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Background The positive-intraoperative-cultures-type prosthetic joint infection (PIOC-PJI) is considered when surgical cultures yield microorganisms in presumed aseptic arthroplasty revisions. Herein we assess the risk factors for failure in the largest cohort of PIOC-PJI patients reported to date. Methods A retrospective, observational, multicenter study was performed during 2007–2017. Surgeries leading to diagnose PIOC-PJI included only one-stage procedures with either complete or partial prosthesis revision. Failure was defined as recurrence caused by the same microorganism. Results 203 cases were included (age 72 years, 52% females). Coagulase-negative staphylococci (n = 125, 62%) was the main etiology, but some episodes were caused by virulent bacteria (n = 51, 25%). Prosthesis complete and partial revision was performed in 93 (46%) and 110 (54%) cases, respectively. After a median of 3.4 years, failure occurred in 17 episodes (8.4%, 95%CI 5.3–13.1). Partial revision was an independent predictor of failure (HR 3.63; 95%CI 1.03–12.8), adjusted for gram-negative bacilli (GNB) infection (HR 2.68; 95%CI 0.91–7.89) and chronic renal impairment (HR 2.40; 95%CI 0.90–6.44). Treatment with biofilm-active antibiotics (rifampin/fluoroquinolones) had a favorable impact on infections caused by staphylococci and GNB. Conclusion Overall prognosis of PIOC-PJI is good, but close follow-up is required in cases of partial revision and in infections caused by GNB.

Resumen Objetivo Existe evidencia cientifica grado iv de la importancia que el antibiotico administrado preoperatoriamente tiene en la prevencion de la infeccion protesica. Hay controversia en si la isquemia aplicada en la cirugia de estos pacientes puede afectar a la concentracion minima inhibitoria del antibiotico en los tejidos periprotesicos. Para estudiar este fenomeno hemos disenado un estudio basado en la determinacion de la concentracion de antibiotico en el tejido sinovial. Material y metodo Estudio clinico prospectivo observacional de 32 pacientes intervenidos de protesis total de rodilla. Se administro 2 g de cefonicid como profilaxis y se utilizo el manguito de isquemia en todos los pacientes, cuantificandose la concentracion antibiotica mediante la cromatografia liquida de alta resolucion en muestras de tejido sinovial del inicio y del final de la intervencion. Resultados La concentracion media de antibiotico fue de 23,16 μg/g (IC del 95%, 19,19-27,13) en las muestras del inicio de la intervencion y de 15,45 μg/g (IC del 95%, 13,20-17,69) en las muestras del final, mostrandose superiores a la concentracion minima inhibitoria del cefonicid, establecida en 8 μg/g, siendo estos resultados estadisticamente significativos para ambas concentraciones (p Discusion La concentracion de antibiotico a lo largo de una intervencion estandar de protesis total de rodilla realizada con isquemia preventiva varia a lo largo de la intervencion sufriendo un descenso paulatino. Aun asi, la concentracion determinada al final de la intervencion no fue inferior a la concentracion minima inhibitoria del antibiotico estudiado. Como conclusion, la utilizacion del manguito de isquemia no aumenta el riesgo de infeccion.

Levofloxacin plus rifampicin (L+R) is the treatment of choice for acute staphylococcal prosthetic joint infection (PJI) managed with debridement and implant retention (DAIR). Long courses have been empirically recommended, but some studies have suggested that shorter treatments could be as effective. Our aim was to prove that a short treatment schedule was non-inferior to the standard long schedule. An open-label, multicentre, randomised clinical trial (RCT) was performed. Patients with an early post-surgical or haematogenous staphylococcal PJI, managed with DAIR and initiated on L+R were randomised to receive 8 weeks of treatment (short schedule) versus a long schedule (3 months or 6 months for hip or knee prostheses, respectively). The primary endpoint was cure rate. From 175 eligible patients, 63 were included (52% women; median age, 72 years): 33 patients (52%) received the long schedule and 30 (48%) received the short schedule. There were no differences between the two groups except for a higher rate of polymicrobial infection in the long-schedule group (27% vs. 7%; P = 0.031). Median follow-up was 540 days. In the intention-to-treat analysis, cure rates were 58% and 73% in patients receiving the long and short schedules, respectively (difference −15.7%, 95% CI −39.2% to 7.8%). Forty-four patients (70%) were evaluable per-protocol: cure rates were 95.0% and 91.7% for the long and short schedules, respectively (difference 3.3%, 95% CI −11.7% to 18.3%). This is the first RCT suggesting that 8 weeks of L+R could be non-inferior to longer standard treatments for acute staphylococcal PJI managed with DAIR.

