Clinical Characteristics, Etiology, and Initial Management Strategy of Newly Diagnosed Periprosthetic Joint Infection: A Multicenter, Prospective Observational Cohort Study of 783 Patients

Patient-Reported Outcomes Following Periprosthetic Joint Infection of the Hip and Knee: A Longitudinal, Prospective Observational Study

BACKGROUND

The role of patient-reported outcome measures (PROMs) as tools for monitoring the impact and outcomes of periprosthetic joint infection (PJI) is not well described. This study analyzed the Oxford Hip Score (OHS) or Oxford Knee Score (OKS) in a prospective observational cohort of patients with hip or knee PJI.

METHODS

The PIANO (Prosthetic joint Infection in Australia and New Zealand, Observational study) cohort prospectively enrolled patients with newly diagnosed PJI from multiple centers. The OHS and OKS were evaluated at PJI diagnosis (baseline) and at 3, 12, and 24 months. Scores and score changes were examined according to PJI type, patient characteristics, and management. A successful functional outcome at 12 months was defined as an OHS of >38 or OHS of >36 and/or an improvement from baseline of >12 or >9, respectively.

RESULTS

Of the 741 participants, PROMs were available at 12 months for 233 with hip and 342 with knee PJI. Significant improvements (p < 0.0001) were seen at 12 months for both the OHS (24.5 to 36) and OKS (25 to 34), with no further improvement at 24 months. Patients with late-acute PJI had a higher median baseline OHS (35; interquartile range [22 to 46]) and OKS (30 [18 to 41]) than those with early PJI (OHS: 19 [15 to 29]; OKS: 22 [16 to 29.5]) or chronic PJI (OHS: 23 [14 to 34]; OKS 22 [14 to 28]). Logistic regression showed that a clinical cure (adjusted odds ratio [aOR] = 1.88, 95% confidence interval [CI] = 1.28 to 2.76, p = 0.001) and early PJI (aOR = 2.56, 95% CI = 1.64 to 4.07, p < 0.0001) independently predicted a successful functional outcome. Chronic renal impairment (aOR = 0.31, 95% CI = 0.13 to 0.71, p = 0.007), congestive cardiac failure (aOR = 0.41, 95% CI = 0.17 to 0.95, p = 0.04), and clinical signs of inflammation (aOR = 0.53, 95% CI = 0.33 to 0.85, p = 0.009) at diagnosis independently predicted failure to achieve a successful functional outcome.

CONCLUSIONS

The OHS and OKS varied significantly at baseline and 12 months according to PJI type, emphasizing the need to consider the PJI type when evaluating treatment success. This study highlights superior functional outcomes associated with early PJI and with achievement of a clinical cure.

LEVEL OF EVIDENCE

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

Development of a multiplex Loop-Mediated Isothermal Amplification (LAMP) for the diagnosis of bacterial periprosthetic joint infection

BACKGROUND

Periprosthetic joint infection (PJI) is one of the most serious and debilitating complications that can occur after total joint arthroplasty. Therefore, early diagnosis and appropriate treatment are important for a good prognosis. Recently, molecular diagnostic methods have been widely used to detect the causative microorganisms of PJI sensitively and rapidly. The Multiplex Loop-Mediated Isothermal Amplification (LAMP) method eliminates the complex temperature cycling and delays caused by temperature transitions seen in polymerase chain reaction (PCR) methods, making it faster and easier to perform compared to PCR-based assays. Therefore, this study developed a multiplex LAMP assay for diagnosing bacterial PJI using LAMP technology and evaluated its analytical and clinical performance.

METHODS

We developed a multiplex LAMP assay for the detection of five bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus agalactiae, Pseudomonas aeruginosa, and Escherichia coli, frequently observed to be the causative agents of PJI. The method of analytical sensitivity and cross-reactivity were determined by spiking standard strains into the joint synovial fluid. The analytical sensitivity of the multiplex LAMP assay was compared with that of a quantitative real-time PCR (qPCR) assay. Clinical performance was evaluated using 20 joint synovial fluid samples collected from patients suspected of having bacterial PJI.

RESULTS

The analytical sensitivity of the gram-positive bacterial multiplex LAMP assay and qPCR were 105/104 CFU/mL, 103/103 CFU/mL, and 105/104 CFU/mL against S. agalactiae, S. epidermidis, and S. aureus, respectively. For P. aeruginosa and E. coli, the analytical sensitivity of the multiplex LAMP and qPCR assays were 105/104 and 106/104 CFU/mL, respectively. The multiplex LAMP assay detects target bacteria without cross-reacting with other bacteria, and exhibited 100% sensitivity and specificity in clinical performance evaluation.

