Infection recurrence factors in one- and two-stage total knee prosthesis exchanges

Nanoadjuvant-triggered STING activation evokes systemic immunotherapy for repetitive implant-related infections

Repetitive implant-related infections (IRIs) are devastating complications in orthopedic surgery, threatening implant survival and even the life of the host. Biofilms conceal bacterial-associated antigens (BAAs) and result in a "cold tumor"-like immune silent microenvironment, allowing the persistence of IRIs. To address this challenge, an iron-based covalent organic framed nanoadjuvant doped with curcumin and platinum (CFCP) was designed in the present study to achieve efficient treatment of IRIs by inducing a systemic immune response. Specifically, enhanced sonodynamic therapy (SDT) from CFCP combined with iron ion metabolic interference increased the release of bacterial-associated double-stranded DNA (dsDNA). Immunogenic dsDNA promoted dendritic cell (DC) maturation through activation of the stimulator of interferon gene (STING) and amplified the immune stimulation of neutrophils via interferon-β (IFN-β). At the same time, enhanced BAA presentation aroused humoral immunity in B and T cells, creating long-term resistance to repetitive infections. Encouragingly, CFCP served as neoadjuvant immunotherapy for sustained antibacterial protection on implants and was expected to guide clinical IRI treatment and relapse prevention.

A Meta-Analysis of Success Rates of One-Stage Versus Two-Stage Revisions in Knee Prosthetic Joint Infections

Prosthetic joint infections (PJIs) pose significant challenges following total joint arthroplasties and cause profound complications. They are associated with significant morbidity and mortality. One-stage revision involves the removal of the infected implant and simultaneous re-implantation of a new prosthesis in a single surgical procedure. The two-stage approach is traditionally more common in the United States and follows a deliberate sequence: the infected implant is first removed, followed by a period of antibiotic therapy, and then a second surgery for implant reinsertion. While two-stage revisions were traditionally considered the gold standard, recent advancements have introduced one-stage revisions as a viable alternative. One-stage revision offers the advantage of being a single procedure, significantly reducing the patient's downtime without a functioning knee. Currently, there has not been a comprehensive exploration of the comparative outcomes between two-stage revisions and one-stage revisions. This systematic review and meta-analysis aimed to assess the outcomes of both one- and two-stage revisions for total knee arthroplasties (TKAs), by utilizing comparison studies as the foundation for analysis. Our search encompassed databases such as MEDLINE (Medical Literature Analysis and Retrieval System Online), Embase, and Cochrane to identify articles examining the comparative efficacy and outcomes of one- and two-stage revision procedures between January 2000 and June 2023. We employed keywords relevant to knee PJIs to identify comparative studies reporting on success rates, reinfection rates, microbiological findings, and other pertinent outcomes. Statistical analysis for this investigation was performed using Review Manager 5.4 (The Cochrane Collaboration, 2020) with a standard significance threshold set at a p-value less than .05. This meta-analysis incorporated six comparison articles and 802 patients. Two-stage revisions (547 patients) were associated with greater success rates (i.e., infection eradication) than one-stage revisions (255 patients) (p = .03). The studies did not suggest a difference in the microbiology of the infections. Two-stage revisions are associated with higher success rates than one-stage revisions in the treatment of knee PJIs. Future randomized controlled trials should evaluate the optimization of the management of these complications.

Systematic review and meta-analysis of single-stage vs two-stage revision for periprosthetic joint infection: a call for a prospective randomized trial

BACKGROUND

Periprosthetic joint infection (PJI) is a severe complication of joint arthroplasty that causes significant pain and economic loss. This study aimed to determine whether the current evidence supports single-stage revision for PJI based on reinfection and reoperation rates.

METHODS

We searched the PubMed, EBSCO, Medline, and Cochrane Library databases from inception to 30 May 2023 to identify studies that compared single-stage revision and two-stage revision for PJI. Data on reinfection and reoperation rates were pooled.

RESULTS

This meta-analysis included a total of 40 studies with 8711 patients. Overall, there was no significant difference between single- and two-stage revision regarding the postoperative reinfection rate and reoperation rate. Subgroup analysis by surgery period and different surgical sites revealed no difference between the two groups in the reinfection and reoperation rates.

CONCLUSIONS

Based on the available evidence, our study did not identify a significant difference in reinfection and reoperation rates between single- and two-stage revision for PJI. Given the limitations in inclusion/exclusion criteria and the observed heterogeneity, we acknowledge the complexity of drawing strong conclusions. Therefore, we suggest that the choice between single- and two-stage revision should be carefully considered on an individual basis, taking into account patient-specific factors and further research developments.

Functional Outcomes of Knee Arthrodesis for Infected Total Knee Arthroplasty

INTRODUCTION

As the occurrence of total knee arthroplasties (TKAs) is forecasted to continue rising, so too will the frequency of prosthetic joint infections (PJIs) and revision TKAs. Multiple revisions can result in an unreconstructible knee. In such instances, the knee may be salvaged through arthrodesis. We evaluated whether height, BMI, and age impacted patient-reported outcome measures (PROMs) in patients who underwent knee arthrodesis after revision TKA due to PJI.

METHODS

We conducted a retrospective review of patients undergoing arthrodesis for an infected TKA at a dedicated orthopedic infection service from 2014 to 2022. Patient demographics and PROMs from 36-Item Short Form Survey (SF-36) and Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaires were collected. Correlation analysis was performed to determine if any association between height, BMI, and age was present with the various PROMs and sub-scores.

RESULTS

Forty-four patients (19 males, 25 females) were included, with a mean follow-up of 48 months. Increases in height (>166 cm), BMI (>30), and age (>62 years) had a statistically significant negative impact on three SF-36 components: health changes (P = 0.016), physical functioning ability (P = 0.0096), and general health components (P = 0.0075).

CONCLUSION

Our results suggest that a knee arthrodesis is an acceptable option in patients with a persistent knee PJI with good functional PROMs and ambulatory status. Patients with shorter height, lower BMI, and younger age showed overall better outcomes. Knee arthrodesis can be an alternative option for amputation in patients with an infected TKA and provide good functional outcomes in selected patients.

