry into the study, surgical parameters such as type of implant; open or closed fracture were documented. Personal characteristics were also documented and included: gender; age; body mass index (BMI); smoker/non-smoker; overall medical condition (Charlson comorbidity index); and chronic immunosuppressive conditions. Any revision surgeries involving the site of interest and all isolated pathogens were recorded throughout the course of treatment and follow-up. The clinical outcome after treatment was measured with a mean follow-up period (FUP) of 26 months, and each patient was then considered to have been “cured” or “not cured”. The isolates were tested for their antibiotic susceptibility and ability to form biofilm. Whole genome sequencing was performed on all isolates and genomic variation was related to features associated with “cured” and “not cured”.


L. E. Amiri M. Antoni G. Jeannot B. Adamczewski J. Kempf P. Clavert

Aim

Shoulder prosthesis chronic infection is a rare but serious complication, likely to lead to re-interventions and poor functional outcome. Two-stage exchange surgery is considered the standard procedure by most authors.

Our hypothesis was that one-stage revision procedure is a valid therapeutic option in the management of chronic infections of shoulder arthroplasty.

Method

This was a mono-center retrospective cohort study. All patients who underwent, during the inclusion period, a one-stage revision procedure for a chronic infection of shoulder arthroplasty were included. All patients underwent clinical evaluation (Constant-Murray score), radiological examination (standard X-rays) and a blood test (Complete Blood Count and C-reactive protein), at a minimal one-year follow-up. Primary endpoint of this study was the infectious outcome and secondary endpoints were the functional and radiographic outcomes.


V. Scheer M. B. Jungeström M. Lerm L. Serrander A. Kalén

Aim

The purpose of this study was to compare the presence of P.acnes on the skin after topical pre-operative application with benzoyl peroxide (BPO) to chlorhexidine soap (CHS) and whether this also affected skin recolonization after surgical preparation and draping.

Method

Forty volunteers – twenty-four men and sixteen women were randomized to pre-operative topical treatment at home with either CHS or BPO in the area of a delto-pectoral approach of their left shoulder. The right served as a control. Five skin swabs were taken in a standardized manner on different occasions: before and after topical treatment, after surgical skin preparation and sterile draping and 120 minutes after draping. A fifth sample was taken on the contralateral untreated side as a control when the patient was draped. The draping took place in an operating room with laminar air flow and skin preparation was performed for 2 minutes with 0.5% chlorhexidine solution in 70% ethanol according to the recommendations of the Swedish National Board of Health and Welfare.

Bacterial colonies were then analyzed on agar plates by colony forming units (CFU) and surface characteristics. P.acnes were identified with matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectrometry.


M. Pradier F. Suy B. Issartel C. Dehecq C. Loiez M. Valette E. Senneville

Aim

Propionibacterium acnes (PA) is an important cause of shoulder prosthetic joint infections (SPJIs) for which the optimal treatment has not yet been determined. Rifampicin and Levofloxacin both showed not benefit in recent experimental models of PA-SPJIs. We describe herein the experience of five different medical French centers in order to assess factors associated with patient's outcome with special emphasize on antibiotic regimens.

Method

A multicentric retrospective study was performed, on consecutive patients with PA – related SPJIs diagnosed on the basis of at least 2 or more positive cultures of either per-operative or joint aspiration and clinical history compatible with a PJI according to the current guidelines. All patients had surgical management, followed by systemic antibiotic therapy. Remission was defined as an asymptomatic patient with functioning prosthesis at the last contact.


M. Girard M. Arboucalot A. Faraud S. Delclaux N. Bonnevialle P. Delobel P. Mansat

Aim

Infections after total elbow arthroplasty are more frequent than after other joint arthroplasties. Therapeutic management varies depending of the patient status, the time of diagnosis of the infection, the status of the implant as well as the remaining bone stock around the implants.

Method

Between 1997 and 2017, 180 total elbow arthroplasties were performed in our department. Eleven (6%) sustained a deep infection and were revised. Infection occurred after prosthesis of first intention in 4 and after a revision procedure in 7. Etiologies were: rheumatoid arthritis in 6, trauma sequela in 4 and osteosarcoma in 1. There were 7 women and 4 men of 59 years on average (22–87). Delay between the prosthesis and the diagnosis of infection was 66 months (0.5–300). The infection was stated as acute (<3week) in one, subacute (between 3 week and 3 months) in 1, and chronic (>3 months) in 9. Isolated bacteria were: Staphylococcus (10), Streptococcus (1), P. acnes (1), and Proteus mirabilis (1). Infection were poly microbial in 2 cases. A simple lavage with debridement was performed in 3 cases (Group 1), a 2-stage revision in 4 (Group 2), and a definitive removal of the prosthesis in 4 (Group 3). Adapted antibiotics were prescribed for all patients during at least 6 weeks.


P. D. Benedetto V. Cainero R. Gisonni A. Beltrame A. Causero

Aim

The aim of the study is to evaluate the specificity and sensibility of leukocyte esterase for the diagnosis of periposthetic joint infection (PJI).