CONCLUSIONS

This multiplex LAMP assay can rapidly detect five high-prevalence bacterial species causing bacterial PJI, with excellent sensitivity and specificity, in less than 1 h, and it may be useful for the early diagnosis of PJI.

Periprosthetic shoulder infection management: one-stage should be the way: a systematic review and meta-analysis

BACKGROUND

There is still no consensus among surgeons on whether to perform a 1- or 2-stage surgical revision in infected shoulder arthroplasties. The aim of this systematic review and meta-analysis is to rigorously synthesize published studies evaluating the clinical outcomes, recurrence of infection, and other clinical complications in order to discuss which is the best strategy for treating periprosthetic joint infection after shoulder arthroplasty.

METHODS

Upon research using the PubMed, Scopus, and Web of Science databases, in November 2022, studies that presented 1- or 2-stage surgical revision as a treatment for periprosthetic joint infection after shoulder arthroplasty and assessed the reinfection rate on these patients, as well as other clinical outcomes, with a minimum follow-up of 12 months, were included. Study quality was evaluated using the Methodological Index for Non-Randomized Studies (MINORS) score. Reinfection and complication rates were extracted, and pooled estimates were calculated using the random-effect model.

RESULTS

After careful screening, 44 studies were included, 5 reporting on 1-stage and 30 on 2-stage revisions and 9 assessing both strategies. A total of 185 shoulders were reported in 1-stage revision studies, whereas 526 shoulders were reported in 2-stage revision studies. The overall pooled random-effects reinfection rate was 6.68% (95% confidence interval [CI]: 3.76-10.13), with low heterogeneity (I2 = 28%, P = .03). One-stage revision showed a reinfection rate of 1.14% (95% CI: 0.00-4.88), whereas 2-stage revision analysis revealed a reinfection rate of 8.81% (95% CI: 4.96-13.33). There were significant statistical differences between 1- and 2-stage reinfection rates (P = .04). The overall pooled rate for other clinical complications was 16.76% (95% CI: 9.49-25.15), with high heterogeneity (I2 = 70%, P < .01). One-stage revision had a complication rate of 6.11% (95% CI: 1.58-12.39), whereas the 2-stage revision complication rate was 21.26% (95% CI: 11.51-32.54). This difference was statistically significant (P = .03).

CONCLUSIONS

This is the first systematic review and meta-analysis showing significant statistical differences between 1- and 2-stage surgical revision in infected shoulder arthroplasties. Provided the right conditions exist, 1-stage revision shows better results in infection control, with lower clinical complications and possible better clinical outcomes.

A population-based epidemiological and health economic analysis of fracture-related infection

Aims

The aim of this study was to perform the first population-based description of the epidemiological and health economic burden of fracture-related infection (FRI).

Methods

This is a retrospective cohort study of operatively managed orthopaedic trauma patients from 1 January 2007 to 31 December 2016, performed in Queensland, Australia. Record linkage was used to develop a person-centric, population-based dataset incorporating routinely collected administrative, clinical, and health economic information. The FRI group consisted of patients with International Classification of Disease 10th Revision diagnosis codes for deep infection associated with an implanted device within two years following surgery, while all others were deemed not infected. Demographic and clinical variables, as well as healthcare utilization costs, were compared.

Results

There were 111,402 patients operatively managed for orthopaedic trauma, with 2,775 of these (2.5%) complicated by FRI. The development of FRI had a statistically significant association with older age, male sex, residing in rural/remote areas, Aboriginal or Torres Strait Islander background, lower socioeconomic status, road traffic accident, work-related injuries, open fractures, anatomical region (lower limb, spine, pelvis), high injury severity, requiring soft-tissue coverage, and medical comorbidities (univariate analysis). Patients with FRI had an eight-times longer median inpatient length of stay (24 days vs 3 days), and a 2.8-times higher mean estimated inpatient hospitalization cost (AU$56,565 vs AU$19,773) compared with uninfected patients. The total estimated inpatient cost of the FRI cohort to the healthcare system was AU$156.9 million over the ten-year period.

Conclusion

The results of this study advocate for improvements in trauma care and infection management, address social determinants of health, and highlight the upside potential to improve prevention and treatment strategies.

