Predictors of Reinfection in Prosthetic Joint Infections Following Two-Stage Reimplantation

A case report of implanted bone displacement after abscess formation

RATIONALE

Implanted bone is a commonly used filling material for bone defects, participating in the formation of new bone. Complications associated with implanted bone include nonunion, infection, etc. Few cases of implanted bone displacement through gravitational abscesses have been reported in the literature. This article aims to improve clinicians' recognition of this phenomenon and discuss preventive measures and treatment strategies for implant-associated infections.

PATIENT CONCERNS

A 7-year-old female patient was admitted to the hospital due to recurrent purulent fluid discharge from the incision site for 3 months following a right hip surgery 4 months ago. Wound secretion culture revealed a methicillin-resistant Staphylococcus aureus infection. The imaging before the first debridement in the external hospital showed that there were 2 high-density shadows around the right femoral greater trochanter, which were implanted bone.

DIAGNOSES

Implant-related infection and chronic osteomyelitis.

INTERVENTIONS

The implant and inflammatory lesions were removed through multiple surgeries and anti-infection treatment.

OUTCOMES

After 6 months of follow-up, there was no sign of infection in the wound.

LESSONS

It is rare-reported that implanted bone displacement is caused by factors such as abscess formation. Treatment and understanding of implanted bone around the greater trochanter of the right femur is important. Early recognition and surgical removal of displaced implanted bone play a crucial role in infection control and disease prognosis.

Results of 331 Two-Stage Exchanges for PJI Following THA: Low Reinfection and Mechanical Failure Rates at 10 Years

BACKGROUND

The relative advantages and disadvantages of 2-stage versus 1-stage management of infection following total hip arthroplasty (THA) are the current subject of intense debate. To understand the merits of each approach, detailed information on the short and, importantly, longer-term outcomes of each must be known. The purpose of the present study was to assess the long-term results of 2-stage exchange arthroplasty following THA in one of the largest series to date.

METHODS

We identified 331 periprosthetic joint infections (PJIs) that had been treated with a 2-stage exchange arthroplasty between 1993 and 2021 at a single institution. Patients were excluded if they had had prior treatment for infection. The mean age at the time of reimplantation was 66 years, 38% of the patients were female, and the mean body mass index (BMI) was 30 kg/m 2 . The diagnosis of PJI was based on the 2011 Musculoskeletal Infection Society criteria. A competing-risk model accounting for death was utilized. The mean duration of follow-up was 8 years.

RESULTS

The cumulative incidence of reinfection was 7% at 1 year and 11% at 5 and 10 years. Factors predictive of reinfection included BMI ≥30 kg/m 2 (hazard ratio [HR] = 2; p = 0.049) and the need for a spacer exchange (HR = 3.2; p = 0.006). The cumulative incidence of any revision was 13% at 5 and 10 years. The cumulative incidence of aseptic revision was 3% at 1 year, 7% at 5 years, and 8% at 10 years. Dislocation occurred in 33 hips (11% at 10 years); 15 (45%) required revision. Factors predictive of dislocation were female sex (HR = 2; p = 0.047) and BMI <30 kg/m 2 (HR = 3; p = 0.02). The mean Harris hip score (HHS) improved from 54 to 75 at 10 years.

CONCLUSIONS

In this series of 331 two-stage exchange arthroplasties that were performed for the treatment of infection, we found a low rate of aseptic revision (8%) and a low rate of reinfection (11%) at 10 years. These long-term mechanical and infection data must be kept in mind when considering a paradigm shift to 1-stage exchanges.

LEVEL OF EVIDENCE

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

Differences in Success Rate of Two-Stage Revision for Periprosthetic Joint Infection of the Knee Depending on the Applied Definition

BACKGROUND

Success rates of two-stage exchange arthroplasty are subject to substantial variance in the literature. An explanation is the lack of a universally accepted definition of what constitutes treatment success for periprosthetic joint infection. Therefore, the main objective of this study was to assess success rates, applying four definitions to identify the one definition that best captures "true" success from both a clinical and patient-centered perspective.

METHODS

This was a retrospective study investigating the outcome of a consecutive series of 78 chronic knee periprosthetic joint infections that were treated with a two-stage revision at a single center between 2017 and 2020. Kaplan-Meier survival analyses were conducted to estimate success rates.

RESULTS

After a mean follow-up of 36 months (range, 25 to 60), 64 patients (82%) were reimplanted after a mean interim period of 90 days (range, 22 to 201). There was one patient (1%) lost to follow-up, and the overall mortality was 15% (n = 12). Kaplan-Meier survival analyses were used to estimate treatment success at two and three years: implant survival was 93% (95% confidence interval [CI]: 82 to 97) and 87% (95% CI: 73 to 94), infection control was 90% (95% CI: 79 to 95) and 87% (95% CI: 73 to 93), success according to Delphi criteria was 88% (95% CI: 78 to 94), and success according to Musculoskeletal Infection Society criteria was 65% (95% CI: 53 to 74) at both timepoints.

CONCLUSIONS

Success rates were ranging between 65 and 93% depending on the applied definition, highlighting the need for universal success criteria. This variability mainly results from the differing approaches to patients who did not undergo reimplantation or passed away within a year of surgery. These patients exemplify cases of fatal treatment failures. Consequently, the Musculoskeletal Infection Society criteria should be routinely employed to accurately report the "true" success rate.

