Implant surface nanofiber (NF) coatings represent an alternative way to prevent/treat periprosthetic joint infection (PJI) via local drug release. We developed and characterized a coaxial erythromycin (EM)-doped PLGA/PCL-PVA NF coating. The purpose of this study was to determine the efficacy of EM-NF coatings (EM0, no EM, EM100 (100 mg/mL), and EM1000 (1000 mg/mL) wt/wt) in a rat PJI model. A strong bond of the EM-NF coating to the surface of titanium (Ti) pins was confirmed by in vitro mechanical testing. Micro-computed tomography (mCT) analysis showed that both EM100 and EM1000 NF effectively reduced periprosthetic osteolysis compared to EM0 at 8 and 16 weeks after implantation. Histology showed that EM100 and EM1000 coatings effectively controlled infection and enhanced periprosthetic new bone formation. The bone implant contact (BIC) of EM100 (35.08%) was higher than negative controls and EM0 (3.43% and 0%, respectively). The bone area fraction occupancy (BAFO) of EM100 (0.63 mm2) was greater than controls and EM0 (0.390 mm2 and 0.0 mm2, respectively). The BAFO of EM100 was higher than that of EM1000 (0.3 mm2). These findings may provide a basis for a new implant surface fabrication strategy aimed at reducing the risks of defective osseointegration and PJI.

Background: Periprosthetic joint infection (PJI) following total knee arthroplasty is a serious complication lacking evidence-based diagnostic and treatment protocols, particularly in ruling out persisting infection before reimplantation. Methods: This retrospective analysis assessed the mid-term outcomes of 66 patients undergoing septic two-stage knee revision surgeries from 2007 to 2013, diagnosed as per the Musculoskeletal Infection Society criteria. After implant removal and antibiotic treatment, reimplantation decisions were based on either joint aspiration, blood counts, and clinical examination (group A) or an open biopsy (group B). Both groups underwent meticulous debridement and spacer exchange during the interim period. Results: Late re-infection occurred in 12.1% of all patients. In group A, 13.8% experienced late re-infection, with 14.3% in subgroup A1 and 13.3% in subgroup A2. In group B, 10% had a late re-infection. No significant difference in re-infection or complication rates was found between the groups. Conclusions: The study did not demonstrate the superiority of group B\'s approach of open biopsy over group A\'s joint aspiration, clinical examination, and blood counts in preventing re-infection or reducing complications.

Periprosthetic joint infection (PJI) is a serious complication after joint arthroplasty. PJI screening and conventional cultures may be inconclusive. Sonication fluid culturing stands out as a valuable adjunct technique for PJI diagnosis. This study aims to determine the clinical relevance of routine sonication for all (a)septic revisions. All patients who underwent (partial) hip or knee revision arthroplasty between 2012 and 2021 were retrospectively reviewed. We formed three groups based on the European Bone and Joint Society PJI criteria: infection confirmed, likely, and unlikely. We analyzed clinical, laboratory, and radiological screening. Sensitivity and specificity were calculated for synovial fluid (preoperative), tissue, and sonication fluid cultures. We determined the clinical relevance of sonication as the percentage of patients for whom sonication confirmed PJI; 429 patients who underwent (partial) revision of hip or knee arthroplasty were included. Sensitivity and specificity were 69% and 99% for synovial fluid cultures, 76% and 92% for tissue cultures, and 80% and 89% for sonication fluid cultures, respectively. Sonication fluid cultures improved tissue culture sensitivity and specificity to 83% and 99%, respectively. In 11% of PJIs, sonication fluid cultures were decisive for diagnosis. This is applicable to acute and chronic infections. Sonication fluid cultures enhanced the sensitivity and specificity of PJI diagnostics. In 11% of PJI cases, causative pathogens were confirmed by sonication fluid culture results. Sonication fluid culture should be performed in all revision arthroplasties.

OBJECTIVE: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.
METHODS: Level III.

