2018 International Consensus Meeting on Musculoskeletal Infection: Research Priorities from the General Assembly Questions

Antibacterial hydrogel coating is associated with lower complication risks after complex high-risk primary and cementless hip revision arthroplasty : a retrospective matched cohort study

Aims

This study aimed to verify the hypothesis that an antibiotic-loaded hydrogel, defensive antimicrobial coating (DAC), reduces overall complication and infection rates when used for high-risk primary and revision total hip arthroplasty (THA).

Methods

This was a retrospective, 1:1 matched cohort study of 238 patients, treated with cementless implants coated with and without DAC. A subgroup analysis was also conducted of patients undergoing second-stage revision THA for periprosthetic joint infection (PJI). Reinfection rates within two years, complications necessitating surgical intervention, and radiological analysis for aseptic loosening were assessed.

Results

Overall, the mean age of the patients was 68.3 years (SD 11.5), with 39 (32.8%) McPherson class A, 64 (53.8%) class B, and 16 (13.4%) class C. Four (3.4%) patients in the DAC group developed complications including one PJI and one delayed wound healing, while 13 (10.9%) patients in the control group developed complications, including five PJIs and three delayed wound healing (p = 0.032). PJI rates (p = 0.136) and delayed wound healing rates (p = 0.337) were not statistically significant. For second-stage revision THA, for PJI there were 86 patients in the DAC group and 45 in the control group. One patient (1.2%) in the DAC group developed complications with no recurrences of infection or delayed wound healing, while ten patients (22.2%) in the control group developed complications including four recurrent PJI and one delayed wound healing (p = 0.003). Recurrent PJI rates were statistically significant (p = 0.005), while delayed wound healing rates were not (p = 0.165). Patients treated with DAC also had lower rates of aseptic loosening (0% compared with 6.7%; p = 0.015). No local or systemic side effects related to the DAC hydrogel coating were observed.

Conclusion

Antibiotic-impregnated hydrogel coatings on cementless implants appear to be associated with decreased complication rates after complex primary or revision THA. For second-stage revision THA for PJI, it is also associated with reduced risk of reinfection and aseptic loosening.

Periprosthetic Joint Infection Occurring Following a Femoral Subcutaneous Cyst: A Rare Complication Post-Total Knee Arthroplasty

Herein, we present a rare case of periprosthetic joint infection (PJI) which was triggered by an infection with a latent subcutaneous cyst on the thigh and occurred in a strange course following total knee arthroplasty (TKA). An 87-year-old female underwent right TKA followed by left TKA 5 months later. Six weeks after left TKA, a painful subcutaneous induration appeared in the left medial thigh. Magnetic resonance imaging revealed a 30∗50-mm multifocal mass. The cystic fluid was brown and cloudy, indicating an infected cyst. Oral antimicrobial therapy was initiated for 7 days. Nine weeks after the left TKA, a left calcaneal fracture occurred. Subsequently, edema of the lower extremities and pain in the left knee gradually developed. Arthrocentesis was performed twice: joint fluid Gram staining and culture examination were negative. However, at 12.5 weeks, an alpha-defensin test of the synovial fluid was positive. Therefore, PJI was diagnosed. DAIR was performed, followed by multiantibiotic therapy. The infection subsided gradually. Edema of the lower limbs was treated with oral diuretics, lymphatic massage, and compression stockings. Consequently, the lower limb edema also improved. In this case, infection of a latent subcutaneous cyst in the thigh occurred and spread around the prosthesis due to leg edema, which was associated with loss of lower limb motion due to a calcaneal fracture. The presence of a potential thigh subcutaneous cyst is a risk factor for PJI. Moreover, lower extremity edema occurs by decreasing lower extremity motion, such as after a calcaneal fracture, and it increases the risk of extending extra-articular infection to the PJI. Potential thigh subcutaneous cysts and lower extremity edema are risk factors for the development of PJI. Orthopedic surgeons need to be aware of these facts during follow-up after TKA.

The application of antibiotic-loaded bone cement in preventing periprosthetic joint infection: an umbrella review

OBJECTIVES

The purpose of this study was to provide thorough, understandable and precise evidence for the clinical use of antibiotic-loaded bone cement (ALBC) in preventing periprosthetic joint infection (PJI).

METHODS

We evaluated the effectiveness of ALBC in preventing PJI by conducting an umbrella review of existing meta-analysis. Four databases, PubMed/MEDLINE, Cochrane Library, Embase and Web of Science, were searched until May 2024. Two reviewers were reviewers for literature screening, and data were extracted independently. AMSTAR 2 guideline and GRADE were also used for quality evaluation. The clinical outcomes were evaluated for effectiveness by several indicators, including surface infection rate (SIR), deep infection rate (DIR), total infection rate (TIR), unadjusted/adjusted all-cause revision rate, and revision rate for PJI.

RESULTS

We synthesized the results of ten meta-analyses. Two meta-analyses had high AMSTAR 2 scores, two had moderate AMSTAR 2 ratings, three had critically low AMSTAR 2 scores, and the remaining meta-analyses had low AMSTAR 2 ratings. In terms of postoperative surgical site infection and revision rate, SIR (OR 1.50, 95% CI 1.14, 1.99, P = 0.004, I2 = 0%), unadjusted all-cause revision rate (RR 1.44, 95% CI 1.08, 1.90, P = 0.011, I2 = 91.8%) and adjusted all-cause revision rate (HR 1.21, 95% CI 1.12, 1.31, P < 0.001, I2 = 0%) in ALBC group were significantly higher than those in non-antibiotic-loaded bone cement (NALBC) group. ALBC group was significantly lower than NALBC group in DIR (OR 0.53, 95% CI 0.39, 0.70, P < 0.0001, I2 = 57%), (RR 0.506, 95% CI 0.341, 0.751, P = 0.001, I2 = 0%) and revision for PJI (RR 0.721, 95% CI 0.628, 0.828, P = 0, I2 = 53%). There was no statistical difference in total infection rate (TIR) between the ALBC group and the NALBC group (OR 0.81, 95% CI 0.51, 1.28, P = 0.37, I2 = 73%).

CONCLUSIONS

On the basis of the results of our analysis, we do not believe that ALBC is more effective than NALBC in preventing PJI after primary total joint arthroplasty (PTJA). No statistically significant difference was found on TIR between the two groups, although it was lower in the ALBC group. In addition, the DIR and revision for PJI are significantly lower in the ALBC group, but the results are of low quality, which calls for high-quality and large-sample studies in the future.

Unconventional Therapies in Periprosthetic Joint Infections: Prevention and Treatment: A Narrative Review

BACKGROUND

as the demand for total joint arthroplasty continues to grow each year, the healthcare burden is expected to increase due to periprosthetic joint infection (PJI). This review article aims to highlight the significance of biofilms in the pathogenesis of PJI and introduce alternative therapies that prevent bacterial adhesion to implants or enhance their eradication when infection occurs.