Method

Between October 2016 and April 2017 we enrolled 65 patients underwent to hip and knee revision arthroplasty due to uncertain joint infection. Synovial fluid was obtained from 64 joints that underwent revision arthroplasty.

Each patient was evaluated in the preoperative time with CRP, ESR and leukoscan, in the intraoperative time with frozen section and leukocyte esterase strip and post-operative with sonication fluid culture, periprosthetic tissues cultures and histological examination. Results of all of these exams were compared to assess the specificity, the sensibility, the positive and negative predicting values of leukocyte esterase for the diagnosis of PJI.


T. Begue G. Rougereau J. Aurégan

Aim

Infections in long bones can be divided in osteitis, osteomyelitis and septic non-unions. All are challenging situations for the orthopaedic surgeon. Treatment is a mix with debridement, radical resection of infected tissue, void filling with different types of products, and antibiotic therapy of different kinds. In cavitary bone defects, bioglasses such as BAG-S53P4 have given good results in early or mid-term follow-up. Results of such treatment in segmental bone defects remain unknown. The goal of our study was to evaluate efficacity of active bioglass BAG-S53P4 in septic segmental bone defects.

Method

A retrospective cohort study has been done in a single specific orthopaedic center devoted to treatment of infected bony situations. All cases were a severe septic bone defect. We have compared the segmental bone defects to the cavitary ones. Results were analyzed on recurrence of infection, bone healing, functional result and complication rate.


C. Triffault-Fillit F. Valour T. Michel S. Goutelle R. Guillo S. Lustig M. Fessy F. Laurent M. Eugenie C. Chidiac T. Ferry

Aim

Current guidelines recommend the combination of vancomycin with either piperacillin-tazobactam (PT) or a third generation cephalosporin (3GC) as empirical antimicrobial therapy of PJI, immediately after surgery. However, clinical and biological safeties of such high dose-combinations are poorly known.

Method

All patients managed in a reference center in France between 2011 and 2016 receiving an empirical antimicrobial therapy for PJI were included in a prospective cohort study. Antimicrobial-related AE upcoming during the empirical treatment phase were describe according to the Common Terminology Criteria for Adverse Events (CTCEA), and severe ones (grade ≥ 3) were reported to pharmacovigilance. AE determinants were assessed using univariate logistic regression.


F. Pierret H. Migaud C. Loiez M. Valette E. Beltrand J. Yombi O. Cornu E. Senneville M. V. Cauter

Aim

The treatment of a chronic prosthetic joint infection (PJI) is a combination of the bacteria's identification, a «carcinological» surgery and an appropriate antibiotherapy. In case of gram positive cocci infection, rifampicin is often used.

The aim of this study is to determine which factors are responsible for the development of resistance to rifampicine.

Method

All patients had a total hip (THA) or knee (TKA) arthroplasty with a chronic infection. They were treated with a two-time surgery. All of them received a bi-antibiotic treatment. In case of gram positive cocci infection, and according to the susceptibility test, they received rifampicin. The 221 patients were operated from July 1997 to November 2013 in 3 university centers (one Belgian and two French) and were retrospectively analysed. The demographical, clinical and bacterial data as well as the antibiotic treatment were collected. The healing was defined as the absence of recurrence during the 2 years following surgery.


M. Bue M. Tøttrup P. Hanberg O. Langhoff H. B. Sorensen T. M. Thillemann T. L. Andersson K. Søballe

Aim

The incidence of orthopaedic methicillin-resistant staphylococcus aureus infections is increasing. Vancomycin may therefore play an increasingly important role in orthopaedic perioperative antimicrobial prophylaxis. Adequate antimicrobial concentrations at target site is essential for prevention of orthopaedic infections. Current studies investigating perioperative bone and soft tissue concentrations of vancomycin are sparse and challenged by a lack of appropriate methods. The aim of this study was therefore to assess the concentration of vancomycin in plasma, subcutaneous tissue and bone after single dose administration using microdialysis (MD) in patients undergoing total knee replacement.

Method

1,000 mg of vancomycin was postoperatively administered intravenously over 100 minutes to 10 male patients undergoing primary total knee replacement. Vancomycin concentrations in plasma, subcutaneous tissue (SCT), cancellous and cortical bone were measured the following 8 hours. MD was applied for sampling in solid tissues. The vancomycin concentration in MD-samples was determined using ultra-high performance liquid chromatography, whilst the free plasma concentration was determined using a chemistry analyzer*.


P. Chauvelot T. Ferry C. Triffault-Fillit E. Braun T. Perpoint F. Laurent F. Michel-Henry S. Lustig C. Chidiac F. Valour

Aim

Corynebacterium is a rare etiologic agent of BJI. We aimed to describe this rare clinical condition and to assess treatment failure determinants.

Method

All adult patients with proven Corynebacterium BJI (i.e. consistent clinical/radiological signs, AND ≥2 reliable positive bacteriological samples, AND treated as such) were included in a retrospective cohort study. After cohort description, determinants of treatment failure (i.e, infection persistence, relapse, requirement of additional surgical procedure, and BJI-related death) were determined using stepwise logistic regression and Kaplan Meier curve analysis.


