A spacer is required to maintain limb length and alignment and to provide a stable limb for mobilisation in two-stage revision total knee arthroplasty (rTKA) for periprosthetic joint infection (PJI). Static spacers are indicated in cases of massive bone loss, compromised soft tissues, and ligamentous and/or extensor mechanism insufficiency. The aim of this study was to compare the use of Ilizarov rods to arthrodesis nails for static spacer constructs in first-stage rTKA for PJI.

This was a retrospective cohort study of 40 patients who underwent two-stage rTKA for PJI between 2019 and 2022. Static spacers were used in all cases, constructed from Ilizarov rods 20 patients and nails in 20 patients. Data collected included number of previous revisions, patient age at first revision, comorbidities and identified organisms. Groups were compared based on outcome measures including complications, reoperations, length of stay and re-revision rates.

The use of Ilizarov rods showed higher rates of intraoperative complications (5% vs. 0%), readmissions (55% vs. 5%), and interstage re-operations (50% vs. 10%). Spacer-related complications occurred in 10 of 20 cases (50%) in the Ilizarov rod group, all due to spacer fractures, compared to none in the nail group (0%) (p < 0.05). Re-revision rates for infection after the second stage were similar between groups (p = 0.75).

The improved safety profile of arthrodesis nails support their use as a temporary static spacer between first and second stage rTKA.

Serum biomarkers and synovial fluid analysis are valuable tools for the preoperative diagnosis of periprosthetic joint infections (PJIs). However, the literature on their utility in megaprostheses is limited. Our study aimed to assess the diagnostic performance and accuracy of four laboratory tests for diagnosing PJI in patients who have megaprostheses.

We retrospectively reviewed 104 patients who underwent 126 revisions after oncologic megaprosthesis reconstruction. Revisions were stratified into aseptic and septic according to the International Consensus Meeting criteria. The PJIs were classified into acute and chronic infections based on time since index surgery. There were four tests assessed: serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), synovial white blood cell (WBC) count, and polymorphonuclear percentage (PMN%). Receiver operating characteristic curve analysis was conducted to assess their performance.

The diagnostic performance of preoperative tests in acute PJIs ranked by area under the curve was CRP (0.86), ESR (0.81), synovial WBC count (0.76), and synovial PMN% (0.69). In chronic PJIs, diagnostic performance ranked by area under the curve was synovial WBC count (0.80), CRP (0.77), ESR (0.71), and synovial PMN% (0.67). New cutoff values for diagnosing acute PJIs were identified as CRP ≥ 42 mg/L, synovial WBC count ≥ 5,500 cells/μL, and synovial PMN% ≥ 92.5%. For chronic PJIs, new cutoff values of CRP ≥ 31 mg/L, ESR ≥ 24.5 mm/hour, synovial WBC count ≥ 5,550 cells/μL, and synovial PMN% ≥ 76.5% were established. These cutoff values improved diagnostic accuracy in both acute and chronic PJIs.

Good to excellent diagnostic performance was seen with all tests except synovial PMN%. Adjusting cutoff values in patients who have megaprosthesis revisions improved diagnostic performance.

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.

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.

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.

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.

Although the two-stage exchange is the gold standard for the treatment of periprosthetic joint infection (PJI) in the United States, there is recent data to suggest that the utilization of a well-functioning destination spacer, also known as a "functional" or "1.5-stage revision," can be a viable treatment option in patients who have a PJI. The purpose of this systematic review was to evaluate the outcomes of patients undergoing a 1.5-stage revision for PJI and compare outcomes to a two-stage revision.

A systematic review was performed through PubMed, Scopus, and Embase databases. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines were followed utilizing two reviewers. Following exclusions, 13 studies (n = 924 patients, 704 knees and 228 hips) were identified and included. A standardized template was utilized to capture demographic information (age, body mass index [BMI]), success/failure rate, mean follow-up time (years), and infection-free survivorship compared to two-stage revision. There were 556 patients (428 knees and 136 hips) who had 1.5-stage revisions included in the analyses. The mean age and body mass index were 65 years (range, 60 to 78) and 31 (range, 23.7 to 34.4), respectively.

At a mean follow-up time of 3.8 ± 1.1 years, the mean success rate was found to be 86.8%. The mean failure rate due to infection was 12.6%. In one study, infection-free survivorship was greater in the 1.5-stage revision cohort when compared to the two-stage revision cohort (94 versus 83%, P = 0.048). The remaining five studies that evaluated infection-free survivorship found no significant difference. However, there was a trend toward decreased the 90-day pain scores, postoperative complications, and cost in the 1.5-stage cohort.

Our systematic review demonstrated that a 1.5-stage revision is a viable and cost-effective treatment option for patients who have PJI. Infection-free survivorship was similar or greater when comparing a 1.5-stage revision to a two-stage revision. A 1.5-revision was associated with lower 90-day pain scores, postoperative complications, and decreased cost when compared to the two-stage revision in short-term follow-up, defined as less than five years. To better describe the procedure, we propose the name change to semipermanent eluting antibiotic revision procedure.

IV.

Peri-prosthetic joint infection (PJI) is a major post-arthroplasty complication that warrants alternative antibacterial approaches to improve prophylaxis and treatment outcomes. Local administration of analgesics post-surgery is common. Recent studies have demonstrated the antimicrobial potential of analgesics and the feasibility of dual drug-eluting ultra-high molecular weight polyethylene (UHMWPE) for local antibacterial applications. However, the antibacterial mechanism of action is poorly understood, and the translational value of antimicrobial dual drug-loaded UHMWPE has not been evaluated. In this study, we utilized the Laurdan assay and gene expression analysis to demonstrate the antibacterial action of bupivacaine hydrochloride (BP) and tolfenamic acid (TA) against Staphylococcus aureus. Furthermore, we incorporated BP and TA into UHMWPE at different weight concentrations and studied their longitudinal drug release and real-time antibacterial properties. The analgesics showed a significant effect on the bacterial membrane properties comparable to known antibiotics and regulated bacterial gene expression. For the dual drug-loaded UHMWPE, the drug release rate from BP/TA combinations was interestingly not a direct function of the loaded drug weight percent, potentially due to the hydrophobicity of TA and the interactions between the two drugs. Combinations of BP and TA at the higher total drug concentration (10 and 20%) showed a prolonged antibacterial effect against S. aureus, with great potential for prophylactic use.

