Introduction. Management of periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is a challenging task. Antibiotic management remains elusive due to differences in epidemiology and resistance between countries and reports. Increasing resistance of bacteria is a concern. The aim of this study was to investigate the development of antibiotic resistance of main causative bacteria in a single center. Methods. A retrospective review of all revision TKA between 2006 and 2018 in a tertiary referral center was performed. Included were cases meeting the consensus criteria for PJI with at least two positive cultures. Three chronological groups were created using a two-step cluster analysis. Results. In 129 cases of PJI there were 161 different bacteria identified by growth in culture. Of all bacteria 76.4% were gram positive, 23.6% were gram negative. Coagulase-negative Staphylococci (CNS) were diagnosed in 46.6% cultures, followed by Staphylococcus aureus in 19.8% of cultures. Overall antibiotic resistance (p=0.454) and Staphylococcus aureus resistance (p=0.788) have not increased during the study period. CNS resistance to teicoplanin (4% to 44%; p<0.001), fosfomycin (16% to 44%, p=0.016) and tetracycline (0% to 28%, p=0.014) increased significantly. Vancomycin had an 84.4% overall sensitivity and 100% CNS sensitivity and remained the most effective agent. Conclusion. The increasing resistance to several antibiotics over a little more than a decade is concerning. This study suggests that referral centres should continuously monitor obtained cultures as this has significant implications for both prophylactic treatment in primary as well as empirical antibiotic treatment in PJI. Resistance profiles may differ between centres and are subject to dynamic changes

Introduction. Surgical management of PJI remains challenging with patients failing treatment despite the best efforts. An important question is whether these later failures reflect reinfection or the persistence of infection. Proponents of reinfection believe hosts are vulnerable to developing infection and new organisms emerge. The alternative hypothesis is that later failure is a result of an organism that was present in the joint but was not picked up by initial culture or was not a pathogen initially but became so under antibiotic pressure. This multicenter study explores the above dilemma. Utilizing next-generation sequencing (NGS), we hypothesize that failures after two stage exchange arthroplasty can be caused by an organism that was present at the time of initial surgery but not isolated by culture. Methods. This prospective study involving 15 institutions collected samples from 635 revision total hip (n=310) and knee (n=325) arthroplasties. Synovial fluid, tissue and swabs were obtained intraoperatively for NGS analysis. Patients were classified per 2018 Consensus definition of PJI. Treatment failure was defined as reoperation for infection that yielded positive cultures, during minimum 1-year follow-up. Concordance of the infecting pathogen cultured at failure with NGS analysis at initial revision was determined. Results. Among the total cohort, 203 revisions were considered infected and 432 were aseptic (based on ICM-criteria). Of the infected cases, 157 were NGS-positive and 46 NGS-negative. Twenty-nine ICM-positive patients (29/157;18.5%) failed by reoperation with an organism confirmed on culture. In 23 of these (23/29;79.3%), the organism at failure was present on NGS at initial revision. The remaining 6 cases detected discordant organisms between initial NGS and culture at failure. Of the 432 ICM-negative patients, NGS identified microbes in 48.1% (208/432) of “aseptic” revisions, and 17 of these failed. Thirteen of the 17 failures (76.5%) were due to an organism previously detected by NGS at initial revision. Conclusion. Our collaborative findings suggest that most failures (79.3%) by infection recurrence could be attributed to an organism previously detected by NGS at index revision surgery. For any figures or tables, please contact the authors directly

Aims. The aim of this study was to determine if the local delivery of vancomycin and tobramycin in primary total knee arthroplasty (TKA) can achieve intra-articular concentrations exceeding the minimum inhibitory concentration thresholds for bacteria causing acute prosthetic joint infection (PJI). Methods. Using a retrospective single-institution database of all primary TKAs performed between January 1 2014 and May 7 2019, we identified patients with acute PJI that were managed surgically within 90 days of the initial procedure. The organisms from positive cultures obtained at the time of revision were tested for susceptibility to gentamicin, tobramycin, and vancomycin. A prospective study was then performed to determine the intra-articular antibiotic concentration on postoperative day one after primary TKA using one of five local antibiotic delivery strategies with tobramycin and/or vancomycin mixed into the polymethylmethacrylate (PMMA) or vancomycin powder. Results. A total of 19 patients with acute PJI after TKA were identified and 29 unique bacterial isolates were recovered. The mean time to revision was 37 days (6 to 84). Nine isolates (31%) were resistant to gentamicin, ten (34%) were resistant to tobramycin, and seven (24%) were resistant to vancomycin. Excluding one Fusobacterium nucleatum, which was resistant to all three antibiotics, all isolates resistant to tobramycin or gentamicin were susceptible to vancomycin and vice versa. Overall, 2.4 g of tobramycin hand-mixed into 80 g of PMMA and 1 g of intra-articular vancomycin powder consistently achieved concentrations above the minimum inhibitory concentrations of susceptible organisms. Conclusion. One-third of bacteria causing acute PJI after primary TKA were resistant to the aminoglycosides commonly mixed into PMMA, and one-quarter were resistant to vancomycin. With one exception, all bacteria resistant to tobramycin were susceptible to vancomycin and vice versa. Based on these results, the optimal cover for organisms causing most cases of acute PJI after TKA can be achieved with a combination of tobramycin mixed in antibiotic cement, and vancomycin powder. Cite this article: Bone Joint J 2020;102-B(6 Supple A):163–169