SEARCH STRATEGY

we conducted a bibliographic search in PubMed using the following MeSH terms as follows: "no antibiotic treatment of PJI", "bacterial biofilm eradication agents", and "unconventional prevention of PJI", among others. Most important results: after an initial analysis of the literature, we selected the most significant topics on novel PJI treatment methods and prevention strategies. A second PubMed search highlighted the following therapeutic modalities: the application of hydrogels on implant surfaces, the use of phage therapy, lysostaphin and antimicrobial peptides, the implementation of two-stage debridement, irrigation, implant retention and antibiotic therapy (DAIR), the intra-articular antibiotic infusion, and the use of methylene blue for biofilm eradication.

CONCLUSIONS

the use of new cement spacers with xylitol, ammonium compounds, or silver nanoparticles is another promising technique to increase the eradication rate in two-stage revision. It is important for professionals to deeply understand the pathogenesis of PJI and the role of biofilms in its development in order to become familiar with these novel techniques that could reduce the burdens on healthcare systems.

The hidden connection between gut microbiota and periprosthetic joint infections: a scoping review

Background: Periprosthetic joint infections (PJIs) pose a significant challenge in orthopedic surgery, and emerging evidence suggests that the gut microbiome may play a crucial role in their development and management. Despite the rarity of these infections, the continuous increase in prosthetic joint arthroplasties has made understanding how to prevent them more pressing. A stronger comprehension of the disruption of the gut microbiome and how this can lead to more of these infections and other pre-surgical risks may be crucial in preventing them. Objective: This article aims to provide a stronger understanding of the topic through the analysis of different pieces of already existing literature to help draw new conclusions and raise potential questions that need answering. Methods: A comprehensive search strategy without filters was employed, and multiple papers were thoroughly analyzed, understood, and compiled into this paper. Conclusions: Despite the limitations of some of the analyzed studies and finite evidence, this paper suggests that there could be a connection between periprosthetic joint infections and a compromised gut microbiome. However, further research is required to draw a definitive conclusion.

A Fused Membrane-Camouflaged Biomimetic Nanosystem for Dual-Targeted Therapy of Septic Arthritis

Due to the inherent aseptic and enclosed characteristics of joint cavity, septic arthritis (SA) almost inevitably leads to intractable infections and rapidly progressing complex pathological environments. Presently, SA faces not only the deficient effectiveness of the gold-standard systemic antibiotic therapy but also the scarcity of effective localized targeted approaches and standardized animal models. Herein, an ingenious multifunctional nanosystem is designed, which involves the methylation of hyaluronic acid (HA), copolymerization with DEGDA, loading with vancomycin (VAN), and then coating with fused macrophage-platelet membrane (denoted as FM@HA@VAN). Upon intra-articular administration, FM@HA@VAN nanoparticles exhibit sustained retention and selectively targeting to infected sites, leveraging macrophage-mediated inflammation homing and platelet-directed bacteria targeting. The acidic microenvironment triggers responsive release of vancomycin, leading to potent bactericidal effects. Subsequently, the exposed HA@VAN nanoparticles are efficiently internalized by activated macrophages, releasing HA to alleviate oxidative stress and achieve chondroprotection by inhibiting pro-inflammatory cytokines, neutralizing ROS and upregulating macrophage M2 polarization. In vivo model and experiments confirm the efficacy of this dual-targeting antibacterial approach, demonstrating its precision in eradicating bacterial infections and alleviating associated pathological processes, including synovial hyperplasia and cartilage erosion. The dual-targeting therapeutic nanosystem, coordinated with fused-membranes, holds promise for enhancing the treatment efficacy of SA.

Piezoelectric Biomaterial with Advanced Design for Tissue Infection Repair

Bacterial infection has become the most dangerous factor in tissue repair, which strongly affects the tissue regeneration efficiency and wellness of patients. Piezoelectric materials exhibit the outstanding advantage of producing electrons without external power supply. The ability of electron enrichment and reactive oxygen species generation through noninvasive stimulations enables piezoelectric materials the potential applications of antibacterial. Many studies have proved the feasibility of piezoelectric materials as a functional addition in antibacterial biomaterial. In fact, numerous piezoelectric materials with ingenious designs are reported to be effective in antibacterial processes. This review summarizes the antibacterial mechanisms of piezoelectric, illuminating their potential in combating bacteria. Recent advancement in the design and construction of piezoelectric biomaterial including defect engineering, heterojunction, synergy with metal and the composite scaffold configuration are thoroughly reviewed. Moreover, the applications and therapeutic effects of piezoelectric materials in common tissues with antibacterial requirements are introduced, such as orthopedics, dental, and wound healing. Finally, the development prospects and points deserving further exploration are listed. This review is expected to provide valuable insight into the relationship between antibacterial processes and piezoelectric materials, further inspiring constructive development in this emerging scientific discipline.

Evaluation of the Use of Preventive Antibiotic Therapy in Patients Undergoing One-Step Prosthetic Revision Surgery with Low Preoperative Infectious Risk

Introduction: The prosthetic knee infection (PKI) rate in most centers ranges from 0.5 to 2% for knee replacements, depending on risk factors. Current PKI definitions may miss the identification of both early and late complications. There is no consensus on preventive or early empiric antibiotic therapy (EEAT) in the one-step exchange strategy for low-risk patients pending microbiology results. The aim of the study was to evaluate the potential role of EEAT in patients with comorbidities in preventing PKI and to evaluate differences in septic failure at 3, 6 and 9 months after prosthetic revision between patients undergoing EEAT and patients not undergoing EEAT. Methods: All adult patients undergoing one-step knee revision surgery at IRCCS Sacro-Cuore Don Calabria Negrar, from January 2018 to February 2021, were retrospectively included in a cohort observational study. Patients on antibiotic therapy before surgery or with preoperative ascertained PKI were excluded. Demographic characteristics, Charlson score, comorbidities, inflammatory markers, microbiological tests, imaging, infectious disease risk score and EEAT data were collected. Any postoperative complication or modification of antibiotic therapy at 14, 30, 90, 180 and 270 days after surgery was collected. Results: A total of 227 patients were included: 114 comorbid low-risk patients received EEAT after surgery, pending microbiological results; while 113 non-comorbid low-risk patients did not receive any antibiotic therapy in the postoperative period. Among the EEAT group, 16 were diagnosed with PKI, compared with 10 in the untreated group. Regarding septic failure during the 9-month follow-up after revision surgery, we registered nine cases in the EEAT arm and four in the untreated arm. In three out of nine cases treated with EEAT who had a post-revision septic failure, the causative microorganism was not successfully empirically targeted by EEAT; in the untreated group, two out of four cases had a post-revision septic failure, despite the targeted treatment of intraoperatively identified causative microorganisms. Conclusions: According to our results, EEAT after revision surgery in patients with comorbidities, who are at higher risk of infection, did not prevent prosthetic knee infections. There was also no evidence of a reduction in subsequent septic failure within nine months of revision surgery between groups. More accurate risk-defining scores are needed to identify patients at risk of PKI complications.