Periprosthetic joint infection (PJI) is a significant and challenging complication following total knee arthroplasty (TKA). This study aimed to evaluate the efficacy and safety of treating chronic knee PJI with and without antibiotic-loaded calcium sulfate during two-stage revision surgery.

This retrospective study analyzed 94 patients with TKA infections who underwent two-stage revision between May 2017 and January 2022 at the First Affiliated Hospital of Zhengzhou University. Key outcomes assessed included infection recurrence rates, postoperative range of motion (ROM), Knee Society Score (KSS), Hospital for Special Surgery (HSS) scores, hematological parameters, and complication rates during the follow-up period.

The demographic characteristics of the two groups showed no significant differences. The infection control rate was significantly higher in the calcium sulfate group (95.7%) compared to the matched control group (80.9%) (P < 0.05). Both groups demonstrated statistically significant improvements in ROM, HSS, and KSS scores compared to preoperative values (P < 0.05). However, intergroup differences in these outcomes were not statistically significant (P > 0.05). Additionally, there was no significant difference in postoperative complication rates between the two groups.

The use of antibiotic-loaded calcium sulfate in two-stage revision surgery for chronic knee PJI ensures sustained local antibiotic release at high concentrations, leading to rapid reduction in inflammatory markers, effective infection control, and a low complication rate. This approach is a safe and effective treatment for chronic knee PJI.

The standard treatment for periprosthetic joint infections (PJI) typically involves a two-stage resection arthroplasty using antibiotic-loaded bone cement (ALBC) spacers. This study hypothesizes that there is no significant correlation between antibiotic levels in blood and synovial fluid and the patient's kidney function, and that the success rates of staged resection arthroplasty are comparable between groups, specifically targeting gram-positive bacterial infections.

This retrospective review included patients treated from 2017 to 2022 with two-stage arthroplasty using vancomycin-loaded ALBC spacers, selectively targeting gram-positive infections. Patients with non-gram-positive infections or those with allergies or treatments affecting serum antibiotic levels were excluded. The study assessed comorbidities, renal function, specifics of the spacers, and vancomycin concentrations in joint fluid and blood.

Among 62 PJI cases analyzed (22 hips and 40 knees), 34 patients (54.8%) had renal insufficiency (RI), associated with significantly lower albumin (2.64 g/dL vs. 3.43 g/dL, p < 0.05) and estimated glomerular filtration rate (eGFR) (58.17 mL/min/1.73 m² vs. 121.74 mL/min/1.73 m², p < 0.05). No significant differences were found in comorbidities, antibiotic regimen, or the weight of the ALBC spacers between the groups (p > 0.05). Both groups exhibited high vancomycin levels in joint fluid, with peak blood vancomycin levels inversely correlated with eGFR (coefficient - 3.612, 95% CI -8.543 to -2.753, p < 0.001). RI patients displayed higher peak blood vancomycin levels (1.23-5.43 mg/L) but remained below toxicity thresholds. The infection-free interval, aseptic revision rates, and bacterial profiles specific to gram-positive species showed no significant differences between the groups.

Systemic absorption of vancomycin from ALBC spacers was evident in patients with RI and inversely correlated with eGFR, yet remained well below toxic thresholds across all patients. These findings suggest that the use of vancomycin-loaded ALBC spacers appears to be safe for managing gram-positive infections in patients with varying renal function. Additionally, renal insufficiency did not adversely affect the infection-free interval, aseptic revision rates, or bacterial diversity.

III.

Periprosthetic infection (PJI) with concomitant extensor mechanism disruption (EMD) and soft-tissue defect-hereinafter termed the "Terrible Triad"-is a devastating complication following total knee arthroplasty. The purpose of this study was to define the surgical and clinical outcomes following management of a cohort of patients who have the Terrible Triad.

From 2000 to 2022, 127 patients underwent operative management for PJI alone, 25 for PJI with soft-tissue defects (defined as defects requiring flap reconstruction or being a factor contributing to the decision of performing above-knee amputation or arthrodesis), 14 for PJI with EMD, and 22 for the Terrible Triad. A composite outcome of infection status, range of motion, extensor lag, and ambulatory status at final follow-up was used to compare the proportion of patients in each group with a favorable overall knee outcome. Differences between groups were determined using one-way analyses of variance with post hoc Tukey's tests and Pearson's Chi-square tests or Fisher's exact tests with post hoc Bonferroni adjustments, where applicable. Odds ratios (OR) were calculated for comparison of the overall knee outcome between groups. A Kaplan-Meier survival analysis for patient mortality was performed.

The mean follow-up was 8.4 years and similar between groups (P = .064). Patients who had the Terrible Triad had a 45.5% incidence of above-knee amputation, or arthrodesis, and an 86.4% incidence of an unfavorable outcome. Compared to patients in the PJI group, patients in the PJI who had a soft-tissue defect (OR = 5.8, 95% CI [confidence interval] 2.2 to 15.7), PJI with EMD (OR = 3.7, 95%CI 1.0 to 12.9), and Terrible Triad groups (OR = 11.6, 95% CI 3.3 to 41.5) showed higher odds of an unfavorable knee outcome.

This study demonstrates that the total knee arthroplasty Terrible Triad is a dreaded diagnosis with poor outcomes. Clinicians and patients might consider early treatment with amputation or arthrodesis.

III.

Cutibacterium acnes (C. acnes; previously known as Propionibacterium acnes or P. acnes) periprosthetic hip and knee infections are under-reported. While culture contamination with C. acnes occurs, true infections are important to recognize and treat. We sought to describe the demographics and treatment outcomes of patients with C. acnes periprosthetic joint infections (PJIs) of the hip and knee.

Patients with C. acnes PJI between January 2005 and December 2018 were retrospectively reviewed utilizing the institutional total joint registry. Patients with monomicrobial PJI and two or more positive cultures were considered to have true C. acnes PJI. Patients with polymicrobial infection or with only one positive culture were excluded. This resulted in 35 PJIs (21 hips and 14 knees); the patients' mean age was 63 years (35 to 84) and 15 (43%) were female. Mean follow-up was five years (1 to 14).