Design Characteristics and Recruitment Rates for Randomized Trials of Peri-Prosthetic Joint Infection Management: A Systematic Review

Prosthetic joint infections (PJI) present a major management challenge for practicing orthopedic surgeons and infectious disease physicians. There are few high-quality data to inform treatment guidelines. The aim of this systematic review was to report the design characteristics and recruitment rates for randomized controlled trials (RCTs) of PJI management. Trials were considered eligible for inclusion if human participants were randomized to any management intervention for PJI. We searched Medline, PubMed, Embase, Web of Science, Cochrane Database, ANZ Clinical Trials Registry, ClinicalTrials.gov, and the EU Clinical Trials Register until the end of May 2023. The systematic review was registered with PROSPERO (CRD42018112646). We identified 15 published RCTs with a total of 1743 participants with PJI. The median (interquartile range [IQR]) number of successfully recruited participants was 63 (38-140), with 0.28 (0.13-0.96) enrolments per site per month. Only four trials (36.4%) achieved the target recruitment. All RCTs applied different primary endpoints and varying definitions of a 'good' outcome. Despite recent improvements, PJI RCTs are characterized by slow recruitment and heterogeneous endpoint assessments, which preclude synthesis in a standard meta-analytic framework. To inform international guidelines, future PJI trials should be run as multi-country trials at high-recruiting sites.

Early switch from intravenous to oral antibiotic treatment in bone and joint infections

OBJECTIVES

The timing of the switch from intravenous (i.v.) to oral antibiotic therapy for orthopaedic bone and joint infections (BJIs) is debated. In this narrative article, we discuss the evidence for and against an early switch in BJIs.

DATA SOURCES

We performed a PubMed and internet search investigating the association between the duration of i.v. treatment for BJI and remission of infection among adult orthopaedic patients.

CONTENT

Among eight randomized controlled trials and multiple retrospective studies, we failed to find any minimal duration of postsurgical i.v. therapy associated with clinical outcomes. We did not find scientific data to support the prolonged use of i.v. therapy or to inform a minimal duration of i.v.

THERAPY

Growing evidence supports the safety of an early switch to oral medications once the patient is clinically stable.

IMPLICATIONS

After surgery for BJI, a switch to oral antibiotics within a few days is reasonable in most cases. We recommend making the decision on the time point based on clinical criteria and in an interdisciplinary team at the bedside.

Therapeutics for Vancomycin-Resistant Enterococcal Bloodstream Infections

Vancomycin-resistant enterococci (VRE) are common causes of bloodstream infections (BSIs) with high morbidity and mortality rates. They are pathogens of global concern with a limited treatment pipeline. Significant challenges exist in the management of VRE BSI, including drug dosing, the emergence of resistance, and the optimal treatment for persistent bacteremia and infective endocarditis. Therapeutic drug monitoring (TDM) for antimicrobial therapy is evolving for VRE-active agents; however, there are significant gaps in the literature for predicting antimicrobial efficacy for VRE BSIs. To date, TDM has the greatest evidence for predicting drug toxicity for the three main VRE-active antimicrobial agents daptomycin, linezolid, and teicoplanin. This article presents an overview of the treatment options for VRE BSIs, the role of antimicrobial dose optimization through TDM in supporting clinical infection management, and challenges and perspectives for the future.

Success of Debridement, Antibiotics, and Implant Retention in Prosthetic Joint Infection Following Primary Total Knee Arthroplasty: Results from a Prospective Multicenter Study of 189 Cases

BACKGROUND

This study aimed to identify the success rate of debridement, antibiotics, and implant retention (DAIR) for prosthetic joint infection (PJI) in a large prospective cohort of patients undergoing total knee arthroplasty (TKA). The ability for different PJI classification systems to predict success was assessed.

METHODS

Prospective data recorded in the Prosthetic Joint Infection in Australia and New Zealand Observational (PIANO) study was analyzed. 189 newly diagnosed knee PJIs were managed with DAIR between July 2014 and December 2017. Patients were prospectively followed up for 2 years. A strict definition of success was used, requiring the patient being alive with documented absence of infection, no ongoing antibiotics and the index prosthesis in place. Success was compared against the Coventry (early PJI = ≤1 month), International Consensus Meeting (early = ≤90 days), Auckland (early = <1 year), and Tsukayama (early = ≤1 month, hematogenous = >1 month with <7 days symptoms, chronic = >1 month with >7 days symptoms) classifications.

RESULTS

DAIR success was 45% (85/189) and was highest in early PJIs defined according to the Coventry (adjusted odds ratio [aOdds Ratio (OR)] = 3.9, P=0.01), the ICM (aOR = 3.1, p=0.01), and the Auckland classifications (aOR = 2.6, P=0.01). Success was lower in both hematogenous (aOR = 0.4, P=0.03) and chronic infections (aOR = 0.1, P=0.003).

CONCLUSION

Time since primary TKA is an important predictor of DAIR success. Success was highest in infections occurring <1 month of the primary TKA and progressively decreased as time since the primary TKA increased.

