Prosthetic joint infection

The Study of Antistaphylococcal Potential of Omiganan and Retro-Omiganan Under Flow Conditions

Staphylococcus aureus is considered one of the leading pathogens responsible for infections in humans and animals. The heterogeneous nature of diseases caused by these bacteria is due to the occurrence of multiple strains, differentiated by several mechanisms of antibiotic resistance and virulence factors. One of these is the ability to form biofilm. Biofilm-associated bacteria exhibit a different phenotype that protects them from external factors such as the activity of immune system or antimicrobial substances. Moreover, it has been shown that the majority of persistent and recurrent infections are associated with the presence of the biofilm. Omiganan, an analog of indolicidin - antimicrobial peptide (AMP) derived from bovine neutrophil granules, was found to exhibit high antistaphylococcal and antibiofilm potential. Furthermore, its analog with a reversed sequence (retro-omiganan) was found to display enhanced activity against a variety of pathogens. Based on experience of our group, we found out that counterion exchange can improve the antistaphylococcal activity of AMPs. The aim of this study was to investigate the activity of both compounds against S. aureus biofilm under flow conditions. The advantage of this approach was that it offered the opportunity to form and characterize the biofilm under more controlled conditions. To do this, unique flow cells made of polydimethylsiloxane (PDMS) were developed. The activity against pre-formed biofilm as well as AMPs-treated bacteria was measured. Also, the incorporation of omiganan and retro-omiganan into the channels was conducted to learn whether or not it would inhibit the development of biofilm. The results of the microbiological tests ultimately confirmed the high potential of the omiganan and its retro-analog as well as the importance of counterion exchange in terms of antimicrobial examination. We found out that retro-omiganan trifluoroacetate had the highest biofilm inhibitory properties, however, acetates of both compounds exhibited the highest activity against planktonic and biofilm cultures. Moreover, the developed methodology of investigation under flow conditions allows the implementation of the studies under flow conditions to other compounds.

A Clinical Review of Prosthetic Joint Infections

Prosthetic arthroplasties are continuing to increase in the United States. While prosthetic joint infections are a less common adverse event, they can have a devastating impact on the patient as well as have a large economic burden on the health care industry. Prosthetic joint infections can be surgically managed by debridement, antibiotics, and implant retention, 1-stage revisions, 2-stage revisions, resection arthroplasties, arthrodesis, and amputations. Antimicrobial therapy typically includes 4 to 6 weeks of parenteral or highly bioavailable oral agents. Suppressive and chronic oral antimicrobial therapy may be pursued depending on the pathogen, clinical scenario, and retention of the prosthesis.

Effect of BMI on the risk of postoperative complications following total hip arthroplasty

Aims

While obesity is associated with an increased risk of complications after total hip arthroplasty (THA), the relationship between BMI and the risk of early postoperative complications has not been fully characterized. This study sought to describe the relationship between BMI and the risk of early postoperative complications, including periprosthetic joint infection (PJI), and composite surgical and composite medical complications.

Methods

Primary, elective THAs performed from 1 October 2015 to 31 December 2021 were identified using the Premier Healthcare Database. The study's primary outcome was the diagnosis of PJI within 90 days of THA. Using BMI as a continuous variable, logistic regression was used to develop restricted cubic splines (RCSs) to determine the impact of BMI on PJI risk. Bootstrap simulation was used to identify an inflection point in the final RCS model. The same technique was used to characterize the effects of BMI on composite medical and surgical complications.

Results

We found that PJI risk increased exponentially beyond a BMI threshold of 37.4 kg/m2. Relative to this threshold, patients with a BMI of 40 or 50 kg/m2 were at a 1.22-fold and 2.55-fold increased risk of developing PJI, respectively. Surgical complications increased at a BMI of 32 kg/m2 and medical complications increased at a BMI of 39 kg/m2. Relative to these cut points, patients with a BMI of 50 kg/m2 were at a 1.36-fold and 2.07-fold increased risk of developing medical and surgical complications, respectively.

Conclusion

The results of this study indicate a non-linear relationship between patient BMI and early postoperative risk of PJI, composite medical complications, and composite surgical complications following THA. The identified cut points with associated odds ratios can serve as tools to help risk-stratify and counsel patients seeking primary THA.

[Infections during joint replacement under immunomodulatory treatment]

Artificial joint replacement, particularly of the hip and knee joints, has become an established treatment option for degenerative and systemic inflammatory joint diseases in Germany; however, with the increasing number of endoprosthetic procedures, the risk of postoperative complications, particularly periprosthetic infections (PPI), also increases. These infections can lead to severe consequences, such as prolonged healing times, redo surgery and functional impairments. Patients with rheumatic diseases and immunosuppressive treatment have a particularly high risk for PPI, as the immune response is severely impaired by medications, such as corticosteroids, disease-modifying antirheumatic drugs (DMARD) and biologics. Preoperative measures, such as a thorough anamnesis and adjustment of the immunosuppressive treatment, are crucial to minimize the risk of infections. Diagnosing a PPI in immunosuppressed patients can be challenging as typical symptoms are often less pronounced. In cases of a suspected infection, an early diagnostic work-up and individualized treatment are required, which may include both antibiotic treatment and surgical interventions. An interdisciplinary management involving rheumatologists, orthopedic (rheumatologic) surgeons and infectious disease specialists is essential for successful treatment. Preventive strategies and targeted perioperative risk management can help to reduce the occurrence of PPI and ensure the long-term health of patients.

Analytical and clinical considerations of synovial fluid calprotectin in diagnosing periprosthetic joint infections

Calprotectin is a protein predominantly found in the cytosol of myeloid cells, such as neutrophils and monocytes. Calprotectin has several functions in innate immunity, such as attenuating bacteria, recruiting and activating immune cells, and aiding in the production of pro-inflammatory cytokines and reactive oxygen species. Due to its presence in inflammatory sites, it has been investigated as a biomarker for various medical conditions, especially Inflammatory bowel diseases (IBD), rheumatoid arthritis (RA), and has gained interest in the diagnosis of several infectious diseases, in particular for diagnosing periprosthetic joint infections (PJI). Synovial fluid calprotectin has demonstrated to be a sensitive and specific biomarker for both confirming as well as excluding PJI. Synovial fluid calprotectin can be measured using enzyme-linked immunosorbent assay (ELISA), immunoturbidimetry, and lateral flow methods. It is a generally stable biomarker, showing no significant decrease or increase in its levels despite blood or lipid contamination, storage duration, freeze-thaw cycles, and enzymatic pretreatments for viscosity reduction. This review discusses the biology and physiology of calprotectin, pathophysiology of PJI, and the clinical and analytical considerations surrounding its use in diagnosing PJI.

Labelling patients as allergic to beta-lactam antibiotics is associated with periprosthetic joint infection up to five years following knee arthroplasty

Aims

Periprosthetic joint infections (PJIs) represent a significant complication of total knee arthroplasty (TKAs). However, the influence of drug or beta-lactam (BL) antibiotic allergy labelling of patients on PJI remains largely unknown. In this study, we examine the association between patients labelled with a BL allergy and the occurrence of PJI among patients undergoing TKA. We also assess the prevalence of incorrect patient labelling and explore the feasibility of a multidisciplinary drug allergy testing initiative to detect mislabelling.

Methods

Longitudinal data from all patients who underwent TKA between January 1993 and December 2021 were analyzed. We investigated the association between different risk factors and PJI, with particular focus on patients labelled as having an antibiotic drug allergy. The outcomes of patients with and without a labelled BL allergy were compared. Additionally, patients labelled as having a BL allergy and who had undergone or were scheduled for TKA were prospectively investigated by formal allergy assessment.

Results

Out of 4,730 TKAs, the overall incidence of PJI was 1.0% (47/4,730). Patients labelled as having a BL allergy had a higher incidence of PJI within the first five years post-TKA compared to those without (3.0% (5/165) vs 0.7% (34/4,565); p = 0.001). The presence of a BL allergy label was identified as an independent risk factor for PJI (hazard ratio 4.86 (95% CI 2.05 to 11.53); p < 0.001). Following negative drug provocation testing, the majority of patients (95% (21/22)) evaluated with BL allergy labels were successfully delabelled.

Conclusion

In this longitudinal study, patients labelled as having a BL allergy were associated with having increased risk of PJI following TKA, particularly within the first five years. Given the high rate of patients being mislabelled, we recommend that patients labelled as having a BL allergy should be prioritized for formal allergy assessment and evaluation. Further studies on the impact of preoperative antibiotic allergy delabelling initiatives should be encouraged.

Self-Powered Oxygen Microbubble Generator for Decontamination of Anaerobic Biofilm-Fouled Bioimplants

Biomedical devices often feature a microgap: confined, minuscule spaces that foster bacterial infiltration and biofilm formation. For instance, peri-implantitis with prevalence rates of 4.7-45% at the patient level is a major complication driven by biofilm infections, characterized by chronic inflammation and implant failure. Anaerobic biofilm residing within the microgap serves as a major source of the peri-implantitis, but tools that remove the biofilm are lacking. Therefore, this study presents a novel preventive strategy employing self-powered microbubbler (SM) for targeted decontamination of micrographs in dental implants. SMs are assembled by doping diatoms with MnO2 nanosheets. These particles are activated to generate O2 microbubbles in H2O2 solution via catalase-mimetic activity and can penetrate the biofilm structures. The resulting oxygen bubbles induce effective mechanical disruption and oxygenation within biofilm-mimicking gelatin hydrogels and Porphyromonas gingivalis biofilms found in the peri-implantitis-affected implants. Such biofilm removal from the microgap restored mechanical stability at implant abutment-fixture connections and reduced bacterial leakage. Multispecies biofilms from patient-derived implants were similarly decontaminated with the mixture of SM-H2O2 outperforming conventional antiseptics like 0.2% chlorhexidine and 3% H2O2 alone. This innovative approach extends beyond dental implants to address biofilm-associated challenges in various biomedical devices with microgap vulnerabilities. Overall, SM-based treatments will offer an efficient and nondamaging solution to enhance the sterility and longevity of various bioimplants with intricated and confined structure.