Metal Ion and Antibiotic Co-loaded Nanoparticles for Combating Methicillin-Rresistant Staphylococcus aureus-Induced Osteomyelitis

Methicillin-resistant Staphylococcus aureus (MRSA) causes osteomyelitis (OM), which seriously threatens public health due to its antimicrobial resistance. To increase the sensitivity of antibiotics and eradicate intracellular bacteria, a Zn2+ and vancomycin (Van) codelivered nanotherapeutic (named Man-Zn2+/Van NPs) was fabricated and characterized via mannose (Man) modification. Man-Zn2+/Van NPs exhibit significant inhibitory activity against extra- and intracellular MRSA and obviously decrease the minimum inhibitory concentration of Van. Man-Zn2+/Van NPs can be easily internalized by MRSA-infected macrophages and significantly accumulated in infected bone via Man-mediated targeting. In vivo experiments in a mouse OM model verified that Man-Zn2+/Van NPs significantly reduce the extra- and intracellular MRSA burden, improve gait patterns, increase bone mass, and decrease inflammatory cytokine expression. The antibacterial mechanism of Man-Zn2+/Van NPs includes destruction of the MRSA membrane, degeneration of intracellular proteins and DNA, inhibition of MRSA glycolysis, and intervention in the energy metabolism of bacteria. Overall, this metal-antibiotic nanotherapeutics strategy provides new insight for combating extra- and intracellular infections caused by MRSA-induced OM.

Prosthetic articulating spacers as a preferred option for two-stage revision arthroplasty in chronic periprosthetic joint infection

PURPOSE

The study aimed to compare the infection control rates, mechanical complications, and functional outcomes between prosthetic and cement spacers in two-stage revision arthroplasty for chronic periprosthetic joint infection (PJI).

PATIENTS AND METHODS

Data from patients treated for chronic PJI in our center from 2014 to 2023 were retrospectively collected and the patients were divided into the prosthetic spacer (PS) and cement spacer (CS) groups based on the type of spacer used for the first-stage surgeries. Data on patients' demographics and clinical scores were harvested. Infection control rates and mechanical complications were compared between the two groups by using chi-square tests and log-rank analysis.

RESULTS

The study involved 113 cases, with a mean age of 64 ± 11.45 years (range, 31-88 years), with 48 cases in the PS group, 65 in the CS group, and all patients were followed up for at least 1 year (average 52.68 ± 26.07 months). Five patients in the PS group (10.42%) and six in the CS group (9.23%) developed recurrent infections, with no significant difference found in infection control rates (P = 0.833). The joint function score after the first-stage surgeries was higher in the PS group than in the CS group (P = 0.021). The incidence of mechanical complications, including dislocation, spacer fracture, and periprosthetic fracture, was significantly lower in the PS group than in the CS group (P = 0.024). The proportion of patients who underwent second-stage surgeries was lower in the PS group than in the CS group (58.3% vs 70.77%, P = 0.169).

CONCLUSION

For most patients with chronic PJI, PS can be used as the preferred option for two-stage revision arthroplasty.

Efficacy of pH-Responsive Surface Functionalized Titanium Screws in Treating Implant-associated S. aureus Osteomyelitis with Biofilms Formation

Implant-associated Staphylococcus aureus (S. aureus) osteomyelitis (IASO) leads to high orthopedic implant failure rates due to the formation of Staphylococcal abscess community within the bone marrow and bacterial colonization in the osteocyte lacuno-canalicular network (OLCN). To address this, antimicrobial peptides (HHC36)-loaded titania nanotubes (NTs) are developed on titanium screws (Ti-NTs-P-A), which integrate pH-responsive polymethacrylic acid to control HHC36 release for eradicating bacteria in IASO. Colony-forming unit assay confirmed that Ti-NTs-P-A screws maintained sustainable antibacterial effectiveness, killing over 65% of S. aureus even after multiple bacterial solution replacements. Notably, Ti-NTs-P-A screws exhibit significant pH-responsive HHC36 release behavior and bactericidal activity, consistent with the phenotype of peptides-killed bacteria from scanning electron microscopy. Transcriptome sequencing results reveal that Ti-NTs-P-A screws interfered with ribosome formation and disrupted the arginine biosynthesis, which is crucial for bacterial survival in acidic environments. In the non-infected implant model, the bone-implant contact ratio of the Ti-NTs-P-A screw is 2.3 times that of the clinically used titanium screw. In an IASO model, Ti-NTs-P-A screws effectively eradicated bacteria within the OLCN, achieving an 80% infection control rate and desirable osteointegration. Collectively, Ti-NTs-P-A screws with pH-responsive antibacterial properties exhibit great potential for eradicating bacteria and achieving osseointegration in IASO.

Local antimicrobial delivery systems for prophylaxis and treatment of periprosthetic traumatological infections

Infections associated with implants are the most serious complications in joint replacement surgeries and can jeopardize the functionality of orthopedic implants. Local antimicrobial delivery could enable antibiotics to attain concentrations above the minimum inhibitory concentration (MIC) threshold at the joint replacement site while preventing systemic side effects. Therefore, there is a dire need for the development of improved biomaterial-based delivery systems for local antibiotic administration in prosthetic infections. In this context, this review highlights the latest breakthroughs in the design of biomaterial-based formulations intended for the prophylaxis and treatment of prosthetic infections. Delivery systems for distinct forms of administration (i.e., direct intra-articular administration, loading into bone cements, coating of implant surfaces, or loading into hydrogels) are here comprehensively compiled with a focus on the design of microparticles and nanosystems for local antimicrobial administration and their impact on distinct in vitro and in vivo models of implant infections.

Povidone-iodine and silver nitrate are equally effective in eradicating staphylococcal biofilm grown on a titanium surface: an in-vitro analysis

BACKGROUND

There is no consensus on the irrigation solution and concentration that should be used when performing a debridement, antibiotics, and implant retention (DAIR) surgery.

AIM

To determine the minimum biofilm eradication concentration (MBEC) of five antibacterial solutions and to compare their efficacies in eradicating staphylococcal biofilm embedded on a titanium surface.