The Association of Benign Prostatic Hyperplasia on Postoperative Complications and Periprosthetic Joint Infections Following Total Shoulder Arthroplasty

Background

A recently proposed risk factor for periprosthetic joint infections (PJI) in men is benign prostatic hyperplasia (BPH). The objective was to explore the association of BPH on 1) 90-day complications, 2) length of stay (LOS), 3) readmission rates, and 4) healthcare expenditures following total shoulder arthroplasty (TSA).

Methods

A retrospective query was performed using a nationwide claims database from January 2005 to March 2014 for male patients undergoing primary TSA. The study cohort included 5067 patients with BPH while 50,720 patients served as the comparison cohort. Logistic regression determined the association of BPH on complications and readmissions. A p value less than 0.001 was significant.

Results

Patients with BPH had higher incidence and odds (36.8 vs. 6.2%; OR: 2.73, p < 0.0001) of all ninety-day medical complications including PJIs (0.49 vs. 0.32%; OR: 1.54, p < 0.001). BPH patients had longer in-hospital LOS (3- vs. 2-days, p < 0.0001). Study group patients had higher 90-day episode of care reimbursements ($13,653 vs. $12,688), p < 0.0001).

Conclusions

BPH is associated with increased complications and healthcare expenditures following total shoulder arthroplasty. The investigation can be used to educate BPH patients of the possible adverse events which may occur within ninety-days following primary TSA for the treatment of glenohumeral osteoarthritis.

Cutibacterium acnes Prosthetic Joint Infections: Is Rifampicin-Combination Therapy Beneficial?

No consensus has been reached on the optimal antibiotic regimen to treat Cutibacterium acnes PJIs (Ca-PJIs). In vitro studies showed excellent rifampicin efficacy against biofilm-associated C. acnes infections, but clinical studies did not confirm the superiority of rifampicin-combined therapy over monotherapy. This prospective cohort study was undertaken to analyze the outcomes of 70 patients who underwent exchange arthroplasty for chronic monomicrobial Ca-PJI and were treated with rifampicin or without between 2004 and 2019. The 37 patients treated from January 2004 to August 2014 were prescribed rifampicin-combination therapy and the 33 treated from September 2014 to December 2019 received monotherapy without rifampicin. The primary endpoint was the 2-year Kaplan-Meier-estimated reinfection-free probability, including relapses and new-pathogen PJIs. The 2-year reinfection-free rate was high and not different for patients who had received rifampicin or not (89.2% vs. 93.8%, respectively; p = 0.524). None of the patients relapsed and six developed new-pathogen PJIs. Our results do not support a benefit of rifampicin-combination therapy for patients who underwent exchange arthroplasty for chronic Ca-PJIs.

Characteristics and outcomes of culture-negative prosthetic joint infections from the Prosthetic Joint Infection in Australia and New Zealand Observational (PIANO) cohort study

Abstract. Introduction: Culture-negative (CN) prosthetic joint infections (PJIs) account for approximately 10 % of all PJIs and present significant challenges for clinicians. We aimed to explore the significance of CN PJIs within a large prospective cohort study, comparing their characteristics and outcomes with culture-positive (CP) cases. Methods: The Prosthetic joint Infection in Australia and New Zealand Observational (PIANO) study is a prospective, multicentre observational cohort study that was conducted at 27 hospitals between 2014 and 2017. We compared baseline characteristics and outcomes of all patients with CN PJI from the PIANO cohort with those of CP cases. We report on PJI diagnostic criteria in the CN cohort and apply internationally recognized PJI diagnostic guidelines to determine optimal CN PJI detection methods. Results: Of the 650 patients with 24-month outcome data available, 55 (8.5 %) were CN and 595 were CP. Compared with the CP cohort, CN patients were more likely to be female (32 (58.2 %) vs. 245 (41.2 %); p = 0.016), involve the shoulder joint (5 (9.1 %) vs. 16 (2.7 %); p = 0.026), and have a lower mean C-reactive protein (142 mg L−1 vs. 187 mg L−1; p = 0.016). Overall, outcomes were superior in CN patients, with culture negativity an independent predictor of treatment success at 24 months (adjusted odds ratio, aOR, of 3.78 and 95 %CI of 1.65–8.67). Suboptimal diagnostic sampling was common in both cohorts, with CN PJI case detection enhanced using the Infectious Diseases Society of America PJI diagnostic guidelines. Conclusions: Current PJI diagnostic guidelines vary substantially in their ability to detect CN PJI, with comprehensive diagnostic sampling necessary to achieve diagnostic certainty. Definitive surgical management strategies should be determined by careful assessment of infection type, rather than by culture status alone.