N. Renz S. Mudrovcic C. Perka A. Trampuz

Aim

To assess the clinical characteristics, diagnostic tests and treatment strategies in orthopedic implant-associated infections (OIAI) caused by Cutibacterium spp.

Method

We retrospectively included consecutive patients with OIAI caused by Cutibacterium spp. treated at our institution from January 2012 to January 2017. OIAI was diagnosed when: (i) macroscopic purulence, sinus tract or exposed implant was present; (ii) acute inflammation in peri-implant-tissue was documented; (iii) Cutibacterium spp. grew in joint aspirate, ≥2 intraoperative peri-implant tissue samples or in sonication fluid of the removed implant (>50 CFU/ml).


F. El Sayed A. Roux J. Rabès P.D. Mazancourt T. Bauer J. Gaillard M. Rottman

Aim

Propionibacterium acnes is a skin commensal colonizing the deeper structures of the pilous bulb. It is responsible for 5–10% of lower limb prosthetic joint infections (PJI) but accounts for as many as 50% of shoulder arthroplasty infections. P. acnes PJIs characteristically feature limited systemic inflammation, limited polymorphonuclear infiltration and clinical signs compatible with aseptic loosening. All current microbiological definitions of PJI require two or more identical commensal isolates to be recovered from the same procedure to diagnose PJI to increase specificity and rule out contamination. Whereas the antimicrobial susceptibility patterns of coagulase negative staphylococci are highly polymorphic and commonly allow the ready distinction of unrelated strains, P. acnes shows a highly stereotypical susceptibility profile and it is impossible to phenotypically assess the clonal relationship of isolates. In order to determine the clonal relationship of multiple P. acnes isolates recovered from arthroplasty revisions, we analyzed by multi-locus sequence typing (MLST) P. acnes isolates grown from PJI in a reference center for bone and joint infection.

Method

We retrospectively selected all cases of microbiologically documented monomicrobial PJI caused by P. acnes diagnosed in our center from January 2009 to January 2014. Microorganisms were identified by MALDI-TOF mass spectrometry (Bruker Daltonics). All corresponding P.acnes isolates biobanked in cryovials frozen at −80°C were subcultured on anaerobic blood agar, DNA extracted by freeze-thawing and bead-milling, and typed according to the 9 gene MLST scheme proposed by Lomholt HB. and al.


E. Takoudju A. Guillouzouic K. Stanimir F. Pecorari S. Corvec

Aim

Although there are no treatment guidelines for Propionibacterium acnes (PA) bone and joint infections (Corvec et al Acta Orthopedica 2016), these infections can be treated with a combination of fluoroquinolones and rifampicin. Rifampicin resistance have already been reported either in in vitro selected mutants or clinical isolates (Furustrand et al JAC 2013, Anaerobe 2015). Minimal inhibitory concentrations of levofloxacin (LVX) ranging from 0,12 to 0.5mg/L are regularly observed but resistance has not yet been investigated. We investigated the in vitro emergence of LVX resistance and characterized the mutations involved in gyrA gene.

Method

The strain of PA ATCC11827 (MIC LVF = 0.25 mg/L) was used. The frequency of mutation was determined after inoculation of 108 PA on blood agar containing concentrations of 2 to 128 times the MIC incubated for 7 days in anaerobiosis at 35 ° C. The emergence of high-level of resistance was also studied from the low-level mutants after a second exposure. For the resistant mutants, the gyrA and parC genes were sequenced and compared to the PA reference sequences.


S. Huber-Wagner S. Pesch C. Kirchhoff M.V. Griensven P. Biberthaler M. Hanschen

Aim

The current treatment concepts of acute and chronic osteitis are associated with unsolved challenges and problems, underlining the need for ongoing medical research. The invention and prevalence of an absorbable, gentamicin-loaded ceramic bone graft, that is well injectable for orthopedic trauma and bone infections, enlarges the treatment scope regarding the rise of posttraumatic deep bone infections. This substance can be used either for infection, dead-space, or reconstruction management. The bone cement, eluting antibiotics continuously to the surrounding tissue, outperforms the intravenous antibiotic therapy and enhances the local concentration levels efficiently. This study aims to evaluate the power and practicability of bone cement in several locations of bone infections.

Method

The occurrence of posttraumatic infections with acute or chronic osteitis increases in trauma surgery along with progression of high impact injuries and consecutively high incidence of e.g. open fractures. We present a case-series of 10 patients with posttraumatic osteitis at different anatomic sites, who were treated in our level I trauma center. All of these patients received antibiotic eluting bone cement* for infection and reconstruction management.


J. Liao

Aim

Infection after vertebroplasty (VP) is a rare but serious complication. Previous literatures showed most pathogens for infection after VP were bacteria; tuberculosis (TB) induced infection after VP was extremely rare. In this study, we reported our treatment experiences of 18 cases with infectious spondylitis after VP, and compared the differences between developed pyogenic and TB spondylitis.