Synovial Glucose and Serum-to-Synovial Glucose Predict Failure After Acute Postoperative Infection in Total Knee Arthroplasty

Background: The treatment of periprosthetic joint infection (PJI) involves various strategies, with debridement, antibiotic, and implant retention (DAIR) being a preferred method for acute infections due to its lower morbidity. However, DAIR success rates vary widely from 30% to 80%. This study investigates the predictive value of synovial glucose and the serum-to-synovial glucose ratio for DAIR outcomes in acute postoperative PJI following total knee arthroplasty (TKA). Methods: This is a retrospective study of 32 DAIR cases, diagnosed with acute postoperative PJI after TKA. Synovial joint aspirations were performed on all patients. We collected all serological and synovial glucose levels. The serum-to-synovial glucose ratio was calculated. Results: Patients with synovial glucose levels below 44 mg/dL and a serum-to-synovial glucose ratio above 50% were identified as high risk for DAIR failure. High-risk patients exhibited a 31.3% failure rate, with half occurring within the first three months post-DAIR. No failures were observed in the low-risk group. Multivariate analysis did not find other significant predictors such as CRP levels, gender, or microbial cultures. Conclusions: Low synovial glucose levels and high serum-to-synovial glucose ratios are predictive of unsuccessful outcomes following DAIR procedures. Patients exhibiting lower synovial concentrations experienced early treatment failure.

Outcomes of the dislocated hip hemiarthroplasty: a multi-centre study

INTRODUCTION

Hip hemiarthroplasties are performed in medically frail and/or comorbid patients who sustain a displaced intracapsular hip fracture. Dislocations occur in approximately 0.6-5.0% patients and are associated with worse outcomes, including mortality when compared against a similar cohort of patients who do not suffer a dislocation of their hemiarthroplasty.This study aimed to quantify the outcomes from the management of dislocated hip hemiarthroplasties in a cohort of contemporaneously used implants and the associated 1-year mortality.

METHODS

A retrospective review of a prospectively collected database of 4116 consecutive patients treated with a cemented hip hemiarthroplasty, in which 63 dislocations were identified was performed.The outcomes of the management of each dislocation were quantified, including the number of dislocations sustained after a preceding successful closed reduction. 1-year mortality was ascertained and stratified for each treatment option.

RESULTS

63 patients with a dislocation of a cemented hip hemiarthroplasty performed for an intracapsular hip fracture were included. Closed reduction was unsuccessful in 72% of (31/43) patients who had a closed reduction of their first dislocation. Failure rates of a second closed reduction increased to 76.9% and 100.0% with a third closed reduction.1-year mortality rate after a dislocation was 46.0% for all patients and lowest in the cohort of patients who were treated with a revision arthroplasty (27.3%).

CONCLUSIONS

Closed reduction of dislocated hip hemiarthroplasty is associated with a high failure rate, especially after a second dislocation. Consideration should be made to perform a revision procedure after a second dislocation with a high suspicion for soft tissue repair failure and/or infection.

Water-Soluble Sulfur-Ylide-Functionalized Polyacrylamides for Antibacterial Surface Applications

Surface fouling induced by biomolecules and microorganisms remains a persistent challenge in materials science, particularly in healthcare applications, where biofilm formation on medical devices may lead to infections and antimicrobial resistance. Antifouling strategies typically rely on the formation of either hydration layers or cytotoxic materials for direct antimicrobial effects. Recent advances in zwitterionic polymers derived from ylides offer a promising yet unexplored toolbox for the construction of antifouling and antimicrobial coatings. While N-oxide-based ylides have been extensively studied as building blocks for antifouling materials, sulfur-ylide-based materials, and the precise underlying mechanisms remain underexplored despite their broader chemical versatility. Here, we present a fully water-soluble acrylamide-based poly(sulfur ylide) and compare its properties to those of previously reported hydrophobic polystyrene-derived analogues. Notably, water-soluble poly(sulfur ylides) retain antimicrobial efficacy on surfaces but lose cytotoxicity in solution, unlike its hydrophobic counterpart. Computational studies reveal that the dipole moment of sulfur ylides is environmentally responsive, stabilizing in hydrophobic environments. Genetic analysis confirms outer membrane destabilization for both polymers but suggests that the hydrophobicity of the polystyrene backbone promotes stronger interactions. We suggest that future work should focus on elucidating additional interactions, including supramolecular behaviors of amphiphilic sulfur ylides, to refine their structure-property relationships and optimize their antifouling and antimicrobial properties.

Extracellular adherence proteins reduce matrix porosity and enhance Staphylococcus aureus biofilm survival during prosthetic joint infection

Biofilms are a cause of chronic, non-healing infections. Staphylococcus aureus is a proficient biofilm-forming pathogen commonly isolated from prosthetic joint infections that develop following primary arthroplasty. Extracellular adherence protein (Eap), previously characterized in planktonic or non-biofilm populations as being an adhesin and immune evasion factor, was recently identified in the exoproteome of S. aureus biofilms. This work demonstrates that Eap and its two functionally orphaned homologs EapH1 and EapH2 contribute to biofilm structure and prevent macrophage invasion and phagocytosis in these communities. Biofilms unable to express Eap proteins demonstrated increased porosity and reduced biomass. We describe the role of Eap proteins in vivo using a mouse model of S. aureus prosthetic joint infection. The Results suggest that the protection conferred to biofilms by Eap proteins is a function of biofilm structural stability that interferes with the leukocyte response to biofilm-associated bacteria.

Management of persistent postoperative wound leakage after total hip and knee arthroplasty: a regional perspective in the north west of England

INTRODUCTION

There is a well-documented association between persistent wound drainage and the development of prosthetic joint infections in total hip (THA) and total knee arthroplasty (TKA). Despite this, there are no national clinical guidelines in the United Kingdom on the diagnosis or management of postoperative wound drainage. We aimed to evaluate what variability exists within clinical practice in the recognition and treatment of persistent wound leakage following THA and TKA.

METHODS

An anonymous online survey consisting of 12 multiple-choice questions was distributed among hip and knee arthroplasty consultants in the north west of England. Topics covered in the questionnaire included definition, diagnosis, classification, timing and treatment of persistent wound drainage.

RESULTS

Twelve orthopaedic centres across the region participated in data collection. A total of 65 consultants completed the questionnaire. Some 45% of respondents used a definition of persistent wound leakage after arthroplasty, which ranged from drainage beyond 48h to that lasting more than 2 weeks. Only 54% of consultants reported having a monitoring system in place for patients with persistent wound drainage after discharge from hospital. There was wide variation in the preferred timing of initiating both non-operative and surgical management of wound leakage, as well as different treatment modalities used. Most respondents rated C-reactive protein as the most useful serological marker in aiding decision making.

CONCLUSION

The results demonstrate a lack of concurrence in the recognition and management of postoperative wound drainage. Formal national clinical guidelines are necessary to standardise practice.

Simultaneous Periprosthetic Joint Infection and Infective Endocarditis: Prevalence, Risk Factors, and Clinical Presentation

BACKGROUND

Infective endocarditis (IE) and periprosthetic joint infections (PJI) occur due to hematogenous bacterial spread, theoretically increasing the risk for concurrent infections. There is a scarcity of literature investigating this specific association. We aimed to assess the prevalence, comorbidities, and clinical presentation of patients who have simultaneous PJI and IE.

METHODS

We retrospectively identified 655 patients (321 men, 334 women; 382 total hip arthroplasty, 273 total knee arthroplasty) who developed a PJI from July 1, 2015, to December 31, 2020, at one institution. There were two groups created: patients diagnosed with PJI with IE (PJI + IE) and PJI patients who did not have IE (PJI). We analyzed clinical outcomes and comorbidities.

RESULTS

There were nine patients who had PJI with IE (1.4% of PJI patients). The C-reactive protein (170.9 versus 78, P = 0.026), Elixhauser comorbidity score (P = 0.002), length of hospital stay (10.9 versus 5.7 days, P = 0.043), and the 2-year postdischarge mortality rate (55.6 versus 9.0%, P = 0.0007) were significantly greater in the PJI + IE group. Comorbidities such as iron deficiency anemia (P = 0.03), coagulopathy (P = 0.02), complicated diabetes mellitus (P = 0.02), electrolyte disorders (P = 0.01), neurologic disease (P = 0.004), paralysis (P = 0.04), renal failure (P = 0.0001), and valvular disease (P = 0.0008) occurred more frequently in the PJI + IE group. Modified Duke's criteria were met for possible or definite IE in eight of the nine patients.

CONCLUSIONS

Concurrent PJIs and IE, although rare, are a potentially devastating disease state with increased length of hospital stay and 2-year mortality rates. This emphasizes the need for appropriate IE workups in patients who have a PJI. The modified Duke's criteria are effective in establishing a diagnosis for IE in this scenario.

Prospective evaluation of real-world performance and clinical impact of the Biofire FilmArray joint infection panel

Limitations of culture-based diagnostic approaches in pathogen detection in joint infections (JI) can be overcome by amplification-based, molecular assays. Recently, a syndromic panel PCR (spPCR) assay (Biofire JI panel; BJA) was approved for pathogen identification from synovial fluid (SF). Here, the performance and the clinical impact of the BJA were assessed in comparison to standard of care diagnostics in a prospective cohort of patients presenting with symptoms consistent with JI. One hundred sixty-five synovial fluids underwent analysis using the BJA. The results were compared with culture-based diagnostics. Discrepant results were re-analyzed using species-specific PCRs or 16S-rDNA sequencing. Clinical data from patients were collected to evaluate the impact on patient management. Twenty-seven of 165 (16.3%) synovial fluid cultures grew bacterial pathogens. In 24/27 cases, the BJA results were concordant. In one case, the cultured pathogen was missed, but three additional pathogens were identified. In 11 culture-negative cases, BJA identified a pathogen. Mean turnaround time in culture-positive samples was 14:11 h and 35:17 h in BJA and culture, respectively. In 11 cases, antibiotic therapy was optimized, based on BJA results. This study demonstrates high sensitivity and specificity (96.3% and 97.8%, respectively) of BJA, as well as a shorter turnaround time than culture-based techniques (21 h faster). Based on analysis of clinical data, antibiotic therapy was optimized due to BJA results in 11 cases. Care must be taken, as important pathogens in prosthetic JI are not included in the panel, restricting its value here.IMPORTANCEPathogen detection is critical for targeted management of joint infections; however, cultural detection of pathogens can be challenging. The Biofire Joint Infection Assay (BJA) is a syndromic panel PCR test that allows culture-independent detection of 31 pathogens. The diagnostic performance and clinical impact were evaluated in a cohort of 160 patients with native and prosthetic joint infections. BJA detected concordant pathogens in 24 of 27 culture-positive cases and enabled the detection of additional pathogens in 11 patients. The time to result was significantly shorter than with standard culture-based diagnostics (14 vs 35 h), and BJA allowed optimization of therapy in 11 patients. The data show that BJA is a relevant addition to the diagnostic options for joint infections. Limitations result from incomplete detection of relevant pathogens, especially in prosthetic joint infections. The use of BJA in daily practice must therefore be accompanied by diagnostic stewardship measures.

