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Background: The challenges of culture-negative periprosthetic joint infection (PJI) have led to the emergence of molecular methods of pathogen identification, including next-generation sequencing (NGS). While its increased sensitivity compared with traditional culture techniques is well documented, it is not fully known which organisms could be expected to be detected with use of NGS. The aim of this study was to describe the NGS profile of culture-negative PJI., Methods: Patients undergoing revision hip or knee arthroplasty from June 2016 to August 2020 at 14 institutions were prospectively recruited. Patients meeting International Consensus Meeting (ICM) criteria for PJI were included in this study. Intraoperative samples were obtained and concurrently sent for both routine culture and NGS. Patients for whom NGS was positive and standard culture was negative were included in our analysis., Results: The overall cohort included 301 patients who met the ICM criteria for PJI. Of these patients, 85 (28.2%) were culture-negative. A pathogen could be identified by NGS in 56 (65.9%) of these culture-negative patients. Seventeen species were identified as common based on a study-wide incidence threshold of 5%. NGS revealed a polymicrobial infection in 91.1% of culture-negative PJI cases, with the set of common species contributing to 82.4% of polymicrobial profiles. Escherichia coli, Cutibacterium acnes, Staphylococcus epidermidis, and Staphylococcus aureus ranked highest in terms of incidence and study-wide mean relative abundance and were most frequently the dominant organism when occurring in polymicrobial infections., Conclusions: NGS provides a more comprehensive picture of the microbial profile of infection that is often missed by traditional culture. Examining the profile of PJI in a multicenter cohort using NGS, this study demonstrated that approximately two-thirds of culture-negative PJIs had identifiable opportunistically pathogenic organisms, and furthermore, the majority of infections were polymicrobial., Level of Evidence: Diagnostic Level II . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H102 )., (Copyright © 2022 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Identification of infective organism causing periprosthetic joint infections (PJIs) is crucial to tailor the best combination of surgical and antimicrobial treatment. Traditional culture, with all its limitations, has been utilized for this purpose. A synovial fluid antibody assay against some common pathogens has been introduced by a commercial entity recently. This study aimed to determine if the antibody testing could be used as a proxy to traditional culture, and whether it provided additional information, in the setting of PJI., Methods: A retrospective study was conducted of patients who underwent revision total hip and knee arthroplasty between January 2019 and 2020. Aspirated synovial fluid was sent for analyses including the commercial antibody testing. All patients had samples harvested for culture per standard of care. Results of the antibody testing and culture, in terms of concordance, were compared. Receiver operating characteristic curve and Youden's criterion were used to compare the 2 methods., Results: A total of 419 patients were included. Using the International Consensus Meeting criteria as reference standard for PJI, antibody testing had a sensitivity and specificity of 40.5% and 93.4%, respectively. There were 59.5% false negative results with antibody testing compared with 50% for culture. Of the 12 patients who had positive results in both tests, 5 (41.7%) had discordant pathogens identified in each test., Conclusion: Synovial fluid antibody testing does not provide clinical benefit when compared to traditional cultures for PJI diagnosis. The antibody testing had a low sensitivity and a high rate of discordance with culture, when both tests were positive., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Prior registry data suggest that perioperative red blood cell (RBC) transfusion may increase the incidence of venous thromboembolism (VTE) in patients status post surgery. However, there are limited data that explore VTE risk after perioperative transfusion in the setting of primary total joint arthroplasty (TJA). Our aim is to investigate the association between perioperative RBC transfusion and the development of symptomatic VTE after adjusting for confounding variables., Methods: We retrospectively reviewed all patients undergoing primary TJA at a single institution from 2001 to 2016. The primary outcome was development of symptomatic VTE (deep vein thrombosis or pulmonary embolism) up to 90 days following primary TJA. To identify the association between RBC transfusion and development of VTE, univariate and multivariate analyses were used, as well as a sensitivity analysis using propensity score matching based on patient comorbidities., Results: Of the 29,003 patients who underwent TJA, 2500 (8.62%) received RBC transfusion perioperatively and 302 (1.04%) developed a postoperative VTE within 90 days of surgery. While univariate analysis did suggest a slightly increased incidence of VTE in association with RBC transfusion (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.09-2.16), this difference was eliminated when multivariate analysis (OR, 0.42; 95% CI, 0.12-1.39) and propensity score matching (propensity-matched OR, 1.2; 95% CI, 0.7-1.8) were employed., Conclusion: Perioperative RBC transfusion does not significantly increase the incidence of symptomatic VTE following primary TJA in the 90-day postoperative period after adjustment for host VTE risk scores and other confounding variables. Perioperative RBC transfusion may be safely administered if indicated following total hip and knee arthroplasty., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Importance: Whether laminar airflow (LAF) in the operating room is effective for decreasing periprosthetic joint infection (PJI) after total joint arthroplasty remains a clinically important yet controversial issue., Objective: To investigate the association between operating room LAF ventilation systems and the risk of PJI in patients undergoing total joint arthroplasty., Design, Setting, and Participants: A retrospective cohort study was conducted of 6972 consecutive patients undergoing primary total knee arthroplasty or total hip arthroplasty at 2 surgical facilities within a single institution from January 1, 2013, to September 15, 2017, with a minimum of 1 year of follow-up. All procedures were performed by 5 board-certified arthroplasty surgeons. Statistical analysis was performed from January 1, 2014, to September 15, 2018., Exposure: Patients underwent total joint arthroplasty in operating rooms equipped with either LAF or turbulent airflow., Main Outcomes and Measures: Patient characteristics were extracted from clinical records. Periprosthetic joint infection was defined according to Musculoskeletal Infection Society criteria within 1 year of the index arthroplasty. A multivariable logistic regression model was performed to explore the potential association between LAF and risk of PJI at 1 year, and then a sensitivity analysis using propensity score matching was performed to further validate the findings., Results: A total of 6972 patients (2797 who underwent total knee arthroplasty and 4175 who underwent total hip arthroplasty; 3690 women [52.9%]; mean [SD] age, 63.9 [10.7] years) were included. The incidence of PJI within 1 year for patients from the facility without LAF was similar to that of patients from the facility with LAF (0.4% [12 of 3027] vs 0.5% [21 of 3945]). In the multivariable logistic regression analysis, after all confounding factors were taken into account, the use of LAF was not associated with a reduction of the risk of PJI (adjusted odds ratio, 0.94; 95% CI, 0.40-2.19; P = .89). After propensity score matching, there was no significant difference in the incidence of PJI within 1 year for patients who underwent total joint arthroplasty at these 2 sites., Conclusions and Relevance: This study suggests that the use of LAF in the operating room was not associated with a reduced incidence of PJI after primary total joint arthroplasty. With an appropriate perioperative protocol for infection prevention, LAF does not seem to play a protective role in PJI prevention.