The median time to positive culture was five days (IQR 5 to 6) and median synovial fluid cell count was 22,583 cells (IQR 15,200 to 53,231). The median ESR was 25 mm/hr (IQR 7 to 37), and CRP was 15 mg/l (IQR 3 to 29). Of the 35 PJIs, 18 (51%) were treated with chronic antibiotic suppression without surgical intervention, and the remainder were treated with two-stage exchange arthroplasty. The two-year survival free of any revision was 94%. Four patients failed treatment due to symptomatic infection, with three treated with two-stage exchange and one treated with irrigation and debridement with modular component exchange for a survival rate of 89% and 83% at two and five years, respectively.

Laboratory evidence of C. acnes PJI in this cohort was typical compared to more conventional organisms. Cultures grew more quickly than previously thought in patients with C. acnes PJI. Treatment with two-stage exchange or chronic antibiotic suppression alone both had few treatment failures at mid-term follow-up.

This review evaluates the decision-making framework for using antibiotic-loaded cement (ALC) in the management of prosthetic joint infection (PJI). Drawing on available literature, we offer orthopaedic surgeons a guided discussion on several critical considerations. First, we explore the impact of antibiotic-loading on the mechanical properties of polymethylmethacrylate (PMMA) cement, assessing both strength and durability. We then explore the optimal antibiotic dosage to load into cement, aiming to achieve effective local concentrations for infection control without compromising mechanical stability. Furthermore, we explore how cement and antibiotic properties affect the overall antibiotic elution characteristics of ALC. Finally, we discuss risks of systemic toxicity, particularly acute kidney injury, when using ALC. The principal goal in this review is to provide a balanced approach based on best available evidence that optimises antibiotic elution from ALC whilst minimising potential harms associated with its use.

We present a unique case of a 56-year-old male patient who ambulated on a hip cement spacer for 11 years. After hemiarthroplasty after a motor vehicle accident, the patient developed periprosthetic joint infection (PJI) several years later, and underwent stage-1 revision. With the resolution of the infection after stage 1, the patient refused the second stage due to satisfaction with the cement spacer for nearly 11 years. To our knowledge, this is the longest reported case of a cement spacer remaining in an ambulating patient. This case demonstrates the mechanical reliability of metal-reinforced cement spacers, which can remain for long periods in selected patients.

A 2-stage revision continues to be the standard treatment for periprosthetic joint infection (PJI) in hip arthroplasty. The use of "functional" spacers may allow patients to return to daily living while optimizing their health for revision surgery. We aimed to evaluate the clinical outcomes of different spacer types regarding infection eradication, mechanical complications, and functional outcomes.

Patients who have complete Musculoskeletal Infection Society criteria for diagnosis of PJI that underwent one-stage or 2-stage revision were queried in an institutional surgical database between 2002 and 2022. Out of 286 patients, 210 met our inclusion criteria and were retrospectively reviewed for demographics, laboratory values, functional and patient-reported outcomes, and subsequent revisions. The study population had 54.3% women, a mean age of 61 years old, and a mean follow-up of 3.7 ± 3.2 years. There was no difference between age, body mass index, or Charlson Comorbidity Index scores between each cohort. Spacers were categorized as nonfunctional static, nonfunctional articulating, or functional articulating. Functional spacers were defined as those that allowed full weight bearing with no restrictions. Delphi criteria were used to define revision success, and failure was defined as a recurrent or persistent infection following definitive surgery.

There was a significantly lower reoperation rate after a definitive implant in the functional articulating cohort (P = .003), with a trending higher infection eradication rate and a lower rate of spacer failure compared to the nonfunctional spacer cohort. At 5 years, functional articulating spacers had a 94.1% survivorship rate, nonfunctional articulating spacers had an 81.2% survival rate, and nonfunctional static spacers had a 71.4% survival rate. In the functional articulating spacer cohort, 14.6% had yet to get reimplanted, with an average follow-up time of 1.4 years.

Within this large cohort of similar demographics, functional articulating spacers may result in better clinical outcomes and infection eradication during 2-stage revision arthroplasty for PJI.

Despite the widely reported success of knee arthroplasty, studies show that 1.6-3 % of patients undergo revision within the first postoperative year predominantly due to infection. Preoperative skin preparation may potentially decrease the bacterial load and consequently, the risk of periprosthetic joint infections. The effects of hair removal on prosthetic joint infection are inconsistent. Our primary aim was to investigate if hair removal with a clipper influenced skin colonisation and bacterial composition.

Forty Caucasian male participants who were planned to undergo knee arthroplasty, (mean age 63.8 years), were included. Patients were randomised to hair removal in a within-person study design. As a control, the opposite leg of the patient was used. Swabs were collected prior to hair removal (baseline), immediately after hair removal (Day 0), and with follow-up after one and seven days.

The intervention showed significant decrease in mean log colony-forming units per. cm2 from baseline 2.97 to 2.67 (P<0.01) immediately after hair removal and sustained at Day 1 (P=0.01). At Day 7, the mean was non-significant compared to baseline. The control group did not show any decrease of skin microbiota at follow-up on Day 0, 1 or 7.No significant differences within the bacterial composition were found between the intervention and control leg at baseline among the six most prevalent detected bacterial species: Staphylococcus epidermidis, Micrococcus luteus, S. hominis, S. capitis, S. haemolyticus and S. aureus. The study did not find any changes in the bacterial composition over time.

Hair removal with a clipper within 24 hours prior to surgery causes a significant non-selective reduction in skin colonisation.

To determine the superior spacer design, a growing number of studies are comparing treatment results between patients having been treated with articulating and static knee spacers in the setting of two-stage revision for periprosthetic joint infection (PJI). In contrast, the primary objective of this study was to compare preoperative characteristics between patients from both spacer groups and examine whether significant differences were present prior to spacer implantation.

This retrospective, single-centre, cohort study examined the preoperative situation of 80 consecutive knee PJIs between 2017 and 2020. All patients underwent two-stage revision, with 35 (44%) receiving an articulating and 45 (56%) a static spacer.