Patient and Health Professional's Perspectives of Periprosthetic Joint Infection: A Systematic Review and Meta-Ethnography

Background: Periprosthetic joint infection (PJI) is a major challenge for surgical teams and patients following an orthopedic surgical procedure. There is limited understanding on patient and health professional's perception of PJI. The aim of this study was to examine the literature to better understand the perspectives of patients, and those who manage PJI. Methods: Published and unpublished literature databases were systematically searched from inception to June 21, 2024. Qualitative studies reporting the perspectives of living with and managing PJI were included. Data were synthesized using a meta-ethnography approach and the GRADE-CERQual tool. Results: Of the 584 citations identified, 10 studies (n = 91 patients; n = 70 health professionals) met the eligibility criteria and were included. Three themes, all moderate-certainty evidence, were identified from the health professional data, including the following: (1) importance of PJI; (2) impact on health professionals; and (3) support for change. From the patient data, six themes on the basis of moderate-certainty evidence were identified: (1) psychological and social impact; (2) physical impacts; (3) relationship with health professionals; (4) relationship with others; (5) uncertainty over the future; and (6) support for change. A novel line of argument was developed offering third-order constructs, on the basis of first- and second-order themes. Conclusion: PJIs are perceived as devastating by both patients and health professionals. They impact on all aspects of a patient's physical, social and psychological health, each interacting on one another over the course of infection and management. Strategies to improve communication, multidisciplinary management, and personalization of care are advocated by both patients and health professionals to promote better outcomes.

Good Results for PJI Caused by Corynebacterium spp. After Algorithmic Surgical Approach and Rifampicin Combination in Implant Retention

Background

Corynebacterium spp. is a rare culprit in periprosthetic joint infections (PJIs), with limited data available on outcomes and appropriate treatment course. The aim of this study was to evaluate the success rate of a clinical cohort of patients with PJI, where Corynebacterium spp. was the causative organism (CPJI), treated according to an institutional algorithm based upon European Bone and Joint Infection Society guidelines.

Methods

From the institutional bone infection registry, 44 patients treated for CPJI between 2007 and 2023 were identified. CPJIs were divided into 2 groups according to the isolated microbes: monomicrobial (14 [32%]) and polymicrobial (30 [68%]). Patients were treated with debridement, antibiotics, and implant retention (DAIR; 14 [32%]) or with 1- or 2-stage implant exchange (reimplantation group; 30 [68%]). In 13 (30%) cases, antibiotic combination with rifampicin was used.

Results

Out of 44 patients, 4 required further treatment. In monomicrobial CPJI, the treatment course was successful in all patients, whereas in polymicrobial CPJI it was successful in 87%. Antibiotic combination including rifampicin was used in 4 monomicrobial cases (29%) and 9 polymicrobial (30%) cases. In the polymicrobial group, DAIR was successful in 90% (9/10), while the reimplantation group had an 85% (17/20) success rate.

Conclusions

In contrast with the previously published papers on CPJI, the results in our cohort were good, with the total cure rate being 91%. The cure rate was slightly lower in the polymicrobial group compared with the monomicrobial: 87% and 100%, respectively. Surgical therapy according to the established institutional algorithm resulted in a high success rate.

Functionalized zeolite regulates bone metabolic microenvironment

The regulation of bone metabolic microenvironment imbalances in diseases such as osteoporosis, bone defects, infections, and tumors remains a significant challenge in orthopedics. Therefore, it has become urgent to develop biomaterials with effective bone metabolic microenvironmental regulatory functions. Zeolites, as advanced biomedical materials, possess distinctive physicochemical properties such as multi-level pore structures, adjustable frameworks, easily modifiable surfaces, and excellent adsorption capabilities. These advantageous characteristics give zeolites broad application prospects in regulating the bone metabolic microenvironment. Therefore, this paper first classifies zeolites used to regulate the bone metabolic microenvironment based on their topological structures and compositional frameworks. Subsequently, it provides a detailed description of modification strategies for zeolite materials aimed at regulating this microenvironment. Next, a comprehensive summary was provided on the preparation strategies for zeolite materials aimed at regulating the bone metabolic microenvironment. Additionally, the paper focuses on the specific applications of zeolite materials in conditions of bone metabolic imbalance, such as osteoporosis, bone defects, orthopedic infections, and bone tumors, highlighting their potential in enhancing osteogenic microenvironments, controlling infections, and treating bone tumors. Finally, it outlines the prospects and challenges associated with the application of zeolites in regulating the bone metabolic microenvironment. This review comprehensively summarizes zeolites used for bone metabolic regulation, aiming to provide guidance for future research and application development.

Exploring the Role of Sonication Fluid Culture in Periprosthetic Joint Infection: A Comparative Study with Conventional Methods

OBJECTIVE

The aim of this study is to evaluate and compare the diagnostic effectiveness of sonication fluid culture (SFC) compared to conventional methods in identifying the causative microorganisms in periprosthetic joint infections.

METHODS

In this study, three cultures were evaluated for diagnosing periprosthetic joint infection intraoperative periprosthetic tissue culture, implant culture, and SFC. The sensitivity, specificity, and predictive values were calculated for each method, using the 2018 definition of periprosthetic hip and knee infection and clinical evaluation as references. Of the 92 patients who had implants removed, 49 were for mechanical reasons and 43 for infection.

RESULTS

Positive cultures were obtained in 13 out of 49 patients with mechanical issues and 31 out of 43 with infections. The sensitivity of periprosthetic tissue cultures (53.5%) is slightly higher than SFC (48.8%), suggesting better detection of positive cases. However, SFC's specificity (83.7%) is higher, indicating more accurate identification of negative cases compared to periprosthetic cultures (73.5%). However, SFC identified additional pathogens in patients with negative periprosthetic tissue and implant cultures. Examination of the infected knee and hip prostheses showed that SFC enhanced pathogen detection, particularly in patients with negative implant cultures. Despite this, SFC was not statistically superior to other methods.

CONCLUSION

This study supports the combined use of periprosthetic tissue culture and SFC for identifying causative microorganisms in implant infections. Despite not being statistically superior, SFC provides additional pathogen detection, especially when other methods fail, thereby enhancing overall diagnostic accuracy.

Diagnosis of Prosthetic Joint Infection of Hips and Knees-One Size Does Not Fit All

There is no consensus on diagnostic criteria for hip and knee periprosthetic joint infections (PJIs). This study evaluated Infectious Diseases Society of America (IDSA), International Consensus Meeting 2018 (ICM2018), and European Bone and Joint Society (EBJIS) criteria, finding IDSA most accurate for early PJI and knee infections, while ICM2018 and EBJIS were superior for delayed and late cases. Diagnostic approaches should consider infection timing and context.

The Application of artificial intelligence in periprosthetic joint infection

Periprosthetic joint infection (PJI) represents one of the most devastating complications following total joint arthroplasty, often necessitating additional surgeries and antimicrobial therapy, and potentially leading to disability. This significantly increases the burden on both patients and the healthcare system. Given the considerable suffering caused by PJI, its prevention and treatment have long been focal points of concern. However, challenges remain in accurately assessing individual risk, preventing the infection, improving diagnostic methods, and enhancing treatment outcomes. The development and application of artificial intelligence (AI) technologies have introduced new, more efficient possibilities for the management of many diseases. In this article, we review the applications of AI in the prevention, diagnosis, and treatment of PJI, and explore how AI methodologies might achieve individualized risk prediction, improve diagnostic algorithms through biomarkers and pathology, and enhance the efficacy of antimicrobial and surgical treatments. We hope that through multimodal AI applications, intelligent management of PJI can be realized in the future.

D-enantiomeric antibiofilm peptides effective against anaerobic Cutibacterium acnes biofilm

The emergence of antibiotic resistance, biofilm formation, and internalization by host cells contribute to a high risk of chronic infections, highlighting the necessity to develop novel therapeutic strategies. Identification of natural host defense peptides (HDPs) with promising antimicrobial and antibiofilm activities led to the development of synthetic peptides with broad-spectrum efficacy. However, few studies have examined their effect on anaerobic bacterial species. This study aimed to test the effect of synthetic HDPs on Cutibacterium acnes, an anaerobe species involved in 10% of prosthesis joint infections (PJI). A preliminary screen identified three peptides (DJK5, AB009-D, and AB101-D) with promising activity against four C. acnes strains (two of which were isolated from PJI). A bactericidal effect was observed for the three peptides with 50% of planktonic bacteria killing for AB009-D and AB101-D after only 3 hours of contact. DJK5 and AB009-D inhibited the C. acnes adhesion on plastic and titanium supports with a 2-log decrease in bacterial cells. In the presence of peptides, the morphology of C. acnes cells was altered with an increase in cell length observed, especially for one of the non-PJI-related strains. Against mature biofilms, AB101-D was the most effective with an approximate 2-log decrease in adhered CFUs, indicating the induction of bacterial dispersion or death. DJK5 also inhibited C. acnes internalization by osteoblasts, with a reduction of the internalized bacteria quantity for three strains. Overall, this study demonstrates that synthetic HDPs are effective against anaerobic bacteria and hold promise as novel therapeutic candidates to prevent or treat C. acnes PJIs.IMPORTANCEThe emergence of antibiotic tolerance highlights the necessity to develop novel therapeutic strategies with promising antimicrobial but also antibiofilm activities. In this study, we tested the effect of synthetic host defense peptides (HDPs) on Cutibacterium acnes, an anaerobic species, rarely studied, whereas involved in 10% of prosthesis joint infections (PJI). In our study, we demonstrate that the selected synthetic HDPs are effective against this anaerobic bacteria, both as a preventive treatment (effect on planktonic growth, bacterial adhesion, and biofilm formation) and against internalization of C. acnes by osteoblasts, revealing that these peptides are promising as novel therapeutic candidates to prevent or treat C. acnes PJIs.