Epidemiology and antibiotic resistance of prosthetic joint infections according to time of occurrence, a 10-year study

OBJECTIVES

To describe the microorganisms responsible for prosthetic joint infections (PJIs) and their antimicrobial susceptibilities, and to propose appropriate empirical antimicrobial treatments (EATs) according to time of occurrence METHODS: : This 10-year retrospective study presents the bacterial etiology of 282 consecutive PJIs in a French hospital according to time of occurrence (adapted from Zimmerli's classification: early, <3 months; delayed, 3-12 months; late acute, >12 months with hematogenous seeding or contiguous spread; late chronic, >12 months without hematogenous seeding). The expected efficacy of various EATs was analyzed for each PJI.

RESULTS

Staphylococci were the most commonly found bacteria (S. aureus (44.3%), coagulase-negative staphylococci (25.2%) with 15.2% and 49.3% methicillin resistance respectively), followed by Gram-negative bacilli (GNB) (17.7%) and streptococci (14.9%). The distribution of species varied between categories, but antibiotics targeting GNBs were required in all categories. Imipenem-vancomycin was the most effective combination (99.3%) but should be reserved for patients with suspected resistant GNB. Cefotaxime-vancomycin was less effective in early/delayed and late PJIs (91.1% and 86.1% respectively), due to resistant GNB and polymicrobial infections. Piperacillin/tazobactam-vancomycin appeared to be appropriate in all situations (>96% efficacy).

CONCLUSION

Proposing universal recommendations remains challenging, but a good understanding of the local epidemiology is important for optimizing EATs.

Non-Antimicrobial Adjuvant Therapy Using Ticagrelor Reduced Biofilm-Related Staphylococcus aureus Prosthetic Joint Infection

Background: Prosthetic joint infection (PJI), frequently caused by Staphylococcus aureus, leads to a significant arthroplasty failure rate. Biofilm is a crucial virulence factor of S. aureus that is intrinsic to the pathogenesis of PJI. Biofilm-related infections are recalcitrant to antibiotic treatment. Surgical and antibiotic therapy could be combined with non-antibacterial adjuvants to improve overall treatment success. Ticagrelor, a P2Y12 receptor inhibitor antiplatelet drug, is known to have anti-staphylococcal antibacterial and antibiofilm activity. However, the molecular mechanism for ticagrelor’s antibiofilm activity and its efficacy in the treatment of S. aureus PJI are unknown.

Methods: To study the in vitro antibacterial and antibiofilm activity of ticagrelor, broth microdilution and crystal violet staining method were used. Ticagrelor’s effect on the expression of S. aureus biofilm genes (icaA, icaD, ebps, fib, eno, and agr) was studied using the relative quantification method. To test ticagrelor’s in vivo efficacy to treat S. aureus PJI, mice were randomized into five groups (n = 8/group): infected femoral implants treated with ticagrelor alone; infected implants treated with cefazolin alone; infected implants treated with ticagrelor and cefazolin; infected implants treated with phosphate buffer solution (PBS)-positive controls, and sterile implants-negative controls. Ticagrelor was administered orally from day 4 to day 7 post-surgery, while cefazolin was injected intravenously on day 7.

Results: Ticagrelor, alone and with selected antibiotics, showed in vitro antibacterial and antibiofilm activity against S. aureus. Strain-specific downregulation of biofilm-related genes, fib, icaD, ebps, and eno, was shown. In an animal model of biofilm-related S. aureus PJI, ticagrelor alone and combined with cefazolin significantly reduced bacterial concentrations on the implants compared with the positive control group. Ticagrelor significantly reduced bacterial dissemination to periprosthetic tissue compared with the positive controls.

Conclusion: Ticagrelor adjuvant therapy reduced S. aureus PJI in an animal model. However, this study is very preliminary to make a conclusion on the clinical implication of the findings. Based on the current results, more studies are recommended to better understand its implication.

The accuracy of reporting of periprosthetic joint infection to the Australian Orthopaedic Association National Joint Replacement Registry

Aims

National joint registries under-report revisions for periprosthetic joint infection (PJI). We aimed to validate PJI reporting to the Australian Orthopaedic Association National Joint Arthroplasty Registry (AOANJRR) and the factors associated with its accuracy. We then applied these data to refine estimates of the total national burden of PJI.

Methods

A total of 561 Australian cases of confirmed PJI were captured by a large, prospective observational study, and matched to data available for the same patients through the AOANJRR.