Characterizing recurrent infections after one-stage revision for periprosthetic joint infection of the knee: a systematic review of the literature

BACKGROUND

Periprosthetic joint infection (PJI) of the knee represents a severe complication after 1.5% to 2% of primary total knee replacement. Although two-stage revision was considered the gold-standard treatment for PJI of the knee, in the last decades, more studies reported the outcomes of one-stage revisions. This systematic review aims to assess reinfection rate, infection-free survival after reoperation for recurrent infection, and the microorganisms involved in both primary and recurrent infection.

MATERIAL AND METHODS

A systematic review of all studies reporting the outcome of one-stage revision for PJI of the knee up to September 2022, according to PRISMA criteria and AMSTAR2 guidelines, was performed. Patient demographics, clinical, surgical, and postoperative data were recorded.

PROSPERO ID

CRD42022362767.

RESULTS

Eighteen studies with a total of 881 one-stage revisions for PJI of the knee were analyzed. A reinfection rate of 12.2% after an average follow-up of 57.6 months was reported. The most frequent causative microorganism were gram-positive bacteria (71.1%), gram-negative bacteria (7.1%), and polymicrobial infections (8%). The average postoperative knee society score was 81.5, and the average postoperative knee function score was 74.2. The infection-free survival after treatment for recurrent infection was 92.1%. The causative microorganisms at reinfections differed significantly from the primary infection (gram-positive 44.4%, gram-negative 11.1%).

CONCLUSION

Patients who underwent a one-stage revision for PJI of the knee showed a reinfection rate lower or comparable to other surgical treatments as two-stage or DAIR (debridement, antibiotics, and implant retention). Reoperation for reinfection demonstrates a lower success compared to one-stage revision. Moreover, microbiology differs between primary infection and recurrent infection. Level of evidence Level IV.

A mapping review on preoperative prognostic factors and outcome measures of revision total knee arthroplasty

To map literature on prognostic factors related to outcomes of revision total knee arthroplasty (rTKA), to identify extensively studied factors and to guide future research into what domains need further exploration. We performed a systematic literature search in MEDLINE, Embase, and Web of Science. The search string included multiple synonyms of the following keywords: "revision TKA", "outcome" and "prognostic factor". We searched for studies assessing the association between at least one prognostic factor and at least one outcome measure after rTKA surgery. Data on sample size, study design, prognostic factors, outcomes, and the direction of the association was extracted and included in an evidence map. After screening of 5,660 articles, we included 166 studies reporting prognostic factors for outcomes after rTKA, with a median sample size of 319 patients (30 to 303,867). Overall, 50% of the studies reported prospectively collected data, and 61% of the studies were performed in a single centre. In some studies, multiple associations were reported; 180 different prognostic factors were reported in these studies. The three most frequently studied prognostic factors were reason for revision (213 times), sex (125 times), and BMI (117 times). Studies focusing on functional scores and patient-reported outcome measures as prognostic factor for the outcome after surgery were limited (n = 42). The studies reported 154 different outcomes. The most commonly reported outcomes after rTKA were: re-revision (155 times), readmission (88 times), and reinfection (85 times). Only five studies included costs as outcome. Outcomes and prognostic factors that are routinely registered as part of clinical practice (e.g. BMI, sex, complications) or in (inter)national registries are studied frequently. Studies on prognostic factors, such as functional and sociodemographic status, and outcomes as healthcare costs, cognitive and mental function, and psychosocial impact are scarce, while they have been shown to be important for patients with osteoarthritis.

Midterm Survival of a Varus-Valgus Constrained Implant following One-Stage Revision for Periprosthetic Joint Infection: A Single-Center Study

Revision total knee arthroplasty (TKA) is challenging to perform in patients with periprosthetic joint infection (PJI) due to the difficulty of eradicating the infection and potential for bone and ligamentous deficits. The current study aimed to evaluate the midterm survival of varus-valgus constrained (VVC) implants used in one-stage revision TKA for chronic PJI at our institution. This retrospective analysis included 132 patients with chronic PJI who underwent one-stage revision using a VVC implant. The average follow-up was 51.6 months (range: 24-85 months). Five-year survival analysis was performed to set recurrent infection and mechanical failure as the end point. Hospital for special surgery (HSS) as functional outcomes was evaluated preoperatively and at the latest follow-up. A total of 12 patients (9.1%) underwent retreatment for reinfection (nine patients) and mechanical failure (three patients). The overall 5-year revision-free survival was 82.7%, the infection-free survival was 91.1%, and the mechanical failure-free survival was 98.3%. The preoperative HSS knee score improved from 35.6 points (range: 24.3-47.7 points) preoperatively to 76.8 points (range: 57.2-87.6 points) at the latest follow-up. Complications were identified in 20 patients (15.2%) which included aseptic osteolysis in 4 cases, acceptable flexion instability in 3 cases, arthrofibrosis in 2 patients, hematomas in 2 cases, calf intermuscular venous thrombosis in 6 patients, and femoral stem tip pain in 3 cases. This is the first study to report the outcomes of one-stage revision using VVC implants for knee PJI. Improved functional outcomes and good midterm survival are demonstrated at an average follow-up of 51.6 months.

Reinfection rates after one- and two-stage revision surgery for hip and knee arthroplasty: a systematic review and meta-analysis

PURPOSE

Revisions for periprosthetic joint infection of knee and hip arthroplasty can be performed following one- or two-stage treatment protocols. Current literature is inconclusive whether one protocol is superior to the other, as prior literature reported similar reinfection rates for both treatment options. We aimed to provide a systematic review and meta-analysis of current literature on septic arthroplasty revisions.

METHODS

Between April 2015 and December 2020, Medline, Embase, and The Cochrane Library were searched for studies reporting reinfection outcomes in patients treated with one-stage and two-stage knee or hip revision arthroplasty. Two reviewers independently extracted data and disagreements were resolved by a third investigator. We utilized a double arcsine transformation, prior to pooling using a random-effects model.

RESULTS

For hip revision arthroplasty, we identified 14 one-stage studies (n = 1237) with a pooled reinfection rate of 5.7% (95% CI 3.7-8.1%), and 46 two-stage studies (n = 5009) with a reinfection rate of 8.4% (95% CI 6.9-9.9%). For knee revision arthroplasty, 6 one-stage studies (n = 527) and 48 two-stage studies (n = 4344) were identified with reinfection rates of 12.7% (7.0-19.7%) and 16.2% (13.7-19.0%), respectively. Overall, reinfection rates did not vary substantially after subgroup analysis. Limitations of our study are the limited amount of one-stage studies that introduce a potential bias.