Introduction. Periprosthetic infection (PJI) after primary total knee arthroplasty (TKA) remains a challenging issue affecting 1–2% of cases. Locally delivered prophylactic antibiotics, including tobramycin or gentamicin mixed in polymethylmethacrylate (PMMA) bone cement and vancomycin powder, are increasingly used despite a lack of high quality evidence for either practice. In this study, we report the antibiotic susceptibility of organisms recovered in culture from patients with acute prosthetic joint infection after primary TKA to gentamicin, tobramycin and vancomycin. Methods. Using a retrospective database of all primary TKA performed at a single institution between January, 1 2014 and July 1, 2018, we identified 18 cases of acute PJI after primary TKA, as defined by the Musculoskeletal Infection Society 2011 guidelines as less than 3 months from symptoms or index surgery to presentation. The use of antibiotic bone cement during the index procedure and time to surgical management of the infection were recorded. Fluid cultures and tissue cultures were obtained intraoperatively at the time of revision. The organisms from positive cultures underwent MIC testing to gentamicin, tobramycin and vancomycin using a gradient diffusion method (ETEST). MIC breakpoints for susceptibility were based on Clinical and Laboratory Standards Institute definitions. Results. 18 cases of PJI after TKA were identified, including 4 polymicrobial infections (22.2%) (Table 1). Average time to revision for infection was 38 days (range: 6–84 days). 34.8% of bacterial isolates were resistant to gentamicin, 39.1% were resistant to tobramycin and 17.4% were resistant to vancomycin. Of the 8 bacterial isolates resistant to gentamicin, 7 (87.5%) were susceptible tobramycin. Of the 9 bacterial isolates resistant to tobramycin, (88.9%) were susceptible to vancomycin. One bacterial isolate, a Fusobacterium nucleatum from a polymicrobial infection was resistant to gentamicin, tobramycin and vancomycin. Conclusion. Over one third of bacteria causing acute PJI after primary TKA were resistant to the aminoglycosides pre-mixed in commercially available bone cements. All but one of the bacteria resistant to gentamicin and tobramycin were susceptible to vancomycin. The addition of vancomycin to bone cement or as powder in the surgical field has the potential to expand antibiotic coverage to include most organisms responsible for acute PJI after TKA. For figures, tables, or references, please contact authors directly

Introduction. Peri-prosthetic infections due to P. acnes may present as Prosthesis dysfunction without any obvious sepsis. We present our experience of efficient management of total knee prosthesis infection secondary to P. acnes which is one of the biggest case series. Materials and methods. From 2008 to 2009, 9 patients diagnosed with P. acnes infection after knee arthroplasty were retrospectively reviewed and analysed for clinical diagnosis; laboratory data (ESR, CRP); Radiological Imaging; number of days for culture growth of P acnes; organism sensitivities; antibiotic regimen and length of treatment and surgical management. Infection was diagnosed by 2 positive cultures. Results. Group 1 had 6 patients with confirmed knee prosthetic infection. 4 patients had no P.acnes detected from knee aspiration samples. All underwent two stage revisions. Group 2 had 3 patients with prosthesis dysfunction and pain without any obvious infection. All patients underwent frozen section histology test. Depending on results 2 patients with positive result had two stage revision surgeries and 1 patient with negative result had Single stage surgery. Antibiotics were administered for variable duration (4-10 weeks). In group 1 the average initial ESR and CRP were 45 mm/h and 28 mg/dl, respectively. 1. In group 2 average ESR was 15 and CRP was 6. The average number of days for positive culture was 6. All cultures were sensitive to Penicillin G and Vancomycin. All patients were treated successfully except one patient from group 1 who needed knee arthrodesis while one patient from group 2 received long term suppressive therapy. Discussion. P. acnes can cause peri-prosthetic infection where classical signs of sepsis are absent and therefore should be suspected in patients who present with subtle, delayed symptoms following joint arthroplasty. Many laboratories discard culture samples after 5 days. In our series the average time period for positive P. acnes culture is 6 days (range 5-10 days). The cultures may not be positive for as long as 10 days. So it is very important to keep the cultures for at least two weeks before discarding

Aims

Achievement of accurate microbiological diagnosis prior to revision is key to reducing the high rates of persistent infection after revision knee surgery. The effect of change in the microorganism between the first- and second-stage revision of total knee arthroplasty for periprosthetic joint infection (PJI) on the success of management is not clear.