METHODS

Meticillin-sensitive Staphylococcus aureus (MSSA) and meticillin-resistant S. aureus (MRSA) ATCC standard strains were grown over porous Ti-6Al-4V acetabular screw-caps. Antibacterial solutions were povidone-iodine, rifampicin, silver nitrate, copper sulphate, and chlorhexidine. MBEC values were calculated for MSSA and MRSA. After 24 h, screw-caps were exposed for 3 min to each solution. Bacterial separation from each specimen was performed with vortex agitation and footprint on agar plate in triplicate. Colony forming units (cfu) were counted pre- and post-agitation, and the delta of cfu/mL was calculated for each solution. A threefold log reduction in cfu was considered a measure of solution efficacy. Comparison between groups was made with Fisher's test.

FINDINGS

MBEC values for MSSA and MRSA, respectively, were as follows: 8000 μg/mL and 16,000 μg/mL for povidone-iodine; 64 μg/mL and 128 μg/mL for rifampicin; 10,000 μg/mL and 5120 μg/mL for silver nitrate; 900 μg/mL and 900 μg/mL for copper sulphate; 16 μg/mL and 32 μg/mL for chlorhexidine. Rifampicin, copper sulphate and chlorhexidine were ineffective against MSSA and MRSA biofilm compared with povidone-iodine (P<0.01) and silver nitrate (P=0.015) that had a delta cfu reduction >8 log. Povidone-iodine and silver nitrate showed negative footprints without visible MSSA (P=0.005) and MRSA (P=0.014).

CONCLUSIONS

Povidone-iodine and silver nitrate were the only irrigating solutions capable of eradicating at least 99.9% of 24-h biofilm.

Comorbidities in Total Hip and Knee Arthroplasty Patients: When Is It Okay to Say No?

Preoperative optimization of modifiable risk factors for total hip and knee arthroplasty remains a foundational cornerstone in reducing postoperative complications and enhancing patient outcomes. With an increasing prevalence of high-risk comorbidities among total joint arthroplasty patients with morbid obesity (body mass index ≥40 kg/m2), uncontrolled diabetes (hemoglobin A1c ≥ 7.5%), and active smoking and tobacco use, many joint arthroplasty surgeons face complex ethical decisions when surgical intervention poses a higher risk for potential harm. Creating definitive numerical cutoffs may lead to access-to-care issues with a difficult balance between helping and harming patients.

Research trends and focus of prosthetic joint infections from 2013 to 2023: bibliometric and visualization studies

Background

Postoperative infections in artificial joints provide considerable difficulties in the field of orthopedics, especially after joint replacement procedures. These infections rank among the most severe postoperative consequences, frequently leading to treatment ineffectiveness and reduced quality of life for surgery patients. Consequently, it is crucial to acquire knowledge about worldwide research trends in this area in order to educate clinical practices and improve therapeutic techniques. This work exploits bibliometric analysis to investigate the present state, developing patterns, and main areas of focus in research on artificial joint infection.

Objective

To analyze the research trends, hotspots, and international collaborations on artificial joint infections worldwide from 2013 to 2023.

Methods

Extractions of raw data were made from the WoSCC (Web of Science Core Collection) database. Detailed information collected includes the quantity of publications, authors, citations, publication year, h-index, references, country/region, journal, and keywords. Analysis of the data was conducted using VOSviewer version 1.6.10.0 and CiteSpace version 6.3.R1.

Results

A total of 1,799 articles published between 2013 and 2023 were included in this analysis, showing a steady increase in publication with the United States leading at 553 articles. Infection rates and topics such as biofilm formation and antimicrobial resistance were highly cited, with Mayo Clinic contributing 65 articles as the most prolific institution.

Conclusion

Research on biofilm infections, antibiotic resistance, and new biomarkers is a key focus, particularly on disrupting biofilms and enhancing diagnostics. There's growing attention in biomarkers like α-defensins and exosomal miRNAs for PJI diagnosis, pointing to new clinical uses. Studies on antimicrobial-coated prosthetics and topical agents are also gaining importance in treatment strategies.

DAIR for periprosthetic joint infections-One week to save the joint?

BACKGROUND

Predicting the success of a Debridement, Antibiotics, and Implant Retention (DAIR) procedure for periprosthetic joint infection (PJI) for hip and knee joint arthroplasty remains a challenge. A failed DAIR might adversely affect the outcome of any future revision surgery for PJI. Hence, the ability to identify and optimize factors predictive of DAIR success would help target the procedure to the appropriate patient cohort and avoid unnecessary surgery for patients where a DAIR is unlikely to eradicate infection.

METHODS

A retrospective review of our prospective Bone Infection Group database was performed to identify all patients who underwent a DAIR of their primary or revision hip or knee arthroplasty. All patients had a confirmed PJI as per MSIS 2013 criteria and an outcome according to the MSIS working group outcome-reporting tool. DAIR surgery was then grouped into groups of "successful" or "unsuccessful" outcomes.

RESULTS

Sixty-four consecutive patients with an acute PJI underwent a DAIR procedure between 2009 and 2020, with 46 procedures performed for knees and 18 for hips. Treatment was successful in 69% (37 knees and 7 hips). The chance of a successful DAIR was significantly greater if performed at or within one week of symptom onset compared to greater than one-week duration (adjusted odds ratio (OR) 0.11; P = 0.027; 95% CI [0.02-0.78])). For DAIR performed at or within one week of symptom onset, the success rate was 93% for knees and 80% for hips. The chance of a successful DAIR however was not influenced by whether the surgeon was an arthroplasty or non-arthroplasty surgeon (OR 0.28; P = 0.13; 95% CI [0.05-1.48])). Isolated Streptococcus infection had a success rate of 100%. Next came Coagulase-negative Staphylococci (71%) and Methicillin-susceptible Staphylococcus Aureus (65%). Polymicrobial infection had the worst outcome, with a success rate of 40%.

CONCLUSION

In our experience, DAIR surgery performed within one week of symptom onset significantly increased the chance of successful infection eradication. Collaborative work is required to ensure arthroplasty patients can access prompt appropriate surgical decision-making as soon as concerns arise, remove barriers to early assessment and minimise delays to surgery.

What Are the Research Highlights of Periprosthetic Joint Infections From the 100 Most Cited Studies?

Background

Periprosthetic joint infections (PJIs) are a serious complication after total joint arthroplasty. Our study aimed to analyze the characteristics and research highlights of the top 100 most cited studies on PJI from an orthopaedic standpoint. Moreover, we sought to assess whether there has been a change in the level of evidence (LOE) throughout time.

Methods

We conducted a search of the PubMed, Embase, and Web of Science databases to identify the top 100 studies primarily focusing on PJI. Study characteristics assessed included publication year, LOE, journal of publication, and type of study. Research highlights of the included studies were classified into 6 sections. Linear regression was employed to assess correlation between LOE and publication year.