Method

From January 2001 to December 2015, 5749 patients underwent VP at our department were reviewed retrospectively. The causative organisms were obtained from tissue culture of revision surgery. Parameters including type of surgery, the interval between VP and revision surgery, neurologic status, and visual analog scale of back pain were recorded. Laboratory data at the time of VP and revision surgery were collected. Risk factors including the Charlson comorbidity index (CCI), preoperative bacteremia, urinary tract infection (UTI), pulmonary TB history were also analyzed.


T. Azamgarhi A. Shah S. Palanivel D. Mack L. Cleaver S. Warren

Introduction

Fungi are a rare and devastating cause of Periprosthetic Joint Infection (PJI). Diagnosis and treatment is a challenge as there are currently no specific guidelines. A recently published review identified 75 case reports of fungal PJI.

Aim

The aim is to describe our experience of treating fungal PJI since 2011 within the Bone Infection Unit at our institution.


A. Bouige C. Fourcade A. Bicart-Sée MP. Félicé L. Gautié G. Krin J. L. Hascoet P. Marlin G. Giordano E. Bonnet

Aim

Prosthetic joint infections (PJI) due to Enterobacter cloacae are rare and often severe. The aim of this study is to describe cases with E. cloacae PJI.

Method

We conducted a retrospective and a monocentric study in an orthopedic unit where complex bone and joint infections are managed. From 2012 to 2016, we included patients with PJI which perioperative samples were positive with E. cloacae. We collected background, clinical, biological and microbiological data of the current infection, surgical and medical treatment, and the outcome of these patients.


G. Bart V. Meyssonnier Y. Kerroumi L. Lhotellier W. Graff D. Passeron A. Mouton J. M. Ziza N. Desplaces S. Marmor V. Zeller

Aim

Treatment of chronic prosthetic joint infection (PJI) combines exchange arthroplasty and effective antibiotic therapy. Staphylococci are the most frequent microorganism isolated in PJIs, with resistance to methicillin found in 15–50% of the cases. Data from randomized trials on treatment of methicillin-resistant staphylococci are lacking and the choice of antibiotic(s) and recommendations vary according to authors. To date, combination therapy including vancomycin is the treatment of choice.

Minocycline, a cyclin antibiotic, is naturally effective against methicillin-resistant staphylococci. We use this antibiotic since many years in combination with vancomycin for the treatment of multi-drug resistant staphylococcal bone and joint infections.

The aim of this study is to analyze the outcome of patients treated with combination antibiotic therapy including minocycline for the treatment of chronic methicillin-resistant staphylococcal PJI.

Method

We conducted a cohort study between 2004 and 2014 in our referral center for bone and joint infections. Data were extracted from the prospective database. All the patients receiving an initial combination therapy including at least 4 weeks of minocycline, given orally, and another IV antibiotic, usually high-dose continuous IV vancomycin, for chronic MR staphylococcal PJI and who underwent one or two stage exchange arthroplasty, were included. They were followed prospectively for at least 2 years.


A. Rakow C. Perka D. Akgün M. Schütz A. Trampuz N. Renz

Aim

The incidence of hematogenous periprosthetic joint infections (hPJI) is unknown and the cases probably largely underreported. Unrecognized and untreated primary infectious foci may cause continuous bacteremia, further spread of microorganisms and thus treatment failure or relapse of infection. This study aimed at improving knowledge about primary foci and microbiological characteristics of this entity to establish preventive measures and improve diagnostic and therapeutic strategies to counteract hPJI.

Method

We retrospectively analysed all consecutive patients with hPJI, who were treated at our institution from January 2010 until December 2016. Diagnosis of PJI was established if 1 of the following criteria applied:(i) macroscopic purulence, (ii) presence of sinus tract, (iii) positive cytology of joint aspirate (>2000 leukocytes/μl or >70% granulocytes), (iv) significant microbial growth in synovial fluid, periprosthetic tissue or sonication culture of retrieved prosthesis components, (v) positive histopathology. PJI was classified as hematogenous if the following criteria were fulfilled additionally: (1) onset of symptoms more than 1 month after arthroplasty AND (2) i) isolation of the same organism in blood cultures OR ii) evidence of a distant infectious focus consistent with the pathogen.


F. Bouchand C. Nich G. Petroni S. Privé E. Truchard B. Davido P. Hardy M. Villart A. Dinh

Aim

Our hospital is a referral center for Bone and Joint Infection (BJI) with a 15-bed orthopedic unit. Patients benefit from a multidisciplinary team management (surgeons, anesthetists, infectious disease physicians, microbiologists, dietician etc.). Computerized drug prescriptions are performed by anesthetists, surgical residents, surgeons and infectious disease physicians. Since 2015, a pharmacist has been included in ward rounds and in weekly multidisciplinary consultative meetings, where antibiotic treatment strategies are decided for hospitalized patients. This work aimed to assess the impact of a pharmacist in this unit to limit prescription errors.