CONCLUSION

The reinfection rates following one- and two-stage hip and knee arthroplasty revisions were similar. Knee reinfection rates have increased compared to the previous analysis. Individual patient characteristics and adequate treatment algorithms are needed for a more individual selection approach, until a randomized trial is performed.

One and a Half-Stage Revision With Prosthetic Articulating Spacer for Definitive Management of Knee Periprosthetic Joint Infection

This paper is a comprehensive review that describes indications, contraindications, clinical outcomes, and pearls and pitfalls of 1.5-stage revision total knee arthroplasty (TKA) utilizing a primary TKA femoral component, all-polyethylene tibial component, and hand-crafted antibiotic cement for the management of chronic periprosthetic joint infection. The 1.5-stage exchange TKA details placement of an articulating spacer for an indefinite period, prolonging revision until reinfection, deterioration of functional status, or construct failure. A 1.5-stage revision TKA technique is a viable option for treatment of chronic periprosthetic knee infections. The inherent advantages of decreased health-care costs, decreased morbidity and mortality, and improved emotional ease from having a single procedure is attractive, especially if reinfection rates are determined to be equivocal to 2-stage revision.

Predictors of failure of two-stage revision in periprosthetic knee infection: a retrospective cohort study with a minimum two-year follow-up

PURPOSE

Despite the standardization of two-stage knee revision protocols, a high percentage of failures still occurs. Identifying the predictors of failure is necessary to determine appropriate management and counsel for patients with a periprosthetic knee infection. This study aimed to identify risk factors predicting the failure, to describe implant survival, and to report the mid-term clinical outcomes of patients undergoing two-stage revision for periprosthetic knee infection.

METHODS

Data of patients who underwent two-stage knee revision from 2012 to 2016 were analyzed, and 108 patients were included. The mean age was 66.6 ± 9.2 years. The mean follow-up was 52.9 ± 15.6 months. Logistic regression was conducted to identify predictors of treatment failure. Kaplan-Meier curves were generated to assess implant survival. Preoperative functional outcomes were compared to those registered at the final follow-up.

RESULTS

Difficult-to-treat infections (OR = 4.2, 95% CI 1.2-14.5, p = 0.025), the number of previous surgeries (OR = 1.8, 95% CI 1.2-2.6, p = 0.005), and the level of tibial bone defect (OR = 2.3, 95% CI 1.1-4.7, p = 0.027) significantly predicted the failure of two-stage knee revision. Survivorship of implants was significantly lower for patients presenting these risk factors (p < 0.05). Mean Knee Society Score improved from 49.0 ± 12.0 to 80.2 ± 13.6 (p < 0.001). Mean Oxford Knee Score improved from 22.2 ± 4.9 to 36.1 ± 6.0 points (p < 0.001).

CONCLUSION

Difficult-to-treat pathogens, the number of previous surgeries, and the level of tibial bone defect were independent risk factors of two-stage knee revision failure. Overall, the two-stage protocol provided a good survival rate and functional outcome.

Outcomes of single- and two-stage revision total knee arthroplasty for chronic periprosthetic joint infection : long-term outcomes of changing clinical practice in a specialist centre

AIMS

Single-stage revision total knee arthroplasty (rTKA) is gaining popularity in treating chronic periprosthetic joint infections (PJIs). We have introduced this approach to our clinical practice and sought to evaluate rates of reinfection and re-revision, along with predictors of failure of both single- and two-stage rTKA for chronic PJI.

METHODS

A retrospective comparative cohort study of all rTKAs for chronic PJI between 1 April 2003 and 31 December 2018 was undertaken using prospective databases. Patients with acute infections were excluded; rTKAs were classified as single-stage, stage 1, or stage 2 of two-stage revision. The primary outcome measure was failure to eradicate or recurrent infection. Variables evaluated for failure by regression analysis included age, BMI, American Society of Anesthesiologists grade, infecting organisms, and the presence of a sinus. Patient survivorship was also compared between the groups.

RESULTS

A total of 292 consecutive first-time rTKAs for chronic PJI were included: 82 single-stage (28.1%); and 210 two-stage (71.9%) revisions. The mean age was 71 years (27 to 90), with 165 females (57.4%), and a mean BMI of 30.9 kg/m² (20 to 53). Significantly more patients with a known infecting organism were in the single-stage group (93.9% vs 80.47%; p = 0.004). The infecting organism was identified preoperatively in 246 cases (84.2%). At a mean follow-up of 6.3 years (2.0 to 17.6), the failure rate was 6.1% in the single-stage, and 12% in the two-stage groups. All failures occurred within four years of treatment. The presence of a sinus was an independent risk factor for failure (odds ratio (OR) 4.97; 95% confidence interval (CI) 1.593 to 15.505; p = 0.006), as well as age > 80 years (OR 5.962; 95% CI 1.156 to 30.73; p = 0.033). The ten-year patient survivorship rate was 72% in the single-stage group compared with 70.5% in the two-stage group. This difference was not significant (p = 0.517).

CONCLUSION

Single-stage rTKA is an effective strategy with a high success rate comparable to two-stage approach in appropriately selected patients. Cite this article: Bone Joint J 2021;103-B(8):1373-1379.