UNASSIGNED: Periprosthetic joint infections (PJIs) remain challenging to eradicate even after surgical management, which in most cases involves either debridement, antibiotics and implant retention (DAIR) or single- or two-staged revision. The purpose of this study is to determine predictors of PJI recurrence after operative management for PJI, and to determine differences in recurrence-free survival between DAIR and staged revision.
UNASSIGNED: This is a retrospective analysis of prospectively collected data of revision hip and knee arthroplasty surgeries due to PJI between 2011 and 2018 at an academic hospital. Any patient undergoing revision surgery for PJI was included except if the index surgery information was unknown. The primary outcome was confirmed PJI recurrence. Multivariable logistic regression analysis was utilized to determine the relationship between the predictor variables and outcome variable. Log rank testing was used to compare recurrence-free survival between DAIR and staged revision.
UNASSIGNED: A total of 89 patients (91 joints) underwent revision surgery due to PJI. Younger age and presence of a sinus tract were statistically significant for risk of PJI recurrence. A multivariable logistic regression model including both variables was significant for predicting recurrence of PJI (χ2=10.2, P=0.006). Survival was not significantly different between patients who underwent DAIR versus a staged revision.
UNASSIGNED: Younger patients and those with a chronic sinus tract are at significantly higher risk of recurrent PJI. This study also demonstrated that PJI can be successfully managed in the majority of cases with DAIR or staged revision.

Debridement, antibiotics, and implant retention (DAIR) is an alternative management strategy for the treatment of periprosthetic joint infection (PJI). While infection eradication rates are lower with DAIR, the benefits including decreased morbidity, improved functional outcomes, and decreased cost may justify the risks when considering this form of treatment compared to traditional one or two stage exchange arthroplasty. Implant longevity in the setting of a successful DAIR is similar to matched patients who have not experienced a PJI. An experienced arthroplasty surgeon well versed in extensile exposure should perform the DAIR. This procedure should not be viewed as a simple \"washout.\" While PJI may be considered a surgical urgency, DAIR can be performed on a planned list if it allows for appropriate staffing and implants for the procedure. Arthroscopic irrigation may be performed for a patient in extremis but it should not be viewed as a definitive procedure to address PJI. Keys to a successful DAIR include accurate tissue sampling to determine the infective organism, meticulous, radical debridement, and exchange of modular components if possible. A multidisciplinary team (MDT) including an infectious disease specialist should be involved prior to surgery in order to guide appropriate antimicrobial therapy throughout the patient\'s course of treatment. In the article below we present our indications, considerations, and technique for performing a DAIR for PJI for hip and knee arthroplasty.

Periprosthetic joint infection (PJI) is a devastating complication of the total joint arthroplasty (TJA). It presents a great challenge for the treating clinician. Diagnosis as well as management can prove difficult with significant morbidity for the patients and cost for patients, health care providers and society as a whole. Outcomes of equally challenging pathology such as tumors and polytrauma have been shown to be improved when patients are managed by a team as specialists as opposed to single individuals. The purpose of this study is to review the role of the multi-disciplinary team (MDT) approach in the diagnosis and management of PJI. We examine the influence of this approach on clinical outcomes in patients with PJI. We also discuss the organisational and logistical issues associated with establishment of a MDT as well as several other issues not mentioned in the contemporary orthopaedic literature. All published literature examining the role of multidisciplinary care in the management of PJI and the influence of this approach to the management and outcomes of patients with this diagnosis were included. Studies published in languages other than English were excluded. There is a paucity of data on the influence of multidisciplinary care on outcomes of the management of PJI. Evidence suggests that the MDT has important role in ensuring all factors in the management of this complex group are considered and best possible care is delivered. Multicentre randomised clinical trials are required to assess the influence of MDT\'S on outcome as well as important questions around the structuring of these teams.