CXCL16/CXCR6/TGF-β Feedback Loop Between M-MDSCs and Treg Inhibits Anti-Bacterial Immunity During Biofilm Infection

Staphylococcus aureus (S. aureus) is a leading cause of Periprosthetic  joint  infection (PJI), a severe complication after joint arthroplasty. Immunosuppression is a major factor contributing to the infection chronicity of S. aureus PJI, posing significant treatment challenges. This study investigates the relationship between the immunosuppressive biofilm milieu and S. aureus PJI outcomes in both discovery and validation cohorts. This scRNA-seq analysis of synovium from PJI patients reveals an expansion and heightened activity of monocyte-related myeloid-derived suppressor cells (M-MDSCs) and regulatory T cells (Treg). Importantly, CXCL16 is significantly upregulated in M-MDSCs, with its corresponding CXCR6 receptor also elevated on Treg. M-MDSCs recruit Treg and enhance its activity via CXCL16-CXCR6 interactions, while Treg secretes TGF-β, inducing M-MDSCs proliferation and immunosuppressive activity. Interfering with this cross-talk in vivo using Treg-specific CXCR6 knockout PJI mouse model reduces M-MDSCs/Treg-mediated immunosuppression and alleviates bacterial burden. Immunohistochemistry and recurrence analysis show that PJI patients with CXCR6high synovium have poor prognosis. This findings highlight the critical role of CXCR6 in Treg in orchestrating an immunosuppressive microenvironment and biofilm persistence during PJI, offering potential targets for therapeutic intervention.

Risk factors of recurrent periprosthetic joint infection of the knee after two-stage reimplantation

INTRODUCTION

Prosthetic joint infection (PJI) is one of the most common and detrimental complications of total knee replacement arthroplasty (TKA). Despite extensive efforts, including two-stage reimplantation, to eradicate PJI, it still recurs in a substantial number of patients. However, the risk factors of recurrence after two-stage reimplantation of the knee have not been established. In this study, it is hypothesized that there will be certain risk factors of recurrence after two-stage reimplantation for PJI of the knee.

MATERIALS AND METHODS

From March 2002 to December 2022, 65 knees that underwent two-stage reimplantation for PJIs in a single, tertiary hospital were retrospectively reviewed, and 44 patient-related, laboratory-related, and surgery-related factors, including body mass index, pathogen type, and the usage of transfusions, were selected as the potential risk factors for recurrence. Survival analysis using the Kaplan-Meier method and subsequent Cox proportional hazard regression were performed.

RESULTS

Out of the 65 knees that underwent two-stage reimplantation, infection recurred in 15 knees (23.1%) in a median 11 (range 4-108) months. The Cox proportional hazards regression showed that infection of revision TKA, mixed pathogen-type infection, and higher serum erythrocyte sedimentation rate (ESR, mm/h) level increases the risk of recurrence (p-values < 0.001, 0.04, and 0.009; hazard ratios 40.29, 1.53, and 1.03, respectively).

CONCLUSIONS

A significant portion of PJI of the knees recurred after two-stage reimplantation. Revision TKA at the time of initial PJI, mixed pathogen-type infection, and higher serum ESR level were three significant risk factors of PJI recurrence. Surgeons should be more cautious in suspecting PJI relapse for these specific occasions.

LEVEL OF EVIDENCE

III, retrospective cohort study.

Identifying potential predictive indicators for reimplantation timing in two-stage revision: a meta-analysis and system review

PURPOSE

The two-stage exchange revision represents a pivotal strategy in the management of prosthetic joint infections, wherein the judicious timing of reimplantation serves as a crucial determinant for therapeutic success. At present, attempts have been made to utilize predictive models to establish the optimal timing for reimplantation; however, their predictive accuracy remains unsatisfactory. This inadequacy primarily arises from the lack of dependable predictive indicators, which demonstrate inconsistent effectiveness across various studies and occasionally yield contradictory outcomes. Therefore, identifying solid predictive indicators is in desperate need.

METHODS

Studies reporting outcomes of the two-stage exchange revision till June, 2023 were systematically retrieved, screened and subject to quality analysis. Basic characteristics of these studies were firstly summarized. Subsequently, factors of interest regarding clinical information, blood and body fluid test results, pathogen test results of the recurrent and recurrent-free cohorts were extracted and submitted to a fixed or random effects model. Meanwhile, evaluation of publication bias and sensitivity was performed.

RESULTS

After filtering, a total of 45 studies were finally involved. Pooled analysis suggested that the recurrent cohort exhibited elevated incidences of body mass index (BMI) > 30, smoking and alcohol habits, diabetes, sinus tract, positive culture, and G-, polymicrobial and drug-resistant infections. Additionally, higher levels of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), synovial white blood cell (WBC) count, and polymorphonuclear percentage (PMN%) were observed in the recurrent cohort. On the other hand, the results of D-dimer and fibrinogen were ambiguous, and no difference regarding peripheral WBC count was observed. Forest plots suggested a low risk of publication bias. Besides, sensitivity analysis indicated good stability of the aforementioned indicators, except D-dimer and fibrinogen.