Antibiotic prophylaxis and incidence of infection following elbow arthroplasty: a nationwide study

BACKGROUND AND PURPOSE

 Periprosthetic joint infection (PJI) after elbow arthroplasty is a serious complication. Evidence of the best antibiotic prophylaxis for elbow arthroplasty is lacking. We aimed to investigate the regimens presently used in Sweden, incidence of PJI, and the bacteria most frequently found in elbow PJI.

METHODS

 A questionnaire was sent out to all Swedish units performing elbow arthroplasty in 2019 asking about antibiotic prophylaxis routines. The Swedish Elbow Arthroplasty Register (SEAR) and national inpatient and outpatient registers (NPR) from the National Board of Health and Welfare were searched for procedures related to all primary total- or hemi-elbow arthroplasties performed during 2019-2021. Results of microbiological analyses of the suspected PJI cases were collected from the respective laboratory.

RESULTS

 Most centers used only cloxacillin (44%) or cloxacillin together with benzylpenicillin (44%), as prophylaxis. 250 primary procedures were performed between 2019 and 2021, and the most used antibiotic prophylaxes were cloxacillin (61%) and cloxacillin with benzylpenicillin (23%). In the NPR, 20 patients (8%) with a diagnosis that could indicate PJI were found and 9 (3.6%) had a confirmed PJI. The most common bacteria were Staphylococcus epidermidis, Cutibacterium acnes, and Staphylococcus aureus.

CONCLUSION

 Most centers used cloxacillin antibiotic prophylaxis for elbow arthroplasty. The incidence of PJI was 3.6%. The most frequent diagnosed pathogen was Staphylococcus epidermidis.

Cutting through infection risk: robotic-assisted vs. conventional total knee replacement surgery - a meta-analysis

BACKGROUND

Surgical site infections (SSI) following knee replacement pose significant challenges, often attributed to microorganism contamination during surgery. Robotic-assisted total knee replacement (RA-TKR) offers potential advantages but may also raise concerns regarding infection risk. This systematic review and meta-analysis aimed to evaluate infection rates following RA-TKR compared to Conventional Total knee replacement (C-TKR) within the first-year post-implantation.

MATERIALS AND METHODS

A systematic search of major databases was conducted from 2005 to November 2023. Eligible studies reported primary C-TKR and RA-TKR interventions, documented SSI incidence, and had a follow-up period of at least 12 months. Data on deep, superficial, and pin-site infections were extracted, and the risk of bias was assessed using the Cochrane Risk of Bias Tool. Summary estimates were generated using a random-effects model.

RESULTS

Eight studies were included, comprising 758,453 knees (6724 RA-TKR, 751,729 C-TKR). The overall SSI rate was 1.57% in conventional TKR and 1.29% in RA-TKR. Deep infection rates were 0.96% and 0.66% in conventional and robotic procedures, respectively, with no significant variation between them (Odds Ratio [OR] 1.27 [95% Confidence Interval [CI], 0.93 to 1.73], I2 = 0%, P-value = 0.13). Superficial and pin-site infection rates were comparable between both procedures (0.61% vs. 0.62%) with no significant difference (OR 1.21 [95% CI, 0.86 to 1.70], I2 = 0%, P-value = 0.28).

CONCLUSION

This meta-analysis shows low SSI rates for both RA-TKR and C-TKR within the first year post-implantation. Both techniques are viable with low SSI incidence, and further research should investigate longer-term outcomes and different robotic systems to refine infection risk understanding in knee arthroplasty.

A novel process to reduce the cost of admission for treatment of infected shoulder arthroplasty

BACKGROUND

With the rapidly increasing volume of total joint arthroplasty procedures, the incidence of periprosthetic joint infection (PJI) and its associated economic burden are expected to rise. Two-stage reimplantation, a common strategy for PJI management, is costly, as it requires multiple surgeries and hospitalizations, with total costs ranging from $35,000 to $42,000. Given the long hospital stays required for these patients, a quality improvement project was undertaken at the authors' institution to reduce cost of admission (COA) and length of stay (LOS).

METHODS

We conducted a retrospective review of patients treated for PJI of the shoulder at a single hospital within a large health system. Patients were included if they had a biopsy-proven shoulder PJI treated with 1 of 2 protocols: a conventional, inpatient focused approach or a new, outpatient focused approach. Conventional management involved prosthesis explantation with intraoperative cultures, antibiotic spacer placement, inpatient infectious disease consultation, and inpatient peripherally inserted central catheter placement. The new protocol consisted of outpatient infectious disease clinic referral and peripherally inserted central catheter placement prior to explantation and spacer placement. COA and LOS were compared between the 2 groups.

RESULTS

Sixteen patients were included, 8 in each group. Patients managed with the outpatient-focused protocol had a significantly reduced COA ($17,711 ± 4078) compared to the conventional protocol ($24,233 ± 4967) with a mean difference of $6521, representing a 26.9% cost reduction per patient (P = .006). LOS was significantly reduced in the outpatient-focused group (median: 1.35 days; interquartile range: 1.21-1.89) compared to the conventional protocol group (median: 2.52 days; interquartile range: 1.81-3.21) (U = 10.50; Z = -2.26; P = .024).

CONCLUSIONS

The pilot quality improvement initiative resulted in a 27% reduction in COA and a significantly reduced LOS for patients with shoulder PJI. This has broad implications across orthopedics for the management of periprosthetic joint replacement and potential for tremendous impact of reducing healthcare costs.

Microbiologic features of prosthetic joint infections at a tertiary referral orthopaedic unit

BACKGROUND

Prosthetic joint infections (PJI) are a potential devasting consequence of arthroplasty surgery. Knowledge of the causative organism and antimicrobial sensitivity increases eradication success rates for PJI.

AIMS

This study aimed to: 1) Observe the PJI microbiome at a tertiary referral arthroplasty unit; 2) Make comparison to similar published observations; and; 3) Establish empiric local antibiotic PJI guidelines.

METHODS

All patients with positive tissue cultures for PJIs over a 4 year period were included. An electronic microbiology laboratory database search was performed to identify isolated microorganisms, sensitivities and resistances. Time from index procedure to PJI onset was recorded. The identified PJI microbiome was compared to current literature.

RESULTS

86 patients involving 88 joints were included. 56% (n = 49) related to hip, 42% (n = 37) to knee and 2% (2) to shoulder arthroplasty procedures. Coagulase Negative Staphylococci (CoNS) were isolated in 32% of cases, Staphylococcus aureus (SA) in 23%, Enterococcus species and Streptococcus species in 9.0%. 19% of case occurred within 3 months of index surgery, 17% from 3-12 months and 64% after 12 months. The microbiome identified varied comparable studies.

CONCLUSION

This study describes a local PJI microbiome with contrasting results from comparable studies. Empiric antibiotic guidelines have been established to target treatment and a local PJI register has since been established to improve patient outcomes and antimicrobial stewardship in an era of antibiotic resistance.

Knee arthrodesis with intramedullary nail in end-stage periprosthetic joint infection with extensor mechanism failure: a retrospective outcome and reinfection rate analysis of a case series

BACKGROUND

Chronic periprosthetic knee infection is a highly debilitating complication. In case of failed R-TKA, with significant bone loss and extensor mechanism failure, re-revision procedures could not even be feasible. The most appropriate therapeutic strategy in these cases remains unclear. This study aims to evaluate the clinical and subjective outcomes, as well as the reinfection rate, in nine patients with extensor mechanism failure following chronic PJI treated with knee arthrodesis using a cemented intramedullary nail with a bridging technique.

METHODS

The series included nine patients who underwent knee arthrodesis with a cemented intramedullary nail at our Institute between 2020 and 2024. All patients were treated by a single operator using a standardized two-stage revision procedure. Clinical scores (OKS and VAS), subjective scores (SF-36), postoperative limb length discrepancy, and the reinfection rate were evaluated for each patient.

RESULTS

All patients achieved good clinical and subjective scores, indicating good functional recovery and pain reduction. No patient had clinically relevant limb length discrepancy. One patient (11.1%) experienced a recurrence of infection. Literature shows that re-revision surgery with extensor mechanism reconstruction has high complication and reinfection rates, while transfemoral amputation results in lower clinical and functional scores. Knee arthrodesis ensures good functionality and a low reinfection rate.

CONCLUSIONS

Knee arthrodesis with a cemented intramedullary nail is a valid therapeutic alternative for patients with extensor mechanism failure following chronic periprosthetic infection. Patients in our study achieved good functional recovery and pain reduction. Further comparative studies with larger series are needed to confirm these results.

Synovial glucose and serum-to-synovial-glucose ratio perform better than other biomarkers for the diagnosis of acute postoperative prosthetic knee infection

Introduction: In native septic arthritis, synovial glucose is a well-established diagnostic marker. However, its diagnostic utility in periprosthetic joint infection (PJI) remains unexplored. Given the diagnostic challenges of acute postoperative PJI, we hypothesized that synovial glucose could serve as a valuable biomarker and aimed to evaluate its diagnostic accuracy. Material and methods:  This is a retrospective diagnostic study in acute postoperative PJI in total knee arthroplasty (TKA). We reviewed all TKA surgeries performed in the past 10 years and cross-checked those patients that consulted to our emergency room during the first 90 d after TKA surgery for knee-related symptoms. We calculated the serum-to-synovial-glucose ratio for each patient (serum-to-synovial-glucose ratio = [(serological glucose - synovial glucose) / serological glucose]), and we formed the receiver operating characteristic (ROC) curves for synovial glucose, serum-to-synovial-glucose ratio, serum C-reactive protein (CRP), synovial white blood cell (s-WBC) count, and polymorphonuclear cell percentage (PMN%); then we extracted the optimal cutoff values. Results: The optimal cutoffs for diagnosing acute postoperative PJI were < 44 mg dL-1 for synovial glucose and > 0.69 for serum-to-synovial-glucose ratio. The area under the curve (AUC) values were 0.861 and 0.889, respectively. ROC curves for serum CRP, s-WBC count, and PMN% showed AUC values of 0.69, 0.714, and 0.66, respectively. The combined ROC curve analysis for serum CRP, s-WBC count, and PMN% showed an AUC of 0.722. When adding synovial glucose, the AUC was 0.859 and with serum-to-synovial-glucose ratio we achieved an AUC of 0.876. Conclusion: Synovial glucose and serum-to-synovial-glucose ratio demonstrated good diagnostic potential for acute postoperative PJI following TKA. These biomarkers exhibited superior accuracy compared to the combination of serum CRP, s-WBC count, and PMN%.