Background: Although there is an increasing trend toward reporting the outcome of hip and knee arthroplasty separately, it remains unknown whether joint-specific reporting is necessary for periprosthetic joint infection (PJI) as sample sizes are already low, given its relatively rare occurrence. The aim of this study is to compare treatment outcomes of PJI occurring after knee and hip arthroplasty. Furthermore, we aim to establish the necessary follow-up time for an accurate reporting of PJI treatment outcomes., Methods: A retrospective study of 792 cases of hip and knee PJI treated with irrigation and debridement or two-stage exchange arthroplasty from 2000 to 2017 was performed. Treatment failure was defined based on the Delphi method-based criteria. The Kaplan-Meier survivorship curves were generated, and a log-rank test was used to evaluate differences in survivorship. A multivariate Cox proportional hazards regression and a sensitivity analysis using propensity matching were performed. A two-piecewise linear regression model was used to examine the threshold effect of time after treatment on survival rates., Results: There were no significant differences between hip and knee PJIs in overall survivorship (P = .71), or when stratified by irrigation and debridement (P = .39), or two-stage exchange arthroplasty (P = .59). There was also no difference by joint in the multivariate or sensitivity analysis. Survival rates had the most dramatic rates of decrease in the initial months after treatment of PJI but began to plateau after 1.09 years., Conclusion: This study reveals no difference in treatment outcomes between knee and hip PJIs. In addition, given the difficulty with obtaining follow-up, we suggest that one-year follow-up is sufficient for an accurate reporting of treatment failure., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: It is unknown whether the outcomes of treatment for periprosthetic joint infection (PJI) are improving with time. This study evaluated trends in PJI treatment outcomes in the hip and knee following 2-stage exchange arthroplasty and irrigation and debridement (I&D) over the last 17 years., Methods: We reviewed 550 two-stage exchange arthroplasties and 194 I&Ds between 2000 and 2016 at our institution. Treatment success was defined according to the Delphi consensus criteria and Kaplan-Meier survivorship curves were generated. A multivariate Cox proportional hazards regression model was generated to determine time trends in the outcome of PJI treatment with the year of surgery included as both a continuous covariate (per 1-year increase) and a categorical covariate (2000-2010 or 2011-2016)., Results: The survivorship of I&D, 2-stage revision, and the total combined cohort were comparable between 2000-2010 and 2011-2016 groups. Multivariate Cox regression analysis showed that the year of surgery was not associated with treatment failure following an I&D or 2-stage exchange arthroplasty, and neither did it increase the risk of non-reimplantation. When year of surgery was considered as a categorical variable, there remained no significant difference in treatment failure following an I&D or 2-stage exchange arthroplasty between the 2000-2010 cohort and 2011-2016 cohort., Conclusion: Despite the increasing clinical focus, research advances, and growing literature relating to PJI, we were unable to detect any substantial improvement in the treatment success rates of PJI at our institution over the 17 years examined in this study. Novel treatments and techniques are certainly needed as current and prior strategies remain far from optimal., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Introduction: A common question by patients considering total joint arthroplasty (TJA) is when can I return to driving. The ability to return to driving has enormous effect on the independence of the patient, ability to return to work, and other activities of daily living. With advances in accelerated rehabilitation protocols, newer studies have questioned the classic teaching of waiting 6 weeks after TJA. The goal of this prospective study was to determine specific patient predictors for return to driving and create individualized models able to estimate return to driving based on patient risk factors for both total knee arthroplasty (TKA) and total hip arthroplasty (THA)., Methods: From July 2017 to January 2018, 554 primary TKA and 490 primary THA patients were prospectively enrolled to obtain information regarding return to driving. Patients were sent a survey every 2 weeks regarding their return to driving. Additional information regarding vehicle type, transmission, and involvement in motor vehicle accidents was collected. Bivariate analysis was done followed by the creation of a multiple linear regression models to analyze return to driving after TKA and THA., Results: The majority (98.2%, 1,025/1,044) of patients returned to driving within 12 weeks of surgery. On average, patients returned to driving at 4.4 and 3.7 weeks for TKA and THA (P < 0.001), respectively. The rate of motor vehicle accidents was 0.7% (7/1,044) within 12 weeks after surgery with no injuries reported. After multivariate analysis, baseline return to driving began at 10.9 days for TKA and 17.1 days for THA. The following predictors added additional time to return to driving for TJA: not feeling safe to drive, limited range of motion, female sex, limitations due to pain, other limitations, discharge to a rehabilitation facility, right-sided procedures, limited ability to break, preoperative anemia, and preoperative use of a cane., Discussion: Important predictors identified for return to driving were sex, joint laterality, limited ability to walk or ability to break, and feeling safe. Surgeons should consider these factors when counseling patients on their postoperative expectations regarding driving after TJA.