No significant differences were observed in terms of patient gender (p = 0.083), age (p = 0.666), comorbidity (p = 0.1) and preoperative clinical function (p = 0.246). Static spacers were significantly more often used in the presence of a periarticular fistula (p = 0.033), infection of a revision implant (p < 0.001), higher degree of bone loss (p < 0.001) and infection caused by a difficult-to-treat pathogen (p = 0.038). Complication and revision rates were similar for both spacer types during the interim period, while patients with articulating spacers demonstrated a superior clinical function (p < 0.001) during the interim period and after reimplantation.

Static spacers are being utilised in significantly more complex and unfavourable preoperative scenarios. Therefore, a preoperative selection bias may be at least partially accountable for any disparities observed in postoperative outcomes. To achieve the best possible results, surgeons should know and respect the distinct indications of static and articulating spacers and consequently understand and use them as complementary surgical options.

Level III.

To explore the clinical efficacy of using two different types of articulating spacers in two-stage revision for chronic knee periprosthetic joint infection (kPJI).

A retrospective cohort study of 50 chronic kPJI patients treated with two types of articulating spacers between January 2014 and March 2022 was conducted. The clinical outcomes and functional status of the different articulating spacers were compared. Overall, 17 patients were treated with prosthetic spacers (prosthetic group (PG)), and 33 patients were treated with cement spacers (cement group (CG)). The CG had a longer mean follow-up period (46.67 months (SD 26.61)) than the PG (24.82 months (SD 16.46); p = 0.001).

Infection was eradicated in 45 patients overall (90%). The PG had a better knee range of motion (ROM) and Knee Society Score (KSS) after the first-stage revision (p = 0.004; p = 0.002), while both groups had similar ROMs and KSSs at the last follow-up (p = 0.136; p = 0.895). The KSS in the CG was significantly better at the last follow-up (p = 0.013), while a larger percentage (10 in 17, 58.82%) of patients in the PG chose to retain the spacer (p = 0.008).

Prosthetic spacers and cement spacers are both effective at treating chronic kPJI because they encourage infection control, and the former improved knee function status between stages. For some patients, prosthetic spacers may not require reimplantation.

Background: The assessment of cardiac risk is challenging for elderly patients undergoing major orthopedic surgery with preoperative functional limitations. Currently, no specific cardiac risk scores are available for these critical patients. Echocardiography may be a reliable and safe instrument for assessing cardiac risks in this population. This study aims to evaluate the potential benefits of echocardiography in elderly orthopedic patients, its impact on anesthesiologic management, and postoperative Major Adverse Cardiac Events (MACEs). Methods: This is a retrospective, one-arm, monocentric study conducted at ''Federico II'' Hospital-University of Naples-from January to December 2023, where 59 patients undergoing hip or knee revision surgery under neuraxial anesthesia were selected. The demographic data, the clinical history, and the results of preoperative Echocardiography screening (pEco-s) were collected. After extensive descriptive statistics, the χ2 test was used to compare the valvopathies and impaired Left Ventricular Function (iLVEF) prevalence before and after echocardiography screening and the incidence of postoperative MACE; a p-value < 0.05 was considered statistically significant. Results: The mean age was 72.5 ± 6.9, and the prevalence of cardiac risk factors was about 90%. The cumulative prevalence of iLVEF and valvopathy was higher after the screening (p < 0.001). The pEco-s diagnosed 25 new valvopathies: three of them were moderate-severe. No patients had MACE. Conclusions: pEco-s evaluation could discover unknown heart valve pathology; more studies are needed to understand if pEco-s could affect the anesthetic management of patients with functional limitations, preventing the incidence of MACE, and assessing its cost-effectiveness.

Periprosthetic joint infection after total knee arthroplasty is commonly treated via 2-stage revision utilizing either articulating or static antibiotic cement spacers. While recent literature exhibits a slight functional advantage in favor of articulating spacers, those patients with a history of recurrent infection/multiple revision procedures are frequently excluded from these studies. The purpose of this study was to report infection eradication rates and efficacy of utilizing antibiotic-loaded locked intramedullary nail for infection for the multiply revised, infected total knee arthroplasty.

A retrospective review was performed of all consecutive patients receiving static spacers between 2017 and 2020 at an academic medical center. Surgical techniques for all patients included irrigation and debridement using a reamer-irrigator-aspirator, injection of antibiotic-loaded calcium sulfate into the intramedullary canal, and nail placement. Antibiotic-loaded cement is then used to create a spacer block in the joint space. A Cox proportional hazard regression was run to identify risk factors for reinfection.

Forty-two knees in 39 patients were identified meeting inclusion criteria. Overall, there was an 68.8% infection eradication rate at an average of 46.9 months following spacer placement. The only risk factors identified on cox regression were increasing number of previous spacers, a surrogate for previous infections (hazards ratio = 14.818, P value = .021), and increasing operative time during spacer placement (hazards ratio = 1.014, P value = .039).

Use of static spacers, in conjunction with reamer-irrigator-aspirator and antibiotic-loaded calcium sulfate, can be effective in treating chronic, complex periprosthetic joint infections in the setting of bone loss and or soft-tissue compromise and produced similar results to more simple infection scenarios.

The practice of implementing an antibiotic holiday before the second stage of hip or knee arthroplasty is currently controversial due to limited evidence for this approach, as per the International Consensus Meeting 2018 on Musculoskeletal Infection. A greater understanding of this issue could augment the quality of Alrayes and Sukeik's mini-review (2023) on diagnosing, managing, and treating periprosthetic knee infections. However, a significant lack of literature exists concerning the optimal duration for the antibiotic holiday, calling for more research before establishing any clinical guidelines.

Periprosthetic joint infections (PJIs) are a devastating complication of joint arthroplasty surgeries that are often complicated by biofilm formation. The development of biofilms makes PJI treatment challenging as they create a barrier against antibiotics and host immune responses. This review article provides an overview of the current understanding of biofilm formation, factors that contribute to their production, and the most common organisms involved in this process. This article focuses on the identification of biofilms, as well as current methodologies and emerging therapies in the management of biofilms in PJI.