Economic Study of 2-Stage Exchange in Patients With Knee or Hip Prosthetic Joint Infection Managed in a Referral Center in France: Time to Use Innovative(s) Intervention(s) at the Time of Reimplantation to Reduce the Risk of Superinfection

Objective: Chronic prosthetic joint infections (PJI) are serious complications in arthroplasty leading to prosthesis exchange and potential significant costs for health systems, especially if a subsequent new infection occurs. This study assessed the cost of chronic PJI managed with 2-stage exchange at the Lyon University Hospital, CRIOAc Lyon reference center, France. A threshold analysis was then undertaken to determine the reimbursement tariff of a hypothetical preventive device usable at the time of reimplantation, which possibly enables health insurance to save money according to the risk reduction of subsequent new infection. This analysis was also performed for a potential innovative device already available on the market, a dual antibiotic loaded bone cement used to fix cemented prosthesis that releases high concentrations of gentamicin and vancomycin locally (G+V cement). Method: Patients >18 years, admitted for a hip or knee chronic PJI managed with 2-stage exchange, between January 1, 2013, and December 31, 2015, were retrospectively identified. Following, resource consumption in relation to inpatient hospital stay, hospitalization at home, rehabilitation care, outpatient antibiotic treatments, imaging, laboratory analysis, and consultations were identified and collected from patient records and taken into account in the evaluation. Costs were assessed from the French health insurance perspective over the 2 years following prosthesis reimplantation. Results: The study included 116 patients (median age 67 y; 47% hip prosthesis). Mean cost of chronic PJI was estimated over the 2 years following prosthesis reimplantation at €21,324 for all patients, and at €51,697 and €15,745 for patients with (n = 18) and without (n = 98) a subsequent new infection after reimplantation, respectively. According to the threshold analysis the reimbursement tariff (i) should not exceed €2,820 for a device which can reduce the risk of a new infection by 50% and (ii) was between €2,988 and €3,984 if the G + V cement can reduce the risk of a new infection by 80% (this reduction risk is speculative and has to be confirmed by clinical trials). Conclusion: This study revealed that chronic PJI requiring a 2-stage revision is costly, with significant costs in relation to the reimplantation procedure (about 15 k€). However, following reimplantation the rate of subsequent new infection remained high, and the cost of reimplantation following a new infection is considerable, reaching 50k€ per patient. These first cost estimates of managing chronic PJI with 2-stage exchange in France underline the economic interest of preventing new infections.

Treatment options in PJI - is two-stage still gold standard?

Total knee arthroplasty (TKA) is a successful treatment for osteoarthritis with good clinical outcomes 1,2. Periprosthetic joint infection (PJI) in TKA has a low incidence between 0.5 and 3% but it is nevertheless one of the most dreadful complications 3-6. Two-staged revisions are considered to be the gold standard for revision in chronic PJI with infection eradication rates of over 90% 7. Recently, similar infection eradication rates after one-staged revision arthroplasty have been reported 8-10, raising the question whether the two-staged approach can still be considered the gold standard. We therefore performed a literature review to analyse the correlation of one-staged and two-staged TKA revisions with recurrent infection rates and functional outcomes. Studies concerning PJI treated by one- or two-staged revision published between 2000 and 2020 were retrieved by searching the databases PubMed/Medline and the Cochrane Database of Systematic Reviews. 29 studies were included in this qualitative synthesis. Mean follow-up was at 4.9 ± 2.6 years. The mean infection eradication rate after one-staged revision vs. two-staged revision in TKA was 87 ± 8.8% vs. 83 ± 11.7%. The functional outcome measured by the mean Knee Society Score (KSS) of one-staged revision vs. two-staged revision in TKA was 80 ± 5.9 vs. 80 ± 3.9 points. One-staged revision arthroplasty in TKA appears to have similar infection eradication rates and functional outcomes compared to two-staged revision arthroplasty. However, these results should be interpreted with caution, since selection bias may have played a significant role. Several criteria to guide the surgeon in selecting the appropriate procedure have been described, but the current recommendations are based on poor evidence as randomized controlled trials are lacking 11,12. Two-staged revision remains a successful treatment option which is rightly the gold standard. However, there is a variety of cases in which one-staged revision is a viable alternative, where similar success rates and functional outcome can be expected 7,13.

One-Stage Arthroplasty or Revision for Seronegative Infections in Hip and Knee

Objective

To assess the safety and effectiveness of one‐stage total joint arthroplasty (TJA) or revision for seronegative infections after total hip arthroplasty (THA) and total knee arthroplasty (TKA).

Methods

This retrospective study included a total of 495 patients who had undergone one‐stage total joint (hip or knee) arthroplasty or revision with a diagnosis of osteoarthritis secondary to sepsis, osteoarthritis or osteonecrosis of the femoral head (ONFH) secondary to internal fixation surgery of the hip joint, and one‐stage revision for prosthesis loosening after THA or TKA from January 2012 to December 2016. Bacterial cultures were taken from all patients (from joint fluid or articular cavity fluid and four to six different parts of soft tissues) during the operation. If the cultures were positive, patients received antibiotic treatment. Microbiology results from surgical samples, clinical evaluations, SF‐12 score (physical component summary [PCS] and mental component summary [MCS]), Harris hip score (HHS) or Hospital for Special Surgery (HSS) score, and patients' satisfaction was recorded at every follow‐up session.

Results

A total of 24 patients had a positive result for bacterial culture (4.85%). The bacterial culture results showed that there were 19 cases (79.16%) of gram‐positive cocci (Staphylococcus aureus), 4 cases (16.67%) of gram‐negative bacilli, and 1 case (4.17%) of fungi. For at least 24 months (mean 35 months) follow‐up, no reinfection was discovered. The mean HHS or HSS score improved significantly from 36.29 points preoperatively to 84.21 points postoperatively (P < 0.001). The mean PCS score improved from 10.15 preoperatively to 20.34 postoperatively, and the mean MCS from 13.22 preoperatively to 21.76 postoperatively, with significant differences. Most of the patients were satisfied.

Conclusion

One‐stage arthroplasty or revision with exhaustive debridement, adequate dosage, and duration of sensitive antibiotics is safe and effective for patients who have seronegative infection of hip or knee joints.

Predictors of Treatment Failure for Hip and Knee Prosthetic Joint Infections in the Setting of 1- and 2-Stage Exchange Arthroplasty: A Multicenter Retrospective Cohort

Background

Prosthetic hip and knee joint infections (PJIs) are challenging to eradicate despite prosthesis removal and antibiotic therapy. There is a need to understand risk factors for PJI treatment failure in the setting of prosthesis removal.

Methods

A retrospective cohort of individuals who underwent prosthesis removal for a PJI at 5 hospitals in Toronto, Canada, from 2010 to 2014 was created. Treatment failure was defined as recurrent PJI, amputation, death, or chronic antibiotic suppression. Potential risk factors for treatment failure were abstracted by chart review and assessed using a Cox proportional hazards model.