Effects of previous arthroscopic knee surgery on the outcomes of primary total knee arthroplasty: a systematic review and PRISMA-compliant meta-analysis

OBJECTIVE

The aim of this study was to evaluate the potential adverse effects of prior arthroscopic knee surgery on the prognosis of primary total knee arthroplasty (TKA).

METHODS

This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive literature search was performed in the PubMed, Embase, Cochrane Library, and other relevant databases up to October 2024. Cohort studies comparing the outcomes of patients with and without previous arthroscopic knee surgery were retrieved. Meta-analysis was performed to assess the differences in postoperative function, complications, and revision rates between the arthroscopy and primary TKA groups.

RESULTS

The analysis included 11 cohort studies comprising a total of 194,367 patients; 13,086 of these patients had a history of knee arthroscopy. The meta-analysis results revealed no significant differences in postoperative range of motion, functional improvement, stiffness, periprosthetic fracture, venous thromboembolism (VTE), and other complications between the groups. However, the arthroscopic group showed a higher risk of postoperative prosthetic joint infection (PJI) and manipulation under anaesthesia (MUA). The revision rate was also higher in the arthroscopic group (Relative Risk (RR) 1.423, 95% Confidence Interval (CI) 1.280 to 1.583). Subgroup analysis revealed an increased PJI risk within one year of arthroscopic TKA (RR 1.314, 95% CI 1.156 to 1.493). Sensitivity analysis confirmed the stability of the results, and Egger's test showed no publication bias.

CONCLUSION

Prior arthroscopic surgery was not found to have significant impacts on the functional outcomes of TKA but was found to increase the risks of postoperative infection and revision.

Analysis of Prosthetic Joint Infections, Risk Factors for Treatment Failure and Effect of Teicoplanin in Treatment: A Single-Center, Retrospective, Observational Study

Objective

This study aimed to identify the risk factors for treatment failure in prosthetic joint infections (PJIs) and the most appropriate approach to these infections, especially the effect of teicoplanin on treatment response.

Materials and Methods

The data of patients who were followed up with a diagnosis of Gram-positive or culture-negative PJI for seven years in a tertiary-care referral hospital were included in the study retrospectively.

Results

One hundred sixty-nine PJI attacks were included in the study. The overall infection eradication rate was 82.7%. Preoperative hemoglobin (Hb) and hematocrit (Hct) levels were higher, and C-reactive protein (CRP) levels were lower in treatment responders ( p=0.006, p=0.003, and p=0.021, respectively). The relationship between CRP and treatment response emerged in the second week, while a significant decline in the erythrocyte sedimentation rate (ESR) levels was seen at the end of treatment. Treatment was successful in 91.7% of cases that underwent two-stage revision surgery and 89.4% in those who used teicoplanin for more than two weeks. In multivariate analysis, two-stage revision surgery and the use of teicoplanin for more than two weeks increased treatment success.

Conclusion

Hb, Hct, and CRP levels could help to predict the treatment response in the preoperative period, and in the postoperative follow-up, CRP could predict the treatment response earlier. Although one-stage surgeries seem practical, the patient's best interests are paramount, and two-stage revisions should be selected whenever needed. Finally, teicoplanin, a practical once-daily, well-tolerated antibiotic, was associated with high treatment success rates in Gram-positive and culture-negative PJIs.

Does Cement Viscosity Impact Antibiotic Elution and In Vitro Efficacy Against Common Prosthetic Joint Infection Pathogens?

BACKGROUND

Polymethylmethacrylate (PMMA) antibiotic-laden bone cement (ALBC) is commonly used in total joint arthroplasty to treat and potentially prevent prosthetic joint infection (PJI). Multiple properties impact the elution characteristics of antibiotics from PMMA-based ALBC, including viscosity. What is not known is how medium-viscosity cement formulations affect antibiotic elution and how different cement products from different manufacturers compare regarding reaching the minimum inhibitory concentration (MIC) of antibiotics for common PJI-causing organisms in an in vitro setting.

QUESTIONS/PURPOSES

(1) Does cement viscosity impact in vitro antibiotic elution characteristics when comparing medium-viscosity ALBC and high-viscosity ALBC formulations from the same manufacturer against four common PJI pathogens? (2) Does the manufacturer of the PMMA-based ALBC product and the type of aminoglycoside (gentamicin versus tobramycin) impact the in vitro antibiotic elution against four common PJI pathogens?

METHODS

Three different PMMA-based ALBC products, including Palacos® R (high viscosity) plus gentamicin (PR+G), Palacos (medium viscosity) plus gentamicin (PMV+G), and Simplex™ P (low viscosity) plus tobramycin (SP+T), and controls for each cement type, including Palacos R, Palacos medium viscosity, and Simplex P, were evaluated. These cements were tested against four common PJI pathogens: methicillin-sensitive Staphylococcus aureus , methicillin-resistant S. aureus (MRSA), methicillin-sensitive S. epidermidis (MSSE), and methicillin-resistant S. epidermidis . A 5-day elution protocol was observed using uniform cylindrical cement samples of each cement product. Each analysis was run with three separate lots of cement, with four samples created per lot and each sample run in duplicate. Standard curves with known antibiotic concentrations were created. Kirby-Bauer assays were then used to determine the zone of inhibition for each cement product against the four common PJI pathogens. The eluted antibiotic concentration was extrapolated for each product over 5 days to determine the interpolated antibiotic concentration for each of the 5 days. Area under the curve (AUC) was calculated as a surrogate for total antibiotics eluted over the 5-day period.

RESULTS

Cement viscosity does not impact antibiotic elution characteristics when comparing a medium-viscosity ALBC and a high-viscosity ALBC from the same manufacturer. The cement products from two manufacturers containing different types of aminoglycosides differ in their in vitro activity over a 5-day period against four common PJI pathogens. There was no difference in interpolated antibiotic concentration against MSSE on Day 1 between PMV+G cement and PR+G (high-viscosity) (mean ± SD medium-viscosity cement gentamicin concentration 73.6 ± 14.0 µg/mL versus high-viscosity gentamicin concentration 80.3 ± 15.5 µg/mL, mean difference -6.8 [95% confidence interval (CI) -27 to 40]; p = 0.9); there was, however, greater interpolated effective antibiotic in PR+G when compared with tobramycin concentration of SP+T (80.3 ± 15.5 µg/mL versus 199.9 ± 81 µg/mL, mean difference -120 [95% CI -153 to -86]; p < 0.001). All antibiotic cement products had zones of inhibition that corresponded to an interpolated concentration above the MIC (> 32 mg/L) for all organisms on Day 1. Concentrations were maintained above the MIC even at Day 2 for only MRSA and MSSE for PMV+G and PR+G. Concentrations dropped below the MIC after Day 1 for all organisms for SP+T. Similar results were seen in the AUC, which was used as a surrogate for total antibiotics eluted over 5 days, where PMV+G and PR+G both had greater antibiotics eluted over 5 days than SP+T except for MSSE, which demonstrated no difference in the AUC.

CONCLUSION

In this study, medium-viscosity ALBC demonstrated similar elution properties compared with high-viscosity ALBC from the same manufacturer. Both the medium- and high-viscosity ALBC cement products from Palacos demonstrated superior in vitro antibiotic elution properties and activity against four common PJI pathogens compared with low-viscosity ALBC from Simplex over a 5-day period.

CLINICAL RELEVANCE

This in vitro study suggests that a surgeon may choose to use Palacos medium-viscosity ALBC (PMV+G) in total joint applications without impacting the in vitro antibiotic elution properties compared with Palacos high-viscosity ALBC (PR+G), and that both the medium- and high-viscosity formulations of ALBC from Palacos may have improved activity against three of four common PJI pathogens compared with Simplex low-viscosity ALBC (SP+T). However, more related research is needed to determine the in vivo activity of these ALBC products and the overall efficacy of routine use of ALBC in general.

Diagnostic value of ratio of blood inflammation to coagulation markers in periprosthetic joint infection

Introduction

Assess the feasibility of utilizing the ratio of blood inflammation to coagulation markers as a potential periprosthetic joint infection (PJI) diagnostic tool.

Materials and methods

A retrospective analysis was conducted, involving 133 PJI and 93 aseptic loosening patients. Levels of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), platelet count, mean platelet volume, fibrinogen, D-dimer, and ratios of CRP to fibrinogen, ESR to fibrinogen, platelet count and mean platelet volume ratio (PC/MPV), and D-dimer were compared. Receiver operating characteristic curves and Youden's index were employed to assess the diagnostic efficacy of these biomarkers.

Results

PJI patients had significantly higher levels of CRP, ESR, PC/MPV ratio, fibrinogen, D-dimer, CRP/(PC/MPV) ratio (CPR), CRP/D-dimer, CRP/fibrinogen (CFR), ESR/(PC/MPV) ratio, ESR/D-dimer, and ESR/fibrinogen. Area under the curve (AUC) values for fibrinogen, CRP, and ESR in diagnosing PJI were comparable. AUC values for CPR and CFR were akin to those of ESR. AUC values for combined CRP and CPR, combined CRP and fibrinogen, combined CRP and CFR, and combined ESR and fibrinogen in diagnosing PJI were akin to that of combined CRP and ESR.

Conclusions

Fibrinogen, CPR, CFR, combined CRP and CPR, combined CRP and fibrinogen, combined CRP and CFR, and combined ESR and fibrinogen could be considered as new adjunct markers for diagnosing PJI.