Method

Prospective monocentric study of all pharmacist's advice or interventions during 15 weeks in 2016 and 2017. A complete pharmaceutical analysis of prescriptions is performed twice a week at least. This analysis is based on doses control and drug interactions, but also takes into account biological and clinical data of patients (patient history, renal function, symptoms, adverse effects…). In case of a prescription error, a computerized message and/or a phone call is sent to the prescriber. Each pharmacist's intervention is recorded and classified according to the French Society of Clinical Pharmacy. The pharmacist collected the number of pharmaceutical advice (when spontaneously solicited by any member of the multidisciplinary team), the different types of prescription errors, the pharmacological class associated to these errors, the types of pharmacist's interventions and their impact on prescriptions.


C. Fourcade B. Aurelie E. Labau G. Giordano A. B. See E. Bonnet

Aim

In private healthcare facilities, the access to a specialized infectious disease (ID) advice is difficult. More, the lack of traceability is problematic and harmful for treatment and follow-up. We have tested an information technology (IT) application to improve medical transmission and evaluate an interdisciplinary ID activity.

Methods

In November 2015, three ID physicians (IDP) created an interdisciplinary activity, visiting patients and giving phone advices among ten private healthcare facilities. They are members of the complex bone and joint infection unit of the community hospital where they are attached. Since September 2016, each advice was prospectively recorded on a protected online information system. These data are available for consultation and modification by the three IDP. It is the first descriptive analysis of this database.


B. Stragier A. Renard L. Vanlaer J. Verhaegen J. Neyt

Aim

The purpose of this single center study was to analyze the robustness and thoroughness of debridement and irrigation in first stage procedures for periprosthetic joint infections in which the latter had been confirmed by fulfilling the PJI criteria produced by the musculoskeletal infection society.

Method

After introduction of ‘a clean phase’ concept in our center, we developed a method of using new instrumentation sets and waterproof cover sheets as well as sets of gloves and aprons after thorough debridement followed by copious irrigation under a splash sheet, once the prosthetic components were removed during which several (6 to 8) tissue biopsies and cultures were harvested. ‘Clean phase’ tissue specimens ad random were again obtained and cultured and compared with ‘dirty phase’ cultures and sonication results. Our zero hypothesis was that we were not able to entirely eradicate bacterial colonization. We tested this hypothesis during a period of 18 months in a consecutive series of first stage revisions for PJI at our center after introduction of the clean phase concept.


G. Chieffo D. Archambeau L. Eyrolle P. Morand J. Loubinoux S. Kerneis R. Gauzit P. Leclerc P. Anract D. Salmon-Ceron

Aim

Periprosthetic joint infection (PJI) is a major complication of prosthetic implantation and needs a combined surgical and antimicrobial treatment. One-stage revision results usually in similar cure rate than two-stage (around 85–92%), but antibiotic therapy duration is not well established. The aim of study was to evaluate the efficacy of a short six-weeks antibiotic course in hip and knee PJIs after one-stage replacement arthroplasty (RA).

Method

This was a retrospective, observational study conducted at Orthopaedic Department of Cochin Hospital, Paris, between 1stJanuary 2010 and 31 December 2015. Inclusion criteria were: age>18 years; clinical/microbiological diagnosis of PJI; one-stage RA; 6-weeks course of antibiotics; follow-up of at least one year. PJIs were classified depending on the delay of infection from implantation as: early(<3 months), delayed(3–24 months), late(>24 months). Pearson's-χ2 and t-tests were used to compare categorical and continuous variables.


J. Lange A. Troelsen S. Solgaard T. Ørsnes K. Otte P. T. Nielsen M. Lamm N. Krarup S. Mikkelsen A. Zawadski K. Søballe
On behalf of the CORIHA research group

Aim

Our aim was to evaluate cementless one-stage revision in chronic periprosthetic hip joint infection.

Method and patients

The study was performed as a multicentre, proof-of-concept, observational study with prospective data collection. Inclusion of patients with a chronic periprosthetic hip joint infection (PJI) were followed by protocolled surgical treatment (cementless one-stage revision - the CORIHA protocol) at one of 8 participating departments of orthopaedic surgery between 2009 – 2014, and the patients enrolled in a 2-year follow-up program. A PJI were diagnosed based on adopted criteria from McPherson and Zimmerli. At the time of initiation of the study in 2009, the collaborating departments performed approximately one-fourth of all nationwide primary HJR and more than one-third of all revisions.

In total 56 PJI patients with a median age of 72 years and a median pre-operative ASA score of 2 met the established eligibility criteria and accepted to participate; 31 (55%) were males.

The cohort had a mean follow-up time of 4.0 years, with all patients followed for minimum 2 years.

The primary outcome were relapse described as re-revision due to infection (regardless of considered as a relapse or new infection). This was evaluated by competing risk analysis (competing risks: aseptic revisions and death).

Secondary, all-cause mortality was evaluated by survival analysis.

The study was approved by the local Committees on Biomedical Research Ethics.