CONCLUSION

To sum up, BMI > 30, smoking and alcohol habits, diabetes, sinus tract, positive culture, and G-, polymicrobial and drug-resistant infections, CRP, ESR, synovial WBC and PMN% exhibited significant differences between recurrent and recurrent-free cohorts. Therefore, these indicators may be considered as potential predictive factors for the further development of a prognostic model that aids the determination of reimplantation timing. Nevertheless, the efficacy of these indicators remains to be further confirmed.

REGISTRATION NUMBER

Prospero ID: CRD42022296568.

What is the diagnostic accuracy of neutrophil to lymphocyte ratio and monocyte to lymphocyte ratio in detecting acute periprosthetic joint infections? A gender-specific analysis

PURPOSE

The accurate and timely diagnosis of periprosthetic joint infection (PJI) is critical for guiding optimal treatment management and success, highlighting the requirement of readily available inexpensive serum biomarkers to increase the diagnostic accuracy for PJI. Many studies have investigated the diagnostic accuracy of neutrophil to lymphocyte ratio (NLR) and monocyte to lymphocyte ratio (MLR). However, there is a lack of existing literature regarding optimal thresholds for acute PJI. The purpose of this study was to reveal the most appropriate cut-off values for MLR and NLR in detecting acute PJI with a gender specific analysis.

METHODS

Patients were classified as having an acute PJI if they met the International Consensus Meeting (ICM) 2018 modified criteria. Patients who had a negative clinical and diagnostic workup for a PJI and the presence of erythema on the index surgical area were included in the erysipelas group (control group). Data obtained from all patients included age, sex, body mass index (BMI), Charlson Comorbidity Index (CCI), procedure type (THA or TKA), serum C-reactive protein (CRP), and blood studies at the admission and culture results were retrieved from the electronic medical record.

RESULTS

ROC curve analysis was used to determine the gender-specific optimal threshold values for CRP, NLR, and MLR. Comparing the sensitivities and specificities of NLR and MLR at the identified best thresholds in males and females, the study found similar sensitivities of NLR in males and females with 0.84 and 0.84, respectively. On the other hand, an MLR of 0.67 or more reported a notably higher specificity in male patients [0.90 (95% CI 0.75-0.96) versus 0.70 (95% CI 0.56-0.80)].

CONCLUSION

NLR and MLR represent commonly ordered, low-cost, simple, and readily available complete cell count laboratory values and should be used as adjunct tests with reasonable diagnostic accuracy in detecting acute PJIs. Moreover, with its excellent specificity and PPV, MLR could provide valuable insight in diagnosing acute PJI, particularly in male patients.

LEVEL OF EVIDENCE

Level III Retrospective Cohort analysis.

Success Rate After 2-Stage Spacer-Free Total Hip Arthroplasty Exchange and Risk Factors for Reinfection: A Prospective Cohort Study of 187 Patients

BACKGROUND

Two-stage prosthesis exchange is the treatment of choice for chronic periprosthetic joint infection (PJI) of a total hip arthroplasty (THA), especially when the bone and surrounding soft tissues are compromised or difficult-to-treat pathogens are implicated. The aims of our study were as follows: (1) to determine the outcome of 2-stage prosthesis exchange for the treatment of PJI after THA and (2) to determine the risk factors for reinfection leading to subsequent revision surgeries after reimplantation.

METHODS

We prospectively enrolled 187 consecutive patients who underwent a 2-stage THA exchange with resection arthroplasty for PJI from 2013 to 2019. The mean (± SD) duration of follow-up was 54.2 ± 24.9 months (range, 36 to 96), and the mean interval until reimplantation was 9.8 ± 8.9 weeks (range, 2 to 38). All patients remained in a spacer-free girdlestone situation between the 2 stages of treatment. Patients who remained infection-free after their 2-stage treatment were considered to have achieved treatment success.

RESULTS

The overall success rate was 85.6%. The cumulative probability of reinfection was 11.5% after one year and 14% after 2 years after reimplantation. High virulence or difficult-to-treat pathogens were significant and independent risk factors for reinfection (HR [hazard ratio] = 3.71, 95% CI [confidence interval]: 1.47 to 9.36, P = .006 and HR = 3.85, 95% CI: 1.73 to 8.57, respectively, P = .001), as was previous 2-stage hip prosthesis exchange (HR = 3.58, 95% CI: 1.33 to 9.62, P = .01). Overall reoperation and revision rates were 26.2 and 16.6%, respectively. Re-infected patients had an 80% higher probability of reoperation than noninfected ones (P < .001, log-rank = 102.6), and they were 55% more likely to undergo revision surgery during their follow-up (P < .001, log-rank = 55.4).

CONCLUSIONS

Reinfection rates after 2-stage spacer-free THA revision for PJI still remain high but are comparable to those including cement spacers. Patients who have had prior failed 2-stage implant exchanges or are infected by high-grade or difficult-to-treat pathogens are at high risk for treatment failure.