As the number of primary total ankle replacements increases for treatment of end-stage ankle arthritis, failures are also expected to rise. Periprosthetic joint infection is among the causes of failures and has been reported to be as high as 5%. Diagnosis is usually made by a combination of clinical examination findings, imaging, laboratory, and microbiological workup. Management is generally separated into limb salvage or amputation. Limb salvage can be challenging and may involve a single versus staged approach. Options include revision arthroplasty or arthrodesis procedures (ankle versus tibiotalocalcaneal), and a multidisciplinary approach is sought to eradicate infection before definitive management.

Prosthetic joint infection (PJI) remains a significant complication following joint arthroplasty, necessitating prompt recognition and intervention to optimize patient outcomes. This case report describes a 65-year-old male who presented with persistent pain, swelling, and purulent discharge from the right hip, three years post-bipolar hemiarthroplasty following a road traffic accident. Clinical examination revealed signs suggestive of PJI, prompting surgical intervention with total hip arthroplasty. Postoperatively, the patient experienced resolution of symptoms and satisfactory recovery. This case underscores the challenges associated with infected joint arthroplasty and highlights the importance of a multidisciplinary approach for effective management. Early diagnosis, appropriate surgical intervention, and comprehensive postoperative care are essential for minimizing morbidity associated with PJIs and optimizing patient outcomes.

Staphylococcus aureus is a leading cause of biofilm-associated prosthetic joint infection (PJI). A primary contributor to infection chronicity is an expansion of granulocytic myeloid-derived suppressor cells (G-MDSCs), which are critical for orchestrating the antiinflammatory biofilm milieu. Single-cell sequencing and bioinformatic metabolic algorithms were used to explore the link between G-MDSC metabolism and S. aureus PJI outcome. Glycolysis and the hypoxia response through HIF1a were significantly enriched in G-MDSCs. Interfering with both pathways in vivo, using a 2-deoxyglucose nanopreparation and granulocyte-targeted Hif1a conditional KO mice, respectively, attenuated G-MDSC-mediated immunosuppression and reduced bacterial burden in a mouse model of S. aureus PJI. In addition, single-cell RNA-Seq (scRNA-Seq) analysis of granulocytes from PJI patients also showed an enrichment in glycolysis and hypoxia-response genes. These findings support the importance of a glycolysis/HIF1a axis in promoting G-MDSC antiinflammatory activity and biofilm persistence during PJI.

Rheumatoid arthritis (RA) is a risk factor for periprosthetic joint infection (PJI) after total joint arthroplasty (TJA). The purpose of this study was to perform a systematic review comparing the failure rates of debridement, antibiotics, and implant retention (DAIR), one-stage exchange arthroplasty/revision (OSR), and 2-stage exchange arthroplasty/revision (TSR) for RA patients with PJI and identify risk factors in the RA population associated with increased treatment failure rate.

PubMed, Ovid MEDLINE, and Ovid Embase databases were screened with the terms "rheumatoid arthritis," "total joint arthroplasty," "prosthetic joint infection," and "treatment for PJI" on August 29, 2021. Four hundred ninety-one studies were screened, of which 86 were evaluated. The primary outcome evaluated was failure of surgical treatment for PJI.

Ten retrospective cohort studies were included after full-text screening, yielding 401 patients with RA. Additional demographic and PJI management data were obtained for 149 patients. Patients with RA who underwent TSR demonstrated a lower failure rate (26.8%) than both DAIR (60.1%) and OSR (39.2%) (χ2 = 37.463, p < 0.00001). Patients with RA who underwent DAIR had a 2.27 (95% CI, 1.66-3.10) times higher risk of experiencing treatment failure than those who underwent TSR. Among risk factors, there was a significant difference in the C-reactive protein of patients who did vs. did not experience treatment failure (p = 0.02).

TSR has a higher rate of success in the management of PJI patients with RA compared with DAIR and OSR. The complete removal of the infected prosthesis and delayed reimplantation may lower the treatment failure rate.

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

Periprosthetic joint infection (PJI) remains a serious complication after total knee arthroplasty (TKA). While debridement, antibiotics, and implant retention (DAIR) are considered for acute PJI, success rates vary. This study aims to assess a new scoring system's accuracy in predicting DAIR success.

119 TKA patients (2008-2019) diagnosed with PJI who underwent DAIR were included for analysis. Data were collected on demographics, laboratory values, and clinical outcomes. This was used for validation of the novel classification system consisting of PJI acuteness, microorganism classification, and host health for DAIR indication. Statistical analysis was carried out using SPSS programming.

Mean follow-up was 2.5 years with an average age of 65.5 ± 9.1 years, BMI of 31.9 ± 6.2 kg/m2, and CCI of 3.04 ± 1.8. Successful infection eradication occurred in 75.6% of patients. The classification system demonstrated 61.1% sensitivity, 72.4% specificity, and 87.3% positive predictive value (PPV) when the DAIR cutoff was a score less than 6. For a cutoff of less than 8, sensitivity was 100%, specificity was 37.9%, and PPV was 83.3%.

To date, no consensus exists on a classification system predicting DAIR success. This novel scoring system, with high PPV, shows promise. Further refinement is essential for enhanced predictive accuracy.

Prosthetic joint infection (PJI) is a complication of arthroplasty that results in significant morbidity. The presence of biofilm makes treatment difficult, and removal of the prosthesis is frequently required. We have developed a non-invasive approach for biofilm eradication from metal implants using intermittent alternating magnetic fields (iAMF) to generate targeted heating at the implant surface. The goal of this study was to determine whether iAMF demonstrated efficacy in an in vivo implant biofilm infection model. iAMF combined with antibiotics led to enhanced reduction of biofilm on metallic implants in vivo compared to antibiotics or untreated control. iAMF-antibiotic combinations resulted in a > 1 - log further reduction in biofilm burden compared to antibiotics or iAMF alone. This combination effect was seen in both S. aureus and P. aeruginosa and seen with multiple antibiotics used to treat infections with these pathogens. In addition, efficacy was temperature dependent with increasing temperatures resulting in a greater reduction of biofilm. Tissue damage was limited (< 1 mm from implant-tissue interface). This non-invasive approach to eradicating biofilm could serve as a new paradigm in treating PJI.