Results

The aggregated citation count of all studies was 19,558 and the median citation number was 129.5. While cohort studies were the most prevalent, articles focusing on analysis of costs associated with PJI care or PJI definition garnered the highest yearly citation counts. The bulk of included studies were concentrated in 3 orthopaedic journals and published in the 2010s. The majority of studies had a LOE II (30%) or III (34%). On regression analysis, LOE was not correlated with publication year (Pearson's r = 0.013, P = .61).

Conclusions

The most cited PJI articles assessed the definition of PJI and PJI cost. Despite growing interest in PJI, the majority of studies had LOE II or III, highlighting the difficulty of conducting prospective randomized controlled trials in PJI patients.

Level of evidence

IV.

Periprosthetic joint infections in patients with rheumatoid arthritis are associated with higher complication and mortality rates

INTRODUCTION

Periprosthetic joint infection (PJI) remains the most devasting complication after total joint arthroplasty (TJA). There has been a significant focus on this topic in recently-published medical literature. However, relatively little has been published about PJI in patients with rheumatoid arthritis (RA), which are often physiologically frail and immunocompromised. A better understanding of PJI in this patient population is therefore crucial. The main aims of this paper are to (1) report complication and mortality rates in a cohort of PJI-RA patients; and (2) clinically characterize them.

METHODS

Medical and surgical records of all RA PJI patients treated surgically from 2003 to 2020 were retrospectively reviewed. Medical history, physical examination, reactive protein (CRP) level, procalcitonin, white blood cell (WBC) count, joint aspiration results, and cultures were used to determine PJI.

RESULTS

54PJIs, 49 of them chronic, were treated in 53RA patients. Mean patient age was 65 yrs. (range = 32-88); 33females and 20 males (one bilateral hip). The overall mortality rate was 18.9%(n = 10), with five deaths directly attributed to PJI. Staphylococci accounted for 34 infections (63%), while 11(20.4%) had multiorganism infections and six culture-negative PJI. At the end of treatment 79.6%(n = 43) still had an implanted TJR, 7.4% (n = 4) had spacers, 5.6%(n = 3) had undergone resection arthroplasty, 3.7%(n = 2) arthrodesis, and one each amputation and exarticulation.

CONCLUSIONS

Mortality and specially complication rates were (are) high in this RA patients group presenting PJI. Delays to diagnosis and treatment may explain some of these poor outcomes.

LEVEL OF EVIDENCE

A cohort level III retrospective study.

Periprosthetic joint infections - a scoping review

Periprosthetic joint infections (PJIs) are dramatic complications after primary total joint arthroplasty. Despite increasing research in this field, the diagnosis, classification, and management of PJI remain a challenge. This is mainly due to the heterogenous clinical presentation of PJI in clinical routine and patient-related factors as secondary diagnosis and periprosthetic tissue condition. The early detection of PJI is essential for adequate treatment. However, there is no definition for PJI with 100 % sensitivity or a negative predictive value. This can potentially lead to a delayed or missed diagnosis of PJI. Furthermore, the surgical and antibiotic treatment is among the most discussed topics in PJI literature. There is no international consensus on the treatment of different PJI entities. Concludingly many aspects of PJI diagnostics and treatment remain controversially discussed and current studies are only comparable to a limited extent due to study heterogeneity and limited comparability.

Latent infections in conversion total hip arthroplasty following internal fixation of femoral neck fractures: a systematic review and meta-analysis of diagnostic methods

BACKGROUND

Accurate diagnosis of latent infections prior to conversion total hip arthroplasty (THA) following internal fixation of femoral neck fractures is crucial for successful surgical outcomes. This systematic review aimed to provide a comprehensive evaluation of the current literature regarding the diagnosis of latent infections before conversion THA.

METHODS

Systematic search of PubMed, EMBASE, and Cochrane (CENTRAL) databases was conducted, and the diagnostic accuracy of various markers and techniques was assessed. The quality of the included studies was evaluated using the QUADAS-2 instrument.

RESULTS

Five studies comprising 661 patients were included in the review. Pooled analysis using C-reactive protein (CRP) as a diagnostic marker resulted in a sensitivity and specificity of 72% and 76%, respectively, while using erythrocyte sedimentation rate (ESR) yielded a sensitivity and specificity of 75% and 78%, respectively. Fibrinogen and platelet count showed lower sensitivity and specificity compared to CRP and ESR. The best combined markers were CRP and serum platelet count, with a sensitivity of 76% and specificity of 86% based on one study.

CONCLUSION

Our review underscored the limitations and inconsistencies present in current diagnostic methods for latent infections in conversion surgery. Future research needs to focus on standardizing threshold values, exploring the potential of synovial fluid analysis, imaging techniques, and molecular methods, as well as developing tailored diagnostic algorithms.

PROSPERO

CRD42023394757.

Vaccines: Do they have a role in orthopedic trauma?

Although vaccines have been hailed as one of the greatest advances in medicine based on their unparalleled cost-effectiveness in eradicating life-threatening infectious diseases, their role in orthopedic trauma-related infections is unclear. This is largely because vaccines are primarily made against pathogens that cause communicable diseases rather than opportunistic infections secondary to trauma, and most successful vaccines are against viruses rather than biofilm forming bacteria. Nonetheless, the tremendous costs to patients and healthcare systems warrant orthopedic trauma vaccine research, which has been a focal topic in recent international consensus meetings on musculoskeletal infection. This subject was also covered at the 2023 Osteosynthesis and Trauma Care Foundation (OTCF) meeting in Rome, Italy, and the purpose of this supplement article is to (1) highlight the osteoimmunology, animal models, translational research and clinical pilots that were discussed, (2) the proposed future directions that could lead to diagnostics and prognostics that are critically needed for evidence-based decision making, and (3) vaccines and passive-immunization strategies that could potentially be utilized to treat patients with orthopedic infections.

Treatment experience with continuous local antibiotic perfusion for periprosthetic joint infection

BACKGROUND

Antibiotic concentrations 100-1000 times higher than the minimum inhibitory concentration are necessary for eradicating biofilms in periprosthetic joint infections (PJI). Achieving this with intravenous antibiotics is challenging, but continuous local antibiotic perfusion (CLAP) can increase the local concentration of antibiotics. Although there are several reports on CLAP therapy in the fracture-related infection, there are only few reports on its application in PJI. Here, we report our experience with CLAP therapy for PJI.

METHODS

Eight patients with PJI (two males and six females, with mean age of 73.5 years [±11.6]) were treated at our department, and their clinical characteristics were analyzed. The parameters considered were the classification of PJI, surgical procedure, duration of CLAP, duration of transvenous antibiotic administration, time of CRP-negative status, whether the infection resolved or recurred, and whether there were complications due to CLAP.