Results

In all, 501 (89.3%) cases of PJI recruited to the prospective observational study were successfully matched with the AOANJRR database. Of these, 376 (75.0%) were captured by the registry, while 125 (25.0%) did not have a revision or reoperation for PJI recorded. In a multivariate logistic regression analysis, early (within 30 days of implantation) PJIs were less likely to be reported (adjusted odds ratio (OR) 0.56; 95% confidence interval (CI) 0.34 to 0.93; p = 0.020), while two-stage revision procedures were more likely to be reported as a PJI to the registry (OR 5.3 (95% CI 2.37 to 14.0); p ≤ 0.001) than debridement and implant retention or other surgical procedures. Based on this data, the true estimate of the incidence of PJI in Australia is up to 3,900 cases per year.

Conclusion

In Australia, infection was not recorded as the indication for revision or reoperation in one-quarter of those with confirmed PJI. This is better than in other registries, but suggests that registry-captured estimates of the total national burden of PJI are underestimated by at least one-third. Inconsistent PJI reporting is multifactorial but could be improved by developing a nested PJI registry embedded within the national arthroplasty registry.

Cite this article: Bone Jt Open 2022;3(5):367–373.

Microbiology of hip and knee periprosthetic joint infections: a database study

OBJECTIVES

Knowledge of the microbiological aetiology of periprosthetic joint infection (PJI) is essential to its management. Contemporary literature from the United States on this topic is lacking. This study aimed to identify the most common microorganisms associated with types of arthroplasty, the timing of infection, and clues to polymicrobial infection.

METHODS

We performed an analytical cross-sectional study of patients 18 years of age or older with hip or knee PJI diagnosed at our institution between 2010 and 2019. PJI was defined using the criteria adapted from those of the Musculoskeletal Infection Society. Cases included PJI associated with primary or revision arthroplasty and arthroplasty performed at our institution or elsewhere.

RESULTS

A total of 2067 episodes of PJI in 1651 patients were included. Monomicrobial infections represented 70% of episodes (n = 1448), with 25% being polymicrobial (n = 508) and the rest (5%, n = 111) culture-negative. The most common group causing PJI was coagulase-negative Staphylococcus species (other than S. ludgunensis) (37%, n = 761). The distribution of most common organisms was similar regardless of arthroplasty type. The S. aureus complex, Gram-negative bacteria, and anaerobic bacteria (other than Cutibacterium species) were more likely to be isolated than other organisms in the first year following index arthroplasty (OR 1.7, 95%CI 1.4-2.2; OR 1.5, 95%CI 1.1-2.0; and OR 1.5, 95%CI 1.0-2.2, respectively). The proportion of culture-negative PJIs was higher in primary than revision arthroplasty (6.5% versus 3%, p 0.0005). The presence of a sinus tract increased the probability of the isolation of more than one microorganism by almost three-fold (OR 2.6, 95%CI 2.0-3.3).

CONCLUSIONS

Joint age, presence of a sinus tract, and revision arthroplasties influenced PJI microbiology.

Long-Term Outcomes of Staged Revision Surgery for Chronic Periprosthetic Joint Infection of Total Hip Arthroplasty

Periprosthetic joint infection (PJI) is a serious complication of total hip arthroplasty. Staged revision surgery is considered effective in eradicating PJI. We aimed to determine the rate of infection resolution after each stage of staged revision surgery (first stage, repeat first stage, second stage, excision arthroplasty, and reimplantation) and to assess functional outcomes and the mortality rate at ten years in a consecutive series of 30 chronic PJI of total hip arthroplasties. Infection resolution was defined as no clinical nor laboratory evidence of infection at 24 months after the last surgery and after a minimum of 12 months following cessation of antimicrobial treatment. Four patients died within 24 months of their final surgery. Nineteen patients, 73% (worst-case analysis (wca) 63%), were infection free after 1 surgery; 22 patients, 85% (wca 73%), were infection free after 2 surgeries; and 26 patients, 100% (wca 87%), were infection free after three and four surgeries. The median Harris Hip Score was 41 prior to first revision surgery and improved to 74 at twelve months and 76 at ten years after the final surgery. Thirteen patients died at a mean of 64 months from first revision, giving a mortality rate of 43% at ten years, which is approximately 25% higher than that of an age-matched general population. The results show that with repeated aggressive surgical treatment, most PJIs of the hip are curable. Ten years after successful treatment of PJI, functional outcomes and pain are improved and maintained compared to before initial surgery, but this must be balanced against the high 10-year mortality. Level of evidence: cohort studies.