Results

A total of 533 individuals with prosthesis removal were followed for a median (interquartile range) of 814 (235–1530) days. A 1-stage exchange was performed in 19% (103/533), whereas a 2-stage procedure was completed in 88% (377/430). Treatment failure occurred in 24.8% (132/533) at 2 years; 53% (56/105) of recurrent PJIs were caused by a different bacterial species. At 4 years, treatment failure occurred in 36% of 1-stage and 32% of 2-stage procedures (P = .06). Characteristics associated with treatment failure included liver disease (adjusted hazard ratio [aHR], 3.12; 95% confidence interval [CI], 2.09–4.66), the presence of a sinus tract (aHR, 1.53; 95% CI, 1.12–2.10), preceding debridement with prosthesis retention (aHR, 1.68; 95% CI, 1.13–2.51), a 1-stage procedure (aHR, 1.72; 95% CI, 1.28–2.32), and infection due to Gram-negative bacilli (aHR, 1.35; 95% CI, 1.04–1.76).

Conclusions

Failure of PJI therapy is common, and risk factors are not easily modified. Improvements in treatment paradigms are needed, along with efforts to reduce orthopedic surgical site infections.

Outcome of single-stage versus two-stage exchange for revision knee arthroplasty for chronic periprosthetic infection

The gold standard for treating chronic periprosthetic joint infection is still considered to be double-stage exchange revision. The purpose of this review is to analyse the difference in terms of eradication rates and functional outcome after single- and double-stage prosthetic exchange for chronic periprosthetic joint infection around the knee.

We reviewed full text articles written in English from 1992 to 2018 reporting the success rates and functional outcomes of either single-stage exchange or double-stage exchange for knee arthroplasty revision performed for chronic infection. In the case of double-stage exchange, particular attention was paid to the type of spacer: articulating or static.

In all, 32 articles were analysed: 14 articles for single-stage including 687 patients and 18 articles for double-stage including 1086 patients. The average eradication rate was 87.1% for the one-stage procedure and 84.8% for the two-stage procedure. The functional outcomes were similar in both groups: the average Knee Society Knee Score was 80.0 in the single-stage exchange group and 77.8 in the double-stage exchange. The average range of motion was 91.4° in the single-stage exchange group and 97.8° in the double-stage exchange group.

Single-stage exchange appears to be a viable alternative to two -stage exchange in cases of chronic periprosthetic joint infection around the knee, provided there are no contra-indications, producing similar results in terms of eradication rates and functional outcomes, and offering the advantage of a unique surgical procedure, lower morbidity and reduced costs.

Cite this article: EFORT Open Rev 2019;4:495-502. DOI: 10.1302/2058-5241.4.190003

Risk Factors for Failure After 1-Stage Exchange Total Knee Arthroplasty in the Management of Periprosthetic Joint Infection

BACKGROUND

One-stage exchange arthroplasty in the management of periprosthetic joint infection was introduced at our institution. The purpose of this study was to analyze the risk factors of failure after periprosthetic joint infection following total knee arthroplasty treated with 1-stage exchange.

METHODS

Ninety-one patients who underwent failed treatment following 1-stage exchange total knee arthroplasty due to periprosthetic joint infection from January 2008 to December 2017 were included. From the same period, we randomly selected a 1:1 matched control group without a subsequent revision surgical procedure. Bivariate analyses, including preoperative, intraoperative, and postoperative factors, as well as logistic regression, were performed to identify risk factors for failure.

RESULTS

Bivariate analysis yielded 10 predictors (variables with significance at p < 0.05) for failure involving re-revision for any reason and 11 predictors for failure involving re-revision for reinfection. The binary logistic regression model revealed the following risk factors for re-revision for any reason: history of a 1-stage exchange for infection (odds ratio [OR], 26.706 [95% confidence interval (CI), 5.770 to 123.606]; p < 0.001), history of a 2-stage exchange (OR, 3.948 [95% CI, 1.869 to 8.339]; p < 0.001), and isolation of enterococci (OR, 16.925 [95% CI, 2.033 to 140.872]; p = 0.009). The risk factors for reinfection in the binary logistic regression analysis were history of 1-stage or 2-stage exchange arthroplasty, isolation of enterococci, and isolation of streptococci (OR, 6.025 [95% CI, 1.470 to 24.701]; p = 0.013).

CONCLUSIONS

We identified several risk factors of failure after 1-stage exchange arthroplasty for periprosthetic joint infection, most of which were not related to the patient comorbidities. Among them, previous exchange due to periprosthetic joint infection and the isolation of Enterococcus or Streptococcus species were associated with a higher risk of failure. Besides a multidisciplinary approach, being aware of the identified risk factors when evaluating patients with periprosthetic joint infection could lead to better outcomes.

LEVEL OF EVIDENCE

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

Total femur replacement in non-oncologic indications: Functional and radiological outcomes from a French survey with a mean 6 years' follow-up

INTRODUCTION

There are few published studies on total femur replacement (TFR) because its indications are rare. Other than malignant diseases, the indications extend to revisions and interprosthetic femur fractures; however, the outcomes of these indications have not been well defined. The aim of this retrospective survey was to analyze the complication rate and functional outcomes of these newer indications.

HYPOTHESIS

The morbidity and outcomes after TFR are comparable to those reported in the literature for non-cancer indications.

MATERIAL AND METHODS

Between 1997 and 2016, 29 TFR procedures were done at 6 French teaching hospitals in 15 women and 14 men, average age 68±14 years [32-85]. The primary indication was degenerative joint disease in the hip and/or knee in 16 cases, mechanical failure of the implant used after tumor resection in 11 cases and femur fracture in 2 cases. The mean number of surgical procedures before TFR was 3.6 (maximum 5) at the hip and 4.5 (maximum 10) at the knee. Six different models were implanted consisting of a rotational hinge knee (except in one case); 20 patients received a dual mobility system and 9 a standard hip replacement bearing. The femoral shaft was partially conserved 21/29 times and the trochanter 25/29 times.