RESULTS

Initial surgery included total knee arthroplasty in five cases, unicompartmental knee arthroplasty in one case, and total hip arthroplasty in two cases. There were four cases of early postoperative infection, two of acute delayed infection, and two of chronic delayed infection. The surgical procedures performed were two-stage revision for two patients, and debridement, antibiotics, and implant retention (DAIR) for the other six. The mean durations of CLAP and transvenous antibiotic administration were 8.5 (±2.4) and 22.4 days (±13.7), respectively, and the mean time to CRP-negative status was 23.3 days (±10.7). All eight patients successfully resolved without additional irrigation or debridement, and no recurrence was observed at the last follow-up after discontinuation of oral antibiotics. No systemic side effects of gentamicin or other complications associated with CLAP were observed.

CONCLUSION

All patients achieved infection resolution with the combined use of CLAP. This suggests that CLAP is a useful treatment option for PJI.

Recent Advances in Antibacterial Strategies Based on TiO2 Biomimetic Micro/Nano-Structured Surfaces Fabricated Using the Hydrothermal Method

Ti and its alloys, widely utilized in orthopedic and dental implants, inherently lack antibacterial properties, posing significant infection risks, especially in the context of growing antibiotic resistance. This review critically evaluates non-antibiotic antibacterial strategies, with a particular focus on surface modifications and micro/nano-structured surfaces. Micro/nano-structured surfaces, inspired by natural topographies, utilize physical mechanisms to eradicate bacteria. Despite their potential, the antibacterial efficacy of these surfaces remains insufficient for clinical application. Titanium dioxide (TiO2), known for its excellent photocatalytic antibacterial activity and biocompatibility, is emerging as an ideal candidate for enhancing micro/nano-structured surfaces. By combining the photocatalytic antibacterial effects of TiO2 with the mechanical bactericidal properties of micro/nano-structured surfaces, superior antibacterial performance can be achieved. The hydrothermal method is frequently employed to fabricate TiO2 micro/nano-structured surfaces, and this area of research continues to thrive, particularly in the development of antibacterial strategies. With demonstrated efficacy, combined antibacterial strategies based on TiO2 micro/nano-structured surfaces have become a prominent focus in current research. Consequently, the integration of physical stimulation and chemical release mechanisms may represent the future direction for TiO2 micro/nano-structured surfaces. This review aims to advance the study of TiO2 micro/nano-structured surfaces in antibacterial applications and to inspire more effective non-antibiotic antibacterial solutions.

The effect of prebiotic fibre on the gut microbiome and surgical outcomes in patients with prosthetic joint infection (PENGUIN) - study protocol for a randomised, double-blind, placebo-controlled trial (ACTRN12623001273673)

BACKGROUND

Prosthetic Joint Infection (PJI) is the most devastating complication of arthroplasty surgery and affects 1-5% of patients. Despite strict adherence to aseptic protocols and preventive measures, infection is the most common reason for revision arthroplasty, and the incidence is increasing. Treatment of PJI is challenging and often requires repeated major surgeries with sequentially poor results. The continued occurrence of PJI, and persistence after treatment, brings into question the current treatment paradigm. Preclinical evidence suggests a link between altered gut health and the risk of PJI in arthroplasty patients. Resistant starches helps to restore gut physiology by enhancing the beneficial microbiome and producing short-chain fatty acids, which have several health-conferring properties. The primary aim of this study is to investigate the effect of a commercially available prebiotic fibre formulation on the gut microbiome in PJI patients planned for a two-stage revision surgery.

METHODS

A double-blind placebo-controlled trial will assess the effect of 8-week supplementation of a commercially available prebiotic supplement in patients presenting with first-time PJI undergoing two-stage revision surgery. The supplementation phase will start after the first stage revision, and 80 patients will be randomised to receive either a test product (34 g of resistant starch) or a placebo (custard powder) daily for eight weeks. Stool and blood specimens will be collected at baseline, four weeks and eight weeks after the first-stage surgery and once at second-stage surgery. Gut microbiome profile, inflammatory cytokines and gut permeability biomarkers will be measured. Tissue specimens will be collected intra-operatively during first and second-stage surgeries. Baseline dietary patterns and gut symptoms will be recorded using validated questionnaires. Treatment outcomes will be reported for both cohorts using the Delphi criterion at one and two years after second-stage surgery.

DISCUSSION

This will be the first study to investigate the relationship between gut health optimisation and preventing PJI recurrence in arthroplasty patients. If supplementation with resistant starch improves gut health and reduces systemic inflammation, optimising the gut microbiome will be a recommended preoperative management strategy for arthroplasty patients.

TRIAL REGISTRATION NO

ACTRN12623001273673.

Initial therapeutic evidence of a borosilicate bioactive glass (BSG) and Fe3O4 magnetic nanoparticle scaffold on implant-associated Staphylococcal aureus bone infection

Implant-associated Staphylococcus aureus (S. aureus) osteomyelitis is a severe challenge in orthopedics. While antibiotic-loaded bone cement is a standardized therapeutic approach for S. aureus osteomyelitis, it falls short in eradicating Staphylococcus abscess communities (SACs) and bacteria within osteocyte-lacuna canalicular network (OLCN) and repairing bone defects. To address limitations, we developed a borosilicate bioactive glass (BSG) combined with ferroferric oxide (Fe3O4) magnetic scaffold to enhance antibacterial efficacy and bone repair capabilities. We conducted comprehensive assessments of the osteoinductive, immunomodulatory, antibacterial properties, and thermal response of this scaffold, with or without an alternating magnetic field (AMF). Utilizing a well-established implant-related S. aureus tibial infection rabbit model, we evaluated its antibacterial performance in vivo. RNA transcriptome sequencing demonstrated that BSG + 5%Fe3O4 enhanced the immune response to bacteria and promoted osteogenic differentiation and mineralization of MSCs. Notably, BSG + 5%Fe3O4 upregulated gene expression of NOD-like receptor and TNF pathway in MSCs, alongside increased the expression of osteogenic factors (RUNX2, ALP and OCN) in vitro. Flow cytometry on macrophage exhibited a polarization effect towards M2, accompanied by upregulation of anti-inflammatory genes (TGF-β1 and IL-1Ra) and downregulation of pro-inflammatory genes (IL-6 and IL-1β) among macrophages. In vivo CT imaging revealed the absence of osteolysis and periosteal response in rabbits treated with BSG + 5%Fe3O4 + AMF at 42 days. Histological analysis indicated complete controls of SACs and bacteria within OLCN by day 42, along with new bone formation, signifying effective control of S. aureus osteomyelitis. Further investigations will focus on the in vivo biosafety and biological mechanism of this scaffold within infectious microenvironment.