The presence of a sinus tract is associated with reinfection after two-stage revision surgery for prosthetic hip joint infection: a case-control study

BACKGROUND

Reinfection rates after two-stage revision (TSR) for prosthetic joint infection (PJI) range from 7.9 to 14%. Many factors, including sinus tracts, are associated with reinfection after this procedure. This study aimed to delineate whether the presence of sinus tract could increase reinfection rate after TSR and to investigate other potential risk factors for reinfection after TSR.

METHODS

We conducted a case-control study by retrospectively reviewing patients who underwent TSR for prosthetic hip joint infection from 2002 to 2022. The case group included patients who developed reinfection after TSR, while the control group consisted of patients who did not experience reinfection. PJI and reinfection after TSR were defined based on Delphi-based international consensus criteria. Patient demographics, past medical history, clinical manifestations, laboratory results, interval between stages, microbiological culture results were collected. Univariate analyses were utilized to assess the effect of sinus tract on reinfection and to identify other risk factors for reinfection after TSR.

RESULTS

Six patients with reinfection after TSR were included as the case group and 32 patients without reinfection were in the control group. Significant difference was observed in percentage of patients with sinus tracts between the two groups (67% in the case group versus 19% in the control group, p = 0.031, OR = 8.7). Significant difference was also found in percentage of patients with positive cultures of synovial fluid and synovium harvested during the first-stage revision between the two groups (100% in the case group versus 50% in the control group, p = 0.030). Additionally, patients in the case group had a significantly higher C-reactive protein (CRP) level prior to the second stage revision than that of patients in the control group (8.80 mg/L versus 2.36 mg/L, p = 0.005), despite normal CRP levels in all patients.

CONCLUSIONS

Our study revealed that the presence of sinus tracts could significantly increase risk of postoperative reinfection after TSR. Positive cultures during the first stage revision and elevated CRP level prior to the second stage revision could also increase the risk of reinfection after TSR. Further studies with a larger sample size are required.

TRIAL REGISTRATION

Retrospectively registered.

Patient-Related Predictors of Treatment Failure After Two-Stage Total Hip Arthroplasty Revision for Periprosthetic Joint Infection: A Systematic Review and Meta-Analysis

BACKGROUND

Periprosthetic joint infection (PJI) treatment has high failure rates even after 2-stage revision. Risk factors for treatment failure (TF) after staged revision for PJI are not well defined, nor is it well established how they correlate with the risks of developing an index PJI. Identifying modifiable risk factors may allow preoperative optimization, while identifying nonmodifiable risk factors can influence surgical options or advise against further surgery. We performed a systematic review and meta-analysis to better define predictors of TF in 2-stage revision for PJI.

METHODS

The PubMed, Embase, and Scopus databases were searched from their inception in December 1976 to April 15, 2023. Studies comparing patient-related variables between patients successfully treated who had 2-staged revision total hip arthroplasty (THA) and patients with persistent infections were included. Studies were screened, and 2 independent reviewers extracted data, while a third resolved discrepancies. Meta-analysis was performed on these data. There were 10,052 unique studies screened, and 21 studies met the inclusion criteria for data extraction.

RESULTS

There was good-quality evidence that obesity, liver cirrhosis, and previous failed revisions for PJI are nonmodifiable risk factors, while intravenous drug use (IVDU) and smoking are modifiable risk factors for TF after 2-stage revision for hip PJI. Reoperation between revision stages was also significantly associated with an increased risk of TF. Interestingly, other risk factors for an index PJI including male gender, American Society of Anesthesiology score, diabetes mellitus, and inflammatory arthropathy did not predict TF. Evidence on Charlson Comorbidity Index was limited.

CONCLUSIONS

Patients with a smoking history, obesity, IVDU, previous failed revision for PJI, reoperation between stages, and liver cirrhosis are more likely to experience TF after 2-stage revision THA for PJI. Modifiable risk factors include smoking and IVDU and these patients should be referred to services for cessation as early as possible before 2-stage revision THA.

Description of reinfection of joint prosthesis after 2-stage replacement (infection of the 2nd stage prosthesis): A multicenter study

INTRODUCTION

Two-stage exchange is the gold standard in the surgical management of prosthetic joint infection (PJI). However, perioperative reinfections (RePJI) can occur to newly inserted prosthesis, which highlights the importance of an adequate antibiotic prophylaxis, although there is scarce evidence in this field. Our objective was to evaluate the characteristics of RePJI, its prognosis and the antibiotic prophylaxis that is commonly used in second-stage surgery.

METHODS

Multicentric retrospective observational study in Spanish hospitals including patients with RePJI between 2009 and 2018.

RESULTS

We included 92 patients with RePJI from 12 hospitals. The most frequent isolated microorganism was Staphylococcus epidermidis in 35 cases (38.5%); 61.1% of staphylococci were methiciliin-resistant. In 12 cases (13%), the same microoganism causing the primary PJI was isolated in RePJI. When comparing with the microbiology of primary PJI, there were more cases caused by Gram-negative bacteria (the most frequent was Pseudomonas spp.) and less by Gram-positive bacteria. Failure occured in 69 cases (75%). There were 43 different courses of antibiotic prophylaxis after the second-stage surgery; the most frequent was a unique preoperative cefazolin dose, but most patients received prophylaxis before and after the second-stage surgery (61 cases).