The diagnosis of persistent infection prior to second-stage reimplantation in 2-stage exchanges for periprosthetic joint infection (PJI) can be challenging as there is no optimal diagnostic tool. This study investigates the usefulness of pre-reimplantation serum C-reactive protein (CRP) and interleukin-6 (IL-6) and its change between both stages to identify patients who have subsequent PJI.

There were 125 patients who underwent planned 2-stage exchange for chronic knee or hip PJI from a single center retrospectively identified. Patients were included if preoperative CRP and IL-6 were available for both stages. Subsequent PJI was defined as 2 positive microbiological cultures at reimplantation or subsequent surgery or death due to PJI during follow-up.

Prior to reimplantation, the median serum CRP (total knee arthroplasties [TKAs]: 1.0 versus 0.5 mg/dL, P = .028; total hip arthroplasties [THAs]: 1.3 versus 0.5 mg/dL, P = .015) and median IL-6 (TKA: 8.0 versus 6.0 pg/mL, P = .052; THA: 7.0 versus 6.0 pg/mL, P = .239) were higher in patients who had subsequent PJI. The IL-6 and CRP values showed moderate sensitivity (TKA/CRP: 66.7%; THA/CRP: 58.8%; TKA/IL-6: 46.7%; THA/IL-6: 35.3%) and good specificity (TKA/CRP: 66.7%; THA/CRP: 81.0%; TKA/IL-6: 86.3%; THA/IL-6: 83.3%). The change in CRP and IL-6 between the stages did not differ between the groups, respectively.

Serum CRP and IL-6 show low to moderate sensitivity and good specificity in the diagnosis of subsequent PJI prior to reimplantation, which questions their usefulness as a rule-out test. Furthermore, the change in between stages does not appear to identify subsequent PJI.

Antibiotic loaded bone cement spacers provide high local antibiotic concentrations, preserve bone stock, and reduce soft tissue contractions. The objective of this in-vitro study was to compare antibiotic release from spacers, aiming to discover the most optimal preparation and identify modifiable factors that can further enhance antibiotic release.

Six distinct spacer preparation were created using three different bone cements and manual incorporation of antibiotics. During a six-week period, the release of antibiotics from each spacer was measured individually at ten predetermined time points using a chemiluminescent immunoassay.

Manually adding 4 g of vancomycin to every 40 g of "Palacos R + G" yielded the most favorable release profile. Throughout all preparations, antibiotic release consistently and significantly decreased over the six-week period. When incorporating a higher concentration of vancomycin, a significantly higher cumulative release of vancomycin was observed, with varying effects on the release of gentamicin. The choice of bone cement had a significant impact on antibiotic release.

To enhance antibiotic release from spacers, surgeons should manually incorporate high antibiotic concentrations into the most appropriate bone cement and keep the interim period as short as possible. Specifically, we suggest manual incorporation of 4 g of vancomycin to every 40 g of gentamicin premixed "Palacos R + G" to create bone cement spacers.

Two-stage exchange with placement of antibiotic cement spacer (ACS) is the gold standard for the treatment of chronic periprosthetic joint infection (PJI), but it could cause a high prevalence of acute kidney injury (AKI). However, the results of the current evidence on this topic are too mixed to effectively guide clinical practice.

We retrospectively identified 340 chronic PJI patients who underwent the first-stage exchange with placement of ACS. The Kidney Disease Improving Global Outcomes guideline was used to define postoperative AKI. Multivariate logistic analysis was performed to determine the potential factors associated with AKI. Furthermore, a systematic review and meta-analysis on this topic were conducted to summarize the knowledge in the current literature further.

In our cohort, the incidence of AKI following first-stage exchange was 12.1%. Older age (per 10 years, OR= 1.509) and preoperative hypoalbuminemia (OR= 3.593) were independent predictors for postoperative AKI. Eight AKI patients progressed to chronic kidney disease after 90 days. A meta-analysis including a total of 2525 PJI patients showed the incidence of AKI was 16.6%, and AKI requiring acute dialysis was 1.4%. Besides, host characteristics, poor baseline liver function, factors contributing to acute renal blood flow injury, and the use of nephrotoxic drugs may be associated with the development of AKI. However, only a few studies supported an association between antibiotic dose and AKI.

AKI occurs in approximately one out of every six PJI patients undergoing first-stage exchange. The pathogenesis of AKI is multifactorial, with hypoalbuminemia could be an overlooked associated factor. Although the need for acute dialysis is uncommon, the fact that some AKI patients will develop CKD still needs to be taken into consideration.

Prosthetic joint infection (PJI) is a destructive complication of knee replacement surgery (KR). In two-stage revision a spacer is required to maintain limb length and alignment and provide a stable limb on which to mobilise. Spacers may be articulating or static with the gold standard spacer yet to be defined. The aims of this scoping review were to summarise the types of static spacer used to treat PJI after KR, their indications for use and early complication rates.

We conducted a scoping review based on the Joanna Briggs Institute's "JBI Manual for Evidence Synthesis" Scoping review reported following Preferred Reporting Items for Systematic Review and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist. MEDLINE, EMBASE and CINAHL were searched from 2005 to 2022 for studies on the use of static spacers for PJI after KR.

41 studies (1230 patients/knees) were identified describing 42 static spacer constructs. Twenty-three (23/42 [54.2%]) incorporated cement augmented with metalwork, while nineteen (19/42, [45.9%]) were made of cement alone. Spacers were most frequently anchored in the diaphysis (22/42, [53.3%]), particularly in the setting of extensive bone loss (mean AORI Type = F3/T3; 11/15 studies 78.3% diaphyseal anchoring). 7.1% (79 of 1117 knees) of static spacers had a complication requiring further surgery prior to planned second stage with the most common complication being infection (86.1%).

This study has summarised the large variety in static spacer constructs used for staged revision KR for PJI. Static spacers were associated with a high risk of complications and further work in this area is required to improve the quality of care in this vulnerable group.