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Fungal periprosthetic joint infections (PJIs) are rare, but their diagnosis and treatment are highly challenging. The purpose of this study was to investigate the clinical outcomes of patients with fungal PJIs treated with two-stage exchange knee arthroplasty combined with prolonged antifungal therapy.

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In cases of severe periprosthetic joint infection (PJI) of the knee, salvage procedures such as knee arthrodesis (KA) or above-knee amputation (AKA) must be considered. As both treatments result in limitations in quality of life (QoL), we aimed to compare outcomes and factors influencing complication rates, mortality, and mobility.

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The diagnosis of periprosthetic joint infection (PJI) continues to present a significant clinical challenge. New biomarkers have been proposed to support clinical decision-making; among them, synovial fluid alpha-defensin has gained interest. Current research methodology suggests reference methods are needed to establish solid evidence for use of the test. This prospective study aims to evaluate the diagnostic accuracy of high-performance liquid chromatography coupled with the mass spectrometry (LC-MS) method to detect alpha-defensin in synovial fluid.

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To map literature on prognostic factors related to outcomes of revision total knee arthroplasty (rTKA), to identify extensively studied factors and to guide future research into what domains need further exploration.

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Metal particles detached from metal-on-metal hip prostheses (MoM-THA) have been shown to cause inflammation and destruction of tissues. To further explore this, we investigated the histopathology (aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL) score) and metal concentrations of the periprosthetic tissues obtained from patients who underwent revision knee arthroplasty. We also aimed to investigate whether accumulated metal debris was associated with ALVAL-type reactions in the synovium.

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The outcome of repeat septic revision after a failed one-stage exchange for periprosthetic joint infection (PJI) in total knee arthroplasty (TKA) remains unknown. The aim of this study was to report the infection-free and all-cause revision-free survival of repeat septic revision after a failed one-stage exchange, and to determine whether the Musculoskeletal Infection Society (MSIS) stage is associated with subsequent infection-related failure.

Aims

The management of periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is challenging. The correct antibiotic management remains elusive due to differences in epidemiology and resistance between countries, and reports in the literature. Before the efficacy of surgical treatment is investigated, it is crucial to analyze the bacterial strains causing PJI, especially for patients in whom no organisms are grown.

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To describe the risk of periprosthetic joint infection (PJI) and reoperation in patients who have an acute, traumatic wound dehiscence following total knee arthroplasty (TKA).

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Debridement, antibiotics, and implant retention (DAIR) remains one option for the treatment of acute periprosthetic joint infection (PJI) despite imperfect success rates. Intraosseous (IO) administration of vancomycin results in significantly increased local bone and tissue concentrations compared to systemic antibiotics alone. The purpose of this study was to evaluate if the addition of a single dose of IO regional antibiotics to our protocol at the time of DAIR would improve outcomes.

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It remains difficult to diagnose early postoperative periprosthetic joint infection (PJI) following total knee arthroplasty (TKA). We aimed to validate the optimal cutoff values of ESR, CRP, and synovial fluid analysis for detecting early postoperative PJI in a large series of primary TKAs.

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For many designs of total knee arthroplasty (TKA) it remains unclear whether cemented or uncemented fixation provides optimal long-term survival. The main limitation in most studies is a retrospective or non-comparative study design. The same is true for comparative trials looking only at the survival rate as extensive sample sizes are needed to detect true differences in fixation and durability. Studies using radiostereometric analysis (RSA) techniques have shown to be highly predictive in detecting late occurring aseptic loosening at an early stage. To investigate the difference in predicted long-term survival between cemented, uncemented, and hybrid fixation of TKA, we performed a randomized controlled trial using RSA.

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In patients with a “dry” aspiration during the investigation of prosthetic joint infection (PJI), saline lavage is commonly used to obtain a sample for analysis. The aim of this study was to investigate prospectively the impact of saline lavage on synovial fluid analysis in revision arthroplasty.

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Periprosthetic joint infection (PJI) is a devastating complication following total knee arthroplasty (TKA). Two-stage revision has traditionally been considered the gold standard of treatment for established infection, but increasing evidence is emerging in support of one-stage exchange for selected patients. The objective of this study was to determine the outcomes of single-stage revision TKA for PJI, with mid-term follow-up.

Aims

The aim of this study was to assess the effects of transferring patients to a specialized arthroplasty centre between the first and second stages (interstage) of prosthetic joint infection (PJI) of the knee.