C. Kolenda J. Josse R. Sierra A. Renzoni F. Laurent

Aim

Toxin-antitoxin (TA) systems are small genetics elements found in the majority of bacteria which encode a toxin causing bacterial growth arrest and an antitoxin counteracting the toxic effect. In Salmonella and E. coli, TA systems were shown to be involved in the formation of persisters. Persisters are a bacterial subpopulation with low growth rate and high tolerance to antibiotics. They could be responsible for antibiotic treatment failure in chronic infections and relapses, notably in bone and joint infections (BJI) caused by Staphylococcus aureus. Currently, two type II TA system families were described in S. aureus, mazEF and axe/txe, but their physiological roles are not well described. In this work, we studied the importance of mazEF in the intracellular survival of S. aureus inside osteoblasts, one of the mechanisms considered in the chronicity of S. aureus BJI.

Methods

Using an ex vivo model of intracellular infection of human osteoblast-like cells (MG-63), two strains of S. aureus HG003 wild type and its isogenic mutant HG003 ΔmazEF were compared in terms of : i) internalization and intracellular survival by lysostaphin protective assay and ii) cytotoxicity by quantifying LDH in the culture supernatant, 24h and 48h after infection.


A. Santoso K. Park T. Yoon S. Youngrok

Aim

Identification of the causal pathogen is crucial in the management of periprosthetic joint infection (PJI) of the hip. Unfortunately, it was often difficult and negative culture could be a common findings. This situation made the treatment of PJI of the hip became more challenging. The negative culture finding resulted in a doubtful diagnosis of infection, and poses difficulty in choosing the appropriate antibiotics. Here we compared the treatment outcome of two-stage revision arthroplasty for culture-negative versus culture-positive PJI of the hip.

Method

We retrospectively reviewed patients who received two-stage revision for PJI of the hip between January 2010 to June 2015. All patients was planned to received articulated antibiotic cement-spacer as the first stage and revision total hip arthroplasty (THA) as the second stage of the procedure. Out of total 94 patients, 10 patients was loss to follow-up and excluded from the study. We devided the rest of 84 patients into two groups: culture-negative group (n: 27) and culture-positive group (n: 57). We compared all relevant medical records and the treatment outcome between the two groups.


C. Peltier T. Vendeuvre S. Teyssedou P. Pries G. Beraud A. Michaud C. Plouzeau-Jayle P. Rigoard

Aim

Spinal infection is the most frequent complication of spine surgery. Its incidence varies between 1% and 14% in the literature, depending on various studied populations and surgical procedures. The aim of this study was to describe a consecutive 2706 case series.

Method

We analyzed a prospective cohort of 2706 patients operated for spine disease between 2013 and 2016 in a University Hospital. The infection rates, germs, time between surgery and infection and outcomes after surgical revision were assessed with a minimum follow-up of 7 months. We developed a mathematical model to analyze risk factors in this difficult-to-treat population.


R. Mills A. Schindeler D. Little

Aim

Implant-associated infection remains one of the biggest challenges facing orthopaedics and there is an urgent clinical need to develop new prophylactic strategies. We have previously shown that CSA-90, a broad-spectrum antimicrobial, prevented infection in an infected open fracture model. In this study we developed a novel model of implant-associated infection, in which to further test the potential of CSA-90 as a prophylactic agent.

Method

All studies were approved by the local animal ethics committee. 3D-printed porous titanium implants were implanted into the distal femora of 18 week-old male Wistar rats under general anaesthesia. The treatment groups' (n=10) implants were pre-coated with 500μg CSA-90 in saline. Staphylococcus aureus* was inoculated either directly around the implant (1×104 CFU) or injected intravenously immediately post-operatively (1×105 CFU). No systemic antibiotic prophylaxis was used. The study ran for six weeks and animals were reviewed daily for signs of infection. An independent, blinded veterinarian reviewed twice-weekly radiographs, and rats demonstrating osteolysis and/or declining overall health were culled early at their instruction. The primary outcome was implant infection, incorporating survival, microbiological, radiological, and histological measures.


V. Artyukh V. Liventsov S. Bozhkova

Aim

To evaluate the efficacy of infection elimination and functional outcomes of the resection hip arthroplasty (RHA) with m. vastus lateralis flap plasty in patients with chronic recurrent periprosthetic joint infection (PJI) one year or later after the surgery.

Method

We retrospectively studied the outcomes of 61 cases with recurrent PJI (more than 3 relapses). All patients underwent RHA with m. vastus lateralis flap plasty from the year 2005 to 2016. There were 35 males (63.6%) and 20 females (36.4%) with the mean age of 54 years. At least in one year after the surgery, the cases were analyzed for the absence of inflammation during the physical exam, functional result with the Harris hip score (HSS), quality of life with the Instrument for measurement of health-related quality of life scale and level of pain with the visual analogue scale (VAS). The results are presented as means with CI95%.