Background: Glucose variability in the postoperative period has been associated with increased rates of periprosthetic joint infection (PJI) following primary arthroplasty. It is unknown how postoperative glucose control affects outcome of surgical treatment of PJI patients. We hypothesized that postoperative glucose variability adversely affects the outcome of 2-stage exchange arthroplasty., Methods: We retrospectively reviewed records of 665 patients with PJI of the knee and hip who underwent 2-stage exchange arthroplasty from 2000 to 2017. Of them, 341 PJIs with a minimum follow-up of 1 year, and either a minimum of 2 glucose values per day or greater than 3 overall during the reimplantation were included. Glucose variability was assessed by calculating the coefficient of variation. Adverse outcomes included treatment failure according to the Delphi consensuses criteria, reinfection, reoperation, and mortality. A subgroup analysis was performed based on patients with or without diabetes., Results: Glucose variability following reimplantation was associated with higher treatment failure, reinfection, and reoperation. Adjusted analysis indicated that for every standard deviation (15%) increase in the coefficient of variation, the risks of treatment failure, reinfection, and reoperation increased by 27%, 31%, and 26%. Although stratifying patients with (n = 81) or without diabetes (n = 260), these associations remained robust in nondiabetic patients, but not in diabetic patients., Conclusion: Higher glucose variability is associated with increased risks of treatment failure, reinfection, and reoperation after 2-stage exchange arthroplasty in PJI patients. Compared to diabetic patients, nondiabetic patients have a higher association between glucose variability and poor outcomes. Reducing adverse outcomes may be achieved with close monitoring and strict postoperative glucose control., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Total joint arthroplasty (TJA) can be successfully carried out under general (GA) or spinal anesthesia (SA). The existing literature does not adequately illustrate which technique is optimal. The purpose of this study is to prospectively compare the effects of anesthesia technique on TJA outcomes., Methods: This 2-year, prospective, observational study was conducted at a single institution where patients receiving primary TJA were consecutively enrolled. Patients were contacted postoperatively to assess for any 90-day complications. The primary outcome of the study was the overall complication rate., Results: A total of 2242 patients underwent total hip arthroplasty (n = 656; 29.26%) or total knee arthroplasty (n = 1586; 70.74%) between 2015 and 2017. Of these procedures, 1325 (59.10%) were carried out under SA and 917 (40.90%) were carried out under GA. Patients in the GA cohort had higher mean Charlson Comorbidity Index scores (0.05 SA vs 0.09 GA; P < .05) and higher average body mass index (29.35 SA vs 30.24 GA; P < .05). On multivariate analysis, patients in the SA cohort had a significantly lower overall complication rate relative to their GA counterparts (7.02% vs 10.14%; odds ratio, 0.66; 95% confidence interval, 0.49-0.90; P < .05). In addition, length of stay in the GA cohort was significantly longer (2.43 [SD, 1.62] vs 2.18 [SD, 0.88] days; P < .01) and a larger percentage of GA patients were discharged to a nursing facility (32.28% vs 25.06%; odds ratio, 0.55; 95% confidence interval, 0.44-0.70; P < .05)., Conclusion: Our study demonstrates that SA for TJA is associated with a decrease in overall complications and healthcare resource utilization., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Chronic renal failure (CRF) is an established risk factor for surgical site infection (SSI) and periprosthetic joint infection (PJI) after primary total joint arthroplasty. However, there is limited literature comparing outcomes between patients who receive dialysis vs renal transplantation. We examined and compared clinical outcomes of patients receiving dialysis vs those who had a prior renal transplantation., Methods: We retrospectively identified 107 patients undergoing primary total joint arthroplasty between 2000 and 2017, who were receiving dialysis (n = 50), or had a prior renal transplantation (n = 57). The cohorts were compared with respect to postoperative complications, including 90-day SSI, PJI, and failure resulting in revision procedure. Multivariate analysis was performed to determine independent risk factors for complications and revision., Results: A significantly higher rate of postoperative complications was seen in dialysis patients (28.0%) compared with renal transplant (7.1%). In particular, increased SSI and PJI rates were observed in dialysis group compared with the transplant cohort (18.0% vs 3.5%). In addition, increased revision rates (24.0% vs 3.5%) and decreased survivorship for the implant were observed in dialysis patients. Multivariate analysis revealed that patients with renal transplant were less likely to require revision arthroplasty and that total knee arthroplasty (vs total hip arthroplasty) was an independent risk factor for failure in dialysis patients., Conclusion: This study provides further evidence that patients on dialysis who are on transplant list should await arthroplasty until transplant has taken place. In dialysis patients who are not transplant candidates, extreme care should be exercised, and additional strategies used to minimize the high complication rate that may be encountered., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Previous studies have demonstrated preoperative anemia to be a strong risk factor for periprosthetic joint infection (PJI) in total joint arthroplasty (TJA). Allogeneic blood transfusion can be associated with increased risk of PJI after primary and revision TJA. Tranexamic acid (TXA) is known to reduce blood loss and the need for allogeneic blood transfusion after TJA. The hypothesis of this study is that administration of intravenous TXA would result in a reduction in PJI after TJA., Methods: An institutional database was utilized to identify 6340 patients undergoing primary TJA between January 1, 2013 and June 31, 2017 with a minimum of 1-year follow-up. Patients were divided into 2 groups based on whether they received intravenous TXA prior to TJA or not. Patients who