Resumen Objetivo Valorar el resultado del recambio en un tiempo en el tratamiento de la infeccion protesica de la rodilla. Material y metodo Se efectuo una revision retrospectiva de 16 pacientes con un seguimiento medio de 7 anos. Se valoro la comorbilidad del paciente, el tipo de infeccion, el germen y la evolucion clinica de la rodilla. Se aplico el Knee Society Score (KSS) y el Knee Society Function Score (KSF) de la American Knee Society para su valoracion clinica y el estudio radiografico correspondiente. Resultados Se curo a 14 pacientes (87,5%) con unos resultados clinicos y funcionales muy satisfactorios (KSS = 80,78 y KSF = 75,07). El germen causal de las 2 reinfecciones fue el Staphylococcus epidermidis. Conclusiones El recambio en un tiempo es una opcion terapeutica valida para el tratamiento de la infeccion protesica, siempre que se indique y se efectue de forma rigurosa.

Purpose To review the results of one-step exchange in the infected total knee arthroplasy. Materials and method Restrospective study of 16 patients with a mean follow-up of 7 years. We studied the comorbidity of the patients, infection classification, microrganisms and clinical evaluation of the knee. We applied the Knee Score and Functional Score of the American Knee in order to carry out the corresponding clinical assessment and radiological study. Results In 14 patients (87,5%) the infection was eliminated with a good clinical and functional result (KS=80,78 and KSF=75,07). In the two remaining cases reinfections was caused by staphylococcus epidermidis. Conclusions One-step reimplantion is a good option for the treatment of infected total knee arthroplasty.

Objective There is level iv evidence that the preoperative administration of antibiotics helps in the prevention of prosthetic infection. There is controversy on whether the ischaemia applied during surgery may affect the minimum inhibitory concentration of the antibiotic in the peri-prosthetic tissues. The aim of this study is to review this phenomenon through the determination of antibiotic concentration in the synovial tissue. Material and method A prospective observational clinical study was conducted on 32 patients undergoing total knee replacement. Cefonicid 2 g was administered as prophylaxis, with a tourniquet used for all patients. The antibiotic concentration was quantified by high performance liquid chromatography in samples of synovial tissue collected at the beginning and at the end of the intervention. Results The mean concentration of antibiotic was 23.16 μg/g (95% CI 19.19–27.13) in the samples at the beginning of the intervention and 15.45 μg/g (95% CI 13.20–17.69) in the final samples, being higher than the minimum inhibitory concentration of cefonicid, set at 8 μg/g. These results were statistically significant for both concentrations ( P Discussion The antibiotic concentration throughout the standard total knee prosthesis surgery performed with tourniquet gradually decreases throughout the intervention. The concentration determined at the end of the intervention was higher than the minimum inhibitory concentration required for the antibiotic studied. In conclusion, the use of a tourniquet does not increase the risk of infection.

It is important to know the spectrum of the microbial aetiology of prosthetic joint infections (PJIs) to guide empiric treatment and establish antimicrobial prophylaxis in joint replacements. There are no available data based on large contemporary patient cohorts. We sought to characterize the causative pathogens of PJIs and to evaluate trends in the microbial aetiology. We hypothesized that the frequency of antimicrobial-resistant organisms in PJIs has increased in the recent years. We performed a cohort study in 19 hospitals in Spain, from 2003 to 2012. For each 2-year period (2003-2004 to 2011-2012), the incidence of microorganisms causing PJIs and multidrug-resistant bacteria was assessed. Temporal trends over the study period were evaluated. We included 2524 consecutive adult patients with a diagnosis of PJI. A microbiological diagnosis was obtained for 2288 cases (90.6%). Staphylococci were the most common cause of infection (1492, 65.2%). However, a statistically significant rising linear trend was observed for the proportion of infections caused by Gram-negative bacilli, mainly due to the increase in the last 2-year period (25% in 2003-2004, 33.3% in 2011-2012; p 0.024 for trend). No particular species contributed disproportionally to this overall increase. The percentage of multidrug-resistant bacteria PJIs increased from 9.3% in 2003-2004 to 15.8% in 2011-2012 (p 0.008), mainly because of the significant rise in multidrug-resistant Gram-negative bacilli (from 5.3% in 2003-2004 to 8.2% in 2011-2012; p 0.032). The observed trends have important implications for the management of PJIs and prophylaxis in joint replacements. N. Benito, (C) 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.