CONCLUSIONS

The most frequent microorganisms in RePJI are coagulase-negative staphylococci, although Gram-negative bacteria, especially Pseudomonas spp. are also common. There is a significant heterogeneity in antibiotic prophylaxis for a second-stage surgery. ReIPJI treatment has a high failure rate.

Impact of antibiotic prophylaxis in second-stage surgery in joint prosthesis infection treated with two-stage exchange. A multicenter case-control study

INTRODUCTION

After two-stage exchange due to prosthetic joint infection (PJI), the new prosthesis carries a high risk of reinfection (RePJI). There isn`t solid evidence regarding the antibiotic prophylaxis in 2nd-stage surgery. The objective of this study is to describe what antibiotic prophylaxis is used in this surgery and evaluate its impact on the risk of developing RePJI.

METHODS

Retrospective multicenter case-control study in Spanish hospitals. The study included cases of PJI treated with two-stage exchange and subsequently developed a new infection. For each case, two controls were included, matched by prosthesis location, center, and year of surgery. The prophylaxis regimens were grouped based on their antibacterial spectrum, and we calculated the association between the type of regimen and the development of RePJI using conditional logistic regression, adjusted for possible confounding factors.

RESULTS

We included 90 cases from 12 centers, which were compared with 172 controls. The most frequent causative microorganism was Staphylococcus epidermidis with 34 cases (37.8%). Staphylococci were responsible for 50 cases (55.6%), 32 of them (64%) methicillin-resistant. Gram-negative bacilli were involved in 30 cases (33.3%), the most common Pseudomonas aeruginosa. In total, 83 different antibiotic prophylaxis regimens were used in 2nd-stage surgery, the most frequent a single preoperative dose of cefazolin (48 occasions; 18.3%); however, it was most common a combination of a glycopeptide and a beta-lactam with activity against Pseudomonas spp (99 cases, 25.2%). In the adjusted analysis, regimens that included antibiotics with activity against methicillin-resistant staphylococci AND Pseudomonas spp were associated with a significantly lower risk of RePJI (adjusted OR = 0.24; 95% IC: 0.09-0.65).

CONCLUSIONS

The lack of standardization in 2nd-satge surgery prophylaxis explains the wide diversity of regimens used in this procedure. The results suggest that antibiotic prophylaxis in this surgery should include an antibiotic with activity against methicillin-resistant staphylococci and Pseudomonas.

The Effect of Retained Hardware on Failure Among Prosthetic Joint Infections of the Knee in the Presence and Absence of Staphylococcus aureus

Background

The risk of failure associated with different surgical strategies for prosthetic joint infections (PJIs) among patients with and without Staphylococcus aureus is uncertain. The purpose of this study was to assess whether S. aureus modifies the association between retained hardware and failure following revision surgery for PJI of the knee.

Methods

This was a single-center retrospective cohort study of 106 first PJIs of the knee between 2016 and 2020 at a rural academic medical center. The exposure was retained hardware following revision surgery for PJI, and the outcomes were recurrent infection, any infection, and a composite outcome including any infection, unplanned revision, failure to undergo reimplantation, amputation, or death within 2 years of revision. We used negative binomial regression to quantify the association between the exposure and outcome and to assess the presence of S. aureus as an effect modifier.

Results

Retained hardware was significantly associated with failure when defined as recurrent infection among S. aureus PJI (adjusted risk difference [aRD], 0.38; 95% CI, 0.12-0.64) but not in the absence of S. aureus (aRD, -0.02; 95% CI, -0.17 to 0.13), and S. aureus was an effect modifier (P interaction = .01).

Conclusions

We report a significant association between the presence of retained hardware and recurrent infection among S. aureus PJI of the knee, but not for non-S. aureus PJI. This could help inform the surgical management of PJI of the knee in cases where the microbiology is known before surgery.

Recurrent Periprosthetic Joint Infections: Diagnosis, Management, and Outcomes

Periprosthetic joint infection (PJI) remains one of the most common complications after total joint arthroplasty. It is challenging to manage, associated with significant morbidity and mortality, and is a financial burden on the health care system. Failure of 2-stage management for chronic PJI is not uncommon. Repeat infections are oftentimes polymicrobial, multiple drug-resistant microorganisms, or new organisms. Optimizing the success of index 2-stage revision is the greatest prevention against failure of any subsequent management options and requires a robust team-based approach.

Evaluation of time to reimplantation as a risk factor in two-stage revision with static spacers for periprosthetic knee joint infection

INTRODUCTION

We investigated the time to reimplantation (TTR) during two-stage revision using static spacers with regard to treatment success and function in patients with chronic periprosthetic joint infection (PJI) of the knee.

METHODS

163 patients (median age 72 years, 72 women) who underwent two-stage exchange for chronic knee PJI between 2012 and 2020 were retrospectively analyzed (based on the 2011 Musculoskeletal Infection Society criteria). A cutoff TTR for increased risk of reinfection was identified using the maximally selected log-rank statistic. Infection control, aseptic revisions and overall survival were analyzed using Kaplan-Meier survival estimates. Adjustment for confounding factors-the Charlson Comorbidity Index (CCI) and C-reactive protein (CRP)-was done with a Cox proportional hazards model.