developed PJI were identified. All PJI patients met the 2018 International Consensus Meeting definition for PJI. A multivariate regression analysis was performed to identify variables independently associated with PJI., Results: Of the patients included, 3683 (58.1%) received TXA and 2657 (41.9%) did not. The overall incidence of preoperative anemia was 16%, postoperative blood transfusion 1.8%, and PJI 2.4%. Bivariate analysis showed that patients who received TXA were significantly at lower odds of infection. After adjusting for all confounding variables, multivariate regression analysis showed that TXA is associated with reduced PJI after primary TJA., Conclusion: TXA can help reduce the rate of PJI after primary TJA. This protective effect is likely interlinked to reduction in blood loss, lower need for allogeneic blood transfusion, and issues related to immunomodulation associated with blood transfusion., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Two-stage exchange arthroplasty remains a popular surgical treatment for patients with chronic periprosthetic joint infection (PJI). Patients who do not receive reimplantation were largely overlooked in the current literature. We aimed at investigating the clinical outcomes of these patients., Methods: Our institutional PJI database was retrospectively reviewed to identify 616 patients (237 hips, 379 knees) who were treated with an intended 2-stage exchange. Of them, 111 (18%) did not receive reimplantation within a minimum follow-up of 1 year. Chart review and targeted interviews were performed to elucidate the cause of attrition. Patients were considered to have failed treatment in the absence of reimplantation if they remained medically unfit for reimplantation, underwent a salvage procedure, or died during the study period., Results: Of the 111 patients without reimplantation, 29 (26.1%) did well with their retained spacer and were unwilling to proceed with reimplantation, 23 (20.7%) underwent salvage procedures, and the remaining 59 (53.2%) were considered medically unfit for reimplantation, with 34 of them dying within 1 year of initial spacer insertion. The overall success rate for 2-stage exchange cohort at 2 years was 65.7% when treatment failure without reimplantation was taken into account. Several factors associated with increased risk of treatment failure without reimplantation were identified using a multivariate regression model., Conclusion: Almost 1 in 5 patients may never receive the intended reimplantation. Among many reasons for attrition, mortality appears to be a relatively common event. The current definition of treatment success does not take into account the attrition group and thus inflates the relative success of 2-stage exchange arthroplasty., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Diagnosing acute periprosthetic joint infection remains a challenge. Several studies have proposed different acute cutoffs resulting in the International Consensus Meeting recommending a cutoff of 100 mg/L, 10,000 cell/μL and 90% for serum C-reactive protein (CRP), synovial white blood cell count (WBC), and polymorphonuclear percentage (PMN%), respectively. However, establishing cutoffs are difficult as the control group is limited to rare early aseptic revisions, and performing aspiration in asymptomatic patients is difficult because of a fear of seeding a well-functioning joint arthroplasty. This study (1) assessed the sensitivity of current thresholds for acute periprosthetic joint infection (PJI) and (2) identified associated factors for false negatives., Methods: We retrospectively reviewed patients with acute PJIs (n = 218), defined as less than 6 weeks from index arthroplasty, treated between 2000 and 2017. Diagnosis of PJI was based on 2 positive cultures of the same pathogen from the periprosthetic tissue or synovial fluid samples. Sensitivities of International Consensus Meeting cutoff values of CRP, synovial WBC, and PMN% were evaluated according to organism type. Multiple logistic regression analysis was performed to determine associated factors for false negatives., Results: Overall, the sensitivity of CRP, synovial WBC, and PMN% for acute PJI was 55.3%, 59.6%, and 50.5%, respectively. Coagulase-negative Staphylococcus (CNS) demonstrated the lowest sensitivity for both CRP (37.5%) and WBC (55.6%). CNS infection was identified as an independent risk factor for false-negative CRP., Conclusions: Current thresholds for acute PJI may be missing approximately half of PJIs. Low virulent organisms, such as CNS, may be responsible for these false negatives. Current thresholds for acute PJI must be reexamined., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Patients with periprosthetic joint infection (PJI) undergoing 2-stage exchange arthroplasty may undergo an interim spacer exchange for a variety of reasons including mechanical failure of spacer or persistence of infection. The objective of this study is to understand the risk factors and outcomes of patients who undergo spacer exchange during the course of a planned 2-stage exchange arthroplasty., Methods: Our institutional database was used to identify 533 patients who underwent a 2-stage exchange arthroplasty for PJI, including 90 patients with a spacer exchange, from 2000 to 2017. A retrospective review was performed to extract relevant clinical information. Treatment outcomes included (1) progression to reimplantation and (2) treatment success as defined by a Delphi-based criterion. Both univariate and multivariate Cox regression models were performed to investigate whether spacer exchange was associated with failure. Additionally, a propensity score analysis was performed based on a 1:2 match., Results: A spacer exchange was required in 16.9%. Patients who underwent spacer exchanges had a higher body mass index (P < .001), rheumatoid arthritis (P = .018), and were more likely to have PJI caused by resistant (0.048) and polymicrobial organisms (P = .007). Patients undergoing a spacer exchange demonstrated lower survivorship and an increased risk of failure in the multivariate and propensity score matched analysis compared to patients who did not require a spacer exchange., Discussion: Despite an additional load of local antibiotics and repeat debridement, patients who underwent a spacer exchange demonstrated poor outcomes, including failure to undergo