T. Falstie-Jensen H. Daugaard J. Lange J. Ovesen K. Søballe

Background

Periprostetic joint infections (PJI) are often difficult to diagnose, to treat and often leave the patient with severe impaired function. The presence of low virulent bacteria is frequently discovered in apparent aseptic revisions of shoulder arthroplasties and pose a challenge to diagnose preoperatively.

Dual Isotope In111 Leucocyte/ Tc99 Bone Marrow SPECT CT scan (L/BMS) is considered the radionuclide gold standard in preoperative diagnosing PJI with reported high specificity and sensitivity in hip and knee arthroplasties.

Unfortunately, it is labour-intensive and expensive to perform and documentation using L/BMS on shoulder arthroplasties lack.

Aim

To investigate if L/BMS succeeds in detecting shoulder PJI compared to tissue cultures obtained perioperatively.


N. Jiang L. Wang B. Yu

Aim

Cyclooxygenase-2 (COX-2) enzyme is one of the major mediators during inflammation reactions, and COX-2 gene polymorphisms of rs20417 and rs689466 have been reported to be associated with several inflammatory diseases. However, potential links between the two polymorphisms and risk of developing post-traumatic osteomyelitis remain unclear. The present study aimed to investigate associations between the rs20417 and rs689466 polymorphisms and susceptibility to post-traumatic osteomyelitis in Chinese population.

Methods

A total of 189 patients with definite diagnosis of post-traumatic osteomyelitis and 220 healthy controls were genotyped for rs20417 and rs689466 using the genotyping method*. Chi-square test was used to compare differences of genotype distributions as well as outcomes of five different genetic models between the two groups.


S. Ikeda K. Uchiyama S. Kishino M. Nakamura K. Yoshida Y. Minegishi K. Sugo K. Fukushima N. Takahira H. Kitasato M. Takaso

Aim

The preparation of antibiotic-containing polymethyl methacrylate (PMMA), as spacers generates a high polymerization heat, which may affect their antibiotic activity; it is desirable to use bone cement with a low polymerization heat. Calcium phosphate cement (CPC) does not generate heat on polymerization, and comparative elution testings are reported that vancomycin (VCM)-containing CPC (VCM-CPC) exceeded the antibiotic elution volume and period of PMMA (VCM-PMMA). Although CPC alone is a weak of mechanical property spacer, the double-layered, PMMA-covered CPC spacer has been created and clinically used in our hospital. In this study, we prepared the double-layered spacers: CPC covered with PMMA and we evaluated its elution concentration, antimicrobial activity and antibacterial capability.

Method

We prepared spherical, double-layered, PMMA-coated (CPC+PMMA; 24 g CPC coated with 16 g PMMA and 2 g VCM) and PMMA alone (40 g PMMA with 2 g VCM) spacers (5 each). In order to facilitate VCM elution from the central CPC, we drilled multiple holes into the CPC from the spacer surface. Each spacer was immersed in phosphate buffer (1.5 mL/g of the spacer), and the solvent was changed daily. VCM concentrations were measured on days 1, 3, 7, 14, 28, 56, and 84. Antimicrobial activity against MRSA and MSSA was evaluated by the broth microdilution method. After measuring all the concentration, the spacers were compressed at 5 mm/min and the maximum compressive load up to destruction was measured.


M. Diefenbeck S. Bischoff E. Lidén P. Poh M. van Griensven W. Hettwer

Aim

A gentamicin-eluting biocomposite consisting of hydroxyapatite (HA) and calcium sulphate (CaS)*1 can provide effective dead space management and bone formation in chronic osteomyelitis. However, radiographic follow-up after implantation of this biomaterial has shown imaging features previously not described with other comparable bone graft substitutes. Last year we presented preliminary results with a follow-up of 6 months. Now we present the radiographic, µCT and histological one-year follow-up of the critical-size bone defect model in sheep. The aim of this study was to simulate the clinical situation in a large animal model to correlate different imaging techniques used in the clinic (Radiography, CT and MRI scans) with histological finding.

Methods

Standardised bone defects were created in ten Merino-wool sheep (age two to four years). Large drill holes (diameter 2.5cm, depth 2cm, volume approx. 10ml) were placed in the medial femoral condyles of both hind legs and filled with gentamicin-eluting biocomposite. Initially surgery was carried out on the right hind leg.

Three months later, an identical intervention was performed on the contralateral side. Animals were sacrificed at three and six weeks and 4.5, six and twelve months. Radiographs and MRI scans were taken immediately after sacrifice. Filled bone voids were harvested en-block and analysed using µCT, and histology.


W. Boot M. D'Este T. Schmid S. Zeiter R.G. Richards D. Eglin T.F. Moriarty

Aim

The treatment of chronic orthopedic device-related infection (ODRI) often requires multiple surgeries and prolonged antibiotic therapy. In a two-stage exchange procedure, the treatment protocol includes device removal and placement of an antibiotic-loaded bone cement spacer to achieve high local antibiotic concentrations. At the second stage, further surgery is required to remove the spacer and replace it with the definitive device. We have recently developed a thermo-responsive hyaluronan hydrogel (THH) that may be loaded with antibiotics and used as delivery system. Since the material is bio-resorbable, it does not require surgical removal and may therefore be suitable for use as treatment strategy in a single-stage exchange.