RESULTS

When TTR exceeded 94 days, the adjusted hazard of reinfection was increased 2.8-fold (95% CI 1.4-5.7; p = 0.0036). The reinfection-free rate was 67% (95% CI 52-79%) after 2 years and 33% (95% CI 11-57%) after 5 years for a longer TTR compared to 89% (95% CI 81-94%) and 80% (95% CI 69-87%) at 2 and 5 years, respectively, for a shorter TTR. Adjusted overall survival and number of aseptic revisions did not differ between the longer TTR and shorter TTR groups. Maximum knee flexion was 90° (IQR 84-100) for a longer TTR and 95° (IQR 90-100) for a shorter TTR (p = 0.0431), with no difference between the groups in Oxford Knee Score. Baseline characteristics were similar (body mass index, age, previous surgeries, microorganisms) for the two groups, except that there was a higher CCI (median 4 vs. 3) and higher CRP (median 3.7 vs 2.6 mg/dl) in the longer TTR group.

CONCLUSION

A long TTR is sometimes unavoidable in clinical practice, but surgeons should be aware of a potentially higher risk of reinfection.

LEVEL OF EVIDENCE

III, retrospective comparative study.

Diagnosis and Prevention of Periprosthetic Joint Infections by Staphylococcus aureus after Hip Fracture: A Systematic Review of the Literature

Hip arthroplasties are surgical procedures widely performed all over the world, seeking to return functionality, relieve pain, and improve the quality of life of patients affected by osteoarthritis, femoral neck fractures, osteonecrosis of the femoral head, among other etiologies. Periprosthetic joint infections are one of the most feared complications due to the high associated morbidity and mortality, with a high number of pathogens that may be associated with its etiology. The aim of the present study was to analyze aspects correlated with the occurrence of infection, diagnosis and prevention of periprosthetic joint infections in the hip associated with Staphylococcus aureus after corrective surgery for hip fractures. This is a systematic review of the literature carried out in the databases indexed in the Medical Literature Analysis and Retrieval System Online (MEDLINE) carried out in accordance with the precepts established by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. Twenty studies that addressed the diagnosis and prevention of periprosthetic joint infections after hip fractures were selected for analysis. It is observed that there is no consensus in the literature on preventive measures for the occurrence of such infectious processes. Among the risk factors for the occurrence and severity of infections by S. aureus after hip arthroplasties, obesity, longer surgical time, older age, immunosuppression, recent use of antibiotics, and multicomorbidities were mentioned. The use of biomarkers for early diagnosis, as well as screening, decolonization, and antibiotic prophylaxis processes are among the preventive procedures proposed in the literature.

Dual Surgical Setup Associated with Reduced Infection Recurrence for Hip and Knee Arthroplasty After Two-Stage Exchange

INTRODUCTION

Two-stage exchange (TSE) is the gold standard for the treatment of chronic periprosthetic joint infection (PJI) after total joint arthroplasty of the hip and knee in the United States. Failure of treatment can have devastating consequences for the patient, including poor functional outcomes, multiple further surgeries, and increased mortality. Several factors associated with infection recurrence have previously been identified in the literature. The purpose of this study was to evaluate whether the use of a dual surgical setup was associated with reduced risk of recurrence after TSE for PJI.

METHODS

A retrospective study was conducted between January 2000 and December 2021 to isolate patients who underwent TSE after total joint arthroplasty of the hip and knee. Failure was defined as infection recurrence requiring surgical intervention. Demographic factors (age, sex, body mass index, smoking status, American Society of Anesthesiologists status), preoperative comorbidities (hypertension, cardiac disease, diabetes status, depression diagnosis, pulmonary disease), operating surgeon, single versus dual setup, hospital setting, use of long-term antibiotics postoperatively after TSE, aspiration data, and infecting organism were compared between cohorts using multivariate regression analysis.

RESULTS

A total of 134 patients were identified who underwent TSE after diagnosis of PJI. The mean follow-up was 67.84 (range, 13 to 236) months. Dual setup (odds ratio, 0.13; confidence interval, 0.02 to 0.52; P = 0.0122) was found to be an independent predictive variable associated with a lower risk of infection recurrence.

CONCLUSION

Utilization of a dual surgical setup is a low-cost modifiable risk factor associated with a lower risk of recurrence of after TSE of the hip and knee for PJI.

Two-stage revision in periprosthetic joint infection of the hip using a new intraoperatively molded articulating spacer design

Purpose

The treatment of periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is still under debate. Two-stage exchange arthroplasty is the most common surgical procedure performed. This study analyzed a new functional articulating hip spacer called "Spaceflex" regarding the mechanical-related complications, the recurrent/persistent infection during the interval period, the overall infection-free survivorship after reimplantation, the overall complication/reoperation after reimplantation and the evaluation of patient-reported outcome measures (PROMs) at three intervals of time: before the first stage, during the interval period, and at the final follow-up after reimplantation.

Methods

A consecutive series of 56 patients with chronic hip PJI undergoing two-stage prosthetic revision using a new intraoperatively molded articulating hip spacer design implanted by the same experienced surgeons was examined from January 2017 to December 2021. The demographic and clinical characteristics of the included patients were analyzed. Specifically, PROMs before the first stage, during the interval period, and at the final follow-up after reimplantation and complications reported during the interval period and after reimplantation were examined.