Assessment of risk factors for early-onset deep surgical site infection following primary total hip arthroplasty for osteoarthritis

The aim of this study was to determine the incidence, annual trend, and perioperative outcomes and identify risk factors of early-onset (≤90 d) deep surgical site infection (SSI) following primary total hip arthroplasty (THA) for osteoarthritis. We performed a retrospective study using prospectively collected patient-level data from January 2013 to March 2020. The diagnosis of deep SSI was based on the published Centre for Disease Control/National Healthcare Safety Network (CDC/NHSN) definition. The Mann–Kendall trend test was used to detect monotonic trends. Secondary outcomes were 90 d mortality and 90 d readmission. A total of 22 685 patients underwent primary THA for osteoarthritis. A total of 46 patients had a confirmed deep SSI within 90 d of surgery representing a cumulative incidence of 0.2 %. The annual infection rate decreased over the 7-year study period (p=0.026). Risk analysis was performed on 15 466 patients. Risk factors associated with early-onset deep SSI included a BMI > 30 kg m-2 (odds ratio (OR) 3.42 [95 % CI 1.75–7.20]; p<0.001), chronic renal disease (OR, 3.52 [95 % CI 1.17–8.59]; p=0.011), and cardiac illness (OR, 2.47 [1.30–4.69]; p=0.005), as classified by the Canadian Institute for Health Information. Early-onset deep SSI was not associated with 90 d mortality (p=0.167) but was associated with an increased chance of 90 d readmission (p<0.001). This study establishes a reliable baseline infection rate for early-onset deep SSI after THA for osteoarthritis through the use of a robust methodological process. Several risk factors for early-onset deep SSI are potentially modifiable, and therefore targeted preoperative interventions of patients with these risk factors is encouraged.

How to Handle Concomitant Asymptomatic Prosthetic Joints During an Episode of Hematogenous Periprosthetic Joint Infection, a Multicenter Analysis

BACKGROUND

Prosthetic joints are at risk of becoming infected during an episode of bacteremia, especially during Staphylocococcus aureus bacteremia. However, it is unclear how often asymptomatic periprosthetic joint infection (PJI) occurs, and whether additional diagnostics should be considered.

METHODS

In this multicenter study, we retrospectively analyzed a cohort of patients with a late acute (hematogenous) PJI between 2005-2015 who had concomitant prosthetic joints in situ. Patients without at least 1 year of follow-up were excluded.

RESULTS

We included 91 patients with a hematogenous PJI and 108 concomitant prosthetic joints. The incident PJI was most frequently caused by Staphylococcus aureus (43%), followed by streptococci (26%) and Gram-negative rods (18%). Of 108 concomitant prosthetic joints, 13 were symptomatic, of which 10 were subsequently diagnosed as a second PJI. Of the 95 asymptomatic prosthetic joints, 1 PJI developed during the follow-up period and was classified as a "missed" PJI at the time of bacteremia with S. aureus (1.1%). Infected prosthetic joints were younger than the noninfected ones in 67% of cases, and prosthetic knees were affected more often than prosthetic hips (78%).

CONCLUSIONS

During an episode of hematogenous PJI, concomitant asymptomatic prosthetic joints have a very low risk of being infected, and additional diagnostic work-up for these joints is not necessary.

Comparison of the success rate after debridement, antibiotics and implant retention (DAIR) for periprosthetic joint infection among patients with or without a sinus tract

BACKGROUND

The relevance between the presence of a sinus tract and the failure risk after debridement, antibiotics and implant retention (DAIR) for periprosthetic joint infection (PJI) after hip or knee arthroplasty is still unclear. This study aimed to compare the success rate of DAIR between patients with or without a sinus tract and to explore the possible risk factors for failure after DAIR in patients with a sinus tract.

METHODS

Consecutive DAIR cases for PJI after hip or knee arthroplasty between January 2009 and June 2019 with a minimum 1-year follow-up in two tertiary joint arthroplasty centers were included. Patients were classified into the sinus tract group and the non-sinus tract group according to the presence of a sinus tract. The success rate after DAIR were compared using Kaplan-Meier survival analysis. Potential risk factors for failure in the sinus group were also explored.

RESULTS

One hundred seven patients were included. At a median 4.4 years of follow-up, 19 of 52 (36.5%) cases failed in the sinus tract group, while 15 of 55 (27.3%) cases failed in the non-sinus tract group. The 1-year and 5-year cumulative success rates were 71.2% (95% confidence interval (CI): 59.8-84.6%) and 56.8% (95% CI: 42.6-75.7%) in the sinus tract group, respectively, which were similar to the counterparts in the non-sinus tract group (P = 0.214). Among patients with a sinus tract, DAIR with the exchange of modular components showed a higher success rate (75.8% versus 47.4%, P = 0.038).