reimplantation and twice the failure rate. The findings of this study may need to be borne in mind when managing patients who require spacer exchange., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Aims: The best marker for assessing glycaemic control prior to total knee arthroplasty (TKA) remains unknown. The purpose of this study was to assess the utility of fructosamine compared with glycated haemoglobin (HbA1c) in predicting early complications following TKA, and to determine the threshold above which the risk of complications increased markedly., Patients and Methods: This prospective multi-institutional study evaluated primary TKA patients from four academic institutions. Patients (both diabetics and non-diabetics) were assessed using fructosamine and HbA1c levels within 30 days of surgery. Complications were assessed for 12 weeks from surgery and included prosthetic joint infection (PJI), wound complication, re-admission, re-operation, and death. The Youden's index was used to determine the cut-off for fructosamine and HbA1c associated with complications. Two additional cut-offs for HbA1c were examined: 7% and 7.5% and compared with fructosamine as a predictor for complications., Results: Overall, 1119 patients (441 men, 678 women) were included in the study. Fructosamine level of 293 µmol/l was identified as the optimal cut-off associated with complications. Patients with high fructosamine (> 293 µmol/l) were 11.2 times more likely to develop PJI compared with patients with low fructosamine (p = 0.001). Re-admission and re-operation rates were 4.2 and 4.5 times higher in patients with fructosamine above the threshold (p = 0.005 and p = 0.019, respectively). One patient (1.7%) from the elevated fructosamine group died compared with one patient (0.1%) in the normal fructosamine group (p = 0.10). These complications remained statistically significant in multiple regression analysis. Unlike fructosamine, all three cut-offs for HbA1c failed to show a significant association with complications., Conclusion: Fructosamine is a valid and an excellent predictor of complications following TKA. It better reflects the glycaemic control, has greater predictive power for adverse events, and responds quicker to treatment compared with HbA1c. These findings support the screening of all patients undergoing TKA using fructosamine and in those with a level above 293 µmol/l, the risk of surgery should be carefully weighed against its benefit. Cite this article: Bone Joint J 2019;101-B(7 Supple C):3-9.

Background: A sinus tract may be encountered in patients with periprosthetic joint infection (PJI) and constitutes a major criterion for diagnosis. The aim of this study is to identify associated factors for the presence of sinus tract and outcome of 2-stage exchange arthroplasty in these patients., Methods: We retrospectively reviewed all patients with PJI following hip and knee arthroplasty from 2000 to 2017. Of them, 161 patients with a sinus tract had a minimum follow-up of 1 year following 2-stage exchange arthroplasty. These patients were matched 1:2 with those without sinus tract by using propensity score matching. Treatment success was assessed using the modified Delphi criteria. A multiple logistic regression analysis was performed to determine the effect of sinus tract on the outcome and associated factors for the presence of sinus tract., Results: Factors significantly associated with sinus tract included smoking (odds ratio [OR] = 1.83), hypothyroidism (OR = 1.62), hypoalbuminemia (OR = 1.52), hip joint involvement (OR = 1.43), and prior revision surgery (OR = 1.37). Patients with sinus tract had a significantly higher rate of failure compared to those without sinus tract (OR = 2.94)., Conclusion: This study demonstrates that the presence of sinus tract in patients with PJI adversely affects the outcome of treatment of these patients. The presence of sinus tract may be a proxy for other issues such as poor periarticular soft tissue, the poor nutritional status of the host, and multiple prior operations. These findings need to be borne in mind when treating patients with PJI and a concomitant sinus tract., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Whether prolonged operative time is an independent risk factor for subsequent surgical site infection (SSI) and periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) remains a clinically significant and underexplored issue. The aim of this study is to investigate the association between operative time and the risk of subsequent SSI and PJI in patients undergoing primary TJA., Methods: We retrospectively reviewed 17,342 primary unilateral total knee arthroplasty and total hip arthroplasty performed at a single institution between 2005 and 2016, with a minimum follow-up of 1 year. A multivariate logistic regression model was conducted to identify the association between operative time and the development of SSI within 90 days and PJI within 1 year., Results: Overall, the incidence of 90-day SSI and 1-year PJI was 1.2% and 0.8%, respectively. Patients with an operative time of >90 minutes had a significantly higher incidence of SSI and PJI (2.1% and 1.4%, respectively) compared to cases lasting between 60 and 90 minutes (1.1% and 0.7%), and those lasting ≤60 minutes (0.9% and 0.7%, P < .01). In the multivariate model, the risk for infection increased by an odds ratio of 1.346 (95% confidential interval 1.114-1.627) for 90-day SSI and 1.253 (95% confidential interval 1.060-1.481) for 1-year PJI for each 20-minute increase in operative time., Conclusion: In patients undergoing primary TJA, each 20-minute increase in operative time was associated with nearly a 25% increased risk of subsequent PJI. We advocate that surgeons pay close attention to this underappreciated risk factor while maintaining safe operative practices, which minimize unnecessary steps and wasted time in the operating room., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Acute periprosthetic joint infection (PJI) is difficult to treat. In this study, we investigated the failure rates of irrigation and debridement (I&D) among patients with acute post-surgical and acute hematogenous PJI, and explored various host and organism-related risk factors that may be associated with treatment failure., Methods: We retrospectively reviewed the cases of 199 total joint arthroplasty