Infection is a major complication associated with orthopedic implants. It often involves the development of biofilms on metal substrates, which act as barriers to the host's immune system and systemic antibiotic treatment. The current standard of treatment is revision surgery, often involving the delivery of antibiotics through incorporation into bone cements. However, these materials exhibit sub-optimal antibiotic release kinetics and revision surgeries have drawbacks of high cost and recovery time. Herein, a new approach is presented using induction heating of a metal substrate, combined with an antibiotic-loaded poly(ester amide) coating undergoing a glass transition just above physiological temperature to enable thermally triggered antibiotic release. At normal physiological temperature, the coating provides a rifampicin depot for >100 days, while heating of the coating accelerates drug release, with >20% release over a 1-h induction heating cycle. Induction heating or antibiotic-loaded coating alone each reduce Staphylococcus aureus (S. aureus) viability and biofilm formation on Ti, but the combination causes synergistic killing of S. aureus as measured by crystal violet staining, determination of bacterial viability (>99.9% reduction), and fluorescence microscopy of bacteria on surfaces. Overall, these materials provide a promising platform enabling externally triggered antibiotic release to prevent and/or treat bacterial colonization of implants.

American Academy of Orthopaedic Surgeons (AAOS) has provided the guidelines for diagnosing a patient with periprosthetic joint infection including the use of positron emission tomography/computed tomography (PET/CT). Systematic evidence focussing on periprosthetic joint infection (PJI) of hip is limited, which also contains limited number of studies. Hence, the current study aims to perform a pooled analysis of all studies that have assessed the diagnostic accuracy of PET/CT for PJI of hip.

Searches were done in PubMed Central, EMBASE, MEDLINE, SCOPUS and Cochrane library until December 2022. Meta-analysis was carried out using random-effects model. With 95% confidence intervals (CIs), pooled sensitivity and specificity were reported.

Twenty-six studies met the inclusion criteria. The pooled sensitivity of PET/CT was 89% (95% CI 84-93%), while the pooled specificity was 86% (95% CI 79-91%). The AUROC was 0.94 (95% CI 0.72-0.99). There was statistically significant heterogeneity (p < 0.001) with I2 value of 96%. The diagnostic odds ratio was 52 (95% CI 26-106). Likelihood ratio positive was 6.5 (95% CI 4.1-10.3) and negative was 0.13 (95% CI 0.08-0.19).

Our study found that PET/CT was found to have higher level of accuracy in terms of sensitivity and specificity. Further large-scale research can help to find answers for such questions and provide final conclusive evidence on the inclusion of the imaging modality into the routine clinical practice guidelines for suspected periprosthetic joint infection patients.

Articulating hip spacers for periprosthetic joint infection (PJI) offer numerous advantages over static spacers such as improved patient mobilization, hip functionality, and soft tissue tension. Our study aimed to determine complication rates of a functional articulating spacer using a constrained liner to determine the role of acetabular cementation mantle and bone loss on the need for second-stage surgery. A retrospective review of 103 patients was performed and demographic information, spacer components and longevity, spacer-related complications, reinfection rates, and grade of bone loss and acetabular cement mantle quality were determined. There was no significant difference in spacer-related complications or reinfection rate between PJI and native hip infections. 33 of 103 patients (32.0%) elected to retain their spacers. Between patients who retained their initial spacer and those who underwent reimplantation surgery, there was not a significant difference in cement mantle grade (p = 0.52) or degree of bone loss (p = 0.78). Functional articulating antibiotic spacers with cemented constrained acetabular liners demonstrate promising early results in the treatment of periprosthetic and native hip infections. The rate of dislocation events was low. Further efforts to improve cement fixation may help decrease the need for second-stage reimplantation surgery.

The best antibiotic spacer for periprosthetic knee joint infection treatment is unknown. Using a metal-on-polyethylene (MoP) component provides a functional knee and may avoid a second surgery. Our study investigated complication rates, treatment efficacies, durabilities, and costs of MoP articulating spacer constructs using either an all-polyethylene tibia (APT) or a polyethylene insert (PI). We hypothesized that while the PI would cost less, the APT spacer would have lower complication rates and higher efficacies and durabilities.

A retrospective review evaluated 126 consecutive articulating knee spacer (64 APTs and 62 PIs) cases from 2016 to 2020 was performed. Demographic information, spacer components, complication rates, infection recurrence, spacer longevity, and implant costs were analyzed. Complications were classified as follows: spacer-related; antibiotic-related; infection recurrence; or medical. Spacer longevity was measured for patients who underwent reimplantation and for those who had a retained spacer.

There were no significant differences in overall complications (P < .48), spacer-related complications (P = 1.0), infection recurrences (P = 1.0), antibiotic-related complications (P < .24), or medical complications (P < .41). Average time to reimplantation was 19.1 weeks (4.3 to 98.3 weeks) for APT spacers and 14.4 weeks (6.7 to 39.7 weeks) for PI spacers (P = .09). There were 31% (20 of 64) of APT spacers and 30% (19 of 62) of PI spacers that remained intact for an average duration of 26.2 (2.3 to 76.1) and 17.1 weeks (1.7 to 54.7) (P = .25), respectively, for patients who lived for the duration of the study. PI spacers cost less than APT ($1,474.19 versus $2,330.47, respectively; P < .0001).

APT and PI tibial components have similar results regarding complication profiles and infection recurrence. Both may be durable if spacer retention is elected, with PI constructs being less expensive.

The most common cause of revision arthroplasty is prosthetic joint infection (PJI). Chronic PJI is commonly treated with two-stage exchange arthroplasty involving the placement of antibiotic-laden cement spacers (ACS) in the first stage, often containing nephrotoxic antibiotics. These patients often have significant comorbidity burdens and have higher rates of acute kidney injury (AKI). This systematic review aims to assess the current literature to identify (1) AKI incidence, (2) associated risk factors, and (3) antibiotic concentration thresholds in ACS that increase AKI risk following first-stage revision arthroplasty.

An electronic search was performed of the PubMed database of all studies involving patients undergoing ACS placement for chronic PJI. Studies assessing AKI rates and risk factors were screened by two authors independently. Data synthesis was performed when possible. Significant heterogeneity prevented meta-analysis.