CONCLUSIONS

The presence of a sinus tract does not affect the success rate of DAIR. Modular component exchange in DAIR was proposed for patients with a sinus tract for an improved infection control rate.

Therapeutic assessment of N-formyl-methionyl-leucyl-phenylalanine (fMLP) in reducing periprosthetic joint infection

Despite many preventive measures, including prophylactic antibiotics, periprosthetic joint infection (PJI) remains a devastating complication following arthroplasty, leading to pain, suffering, morbidity and substantial economic burden. Humans have a powerful innate immune system that can effectively control infections, if alerted quickly. Unfortunately, pathogens use many mechanisms to dampen innate immune responses. The study hypothesis was that immunomodulators that can jumpstart and direct innate immune responses (particularly neutrophils) at the surgical site of implant placement would boost immune responses and reduce PJI, even in the absence of antibiotics. To test this hypothesis, N-formyl-methionyl-leucyl-phenylalanine (fMLP) (a potent chemoattractant for phagocytic leukocytes including neutrophils) was used in a mouse model of PJI with Staphylococcus aureus (S. aureus). Mice receiving intramedullary femoral implants were divided into three groups: i) implant alone; ii) implant + S. aureus; iii) implant + fMLP + S. aureus. fMLP treatment reduced S. aureus infection levels by ~ 2-Log orders at day 3. Moreover, fMLP therapy reduced infection-induced peri-implant periosteal reaction, focal cortical loss and areas of inflammatory infiltrate in mice distal femora at day 10. Finally, fMLP treatment reduced pain behaviour and increased weight-bearing at the implant leg in infected mice at day 10. Data indicated that fMLP therapy is a promising novel approach for reducing PJI, if administered locally at surgical sites. Future work will be toward further enhancement and optimisation of an fMLP-based therapeutic approach through combination with antibiotics and/or implant coating with fMLP.

The diagnostic effect of α-defensin, D-dimer, and IL-6 in periprosthetic joint infection: A systematic review and diagnostic meta-analysis

BACKGROUND

Periprosthetic joint infection (PJI) is the most common complication after artificial joint replacement as previously reported. However, the main problem at present is its difficulty in diagnosis. This systematic review and meta-analysis aimed to compare the diagnostic accuracy of α-defensin, D-dimer, and interleukin-6 (IL-6) in clinical practice.

METHOD

Online databases were systematically searched until June 18th, 2020 with keywords and medical sub-headings terms. Studies mentioned the sensitivity and specificity of biological markers in detecting PJI were included in our study. The sensitivity, specificity, and diagnostic odds ratios (DORs) were obtained after integration.

RESULTS

A total of 34 studies with 1036 patients diagnosing as PJI were included for comparing α-defensin, D-dimer, and IL-6. The sensitivity and specificity of α-defensin for PJI were 0.88 and 0.96, and the DOR was 189 (95% CI 72-496), respectively. The sensitivity and specificity of D-dimer (0.82 and 0.72) and IL-6 (0.80 and 0.89) were lower than α-defensin.

CONCLUSION

The detection of α-defensin is a promising biomarker for diagnosing PJI. The optional cut-off needs to be curtained when using other biomarkers.

Epidemiology of complex bone and joint infections in France using a national registry: The CRIOAc network

OBJECTIVES

In France, a network of reference centers for bone and joint infections (BJI) was created in 2008, focused on the management of complex BJI (previous failure, difficult-to-treat microorganisms, heavy comorbidities or surgical procedures). A national registry was implemented from 2012, collecting decisions advised in periodic multidisciplinary meetings. We present here an epidemiological overview.

METHODS

All consecutive adult patients presented from 2014 to 2019 in 23/30 reference centers were included in this cohort. Characteristics of patients, BJI, and medico-surgical management advice were described.

RESULTS

27,483 individual patients were included, corresponding to 28,365 distinct infectious episodes, which 17,328 were complex. Median age was 65 years, with 62% of men, 1/3 patients presented more than 2 comorbidities. Prosthetic joint infections (PJI) represented 42% of all BJIs (11,812 episodes). Staphylococcus aureus, coagulase-negative staphylococci and polymicrobial PJI represented 26%, 25% and 16% respectively. DAIR (debridement, antibiotics and implant retention) was proposed for 3,157 (27%), whereas one-stage and two-stage revision for 3,683 (31%) and 1,764 (15%). An antibiotic treatment was advised in 10,493 episodes (87%), with combination therapy in 88%.

CONCLUSION

This national network allows an optimized management of complex BJIs. Its cohort is a unique opportunity to draw up a detailed epidemiological picture and to follow the trends of these infrequent infections.