Results

The new functional articulating hip spacer was characterized by a low mechanical complication rate (5.8%) and an overall two-stage procedure success rate of 90.6% at the last follow-up. PROMs improved with the spacer during the interval period and at the final follow-up. Furthermore, the reinfection rate was in line with other case series with different spacer designs. Finally, low postoperative complication rates after reimplantation have been demonstrated.

Conclusions

Two-stage revision performed with a modular articulating spacer allows patients to preserve satisfactory functional and quality-of-life outcomes in the postoperative period, with a low risk of mechanical complications and without increasing the reinfection rate.

The Challenge of Emerging Resistant Gram-Positive Pathogens in Hip and Knee Periprosthetic Joint Infections

➤ An increase in resistant bacterial pathogens has occurred over the last 4 decades.➤ Careful patient selection and improving or correcting risk factors for periprosthetic joint infection (PJI) before elective surgical treatment are strongly recommended. ➤ Appropriate microbiological methods, including those used to detect and grow Cutibacterium acnes, are recommended. ➤ Antimicrobial agents used in the prevention or management of infection should be selected appropriately and the duration of therapy should be carefully considered in order to mitigate the risk of developing bacterial resistance.➤ Molecular methods including rapid polymerase chain reaction (PCR) diagnostics, 16S sequencing, and/or shotgun and/or targeted whole-genome sequencing are recommended in culture-negative cases of PJI.➤ Expert consultation with an infectious diseases specialist (if available) is recommended to assist with the appropriate antimicrobial management and monitoring of patients with PJI.

Utility of Diagnostic Tests Before Reimplantation in Patients Undergoing 2-Stage Revision Total Joint Arthroplasty: A Systematic Review and Meta-analysis

INTRODUCTION

Periprosthetic joint infection (PJI) is a devastating complication after total joint arthroplasty (TJA), with treatment failure occurring in 12% to 28% after 2-stage revision. It is vital to identify diagnostic tools indicative of persistent infection or treatment failure after 2-stage revision for PJI.

METHODS

The Cochrane Library, PubMed (MEDLINE), and EMBASE were searched for randomized controlled trials and comparative observational studies published before October 3, 2021, which evaluated the utility of serum/plasma biomarkers (erythrocyte sedimentation rate [ESR], C-reactive protein [CRP], interleukin-6 [IL-6], fibrinogen, D-dimer), synovial biomarkers (white blood cell [WBC] count, neutrophil percentage [PMN %], alpha-defensin [AD], leukocyte esterase [LE]), tissue frozen section, tissue culture, synovial fluid culture, or sonicated spacer fluid culture indicative of persistent infection before the second stage of 2-stage revision for PJI or treatment failure after 2-stage revision for PJI.

RESULTS

A total of 47 studies including 6,605 diagnostic tests among 3,781 2-stage revisions for PJI were analyzed. Among those cases, 723 (19.1%) experienced persistent infection or treatment failure. Synovial LE (sensitivity 0.25 [0.10-0.47], specificity 0.99 [0.93-1.00], positive likelihood ratio 14.0 [1.45-135.58]) and serum IL-6 (sensitivity 0.52 [0.33-0.70], specificity 0.92 [0.85-0.96], positive likelihood ratio 7.90 [0.86-72.61]) had the highest diagnostic accuracy. However, no biomarker was associated with a clinically useful negative likelihood ratio. In subgroup analysis, synovial PMN %, synovial fluid culture, serum ESR, and serum CRP had limited utility for detecting persistent infection before reimplantation (positive likelihood ratios ranging 2.33-3.74; negative likelihood ratios ranging 0.31-0.9) and no utility for predicting failure after the second stage of 2-stage revision.

CONCLUSIONS

Synovial WBC count, synovial PMN %, synovial fluid culture, serum ESR, and serum CRP have modest sensitivity and specificity for predicting persistent infection during the second stage of 2-stage revision, suggesting some combination of these diagnostic tests might be useful before reimplantation. No biomarker or culture accurately predicted treatment failure after reimplantation.

LEVEL OF EVIDENCE

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

Which Patients with Chronic Periprosthetic Joint Infection Are Less Suitable to Successful Two Stage Exchange Arthroplasty Surgery? A Retrospective Clinical Trial

BACKGROUND

Two-stage exchange (TSE) arthroplasty is currently considered the gold standard for chronic periprosthetic joint infections (PJIs), despite a failure rate reported in up to 10% of patients. Little is known about the risk factors that may compromise successful TSE arthroplasty management in such patients. The main purpose of the current study was to highlight the potential risk factors of patients with chronic PJIs after THA managed by implant removal, outlining the differences between reimplanted patients and those that were never reimplanted because of a non-eradicated infection.

METHODS

We conducted a retrospective observational study of patient candidates for TSE arthroplasty surgery, managed at the authors' institution, over a four-year timeframe. The data were retrieved from the hospital's information database. The enrolled population was divided into two Groups: A, reimplanted; B, non-reimplanted because of a non-eradicated infection within one year. For each Group, demographic information, PJI-related risk factors, type of pathogen and presence of single or polymicrobial infection, were collected and analyzed.