RESULTS

Five patients suffered a general complication and 12 suffered a local complication (including 4 hematomas and 2 hip dislocations). Eight patients (28.6%) suffered a surgical site infection, although three had a prior infection. Among the 12 patients with a history of infection or progressive infection before the TFR, 9 healed and 3 had the infection continue. At a minimum follow-up of 2 years and mean of 6 years, 23 TFR implants were still in place and not infected; the other 6 had been removed or were infected, including one patient who underwent disarticulation. The median survival of the non-infected TFR was 15 years. At 10 years, 70% of TFR implants were still in place and non-infected. Walking was possible with or without a cane in 15 patients (51.7%), with two canes or a walker in 12 patients (41.3%) and impossible in 2 patients. Active knee flexion averaged 79.4°±30.3° [0°-120°]; 17 patients (62.9%) had 90° or more flexion; two patients (7.4%) had no flexion. The extension deficit averaged 3.7°±7°[-20° to 10°] and 20 patients had no flexion deformity. The leg length difference averaged 1.3cm±2.3 [0-10]; 19 patients (67.8%) had no difference in leg length.

DISCUSSION

Our starting hypothesis was confirmed for the complication rate and clinical outcomes. The benefits of dual mobility cups are emphasized. While the indications for TFR are rare, they will likely increase in the coming years.

LEVEL OF EVIDENCE

IV, Retrospective cohort study….

Comparison of infection eradication rate of using articulating spacers containing bio-inert materials versus all-cement articulating spacers in revision of infected TKA: a systematic review and meta-analysis

PURPOSE

To assess the infection eradication rate when using two types of articulating spacers (prosthetic articulating spacers and all-cement articulating spacers) in two-stage revision of infected total knee arthroplasty (TKA).

METHODS

We comprehensively searched PubMed, Embase, and the Cochrane Library databases and performed a systematic review and meta-analysis of retrospective comparative studies assessing two types of articulating spacers. A quality assessment of the included studies was performed following the STROBE statement.

RESULTS

Thirty retrospective studies, including a total of 821 knees, were identified. The pooled infection control rates in stage I were as follows: 0.98 (95% confidence interval [CI], 0.97 to 1.00) and 0.98 (95% CI, 0.96 to 0.99) for the prosthetic articulating spacer group and all-cement articulating spacer group, respectively. The pooled postoperative reinfection rate was 0.05 (95% CI, 0.03 to 0.08) for the prosthetic spacer group and 0.03 (95% CI, 0.01 to 0.06) for the all-cement spacer group. Results of the subgroup analyses showed that the weight of the antibiotic cement, antibiotic type, mean period of spacers in situ, postoperative antibiotic treatment period, and postoperative antibiotic treatment approach had no effect on the reinfection rates (p < 0.05).

CONCLUSIONS

Compared to all-cement articulating spacers, articulating spacers containing bio-inert materials have a similar infection control rate but a higher postoperative reinfection rate. Although the 95% CIs of reinfection rates in the two groups overlapped, our results indicate that articulating spacers containing bio-inert materials may be associated with higher reinfection rates and poorer clinical outcomes than all-cement articulating spacers.

Single-stage treatment of chronically infected total hip arthroplasty with cementless reconstruction: results in 126 patients with broad inclusion criteria

AIMS

Single-stage revision is not widely pursued due to restrictive inclusion criteria. In this study, we evaluated the results of single-stage revision of chronically infected total hip arthroplasty (THA) using broad inclusion criteria and cementless implants.

PATIENTS AND METHODS

Between 2010 and 2016, 126 patients underwent routine single-stage revision with cementless reconstruction with powdered vancomycin or imipenem poured into the medullary cavity and re-implantation of cementless components. For patients with a culture-negative hip, fungal infections, and multidrug-resistant organisms, a direct intra-articular infusion of pathogen-sensitive antibiotics was performed postoperatively. Recurrence of infection and clinical outcomes were evaluated. Three patients died and 12 patients (none with known recurrent infection) were lost to follow-up. There were 111 remaining patients (60 male, 51 female) with a mean age of 58.7 (sd 12.7; 20 to 79).

RESULTS

Of these 111 patients, 99 (89.2%) were free of infection at a mean follow-up time of 58 months (24 to 107). A recurrent infection was observed in four of the 23 patients (17.4%) with culture-negative infected hip. The success rate in patients with multidrug-resistant organisms was 84.2% (16/19). The mean postoperative Harris hip score was 79.6 points (63 to 92) at the most recent assessment.

CONCLUSION

Routine single-stage revision with cementless reconstruction can be a viable option for the treatment of chronically infected THA. The results of this study will add to the growing body of evidence supporting routine use of single-stage revision for the treatment of chronically infected THA. Cite this article: Bone Joint J 2019;101-B:396-402.

Single-Stage Revision Surgery in Infected Total Knee Arthroplasty: A PRISMA Systematic Review

Periprosthetic joint infection in total knee arthroplasty is a significant complication that is a common reason for revision surgery. The current standard of care is two-stage revision surgery. There is however increasing evidence to support the use of single-stage revision surgery. We conducted a PRISMA systematic review of the current evidence on the use of single-stage revision for infected total knee arthroplasty. Four databases (PubMed, Embase, Science Direct, and Cochrane Library) were systematically screened for eligible studies. The risk bias of each study was identified using ROBINS-I tool, and the quality of evidence was assessed using the GRADE criteria. Sixteen articles were retained after applying the inclusion and exclusion criteria that evaluated 3645 knee single-stage revision surgeries. Our review reveals satisfactory outcomes for single-stage revision in the management of infected total knee arthroplasty. The reinfection rates in the studies included in our review varied however the majority reported low reinfection rates and good functional outcomes. Although strict patient selection criteria have yielded successful results, good results were also reported when these criteria were not applied. The greater use of risk factors in identifying patients likely to have a successful outcome needs to be balanced with the practical benefits of performing a single stage procedure in higher risk patients. Future large clinical randomized control trials are required to confirm our results.

Significant increase of pathogen detection rate by dry arthroscopic biopsies at suspected low-grade infection following total knee arthroplasty: a prospective observational study

INTRODUCTION

The differentiation between stiff-knee and low-grade periprosthetic joint infection (PJI) is the current diagnostic challenge in total knee (TKA) revision arthroplasty. The aim of this study was to investigate the additional value of dry biopsies, compared to wet biopsies, in patients presenting with knee stiffness following primary TKA.