Periprosthetic joint infection (PJI) is a major complication after knee arthroplasty, with approximately a quarter of knee arthroplasty revisions citing PJI as an indication. With the demand for knee arthroplasty predicted to increase, coupled with a lack of evidence for decreasing PJI risk, an appreciation of the burdens of PJI on both patients and health care systems is vital. Patients with PJI can experience a reduced quality of life as well as increased morbidity, whilst the management of PJI has significant economic implications. Surgical options include debridement, antibiotics and implant retention (DAIR), single-stage revision, two-stage revision and salvage procedures. DAIR involves the systematic debridement of all infected and unhealthy tissues coupled with directed antibiotic therapy, with definitive infection clearance the objective. In contrast to single- and two-stage revision procedures for PJI, DAIR does not involve the removal of fixed implants, with only modular components exchanged. Potential benefits of DAIR include reduced tissue destruction, reduced morbidity and reduced healthcare burdens, but with a higher reinfection risk compared to staged revision techniques, and utility largely restricted to acute bacterial PJI. A review of contemporary DAIR outcomes is of value given advances in the understanding of PJI biology; the development of consensus-based definitions for PJI diagnosis and treatment outcomes; and evolution of DAIR indications and technique. This review discusses outcomes of DAIR for knee PJI, published over the last two decades.

BACKGROUND: Periprosthetic joint infections (PJIs) of total hip arthroplasty (THA) or total knee arthroplasty (TKA) may occur in the setting of an uninfected ipsilateral prosthetic joint. However, the risk to that uninfected ipsilateral joint is unknown. We analyzed the survivorship free from PJI in at risk THAs and TKAs following treatment of an ipsilateral knee or hip PJI, respectively.
METHODS: Using our institutional total joint registry, we identified 205 patients who underwent treatment for PJI (123 THAs and 83 TKAs) with an at-risk ipsilateral in situ knee or hip, respectively, between 2000 and 2019. In total, 54% of index PJIs were chronic and 46% were acute. The mean age was 70 years, 47% were female, and the mean body mass index was 32. Kaplan-Meier survivorship analyses were performed. Mean follow-up was 6 years.
RESULTS: The 5-year survivorship free of PJI in an at-risk THA after an ipsilateral TKA was treated for PJI was 97%. The 5-year survivorship free of PJI in an at-risk TKA when the ipsilateral THA was treated for PJI was 99%. Three PJIs occurred (2 THAs and 1 TKA), all over 1 year from the index ipsilateral PJI treatment. One hip PJI was an acute hematogenous infection that resulted from pneumonia. The other 2 new PJIs were caused by the same organism as the index PJI and were due to a failure of source control at the index joint.
CONCLUSIONS: When diagnosed with PJI in a single joint, the risk of developing PJI in an ipsilateral prosthetic joint within 5 years was low (1 to 3% risk). In the rare event of an ipsilateral infection, all occurred greater than one year from the index PJI and 2 of 3 were with the same organism when source infection control failed.
METHODS: Prognostic Level III.

BACKGROUND: Synovial calprotectin is a promising biomarker for diagnosing chronic periprosthetic joint infections (PJIs), but its diagnostic value has not been directly compared to synovial leukocyte count and polymorphonuclear neutrophils. This study aimed to: (1) evaluate and compare the diagnostic accuracy between these markers in patients undergoing revision arthroplasty for chronic PJI or aseptic reasons; and (2) determine the best rule-out and rule-in test for PJI.
METHODS: Synovial fluid samples from patients undergoing revision arthroplasty in hip and knee joints were collected and analyzed. Patients diagnosed with an acute PJI, patients treated with antibiotics 2 weeks prior to revision surgery, and/or patients who had active inflammatory joint disease were excluded. Periprosthetic joint infections were diagnosed based on the presence of a sinus tract and/or positive intraoperative cultures according to the European Bone and Joint Infection Society microbiological criteria.
RESULTS: A total of 137 patients were included, of whom 19 (14%) were diagnosed with a PJI. Overall, synovial calprotectin had the highest diagnostic accuracy of all studied markers (area under the curve 96%). Synovial calprotectin, with a cutoff of 50 mg/L, had the highest negative predictive value of 100%. However, PMNs (> 80%) combined with a leukocyte count (> 3,000 cells/μL) showed the highest positive likelihood ratio of an infection (PLR 17).
CONCLUSIONS: Synovial calprotectin is the most accurate biomarker for ruling out a chronic PJI, while the combination of synovial leukocyte count and PMN is most reliable for ruling in a chronic PJI.