Diagnostic accuracy of 16S rDNA PCR, multiplex PCR and metagenomic next-generation sequencing in periprosthetic joint infections: a systematic review and meta-analysis

BACKGROUND

The diagnostic accuracy of 16S rDNA PCR, multiplex PCR (mPCR), and metagenomic next-generation sequencing (mNGS) in periprosthetic joint infections (PJIs) remains unclear.

OBJECTIVES

This study aims to evaluate the diagnostic accuracy of 16S rDNA PCR, mPCR, and mNGS in PJI.

METHODS

Data sources: Data sources included PubMed and Embase (January 1, 2000-March 1, 2024), with no language restrictions.

STUDY ELIGIBILITY CRITERIA

Studies containing sufficient data to construct a 2 × 2 contingency table allowing for sensitivity and specificity calculation were considered.

PARTICIPANTS

Participants included adults (≥18 years) with PJI and appropriate control groups.

TESTS

Tests included 16S rDNA PCR, mPCR, and mNGS.

REFERENCE STANDARD

Diagnosis required adherence to Musculoskeletal Infection Society, Infectious Diseases Society of America, International Consensus Meeting, European Bone and Joint Infection Society criteria. Studies employing alternative author-defined criteria were included only if they did not rely solely on positive cultures to define PJI.

ASSESSMENT OF RISK OF BIAS

Quality Assessment of Diagnostic Accuracy Studies 2 was used.

METHODS OF DATA SYNTHESIS

A bivariate model calculated pooled diagnostic odds ratios (DORs), sensitivities, and specificities, each with 95% CIs.

RESULTS

Seventy-nine studies were included, comprising 3940 PJI cases and 4700 uninfected controls. Pooled sensitivity/specificity were 80.0% (95% CI, 75.4-84.3%)/94.0% (95% CI, 91-96%) for 16S rDNA PCR; 62.2% (52.5-70.9%)/96.2% (93.2-97.9%) for mPCR; and 88.6% (83.3-92.4%)/93.2% (89.5-95.6%) for mNGS. Notably, mNGS had the highest DOR (105.9; 95% CI, 60-186.9). A sensitivity analysis excluding lower-quality studies resulted in increased DORs for all methods.

DISCUSSION

These molecular techniques display strong diagnostic accuracy for identifying PJI. Although mNGS yielded the highest DOR, numerous technical and practical challenges preclude its routine use for PJI diagnosis. Significant heterogeneity across studies warrants cautious interpretation and underscores the need for future comparative research.

Is the isolation of S. epidermidis from pre-operative synovial fluid culture a predictor of S. epidermidis prosthetic joint infection?

Pathogen identification is key to the management of periprosthetic joint infection (PJI). Staphylococcus epidermidis is a major cause of PJI. Differentiating between invasive and contaminating S. epidermidis from joint specimens is challenging, and usually S. epidermidis is only considered a true invasive isolate when grown from two or more independent tissue samples. Thus, the detection of S. epidermidis in single synovial fluid (SF) samples from preoperative athrocentesis makes it difficult to draw definitive conclusions about its clinical significance, especially when grown from contamination-prone broth enrichment cultures (BEC). This study evaluates the diagnostic value of S. epidermidis detection in preoperative synovial cultures for the diagnosis of S. epidermidis-related PJI diagnosed by intraoperative tissue culture (TC). A total of 292 patients were included in the study, of whom 271 had prosthetic joint infection (PJI) according to EBJIS criteria. Preoperative synovial fluid (SF) cultures detected Staphylococcus epidermidis in 32.5% cases (SF-epi), other pathogens in 43.2% cases (SF-other), and were negative in 24.3%. Intraoperative tissue cultures TC identified clinically significant S. epidermidis in 30.1% of cases. The overall agreement between SF and tissue cultures was 66.1%, and the presence of S. epidermidis in SF was confirmed by TC in 70.5%. The diagnostic accuracy of SF cultures for S. epidermidis PJI was 83.2%, with sensitivity of 76.1% and specificity of 86.3% to detect S. epidermidis PJI. The positive likelihood-ration (LR+) was 5.5. When S. epidermidis from SF-BEC were excluded from analysis, specificity increased to 94.2%, and LR + was 7, but diagnostic sensitivity dropped to 40.5%. This study highlights the important value of using preoperative SF fluid cultures for the diagnosis of S. epidermidis PJI. The integration of BEC improves diagnostic accuracy and sensitivity in S. epidermidis PJI, and thus providing valuable information to guide clinical practice. For definitive antibiotic treatment decisions intraoperative tissue cultures remain mandatory.

Periprosthetic Infection of Transfibular Ankle Arthroplasties Managed with Implant Retention: Anatomical Limitations of Surgical Debridement

Background: Prosthetic ankle infection is an infrequent and rarely explored prosthetic joint infection (PJI). In early infection, the debridement of implants inserted using the transfibular approach has certain peculiarities that pose a diagnostic and therapeutic challenge, the impact of which on infection prognosis is still unknown. Methods: This study prospectively collected all cases of transfibular prosthetic ankle infection at a tertiary hospital between 2014 and 2022, describing their demographic, clinical, microbiological, and management characteristics, along with the outcome over a long follow-up. This cohort was compared with a cohort of infected fibular plates without prostheses implanted in the same period of time. Results: Seven cases of ankle PJI were analysed, all of them implanted using a transfibular approach. They were all early prosthetic infections. The median age was 63 years (range 54-74) with a predominance of women (71.4%), three patients with diabetes (42.9%), and one patient with rheumatoid arthritis (14.3%). The aetiology was predominantly staphylococcal (4 [57.1%] methicillin-susceptible S. aureus and 1 [14.3%] S. epidermidis). All cases were managed with irrigation and debridement limited to the fibular plate, four of which failed (57%). By comparison, eleven cases of infected fibular plates without prostheses implanted were analysed. There were no differences in clinical, microbiological, or therapeutic management characteristics between the groups. Failure among infected fibular plates occurred in only two cases (18%). Conclusions: Debridement of infected transfibular ankle prostheses suggests a worse evolution than would be expected for other joint infections. This could be explained by the nature of the debridement, limited to the fibular component. Further detailed studies of the surgical possibilities in prosthetic ankle infections are necessary to improve the prognosis of these infections, given their impact on joint function.

Prolonged incubation time unwarranted for acute periprosthetic joint infections

Current laboratory protocols for periprosthetic joint infections (PJIs) involve a standard 10- to 14-day incubation period. However, recent evidence indicates considerable variability in the time to diagnosis (TTD) between acute and chronic PJIs. TTD is also influenced by the employed culture media and sample types. Enriched liquid media, such as broths and blood culture bottles, along with sonication fluid culture, are commonly used, though their incremental benefit for PJI diagnosis remains debated. We retrospectively analyzed 187 confirmed hip and knee PJIs, each with at least three intraoperative samples. Comparison of TTD among early acute (n = 68), late acute (n = 52), and late chronic (n = 67) PJIs revealed a significant difference, particularly between late acute and late chronic infections (P < 0.004). Early acute and late acute PJIs were diagnosed within 5 days in 97.1% and 98.1% of cases, respectively, contrasting with 14 days required for 97.1% of late chronic PJIs. Enriched liquid media significantly improved species detection, especially in polymicrobial and anaerobic infections. Pediatric and anaerobic blood culture bottles demonstrated superior efficacy over thioglycolate broths for diagnostic confirmation. Sonication fluid culture was essential for confirming diagnoses in 17.6% of cases. Our findings highlight that clinical presentation, rather than time since primary arthroplasty, should guide incubation duration: both early acute and late acute PJIs can be diagnosed within 5 days. Medical microbiology laboratories should consider shorter incubation times for acute PJIs to optimize diagnostic efficiency. The use of blood culture bottles and sonication fluid culture proves invaluable for accurate PJI diagnosis.

IMPORTANCE

While molecular techniques are becoming increasingly employed, culture remains the gold standard for diagnosing periprosthetic joint infections. However, guidance for laboratory protocols is limited and highly variable. This article aims to increase diagnostic efficiency by providing concrete recommendations for medical microbiology laboratories.

Periprosthetic Joint Infection: Are Patients Still Better off Than if Primary Arthroplasty Had Not Been Performed?

BACKGROUND

This study sought to evaluate patient-reported outcome measures (PROMs) before primary total joint arthroplasty (TJA) and after successful treatment for periprosthetic joint infection (PJI), with the hypothesis that patients still demonstrate clinical improvement despite the occurrence of PJI.

METHODS

A single tertiary academic center's institutional database was retrospectively reviewed for patients who underwent primary TJA, developed PJI, and were managed for PJI from January 2019 to December 2023. Patients who did not have PROMs recorded were excluded from the study. Preoperative and postoperative generic and joint-specific PROMs were collected. Patient preprimary and postfinal revision surgery for PJI PROMs were subsequently compared. The minimum follow-up after PJI treatment was 6 months. A total of 55 patients (31 total knee arthroplasty and 24 total hip arthroplasty) were included with a mean follow-up of 1.8 years (range, 6 months to 4.5 years). All PJIs were managed via debridement, antibiotics, and implant retention, 1-stage, 1.5-stage, 2-stage revision, or resection arthroplasty.

RESULTS

After final revision surgery for PJI in total knee arthroplasty, patients had lower median patient-reported outcome measure information system (PROMIS) pain interference scores than before their primary surgery (62.0 [55.0, 67.0] versus 67.0 [65.0, 70.5]; P < 0.01). However, median PROMIS physical function postfinal revision for PJI and preprimary scores were similar (38.0 [33.0, 42.0] versus 34.0 [29.5, 40.0]; P = 0.08). After final revision surgery for PJI in total hip arthroplasty, patients had lower median PROMIS pain interference scores than before their primary surgery (57.5 [53.8, 64.0] versus 68.0 [66.5, 74.0]; P < 0.01). After final revision surgery for PJI, patients also had higher median PROMIS physical function scores than before their primary surgery (39.5 [33.5, 48.2] versus 29.5 [28.8, 34.2]; P < 0.01).

CONCLUSIONS

Patients who have been successfully managed for PJI show improvement in generic and joint-specific PROMs compared to their preprimary TJA PROMs.