patients who underwent I&D for acute post-surgical PJI (<3 months postoperatively) and acute hematogenous PJI (≥3 months postoperatively, with abrupt symptoms lasting <3 weeks) at a single center during the period of 2005 to 2016. Only patients meeting the Musculoskeletal Infection Society (MSIS) criteria for PJI were included. Patient demographics, comorbidities, physical examination findings, laboratory results, and organism profile were identified. Treatment failure, as defined by the Delphi criteria, was determined for 1-year follow-up. Primary statistical analysis involved univariate and multivariate regression., Results: The failure rate was 37.7% (75 of 199) at 1 year. Among the patients with acute hematogenous infections, the rate of failure (56%, 29 of 52) was almost 2 times higher than that of patients with acute post-surgical infections (31%, 46 of 147) (adjusted odds ratio [OR], 2.36; 95% confidence interval [CI], 1.16 to 4.81; p = 0.018). Host predictors of failure included prior revision surgery (adjusted OR, 2.55; 95% CI, 1.22 to 5.32; p = 0.013) and a higher Charlson Comorbidity Index (adjusted OR, 1.22; 95% CI, 1.01 to 1.51; p = 0.048). Specific comorbidities associated with failure included chronic obstructive pulmonary disease (p = 0.026), diabetes (p = 0.004), and a history of malignancy (p = 0.005). Patients with polymicrobial infections (adjusted OR, 2.40; 95% CI, 1.10 to 5.20; p = 0.028) were also more likely to experience failure of treatment after I&D. The clinical and laboratory risk factors associated with failure were the presence of intraoperative purulence (p = 0.05), elevated systolic blood pressure (p = 0.05), tachycardia (p = 0.06), and higher serum C-reactive protein level (p = 0.003)., Conclusions: This study revealed that I&D is associated with a high rate of failure for patients with an acute hematogenous PJI. The study also identified a number of risk factors for failure. The findings of this study may allow better decision-making by surgeons regarding the surgical management of patients with acute PJI., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background: Recent surgical site infection prevention guidelines recommend that no additional prophylactic antibiotics be administered after the surgical incision is closed in clean-contaminated procedures. Although there is ample evidence to support this recommendation in non-arthroplasty surgery, there is concern about extending these guidelines to surgical procedures with an implant such as total joint arthroplasty (TJA). The aim of this study was to compare the efficacy of a single dose of prophylactic antibiotics with that of multiple doses of antibiotics for prevention of periprosthetic joint infection (PJI) in patients undergoing TJA., Methods: A retrospective study of 20,682 primary TJAs carried out from 2006 to 2017 was performed. Patients who received a single dose of prophylactic antibiotics (n = 4,523) were compared with patients who received multiple doses of antibiotics (n = 16,159). A previously validated PJI risk score was assigned to each patient. Patients who developed PJI within 1 year were identified, and a multivariate logistic regression analysis was performed to control for potential confounders. Analyses using propensity score matching and regression adjustment were also performed., Results: The overall PJI rate was 0.60% (27 of 4,523) for patients who received a single dose of antibiotics compared with 0.88% (142 of 16,159) for those who received multiple doses. There was no difference in the PJI rate between patients who received a single dose of antibiotics and those who received multiple doses in the univariate (adjusted odds ratio [OR] = 0.674, p = 0.064), multivariate (OR = 0.755, p = 0.205), or propensity score matched analysis (OR = 0.746, p = 0.277). Furthermore, multiple doses did not demonstrate any additional benefit for patients with a high preoperative risk of PJI (p = 0.136)., Conclusions: This study supports the notion that the administration of additional antibiotics following skin closure may not be required for primary TJA, regardless of the patient's preoperative risk of PJI. The findings of this large retrospective study highlight the need for a randomized, prospective study on which to base guidelines., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background: Two-stage exchange arthroplasty remains the preferred surgical treatment method for patients with chronic periprosthetic joint infection (PJI). The success of this procedure is not known exactly as various definitions of success have been used. This study aimed at analyzing the difference in outcome following 2-stage exchange arthroplasty using different definitions for success., Methods: A retrospective study of 703 patients with PJI who underwent resection arthroplasty and spacer insertion between January 1999 and June 2015 was performed. Chart review identified intraoperative cultures at the time of spacer, reimplantation, and any subsequent reinfections or surgeries following spacer insertion. After applying the exclusion criteria, a total of 570 patients were included in the analysis. Five definitions of treatment success were assessed: (1) Delphi consensus success, (2) modified Delphi consensus success, (3) microbiological success, (4) implant success, and (5) surgical success., Results: Of the 570 patients with PJIs, 458 were reimplanted at a mean of 4.1 months. Mortality was 13.9% with 6.7% occurring before reimplantation. Treatment success was highly variable depending on the definition used (54.2%-88.9%). In 19.6% of PJI cases, the Delphi consensus definition could not be assessed as reimplantation never occurred. Furthermore, 67.0% of these patients underwent reoperations, which may not be accounted for in the Delphi consensus definition., Conclusion: Treatment success rates vary dramatically depending on the definition used at our institution. We hope these definitions can help bring forth awareness for standardized reporting of outcomes, but further validation and agreement of these definitions among surgeons and infectious disease physicians is crucial., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Opioids have well-known immunosuppressive properties and preoperative opioid consumption is relatively common among patients undergoing total joint arthroplasty (TJA). The hypothesis of