This aim of this study was to evaluate gentamicin sulphate (Genta)-loaded THH (THH-Genta) for treating a chronic Staphylococcus aureus ODRI in sheep using a single-stage procedure.

Methods

Twelve Swiss-alpine sheep received an IM tibia nail and an inoculation of a gentamicin-sensitive clinical strain of Staphylococcus aureus. After letting a chronic infection develop for 8 weeks, a revision procedure was performed: the implant was removed, the IM canal debrided and biopsies were taken for culture. The IM canal was then filled with 25ml THH-Genta (1% Genta) or left empty (control group) prior to the implantation of a sterile nail. An ultrafiltration probe was placed within the IM cavity to collect extracellular fluid and determine local antibiotic levels for 10 days. Both groups received systemic amoxicillin and clavulanic acid for 2 weeks, followed by 2 weeks without treatment for antibiotic washout. At euthanasia, IM nail, bone marrow, bone and tissue samples were harvested for quantitative bacteriology.


S. Karbysheva K. Yermak L. Grigoricheva A. Trampuz

The diagnosis of prosthetic-joint infection (PJI) is challenging, as bacteria adhere on implant and form biofilm. Therefore, current diagnostic methods, such as preoperative culture of joint aspirate have limited sensitivity with false-negative results.

Aim

To evaluate the performance of measurement synovial fluid (SF) D-lactate (as a pathogen-specific marker) for the diagnosis of PJI and estimate of treatment success.

Method

224 patients undergoing removal knee or hip prosthesis were included in the study between January 2015 and March 2017. 173 patients of this group had aseptic loosening of prosthesis and 87 were diagnosed with PJI. Prior to surgery, synovial fluid routine culture, D-lactate test, leukocyte count and neutrophils (%) were performed for each patient. In order to evaluate a treatment success, the measurement of SF D-lactate before second two-stage exchange procedure (after treatment) was implemented in 30 patients. Diagnosis of PJI was established according to modified Zimmerli criteria.


T. Street N. Sanderson B. Atkins A. Brent K. Cole D. Foster M. McNally S. Oakley L. Peto A. Taylor T. Peto D. Crook D. Eyre

Aim

Culture of multiple periprosthetic tissue samples is the current gold-standard for microbiological diagnosis of prosthetic joint infections (PJI). Additional diagnostic information may be obtained through sonication fluid culture of explants. These current techniques can have relatively low sensitivity, with prior antimicrobial therapy or infection by fastidious organisms particularly influencing culture results. Metagenomic sequencing has demonstrated potential as a tool for diagnosis of bacterial, viral and parasitic infections directly from clinical samples, without the need for an initial culture step. We assessed whether metagenomic sequencing of DNA extracts from sonication fluid can provide a sensitive tool for diagnosis of PJI compared to sonication fluid culture.

Method

We compared metagenomic sequencing with standard aerobic and anaerobic culture in 97 sonication fluid samples from prosthetic joint and other orthopaedic device-related infections. Sonication fluids were filtered to remove whole human cells and tissue debris, then bacterial cells were mechanically lysed before DNA extraction. DNA was sequenced and sequencing reads were taxonomically classified using Kraken. Using 50 derivation samples, we determined optimal thresholds for the number and proportion of bacterial reads required to identify an infection and confirmed our findings in 47 independent validation samples.


J. Pützler S. Zeiter A. Vallejo D. Gehweiler M. Raschke G. Richards F. Moriarty

Aim

Treatment regimens for fracture-related infection (FRI) often refer to the classification of Willenegger and Roth, which stratifies FRIs based on time of onset of symptoms. The classification includes early (<2 weeks), delayed (2–10 weeks) and late (>10 weeks) infections. Early infections are generally treated with debridement and systemic antibiotics but may not require implant removal. Delayed and late infections, in contrast, are believed to have a mature biofilm on the implant, and therefore, treatment often involves implant removal. This distinction between early and delayed infections has never been established in a controlled clinical or preclinical study. This study tested the hypothesis that early and delayed FRIs respond differently to treatment comprising implant retention.

Method

A complete humeral osteotomy in 16 rabbits was fixed with a 7-hole-LCP and inoculated with Staphylococcus aureus. The inoculum size (2×106 colony forming units per inoculum) was previously tested without antibiotic intervention to result in infection of all animals persisting for at least 12 weeks.4 The infection was allowed to develop for either 1 (early group) or 4 (delayed group) weeks (n= 8 per group) after bacterial inoculation. At these time points, treatment involved debridement and irrigation of the wound (no implant removal) and quantitative bacteriological evaluation of the removed materials. Systemic antibiotics were administered according to a common clinical regimen (2 weeks: rifampin + nafcillin, followed by 4 weeks: rifampin + levofloxacin). After an additional one-week antibiotic washout period, animals were euthanized and a quantitative bacteriology of soft tissue, implant (after sonication) and bone was performed.