RESULTS

In total, 21 patients were included in the study, 14 patients in Group A and 7 in Group B. Major Depression (p = 0.049) and polymicrobial infection (p = 0.04) were more commonly observed in patients that were not reimplanted in the study period. No differences between the two groups were observed when other characteristics were compared.

CONCLUSIONS

Patients with major depression, or those hosting polymicrobial periprosthetic hip infections, are more susceptible to failure of TSE arthroplasty procedures for chronic PJIs, hampering THA reimplantation. Current findings may drive further research and contribute to the understanding of the role of these risk factors in chronic PJI patients.

Diagnostic Utility and Thresholds for Commonly Obtained Serum and Synovial Markers Prior to Reimplantation in Periprosthetic Joint Infection

BACKGROUND

Accurate diagnosis of persistent periprosthetic joint infection (PJI) during 2-stage exchange remains a challenge. This study evaluated the diagnostic performance and thresholds of several commonly obtained serum and synovial markers to better guide reimplantation timing.

METHODS

This was a retrospective review of 249 patients who underwent 2-stage exchange with antibiotic spacers for PJI. Serum and synovial markers analyzed included white blood cell (WBC) count, polymorphonuclear percentage (PMN%), neutrophil-to-lymphocyte ratio (NLR), and absolute neutrophil count (ANC). Serum markers analyzed were erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), as well as percentage change in ESR and CRP from initial diagnosis to reimplantation. Area under the curve (AUC) analyses were performed to determine diagnostic accuracy of detecting PJI.

RESULTS

In TKAs, synovial ANC and WBC had the highest AUCs (0.76), with thresholds of 2,952 and 3,800 cells/μL, respectively. The next best marker was serum CRP (0.73) with a threshold of 5.2 mg/dL. In THAs, serum CRP had the highest AUC (0.84) with a threshold of 4.3 mg/dL, followed by synovial PMN% (0.80) with a threshold of 77%. Percentage change in serum ESR or CRP provided low diagnostic value overall.

CONCLUSION

Regarding serum markers, CRP consistently performed well in detecting persistent PJI in patients with antibiotic spacers. Absolute values of serum CRP and ESR had better diagnostic value than trends for guiding reimplantation timing. Diagnostic performance differed with joint type; however, synovial markers outperformed serum counterparts. No marker alone can be utilized to diagnose residual PJI in these patients, and further work is needed in this domain.

Influence of the Type of Bone Cement Used in Two-Stage Exchange Arthroplasty for Chronic Periarticular Joint Infection on the Spacer Replacement and Reinfection Rate

BACKGROUND

Antibiotic-loaded bone cement (ALBC) spacers are used in the first stage when treating periprosthetic joint infection (PJI). This study aimed to investigate whether a spacer made from commercial ALBC or plain bone cement with additional antibiotics could affect the spacer exchange rate before reimplantation.

METHODS

Patients undergoing two-stage exchange arthroplasty due to chronic PJI from January 2014 to August 2021 were retrospectively reviewed. The exclusion criteria included arthroplasty in the setting of septic arthritis, megaprosthesis, atypical pathogen infection, spacer placement unrelated to PJI, and spacer exchange due to mechanical complications. The patient demographics, brand of cement, and microbiology were recorded manually. The primary outcome was the incidence of spacer exchange due to persistent infection and the secondary outcome was the incidence of reinfection after reimplantation. A multivariate logistic regression analysis and Chi-square test were conducted to identify the effect of cement type on the spacer exchange.

RESULTS

A total of 334 patients underwent two-stage exchange arthroplasty for PJI. The spacer exchange rates in the commercial and non-commercial ALBC groups were 6.4% and 25.1%, respectively (p = 0.004). After controlling for confounding factors, there were significant differences between the commercial group and non-commercial groups in the spacer exchange rate (adjusted OR = 0.25; 95% CI = 0.72-0.87, p = 0.029). The use of commercial ALBC was not associated with a lower reinfection rate after reimplantation (p = 0.160).

CONCLUSIONS

In a two-stage exchange arthroplasty scenario, the spacer comprised of commercial ALBC resulted in a lower spacer exchange rate than the plain bone cement, both of which had additional antibiotics. However, the use of commercial ALBC was not associated with a lower incidence of reinfection following reimplantation.

Is long time to reimplantation a risk factor for reinfection in two-stage revision for periprosthetic infection? A systematic review of the literature

The two-stage revision arthroplasty is a common treatment option for chronic periprosthetic infection (PJI). The time to reimplantation (TTR) reported in the literature varies substantially from a few days to several hundred days. It is hypothesized that longer TTR could be associated with worse infection control after second stage. A systematic literature search was performed according to Preferred Reporting items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, in Pubmed, Cochrane Library and Web of Science Core Collection in clinical studies published until January 2023. Eleven studies investigating TTR as a potential risk factor for reinfection met the inclusion criteria (ten retrospective and one prospective study, published 2012-2022). Study design and outcome measures differed notably. The cutoff points above which TTR was regarded as "long" ranged from 4 to 18 weeks. No study observed a benefit for long TTR. In all studies, similar or even better infection control was observed for short TTR. The optimal TTR, however, is not yet defined. Larger clinical studies with homogeneous patient populations and adjustment for confounding factors are needed.