MATERIALS AND METHODS

Single center, prospective observational study. Consecutive patients with joint stiffness of unknown origin following primary TKA were enrolled. Patient assessment followed the diagnostic standard algorithm. During diagnostic arthroscopy, synovial fluid (synovial WBC, PMN%) and five dry biopsies (dry) were collected. Then fluid was infused and another five microbiology (wet) and five histological biopsies gathered, all from identical locations. The primary outcome parameter was the difference between the pathogens in wet and dry biopsies.

RESULTS

71 patients (61% females, 67 ± 10 years) were eligible. Preoperative blood serology mean CRP (0.7 ± 1.5 mg/dl; p = 0.852), WBC (6.6 ± 1.7 G/l; p = 0.056), and synovial fluid mean WBC (1639 ± 2111; p = 0.602), PMN% (38 ± 28; p = 0.738) did not differ between patients with negative, positive wet or dry biopsies. The histology was in 11% positive (p = 0.058). In 32% at least one pathogen was detected, 48% from wet, 44% from dry biopsies. An inhomogeneous distribution was found. Cutibacterium acnes (100%) was solely found in wet, Micrococcus luteus (75%), Staphylococcus capitis (67%), and Micrococcus lylae (100%) were predominantly found in dry biopsies. Additional dry biopsies increased the pathogen detection rate by 49%.

CONCLUSION

The addition of dry biopsies to the current standard diagnostic algorithm for PJI increased the pathogen detection rate by 49%.

One-stage exchange with antibacterial hydrogel coated implants provides similar results to two-stage revision, without the coating, for the treatment of peri-prosthetic infection

PURPOSE

Aim of this study was to verify the hypothesis that a one-stage exchange procedure, performed with an antibiotic-loaded, fast-resorbable hydrogel coating, provides similar infection recurrence rate than a two-stage procedure without the coating, in patients affected by peri-prosthetic joint infection (PJI).

METHODS

In this two-center case-control, study, 22 patients, treated with a one-stage procedure, using implants coated with an antibiotic-loaded hydrogel [defensive antibacterial coating (DAC)], were compared with 22 retrospective matched controls, treated with a two-stage revision procedure, without the coating.

RESULTS

At a mean follow-up of 29.3 ± 5.0 months, two patients (9.1%) in the DAC group showed an infection recurrence, compared to three patients (13.6%) in the two-stage group. Clinical scores were similar between groups, while average hospital stay and antibiotic treatment duration were significantly reduced after one-stage, compared to two-stage (18.9 ± 2.9 versus 35.8 ± 3.4 and 23.5 ± 3.3 versus 53.7 ± 5.6 days, respectively).

CONCLUSIONS

Although in a relatively limited series of patients, our data shows similar infection recurrence rate after one-stage exchange with DAC-coated implants, compared to two-stage revision without coating, with reduced overall hospitalization time and antibiotic treatment duration. These findings warrant further studies in the possible applications of antibacterial coating technologies to treat implant-related infections.

LEVEL OF EVIDENCE

III.

Surgery Before Subspecialty Referral for Periprosthetic Knee Infection Reduces the Likelihood of Infection Control

BACKGROUND

Failure to control a periprosthetic joint infection (PJI) often leads to referral of the patient to a tertiary care institution. However, there are no data regarding the effect of prior surgical intervention for PJI on subsequent infection control.

QUESTIONS/PURPOSES

(1) Is the likelihood of 2-year infection-free survival worse if an initial surgery for PJI was performed before referral to a tertiary care center when compared with after referral for definitive treatment? (2) Is the likelihood of identifying a causal organism during PJI worse if the initial surgery for PJI was performed before referral to a tertiary care center when compared with after referral for definitive treatment? (3) We calculated how many patients are harmed by the practice of surgically attempting to treat PJI before referral to a tertiary care center when compared with treatment after referral to a tertiary care center for definitive treatment.

METHODS

Among 179 patients (182 TKAs) who were referred for PJI between 2004 and 2014, we retrospectively studied 160 patients (163 TKAs) who had a minimum of 2 years of followup after surgical treatment or had failure of treatment within 2 years. Nineteen TKAs (19 patients) were excluded from the study; 13 patients (7%) had < 2-year followup, three patients had infected periprosthetic fractures, and three patients had infected extensor mechanism reconstruction. Eighty-six patients (88 TKAs, two bilateral [54%]) had no surgical treatment before referral to our institution for PJI management, and 75 patients (75 TKAs [46%]) had PJI surgery before referral. The mean followup was 2.4 ± 1.2 years for patients with PJI surgery before referral and 2.8 ± 1.3 years for patients with no surgery before referral (p = 0.065). Infection-free survival was defined as prosthesis retention without further surgical intervention or antibiotic suppression. During the period, further surgical intervention generally was performed after failure of irrigation and débridement, a one- or two-stage procedure, or between stages of a two-stage reimplantation without documentation of an eradiated infection, and antibiotic suppression generally was used when patients were not medically sound for surgical intervention or definitive implants were placed after the second of a two-stage procedure with positive cultures; these criteria were applied similarly to all patients during this time period in both study groups. Endpoints were assessed using a longitudinally maintained institutional database, and the treating surgeons were not involved in data abstraction. Relative and absolute risk reductions with 95% confidence intervals (CIs) as well as a Kaplan-Meier survival curve with a Cox proportional hazard model were used to evaluate survival adjusting for significant covariates. The number needed to harm is calculated as the number needed to treat. It is the reciprocal of the absolute risk reduction or production by an intervention.

RESULTS

The cumulative infection-free survival rate of TKAs at 2 years or longer was worse when PJI surgery was performed before referral to a tertiary center (80%; 95% CI, 69%-87%) compared with when no PJI surgery was performed before referral (94%; 95% CI, 87%-98%; log-rank test p = 0.006). Additionally, PJI surgery before referral resulted in a lower likelihood of causative microorganism identification (52 of 75 [69%]) compared with patients having surgery at the tertiary center (77 of 88 [88%]; odds ratio, 2.71; 95% CI, 1.28-4.70; p = 0.006). With regard to the infection-free survival rate of TKAs, the number needed to harm was 7.0 (95% CI, 4.1-22.5), meaning the referral of less than seven patients to a tertiary care center for definitive surgical management of PJI before intervention at the referring hospital prevents one infection-related failure. With regard to the culture negativity in PJI, the number needed to harm was 5.5 (95% CI, 3.3-16.7), meaning the referral of less than six patients to a tertiary care institution for PJI before surgery at the outside hospital prevents the diagnosis of one culture-negative infection.