Chlorhexidine or Povidone-Iodine Solution Irrigation versus Saline Irrigation for the Prevention of Postoperative Infections in Primary Total Joint Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

This study evaluated the effectiveness of antiseptic irrigation solutions, specifically chlorhexidine, and povidone-iodine, compared to normal saline after primary total joint arthroplasty (TJA) in preventing periprosthetic joint infection (PJI).

METHODS

Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched MEDLINE, Embase, and the Cochrane Library databases for studies comparing the use of different intraoperative irrigation following primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). A total of 11 studies, including 67,742 patients, were included. The outcome of interest was the rate of deep infections. Statistical analysis was conducted using a random-effect model, with heterogeneity assessed via I2 statistics.

RESULTS

The random-effect model analysis revealed a PJI rate of 1.02% (95% CI [confidence interval]: 0.77 to 1.35; I2 = 90%) for the total cohort. Among 24,025 patients who received irrigation with either povidone-iodine or chlorhexidine, the PJI rate was 0.86% (95% CI: 0.63 to 1.17; I2 = 75%). Povidone-iodine significantly reduced the risk of PJI compared to saline (RR [risk ratio] 0.60, 95% CI: 0.37 to 0.95; P = 0.029; I2 = 61%). However, no significant difference was observed in the subgroups for THA (RR 0.92, 95% CI: 0.52 to 1.61; P = 0.57; I2 = 0%) and TKA (RR 0.92, 95% CI: 0.47 to 1.77; P = 0.21; I2 = 35%). Chlorhexidine also reduced the risk compared to saline (RR 0.60, 95% CI: 0.45 to 0.82; P = 0.001; I2 = 0%). There was no significant difference between povidone-iodine and chlorhexidine (RR = 1.60, 95% CI: 0.84 to 3.06; P = 0.154; I2 = 0%).

CONCLUSION

In this meta-analysis, chlorhexidine and povidone-iodine had a significantly reduced risk of PJI as compared with saline irrigation in TJA. There was no significant difference between chlorhexidine and povidone-iodine.

Novel Method for the Rapid Establishment of Antibiotic Susceptibility Profiles in Bacterial Strains Linked to Musculoskeletal Infections Using Scattered Light Integrated Collector Technology

Bacterial antibiotic resistance is an important challenge that the healthcare system is continually battling and a major problem in the treatment of musculoskeletal infections such as periprosthetic joint infections. Current methods to identify infectious microbes and define susceptibility to antibiotics require two to ten days from isolation to the establishment of an antibiogram. This slow process limits advances in antimicrobial drug discovery and, in the clinical context, delays the delivery of targeted treatments, with potentially devastating outcomes for patients. With this in mind, we strived to establish a quicker and more sensitive method to deliver antibiotic susceptibility profiles of clinically relevant microbes using Scattered Light Integrated Collector (SLIC) technology. We established antibiotic panels to obtain an approximate identification of a wide variety of microbes linked to periprosthetic joint infections and determine their susceptibility to antibiotics. We challenged microbes isolated from patients with our tailored antibiotic panels and found that SLIC detects perturbations in bacterial growth accurately and reproducibly within minutes of culture. Indeed, we could show that SLIC can be used to measure the dose-dependent inhibitory or bacteriolytic activity of broad classes of antibiotics. Our panel design enabled us to establish a profile similar to an antibiogram for the tested bacteria within 90 min. Our method can provide information on the class of bacteria tested and potential treatment avenues in parallel. Our proof-of-principle experiments using isolated clinical strains of bacteria demonstrate that SLIC, together with our specifically designed antibiotic panels, could be used to rapidly provide information on the identity of an infecting microbe, such as those associated with periprosthetic joint infections, and guide physicians to prescribe targeted antibiotic treatment early-on. The constant emergence of resistant strains of bacteria pushes the pharmaceutical industry to develop further effective drugs. Our optimized method could significantly accelerate this work by characterizing the efficacy of new classes of compounds against bacterial viability within minutes, a timeframe far shorter than the current standards.

Synergistic antibacterial drug elution from UHMWPE for load-bearing implants

Total joint replacement is a successful procedure for restoring the patient's musculoskeletal mobility and quality of life, but it carries the risk of severe peri-prosthetic joint infections (PJI) and is accompanied by post-operative pain. Cocktails of multiple drugs are often used for prevention/treatment of PJI and for addressing pain. Local drug delivery systems are promising for improving the outcome of the treatment and decreasing the side effects of systemic drugs. To this end, the ultra-high molecular weight polyethylene (UHMWPE) bearing surface of the joint implant is here proposed as a platform for simultaneous release of multiple therapeutics. The combined use of non-antibiotic drugs and antibiotics, and their incorporation into UHMWPE allows to obtain novel antibacterial implant materials. The combined elution of analgesics and antibiotics from UHMWPE is found to be synergistically effective in eradicating Staphylococcus aureus, as the non-antibiotic compound significantly enhances the antibacterial activity of the antibiotic. The drug properties and the employed method for their incorporation into UHMWPE are found to dictate the morphology, thus the mechanical properties of the resulting material. By adopting various fabrication methods, novel formulations showing an enhanced antibacterial activity and outstanding mechanical properties are here proposed to amplify the functionality of polymeric implant materials.

Dual-Energy Computed Tomography Iodine Maps: Application in the Diagnosis of Periprosthetic Joint Infection in Total Hip Arthroplasty

BACKGROUND

The challenge of early and rapid diagnosis of periprosthetic joint infection (PJI) remains important. This study aimed to assess the efficacy of dual-energy computed tomography (DECT) iodine maps for diagnosing PJI in total hip arthroplasty.

METHODS

We prospectively enrolled 68 patients who had postoperative joint pain after hip arthroplasty. All patients underwent preoperative DECT iodine imaging to quantify iodine concentration (IC) in periprosthetic tissues during arterial and venous phases. The diagnostic efficacy of DECT iodine maps was evaluated by constructing receiver operating characteristic curves according to the Musculoskeletal Infection Society criteria.

RESULTS

Compared with erythrocyte sedimentation rate (area under the curve [AUC] = 0.837), polymorphonuclear cell percentage (AUC = 0.703), and C-reactive protein (AUC = 0.837), periprosthetic tissue venous-phase IC (AUC = 0.970) and arterial-phase IC (AUC = 0.964) exhibited outstanding discriminative capability between PJI and aseptic failure. The PJI cut-off point was venous IC = 1.225 mg/mL, with a sensitivity of 92.31% and specificity of 90.48%; for arterial IC = 1.065 mg/mL, the sensitivity was 96.15% and specificity was 90.70%.

CONCLUSIONS

This study demonstrates the great potential of DECT iodine maps for the diagnosis of PJI around hip arthroplasty, which helps to differentiate between periprosthetic infection and aseptic failure after hip arthroplasty.

A Smart Semi-Implantable Device Integrating Microchannel-Enhanced Sampling and Multiplex Biochemical Testing for Deep Wound Monitoring and Pathogen Identification

Monitoring deep wounds is challenging but necessary for high-quality medical treatment. Current methodologies for deep wound monitoring are typically limited to indirect clinical symptoms or costly non-real-time imaging diagnosis. Herein, a smart system is proposed that enables in situ monitoring of deep wounds' status through a semi-implantable device composed of 2 seamlessly connected functional components: 1) the well-designed, microchannel-structured sampling needles that efficiently and conveniently collect samples from deep wound anatomical locations, and 2) the multiplex biochemical testing compartment that facilitates the immediate and persistent detection of multiple biochemical indicators based on a color image processing software accessible to a conventional smartphone. With the 3 representative preclinical deep wound models, the study demonstrates the device's potential to monitor wound infection, inflammation, healing progress, and reduce inflammation when applied to deep skin injury, surgical implantation, and postoperative intestinal leakage. The device's capability to rapidly and accurately identify pathogenic bacteria is also demonstrated both in vitro and in vivo, potentially facilitating precise intervention in infected wounds. Coupled with the device's favorable biocompatibility and cost-effectiveness, this intelligent system emerges as a promising tool for safe and effective management of complicated deep wounds.

A "1.5-Stage" Spacer Construct Using Revision Components for the Management of Periprosthetic Joint Infection of the Knee

BACKGROUND

The two-stage surgical protocols used for the treatment of periprosthetic joint infection following total knee arthroplasty are associated with marked patient morbidity. As such, alternatives, such as durable "1.5-stage" spacer constructs, have gained popularity. We sought to describe the outcomes of a novel "1.5-stage" spacer construct utilizing revision stemmed-tibia implants.

METHODS

Patients who underwent a "1.5-stage" for the management of a knee periprosthetic joint infectionat our institution were screened for inclusion. A "1.5-stage" was defined as a spacer placed with the intent of not performing a second stage, without the use of press-fit stems or cemented intramedullary fixation as is often done during a single-stage protocol. Procedures were categorized into two groups based on construct type: (1) hand-made constructs utilizing all-polyethylene tibial components; or (2) constructs utilizing stemmed-revision components precoated with cement before insertion. Patient demographics, comorbidities, and surgical details were collected and reported. The two-year Kaplan-Meier survival estimates for all-cause revision, revision for spacer loosening, and revision due to infection recurrence were reported. In total, 46 "1.5-stage" procedures were identified, including 12 handmade and 34 stemmed-revision constructs.

RESULTS

The stemmed-revision cohort was less likely to undergo reoperation for any reason (17.6 versus 50.0%, P = 0.028) or a revision for spacer loosening (0.0 versus 25.0%, P = 0.003) compared to the hand-made cohort. There were no differences with respect to infection recurrence or time to revision. The 2-year survival from revision for loosening was higher in the stemmed cohort compared to the handmade cohort though not statistically different (100%, 95% CI [confidence interval]: 2.5 to 100.0 versus 72.9%, 95% CI: 26.3 to 96.6%, P = 0.330).

CONCLUSIONS

A "1.5-stage" spacer construct using stemmed-revision components was associated with promising short-term results. Durable spacer constructs may be a viable option for select patients; however, longer-term follow-up is needed to identify patients who stand to benefit the most from this technique.