Bead-beating assay during synovial fluid DNA extraction improves real-time PCR accuracy for periprosthetic joint infection

Polymerase chain reaction (PCR)-based genetic diagnosis is a rapid and sensitive method to diagnose periprosthetic joint infection (PJI). DNA extraction using bead beating is an effective method for collecting bacterial genes in Gram-positive bacteria. We compared the detection accuracy between the conventional and bead-beating DNA extraction assay. The detection rate improved from 86.7% using the conventional method to 95.6% using the bead-beating. Our results suggest that bead-beating during DNA extraction can improve the accuracy of PCR-based genetic diagnosis of PJI.

Causes of Revision of Total Knee Arthroplasties in a Tertiary Hospital in Brazil

Objective  To identify the causes of revision of total knee arthroplasty in a referral center in Brazil. Methods  This is a case series, with 80 patients undergoing revision surgery for total knee arthroplasty (RTKA) at a referral center for knee surgery, between August 2019 and November 2021, with a mean age of 69.6 years. Of these patients, 60.23% were female and 39.77% were male. The average body mass index (BMI) was 30.23 kg/m 2 . The causes of TKA failure were defined as: periprosthetic infection according to the 2018 International Consensus Meeting criteria, ligament instability, range of motion limitation, periprosthetic fracture, malalignment, aseptic loosening, pain due to non-replacement of the patellar cartilage, polyethylene wear, fracture of implants, insufficiency of the extensor mechanism. Results  Periprosthetic joint infection (PJI) was the main cause of revision total knee arthroplasty (TKA), corresponding to 47.73% of cases. Aseptic loosening of one or more components represented the second most frequent reason for TKA failure, accounting for 35.23% of revisions. Range of motion limitation represented the third most frequent cause, accounting for 5.68% of surgeries. Instability was the fourth most frequent reason for RTKA, occurring in 4.55% of patients. The other causes of revision were: periprosthetic fracture (3.41%), failure due to rupture of the extensor mechanism (2.27%), and pain attributed to non-replacement of the patellar cartilage (1.14%). Conclusions  Periprosthetic joint infection was the most frequent cause of TKA revision in our series. Other reasons for TKA failures were, in descending order: aseptic loosening, limited range of motion, and instability.

Eradication of Staphylococcus aureus in Implant-Associated Osteomyelitis by an Injectable In Situ-Forming Depot Antibiotics Delivery System

BACKGROUND

Bone infections with Staphylococcus aureus are notoriously difficult to treat and have high recurrence rates. Local antibiotic delivery systems hold the potential to achieve high in situ antibiotic concentrations, which are otherwise challenging to achieve via systemic administration. Existing solutions have been shown to confer suboptimal drug release and distribution. Here we present and evaluate an injectable in situ-forming depot system termed CarboCell. The CarboCell technology provides sustained and tuneable release of local high-dose antibiotics.

METHODS

CarboCell formulations of levofloxacin or clindamycin with or without antimicrobial adjuvants cis-2-decenoic acid or cis-11-methyl-2-dodecenoic acid were tested in experimental rodent and porcine implant-associated osteomyelitis models. In the porcine models, debridement and treatment with CarboCell-formulated antibiotics was carried out without systemic antibiotic administration. The bacterial burden was determined by quantitative bacteriology.

RESULTS

CarboCell formulations eliminated S. aureus in infected implant rat models. In the translational implant-associated pig model, surgical debridement and injection of clindamycin-releasing CarboCell formulations resulted in pathogen-free bone tissues and implants in 9 of 12 and full eradication in 5 of 12 pigs.

CONCLUSIONS

Sustained release of antimicrobial agents mediated by the CarboCell technology demonstrated promising therapeutic efficacy in challenging translational models and may be beneficial in combination with the current standard of care.

[Translated article] Total hip arthroplasty with second generation dual mobility system as a treatment for primary coxarthrosis, medium-term results

INTRODUCTION

Osteoarthritis is a disabling pathology characterised by joint pain and stiffness. A prevalence of coxarthrosis of 7.4% is reported in our country. Total hip joint replacement is indicated in advanced stages, a procedure that is not free of complications, the most frequent being prosthetic dislocation, which can be prevented with dual mobility systems. The following study aims to determine the rate of complications and clinical outcomes in dual mobility systems in primary coxarthrosis.

MATERIALS AND METHODS

A retrospective study included 120 cases in 114 patients diagnosed with grade III coxarthrosis, mean age was 62.43 years, with a mean follow-up of 4.5 years. Joint replacement was performed by Hardinge approach. All cases were assessed clinically using the Harris Hip Score (HHS) and radiologically to demonstrate mid-term results.

RESULTS

The preoperative value on the HHS scale had a mean of 56.45, postoperative at one month 74.23; 6 months 85.40; 1 year 94.01 and at 5 years 94.84 points, representing a functional improvement of 17.78 postoperative month; 28.95 at 6 months postoperative; 37.56 at one year postoperative and 38.39 points at 5 years postoperative. A complication rate of 3.44%; 0.86% of complications were associated with the prosthetic components.

CONCLUSION

The dual mobility system should be considered as a therapeutic option in primary hip joint replacement due to excellent functional results and low complication rates.

EVIDENCE LEVEL

IV. Retrospective observational case series study.

Total hip arthroplasty with second generation dual mobility system as a treatment for primary coxarthrosis, medium-term results

INTRODUCTION

Osteoarthritis is a disabling pathology characterized by joint pain and stiffness. A prevalence of coxarthrosis of 7.4% is reported in our country. Total hip joint replacement is indicated in advanced stages, a procedure that is not free of complications, the most frequent being prosthetic dislocation, which can be prevented with dual mobility systems. The following study aims to determine the rate of complications and clinical outcomes in dual mobility systems in primary coxarthrosis.

MATERIALS AND METHODS

A retrospective study included 120 cases in 114 patients diagnosed with grade III coxarthrosis, mean age was 62.43 years, with a mean follow-up of 4.5 years. Joint replacement was performed by Hardinge approach. All cases were assessed clinically using the Harris Hip Score (HHS) and radiologically to demonstrate mid-term results.

RESULTS

The preoperative value on the HHS scale had a mean of 56.45, postoperative at one month 74.23; 6 months 85.40; 1 year 94.01 and at 5 years 94.84 points, representing a functional improvement of 17.78 postoperative month; 28.95 at 6 months postoperative; 37.56 at one year postoperative and 38.39 points at 5 years postoperative. A complication rate of 3.44%; 0.86% of complications were associated with the prosthetic components.

CONCLUSION

The dual mobility system should be considered as a therapeutic option in primary hip joint replacement due to excellent functional results and low complication rates.