CONCLUSIONS

Surgical treatment of a PJI before referral for subspecialty surgical management increases the risk of failure of subsequent surgical management. The prevalence of culture-negative PJI was much higher if surgery was attempted before referral to a tertiary care center when compared with referral before treatment. This suggests that surgical treatment of PJI before referral to a treating center with specialized expertise in PJI compromises the infection-free survival and impacts infecting organism isolation.

LEVEL OF EVIDENCE

Level III, therapeutic study.

[Treatment of periprosthetic infections]

The increasing number of prosthesis implantations and higher life expectancy lead to a growing number of periprosthetic infections (PPI). Optimal therapy necessitates interdisciplinary coordination of surgical and antimicrobial treatment. Challenges in the treatment are the increased occurrence of resistant pathogens, selection of adequate antimicrobial and surgical treatment strategies, inappropriate pretreatment and comorbidities of patients. Current treatment concepts lead to a high success rate in terms of infection eradication, when correctly applied. The individual expectations and underlying conditions of each patient must be considered when determining the therapy concept. The first step is to distinguish between acute and chronic infections. In acute infections the prosthesis can be retained but chronic infections necessitate a complete exchange of the prosthesis. Complicating factors, such as compromising soft tissue and bone conditions, osteomyelitis and infections caused by difficult-to-treat bacteria should, however, always be treated by a complete exchange of the prosthesis, even for acute infections. The antimicrobial treatment must be tailored to the causative agent, the surgical strategy as well as comorbidities and drug intolerances of the patient. It is important to distinguish between biofilm-active eradication therapy with rifampicin for gram-positive pathogens and quinolones for gram-negative organisms and suppression therapy. This article gives a structured presentation of the therapy algorithm.

Microbiological diagnosis in revision of infected knee arthroplasties in Denmark

BACKGROUND

Revision of infected knee arthroplasties is associated with high failure rates (30-40%). An understanding of the microbiology is important to optimize treatment and outcome. We describe microbiological diagnostic practice and diagnosis in revision of infected knee arthroplasties.

METHODS

One hundred and two partial revisions (open debridement and exchange of tibial insert) and 213 two-stage procedures performed due to infection in 275 patients from 1 July 2011 to 30 June 2013 were included and analysed by linkage to data from a nationwide registry on microbiological test results.

RESULTS

78 (24.8%) revisions were culture negative, 192 (60.9%) showed monomicrobial growth and 43 (14.3%) polymicrobial growth. Staphylococcus aureus was the most frequent isolate in mono-culture in 70 (22.2%) revisions and in polymicrobial culture in 15 revisions with a total frequency of 27.0%. Only one case (1.4%) of methicillin-resistance was registered. Coagulase-negative staphylococci (CoNS) were frequent, sole pathogen in 65 revisions and in polymicrobial cultures in 28 revisions with a total frequency of 29.5%. A pre-operative knee aspiration was performed in 50% and preoperative blood cultures were performed in 22% of cases. In 73% of the preoperative knee-aspirations bacteriological findings were fully or partially in accordance with intraoperative cultures. In 54% of the later re-revisions due to infection (treatment-failures) the cultured species differed from or was not detected at index revision surgery.

CONCLUSIONS

The 25% culture negative cases in combination with only 50% preoperative knee aspirations and prevailing high failure rates confirm the need for improvement of diagnostic practice and treatment of infected knee arthroplasties.

16S rRNA analysis provides evidence of biofilms on all components of three infected periprosthetic knees including permanent braided suture

Bacterial biofilms are the main etiological agent of periprosthetic joint infections (PJI); however, it is unclear if biofilms colonize one or multiple components. Because biofilms can colonize a variety of surfaces, we hypothesized that biofilms would be present on all components. 16S ribosomal RNA (rRNA) gene sequencing analysis was used to identify bacteria recovered from individual components and non-absorbable suture material recovered from three PJI total knee revision cases. Bray-Curtis non-metric multidimensional scaling analysis revealed no significant differences in similarity when factoring component, material type, or suture versus non-suture material, but did reveal significant differences in organism profile between patients (P < 0.001) and negative controls (P < 0.001). Confocal microscopy and a novel agar encasement culturing method also confirmed biofilm growth on a subset of components. While 16S sequencing suggested that the microbiology was more complex than revealed by culture contaminating, bacterial DNA generates a risk of false positives. This report highlights that biofilm bacteria may colonize all infected prosthetic components including braided suture material, and provides further evidence that clinical culture can fail to sufficiently identify the full pathogen profile in PJI cases.

Eradication rates, risk factors, and implant selection in two-stage revision knee arthroplasty: a mid-term follow-up study

Background

Two-stage revision (TSR) knee arthroplasty is an established treatment, but failure to control infection still occurs in 4–50 % of cases. The aim of this study was to assess the infection eradication rate, risk factors for failure, and the clinical outcome after two-stage revision knee arthroplasty.

Methods

This retrospective study included 59 patients who had undergone at least one two-stage revision procedure due to periprosthetic joint infection (PJI). Demographic data, comorbidities, types of implant, and complications were analyzed. Univariate and multivariate logistic regression analysis were used to identify risk factors for failure.

Results

The infections were controlled in 55 patients (93.2 %). The follow-up period was 4.1 (±2.7) years. Infection control was achieved after the first TSR in 42 patients (71.2 %) and after the second TSR in 13 (76.5 %). The percentage of arthrodesis procedures in patients with infection control increased from 16.75 % after one TSR to 69.2 % after two TSRs. Multivariate logistic regression analysis identified body mass index (BMI) (odds ratio 1.22; 95 % confidence intervals, 1.07 to 1.40; p = 0.004) and smoking (OR 21.52; 95 % CI, 2.60 to 178.19; p = 0.004) as risk factors for failure.

Conclusions

Two-stage revision protocols can achieve acceptable results even after a second procedure. It is still unclear whether the choice of implant influences failure rates. Risk factors for failure after two-stage revision were identified. Studies with larger sample sizes are needed in order to support these findings and identify further risk factors. To reduce failure rates, programs should be established to treat or minimize risk factors in patients with PJI.