this study was that utilization of opioids preoperatively would increase the incidence of subsequent periprosthetic joint infection (PJI) in patients undergoing primary TJA., Methods: A comparative cohort study design was set up that used a cohort of 23,754 TJA patients at a single institution. Patient records were reviewed to extract relevant information, in particular details of opioid consumption, and an internal institutional database of PJI was cross-referenced against the cohort to identify patients who developed a PJI within 2 years of index arthroplasty. Univariate and multivariate linear regression analyses were used to examine the potential association between preoperative opioid consumption and the development of PJI., Results: Among the total cohort of 23,754 patients, 5051 (21.3%) patients used opioids before index arthroplasty. Preoperative opioid usage overall was found to be a significant risk factor for development of PJI in the univariate (odds ratio, 1.63; P = .005) and multivariate analyses (adjusted odds ratio, 1.53 [95% confidence interval, 1.14-2.05], P = .005)., Conclusion: Preoperative opioid consumption is independently associated with a higher risk of developing a PJI after primary TJA. These findings underscore a need for caution when prescribing opioids in patients with degenerative joint disease who may later require arthroplasty., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: While the preferred surgical treatment for chronic periprosthetic joint infection (PJI) in North America is a 2-stage exchange arthroplasty, the optimal time between first-stage and reimplantation surgery remains unknown. This study was conceived to examine the association between time to reimplantation and treatment failure., Methods: Using an institutional database, we identified PJI cases treated with 2-stage exchange arthroplasty between 2000 and 2016. Musculoskeletal Infection Society criteria were used to define PJI, and treatment failure was defined using Delphi criteria. The interstage interval between first-stage and reimplantation surgery for each case was collected, alongside demographics, patient-related and organism-specific data. Multivariate logistic regression analyses were used to examine association with treatment failure., Results: Our final analysis consisted of 282 patients with an average time to reimplantation of 100.2 days (range, 20-648). Sixty-three patients (22.3%) failed at 1 year based on Delphi criteria. Time to reimplantation was not significantly associated with failure in both univariate (P = .598) and multivariate (P = .397) models. However, patients reimplanted at >26 weeks were twice as likely to fail in comparison to those reimplanted within <26 weeks (43.8% vs 21.1%), and this finding reached marginal significance (P = .057). Patients who failed had significantly more comorbidities (P = .008). Charlson comorbidity index was the only variable significantly associated with treatment failure in regression analysis (odds ratio, 1.40; 95% confidence interval, 1.06-1.86; P = .019)., Conclusion: The length of the interstage interval was not a statistically significant predictor of failure in patients undergoing 2-stage exchange arthroplasty for PJI., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Inpatient rehabilitation facilities (IRFs) and skilled nursing facilities (SNFs) represent a significant portion of post-operative expenses of bundled payments for total knee arthroplasty (TKA). Although many surgeons no longer routinely send patients to IRFs or SNFs, some patients are unable to be discharged directly home. This study identified patient factors for discharge to post-acute care facilities with an institutional protocol of discharging TKA patients home., Methods: A retrospective review of patients undergoing primary unilateral TKA at a single institution from 2012 to 2017 was performed. All surgeons discharged patients home as a routine protocol. An electronic query followed by manual review identified discharge disposition, demographic factors, co-morbidities, and other patient factors. In total, 2281 patients were identified, with 9.6% discharged to SNFs or IRFs and 90.4% discharged home. Univariate and multivariate analyses were conducted to create 2 predictive models for patient discharge: pre-operative visit and hospital course., Results: Among 43 variables studied, 6 were found to be significant pre-operative risk factors for a discharge disposition other than home. In descending order, age 75 or greater, female, non-Caucasian race, Medicare status, history of depression, and Charlson Comorbidity Index were predictors for patients going to IRFs. In addition, any in-hospital complications led to a higher likelihood of being discharged to IRFs and SNFs. Both models had excellent predictive assessments with area under curve values of 0.79 and 0.80 for pre-operative visit and hospital course., Conclusion: This study identifies pre-operative and in-hospital factors that predispose patients to non-routine discharges, which allow surgeons to better predict patient post-operative disposition., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: The introduction of the Musculoskeletal Infection Society (MSIS) criteria for periprosthetic joint infection (PJI) in 2011 resulted in improvements in diagnostic confidence and research collaboration. The emergence of new diagnostic tests and the lessons we have learned from the past 7 years using the MSIS definition, prompted us to develop an evidence-based and validated updated version of the criteria., Methods: This multi-institutional study of patients undergoing revision total joint arthroplasty was conducted at 3 academic centers. For the development of the new diagnostic criteria, PJI and aseptic patient cohorts were stringently defined: PJI cases were defined using only major criteria from the MSIS definition (n = 684) and aseptic cases underwent one-stage revision for a noninfective indication and did not fail within 2 years (n = 820). Serum C-reactive protein (CRP), D-dimer, erythrocyte sedimentation rate were investigated, as well as synovial white blood cell count, polymorphonuclear percentage, leukocyte esterase, alpha-defensin, and synovial CRP. Intraoperative findings included frozen section, presence of purulence, and isolation of a pathogen by culture. A stepwise approach using random