The Utility of Synovial Fluid Interleukin-10 in Diagnosing Chronic Periprosthetic Joint Infection: A Prospective Cohort Study

Background

Diagnosing chronic periprosthetic joint infection (PJI) is challenging. Synovial fluid interleukin-10 (SF IL-10), an anti-inflammatory cytokine produced by leukocytes, plays a pivotal role in inflammation and infection regulation. However, limited research has explored the diagnostic potential of SF IL-10 in chronic PJI patients.

Objective

The study aimed to investigate the relationship between SF IL-10 and incidence of chronic PIJ, and to evaluate its diagnostic reliability.

Design and Methods

We analyzed data from 137 patients who underwent revision surgery for aseptic loosening or chronic PJI between 2017 and 2019 in our hospital. PJI diagnoses followed the 2013 International Consensus Meeting criteria. We measured serum ESR, serum CRP, SF PMN%, SF WBC and SF IL-10 levels, using logistic regression and receiver operating characteristic (ROC) curves to evaluate associations and diagnostic accuracy.

Results

Demographic data showed no significant differences. However, SF IL-10 levels differed significantly between groups. Logistic regression indicated a strong association between SF IL-10 and chronic PJI (OR = 1.11, 95% CI 1.05~1.17, p < 0.001). At a cut-off of 10.305 pg/mL, SF IL-10 had an area under the ROC curve (AUC) of 0.891, with 92.16% sensitivity and 77.91% specificity. Adding SF IL-10 to traditional models improved risk prediction for chronic PJI (net reclassification improvement [NRI]: 0.167 [0.023 ~ 0.312]; integrated discrimination improvement [IDI]: 0.160 [0.096 ~ 0.224]).

Conclusion

Higher SF IL-10 levels were significantly associated with chronic PJI in revision surgery patients, and incorporating SF IL-10 into the traditional risk model enhanced its predictive value for chronic PJI in these patients.

Structural characteristics, functions, and counteracting strategies of biofilms in Staphylococcus aureus

Background

Staphylococcus aureus (S. aureus) is a prevalent pathogen associated with a wide range of infections, exhibiting significant antibiotic resistance and posing therapeutic challenges in clinical settings. The formation of biofilms contributes to the emergence of resistant strains, further diminishing the efficacy of antibiotics. This, in turn, leads to chronic and recurrent infections, ultimately increasing the healthcare burden. Consequently, preventing and eliminating biofilms has become a critical focus in clinical management and research.

Aim of review

This review systematically examines the mechanisms underlying biofilm formation in S. aureus and its contribution to antibiotic resistance, emphasizing the essential roles biofilms play in maintaining structural integrity and enhancing resistance. It also analyses the protective mechanisms that fortify S. aureus biofilms against antimicrobial treatments. Furthermore, the review provides a comprehensive overview of recent therapeutic innovations, including enzymatic therapy, nanotechnology, gene editing, and phage therapy.

Key scientific concepts of review

Emerging therapeutic strategies present novel approaches to combat S. aureus biofilm-associated infections through various mechanisms. This review discusses recent advancements in these therapies, their practical challenges in clinical application, and provides an in-depth analysis of each strategy's mechanisms and therapeutic potential. By mapping future research directions, this review aims to refine anti-biofilm strategies to control infection progression and effectively mitigate recurrence.

Safety of vancomycin-loaded cement spacers for treating gram-positive periprosthetic joint infections in two-stage resection arthroplasty among patients with renal insufficiency

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

LEVEL OF EVIDENCE

III.

Mid- to Long-Term Outcomes of Two-Stage Revision Arthroplasty for Periprosthetic Joint Infection of the Shoulder

Background/Objectives: Periprosthetic joint infection (PJI) after shoulder arthroplasty is often treated with a two-stage approach, but the data on the mid- to long-term outcomes remain scarce. This study aimed to evaluate the clinical outcomes of two-stage revision arthroplasty for shoulder PJI with a minimum follow-up of five years. Methods: This retrospective study identified 59 shoulders in 58 patients who underwent the first stage of a two-stage revision arthroplasty for shoulder PJI at our institution between 2007 and 2018. Of these, 29 shoulders in 29 patients (49.2%) did not undergo reimplantation or the patient passed away before reaching five years of follow-up. The remaining 30 shoulders in 29 patients were included in the study. The clinical assessments included the active range of motion, the visual analogue scale (VAS) for pain, the Subjective Shoulder Value (SSV), the Constant Score (CS), and the 12-Item Short Form Survey (SF-12), supplemented by detailed clinical and radiological evaluations. Results: The mean age of the 29 patients was 75.9 ± 10.4 years. The average follow-up duration was 8.3 ± 2.8 years. The most common indications for primary shoulder arthroplasty were primary osteoarthritis (n = 12, 40%) and fractures (n = 12, 40%). At the first stage, nine cases (30%) showed negative cultures, while C. acnes and S. epidermidis were each identified in eight cases (26.7%). Four shoulders (13.3%) experienced recurrent infections. At the follow-up, the mean abduction was 86 ± 48.1°, the mean forward flexion was 97.8 ± 50.1°, the mean external rotation was 20.5 ± 19.9°, and the internal rotation reached the lumbosacral region. The mean VAS pain score was 1.5 ± 2.1, the mean SSV was 51.8 ± 28.4%, the mean CS was 54.6 ± 21.0, and the mean SF-12 was 81.0 ± 16.0. Conclusions: Two-stage revision arthroplasty for shoulder PJI results in satisfactory subjective and objective outcomes, with a low overall reinfection rate. However, the high rates of mortality and failure to reimplant must be carefully considered when managing expectations in this challenging cohort.

Lyme disease periprosthetic joint infection

Periprosthetic joint infection (PJI) is a devastating complication of total joint surgery. Surgical management of PJI has increased surgical risks and is costly to the healthcare system. This case study presents a unique clinical scenario involving a patient who was diagnosed with Lyme PJI at the total knee arthroplasty site after undergoing surgical management. Lyme PJI is a rare condition, and there is limited guidance on the diagnosis and management of this condition. It should be considered in the differential of certain individuals with appropriate epidemiological risk factors. This report aims to highlight the complexities associated with the diagnosis and management of periprosthetic Lyme infections.

Microbiological Profile of Periprosthetic Joint Infections: A Retrospective Analysis from North India

With the rise in total joint arthroplasties, prosthetic joint infections (PJIs) have become a significant complication, leading to high morbidity. The causative organisms of PJIs vary by region, and the rates of drug-resistant organisms are growing, thus complicating the initial empiric choice of antibiotics. This retrospective study analyzed records of patients with orthopedic implants and intraoperative tissue samples sent for sonication and culture at a tertiary care hospital in India. The most common organism was Staphylococcus aureus (14 out of 86 bacterial isolates, 16.3%), followed by Pseudomonas aeruginosa (12 out of 86, 13.9%), and both Staphylococcus epidermidis and Klebsiella pneumoniae (11 each out of 86, 12.8%). There was a high prevalence of multidrug-resistant organisms, and 35% of the gram-negative organisms were carbapenem resistant. Our study reveals that in our setting, PJIs are chiefly driven by multidrug resistant gram-negative bacteria.

Modifications to the Geriatric Nutritional Risk Index Predicts Complications After Total Joint Arthroplasty

BACKGROUND

Preoperative malnutrition is a known risk factor for postoperative complications following total joint arthroplasty (TJA); however, there is scant literature comparing which nutritional index is best at predicting these outcomes. The purpose of this study was to investigate the utility of the Maastricht index, Onodera's Prognostic Nutritional Index, the Geriatric Nutritional Risk index, and a novel, modified Geriatric Nutritional Risk Index (mGNRI) in predicting periprosthetic joint infection (PJI), wound complications (WCs), readmission, and reoperation rates after TJA.

METHODS

A single-center, retrospective cohort study was performed of patients who underwent primary TJA from January 2016 to December 2021. The 90-day preoperative albumin, prealbumin, and total lymphocyte count were collected. Outcome measures were PJI, WC, readmission, and return to the operating room. Youden's index (YI) and Receiver operator characteristic curves were used to determine optimal cutoff points. Multivariable logistic regression was used to adjust for potential confounders, including body mass index, age, and the Charlson comorbidity index.

RESULTS

There were 1,575 patients included in the study. The mGNRI had the greatest accuracy (area under the curve = 0.633; optimal cutoff point = 92.8) in predicting postoperative adverse outcomes. Complication rates were significantly higher in the low mGNRI group (≤ 92.8). When controlled for body mass index, Charlson comorbidity index, and age, the odds of PJI, WC, readmission, and reoperation in patients who had low mGNRI were 6.61 (P = 0.005), 3.04 (P = 0.021), 2.25 (P = 0.020), and 2.75 (P = 0.024), respectively.

CONCLUSIONS

The mGNRI is an easy-to-calculate nutritional index and an excellent predictor of postoperative complications following TJA. The mGNRI outperformed Geriatric Nutritional Risk index, Maastricht index, and Onodera's Prognostic Nutritional Index in predicting postoperative complications. Our results suggest that patients who fall below the mGNRI threshold of 92.8 should be carefully considered for nutritional optimization prior to TJA.

Miconazole-splitomicin combined β-glucan hydrogel for effective prevention of Candida albicans periprosthetic joint infection

As one of the most common and serious infections caused by Candida albicans (C. albicans), periprosthetic joint infection (PJI) increasingly concerns surgeons and scientists. Generally, biofilms shield C. albicans from antifungal agents and immune clearance and induce drug-resistant strains. Developing novel strategies for PJI to get rid of current drug-resistant problems is highly needed. In our study, splitomicin (SP) can inhibit the mycelium formation of C. albicans and enhance the drug sensitivity of C. albicans to miconazole nitrate (MCZ). The combination of SP and MCZ significantly inhibited the viability, proliferation and adhesion of C. albicans, reduced the yeast to hyphae transition and biofilm formation. When SP and MCZ were coloaded in the β-glucan hydrogel, a viscoelastic solid with porous 3D network, sustained release and erosion properties was obtained. In the in vivo PJI mice model, SP-MCZ-β-glucan hydrogel effectively reduced the colonization and aggregation of C. albicans around the implant, reduced the pathological changes caused by C. albicans in the femur tissue. Therefore, SP-MCZ-β-glucan hydrogel holds a great promise for the management of C. albicans infection around joint prosthesis.