Eight observational studies consisting of 540 knee PJIs and 943 hip PJIs met inclusion criteria. There were 309 (21%) cases involving AKI. The most commonly reported risk factors included perfusion-related factors (lower preoperative hemoglobin, transfusion requirement, or hypovolemia), older age, increased comorbidity burden, and nonsteroidal anti-inflammatory drug consumption. Only two studies found increased risk with greater ACS antibiotic concentration (> 4 g vancomycin and > 4.8 g tobramycin per spacer in one study, > 3.6 g of vancomycin per batch or > 3.6 g of aminoglycosides per batch in the other); however, these were reported from univariate analyses not accounting for other potential risk factors.

Patients undergoing ACS placement for chronic PJI are at an increased risk for AKI. Understanding the risk factors may lead to better multidisciplinary care and safer outcomes for chronic PJI patients.

Orthopaedic infections remain challenging complications to treat, with profound economic impact in addition to patient morbidity. The overall estimates of infection after orthopaedic surgery with internal devices has been estimated at 5%, with hospital costs eight times that of those without fracture-related infections and with significantly poorer functional and pain interference PROMIS scores. Orthopaedic infection interventions have been focused on prevention and treatment options. The creation of new modalities for orthopaedic infection treatment can benefit from the understanding of the temporal relationship between bacterial colonization and host-cell integration, a concept referred to as "the race for the surface." Regarding prevention, host modulation and antibiotic powder use have been explored as viable options to lower infection rates. Orthopaedic infection treatment has additionally continued to evolve, with PO antibiotics demonstrating equivalent efficacy to IV antibiotics for the treatment of orthopaedic infections in recent studies. In conclusion, orthopaedic infections remain difficult clinical dilemmas, although evolving prevention and treatment modalities continue to emerge.

Periprosthetic joint infection (PJI) is the most devastating complication following total joint arthroplasty (TJA) and is posing a global healthcare challenge as the demand for TJA mounts. Two-stage exchange arthroplasty with the placement of antibiotic-loaded spacers has been shown to be efficacious against chronic PJI. This study aimed to review the key concepts, types, and outcome evaluations of articulating spacers in the two-stage exchange for PJI. Previous studies indicated that articulating spacers have been widely used due to better functional improvement and a comparable infection control rate relative to static spacers. Several types of articulating spacers are reportedly available, including hand-made spacers, spacers fashioned from molds, commercially preformed spacers, spacers with additional metal or polyethylene elements, new or autoclaved prosthesis, custom-made articulating spacers, and 3D printing-assisted spacers. However, limited evidence suggested no significant difference in clinical outcomes among the different subtypes of articulating spacers. Surgeons should be familiar with different treatment strategies when using various spacers to know which is the most appropriate.

Prosthetic joint infections (PJI) and especially tuberculosis (TB) PJI are rare diseases and hard to cure. The effectiveness of treatments for tuberculous PJI still remains a problem. The objective of this research was to indicate the success of two-stage revision replacement and also giving the associated criteria.

From 2015 to 2020, five patients with tuberculous PJI were treated with two-stage revision at Cho Ray hospital, Vietnam. We collected the dataset which included demographic data, the interval from the time of joint replacement to reported infection, records of tuberculous PJI, administration of anti-TB medications (duration, months), history of operation(s), duration of follow-up, and specific type(s) of antibiotics loaded in bone cement. The approval for this study was made by the institutional review board from Cho Ray Hospital, Vietnam. We conducted a literature review based on the keywords "PJI" and "TB" on PubMed.

Five patients [median age 66 years (range 35-84)] had found tuberculous PJI. The median time from arthroplasty to diagnosis was 19 months (range 4-48). The diagnosis was confirmed by joint aspirates or synovial tissue. Positive PCR was also reported in all cases. The average duration of anti-tuberculosis polytherapy administration was 14.4 months. The operative techniques on five patients included debridement and using spacer loaded with 2 g streptomycin (and 2 g vancomycin if they got a coinfection) for 1 pack of bone cement, and revision arthroplasty. In most cases, the outcome of treatment using two-stage revision replacement was 80%. Overall, the auxiliary bacterial infections were recognized in three patients with tuberculous PJI and Staphylococcus aureus. Streptomycin and vancomycin were loaded in a cement spacer to increase the success rate, and tuberculous PJI was controlled for all patients.

Tuberculous PJI can be controlled with two-stage revision replacement with an antibiotic-loaded cement spacer that is molded intraoperatively with custom mold and prolonged anti-tuberculosis treatment in all cases.

IV.

Periprosthetic joint infection (PJI) following total knee arthroplasty is one of the most catastrophic and costly complications that carries significant patient wellness as well as economic burdens. The road to efficiently diagnosing and treating PJI is challenging, as there is still no gold standard method to reach the diagnosis as early as desired. There are also international controversies with respect to the best approach to manage PJI cases. In this review, we highlight recent advances in managing PJI following knee arthroplasty surgery and discuss in depth the two-stage revision method.

The purposes of this study were to determine demographics and characteristics of patients who underwent spacer exchange for persistent infection in the setting of two-stage arthroplasty for periprosthetic joint infection, to describe the microbiology of pathogens involved, to analyze survivorship free from infection in these patients.

The institutional prospectively collected database was reviewed to enroll patients with minimum 2 years follow-up. Patients who underwent two-stage procedure for septic arthritis were excluded, as were patients who had spacer fracture or dislocation.

A total of 34 patients (41 procedures) were included. Mean age was 65.0 ± 12.8 years. Mean follow-up was 53.4 ± 24.8 months. Mean number of previous procedures was 3.6 ± 1.2. A total of 27 (79.4%) patients underwent final reimplantation. The most frequently isolated pathogen in spacer exchange was Staphylococcus epidermidis (10 cases, 28.6%). Polymicrobial cultures were obtained from 9 (25.71%) patients, 10 (28.6%) presented culture-negative infections. A total of 11 (32.4%) resistant pathogens were isolated, and 16 (47.0%) difficult to treat pathogens were detected. Eradication rate was 78.8%. Overall survivorship of implants after final reimplantation was 72.8% at 51.8 months.

Surgeons should be aware that subjects necessitating spacer exchange often present multiple comorbidities, previous staged revision failures, soft-tissue impairment and difficult to treat infection. In these patients, spacer exchange provides good clinical results and infection eradication, preventing arthrodesis or amputation.

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.

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.

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.

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