forest analysis and multivariate regression was used to generate relative weights for each diagnostic marker. Preoperative and intraoperative definitions were created based on beta coefficients. The new definition was then validated on an external cohort of 222 patients with PJI who subsequently failed with reinfection and 200 aseptic patients. The performance of the new criteria was compared to the established MSIS and the prior International Consensus Meeting definitions., Results: Two positive cultures or the presence of a sinus tract were considered as major criteria and diagnostic of PJI. The calculated weights of an elevated serum CRP (>1 mg/dL), D-dimer (>860 ng/mL), and erythrocyte sedimentation rate (>30 mm/h) were 2, 2, and 1 points, respectively. Furthermore, elevated synovial fluid white blood cell count (>3000 cells/μL), alpha-defensin (signal-to-cutoff ratio >1), leukocyte esterase (++), polymorphonuclear percentage (>80%), and synovial CRP (>6.9 mg/L) received 3, 3, 3, 2, and 1 points, respectively. Patients with an aggregate score of greater than or equal to 6 were considered infected, while a score between 2 and 5 required the inclusion of intraoperative findings for confirming or refuting the diagnosis. Intraoperative findings of positive histology, purulence, and single positive culture were assigned 3, 3, and 2 points, respectively. Combined with the preoperative score, a total of greater than or equal to 6 was considered infected, a score between 4 and 5 was inconclusive, and a score of 3 or less was not infected. The new criteria demonstrated a higher sensitivity of 97.7% compared to the MSIS (79.3%) and International Consensus Meeting definition (86.9%), with a similar specificity of 99.5%., Conclusion: This study offers an evidence-based definition for diagnosing hip and knee PJI, which has shown excellent performance on formal external validation., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Aims: The diagnosis of periprosthetic joint infection can be difficult due to the high rate of culture-negative infections. The aim of this study was to assess the use of next-generation sequencing for detecting organisms in synovial fluid., Materials and Methods: In this prospective, single-blinded study, 86 anonymized samples of synovial fluid were obtained from patients undergoing aspiration of the hip or knee as part of the investigation of a periprosthetic infection. A panel of synovial fluid tests, including levels of C-reactive protein, human neutrophil elastase, total neutrophil count, alpha-defensin, and culture were performed prior to next-generation sequencing., Results: Of these 86 samples, 30 were alpha-defensin-positive and culture-positive (Group I), 24 were alpha-defensin-positive and culture-negative (Group II) and 32 were alpha-defensin-negative and culture-negative (Group III). Next-generation sequencing was concordant with 25 results for Group I. In four of these, it detected antibiotic resistant bacteria whereas culture did not. In another four samples with relatively low levels of inflammatory biomarkers, culture was positive but next-generation sequencing was negative. A total of ten samples had a positive next-generation sequencing result and a negative culture. In five of these, alpha-defensin was positive and the levels of inflammatory markers were high. In the other five, alpha-defensin was negative and the levels of inflammatory markers were low. While next-generation sequencing detected several organisms in each sample, in most samples with a higher probability of infection, there was a predominant organism present, while in those presumed not to be infected, many organisms were identified with no predominant organism., Conclusion: Pathogens causing periprosthetic infection in both culture-positive and culture-negative samples of synovial fluid could be identified by next-generation sequencing. Cite this article: Bone Joint J 2018;100-B:127-33., (©2018 The British Editorial Society of Bone & Joint Surgery.)

Background: Next-generation sequencing is a well-established technique for sequencing of DNA and has recently gained attention in many fields of medicine. Our aim was to evaluate the accuracy of next-generation sequencing in identifying the causative organism(s) in patients with periprosthetic joint infection., Methods: In this prospective study, samples were collected from 65 revision arthroplasties (39 knees and 26 hips) and 17 primary arthroplasties (9 hips and 8 knees). Synovial fluid, deep tissue, and swabs were obtained at the time of the surgical procedure and were shipped to the laboratory for next-generation sequencing. Deep-tissue specimens were also sent to the institutional laboratory for culture. Sensitivity and specificity were calculated for next-generation sequencing, using the Musculoskeletal Infection Society (MSIS) definition of periprosthetic joint infection as the standard., Results: In 28 revisions, the cases were considered to be infected; cultures were positive in 17 cases (60.7% [95% confidence interval (CI), 40.6% to 78.5%]), and next-generation sequencing was positive in 25 cases (89.3% [95% CI, 71.8% to 97.7%]), with concordance between next-generation sequencing and culture in 15 cases. Among the 11 cases of culture-negative periprosthetic joint infection, next-generation sequencing was able to identify an organism in 9 cases (81.8% [95% CI, 48.2% to 97.7%]). Next-generation sequencing identified microbes in 9 (25.0% [95% CI, 12.1% to 42.2%]) of 36 aseptic revisions with negative cultures and in 6 (35.3% [95% CI, 14.2% to 61.7%]) of 17 primary total joint arthroplasties. Next-generation sequencing detected several organisms in most positive samples. However, in the majority of patients who were infected, 1 or 2 organisms were dominant., Conclusions: Next-generation sequencing may be a useful adjunct in identification of the causative organism(s) in culture-negative periprosthetic joint infection. Our findings suggest that some cases of monomicrobial periprosthetic joint infection may have additional organisms that escape detection when culture is used. Further study is required to determine the clinical implications of isolated organisms in samples from patients who are not thought to be infected., Level of Evidence: Diagnostic Level I. See Instructions for Authors for a complete description of levels of evidence.