EVIDENCE LEVEL

IV. Retrospective observational case series study.

Mechanobiology of bacterial biofilms: Implications for orthopedic infection

Postoperative bacterial infections are prevalent complications in both human and veterinary orthopedic surgery, particularly when a biofilm develops. These infections often result in delayed healing, early revision, permanent functional loss, and, in severe cases, amputation. The diagnosis and treatment pose significant challenges, and bacterial biofilm further amplifies the therapeutic difficulty as it confers protection against the host immune system and against antibiotics which are usually administered as a first-line therapeutic option. However, the inappropriate use of antibiotics has led to the emergence of numerous multidrug-resistant organisms, which largely compromise the already imperfect treatment efficiency. In this context, the study of bacterial biofilm formation allows to better target antibiotic use and to evaluate alternative therapeutic strategies. Exploration of the roles played by mechanical factors on biofilm development is of particular interest, especially because cartilage and bone tissues are reactive environments that are subjected to mechanical load. This review delves into the current landscape of biofilm mechanobiology, exploring the role of mechanical factors on biofilm development through a multiscale prism starting from bacterial microscopic scale to reach biofilm mesoscopic size and finally the macroscopic scale of the fracture site or bone-implant interface.

Role of Preoperative Intra-Articular Corticosteroid Injections on Periprosthetic Joint Infection in Total Hip Arthroplasty and Its Association With Preoperative Timing: A Single-Center Series of 5,909 Hips

BACKGROUND

Preoperative intra-articular corticosteroid injections to the hip joint increase the risk of periprosthetic joint infection (PJI) during primary total hip arthroplasty (THA). This study aimed to determine the relationship between preoperative timing of intra-articular corticosteroid injections and PJI risk following THA using data from a single-center hospital.

METHODS

This single-center, retrospective cohort study included patients who underwent a THA between 2014 and 2020. Medical records were checked for intra-articular corticosteroid injections and PJI within 1 year of surgery. Patients were categorized into groups based on whether they received "no injection" or "injection 0 to 3 months," "3 to 6 months," and "> 6 months prior to THA." Hazard ratios (HRs) for these groups were calculated using multivariate Cox regression analysis, correcting for potential confounders, and presented with 95% confidence intervals [95% CIs].

RESULTS

In total, 4,507 patients (5,909 THAs) were identified. A total of 1,581 patients (27%) received an injection prior to THA. Without considering the timing factor, no increased risk for PJI following an intra-articular injection was noted (P = .19). Comparing the specified groups using multivariate analysis, corticosteroid injection within 3 months of THA showed an increased risk of PJI (HR 2.63, 95% CI 1.18 to 5.87, P = .018), but this effect was not observed for the "injection 3 to 6 months" group (HR 1.51, 95% CI 0.74 to 3.08, P = .264).

CONCLUSIONS

Corticosteroid injections administered up to 3 months prior to THA increased the risk of PJI within 1 year after THA, with an HR of 2.63; however, injections between 3 and 6 months before surgery did not have a significantly higher infection rate.

Integrative gene expression analysis and animal model reveal immune- and autophagy-related biomarkers in osteomyelitis

BACKGROUND

Osteomyelitis (OM) is recognized as a significant challenge in orthopedics due to its complex immune and inflammatory responses. The prognosis heavily depends on timely diagnosis, accurate classification, and assessment of severity. Thus, the identification of diagnostic and classification-related genes from an immunological standpoint is crucial for the early detection and tailored treatment of OM.

METHODS

Transcriptomic data for OM was sourced from the Gene Expression Omnibus (GEO) database, leading to the identification of autophagy- and immune-related differentially expressed genes (AIR-DEGs) through differential expression analysis. Diagnostic and classification models were subsequently developed. The CIBERSORT algorithm was utilized to examine immune cell infiltration in OM, and the relationship between OM clusters and various immune cells was explored. Key AIR-DEGs were further validated through the creation of OM animal models.

RESULTS

Analysis of the transcriptomic data revealed three AIR-DEGs that played a significant role in immune responses and pathways. Nomogram and receiver operating characteristic curve analyses were performed, demonstrating excellent diagnostic capability for differentiating between OM patients and healthy individuals, with an area under the curve of 0.814. An unsupervised clustering analysis discerned two unique patterns of autophagy- and immune-related genes, as well as gene patterns. Further exploration into immune infiltration exhibited notable variances across different subtypes, especially between OM cluster 1 and gene cluster A, highlighting their potential role in mitigating inflammatory responses by regulating immune activities. Moreover, the mRNA and protein expression levels of three AIR-DEGs in the animal model were aligned with those in the training and validation data sets.

CONCLUSIONS

From an immunological perspective, a diagnostic model was successfully developed, and two distinct clustering patterns were identified. These contributions offer a significant resource for the early detection and personalized immunotherapy of patients with OM.

A semi-automated cell tracking protocol for quantitative analyses of neutrophil swarming to sterile and S. aureus contaminated bone implants in a mouse femur model

Implant-associated osteomyelitis remains a major orthopaedic problem. As neutrophil swarming to the surgical site is a critical host response to prevent infection, visualization and quantification of this dynamic behavior at the native microenvironment of infection will elucidate previously unrecognized mechanisms central to understanding the host response. We recently developed longitudinal intravital imaging of the bone marrow (LIMB) to visualize host cells and fluorescent S. aureus on a contaminated transfemoral implant in live mice, which allows for direct visualization of bacteria colonization of the implant and host cellular responses using two-photon laser scanning microscopy. To the end of rigorous and reproducible quantitative outcomes of neutrophil swarming kinetics in this model, we developed a protocol for robust segmentation, tracking, and quantifications of neutrophil dynamics adapted from Trainable Weka Segmentation and TrackMate, two readily available Fiji/ImageJ plugins. In this work, Catchup mice with tdTomato expressing neutrophils received a transfemoral pin with or without ECFP/EGFP-expressing USA300 methicillin-resistant Staphylococcus aureus (MRSA) to obtain 30-minute LIMB videos at 2-, 4-, and 6-hours post-implantation. The developed semi-automated neutrophil tracking protocol was executed independently by two users to quantify the distance, displacement, speed, velocity, and directionality of the target cells. The results revealed high inter-user reliability for all outcomes (ICC > 0.96; p > 0.05). Consistent with the established paradigm on increased neutrophil swarming during active infection, the results also demonstrated increased neutrophil speed and velocity at all measured time points, and increased displacement at later time points (6 hours) in infected versus uninfected mice (p < 0.05). Neutrophils and bacteria also exhibit directionality during migration in the infected mice. The semi-automated cell tracking protocol provides a streamlined approach to robustly identify and track individual cells across diverse experimental settings and eliminates inter-observer variability.

Prospects and challenges for the application of tissue engineering technologies in the treatment of bone infections

Osteomyelitis is a devastating disease caused by microbial infection in deep bone tissue. Its high recurrence rate and impaired restoration of bone deficiencies are major challenges in treatment. Microbes have evolved numerous mechanisms to effectively evade host intrinsic and adaptive immune attacks to persistently localize in the host, such as drug-resistant bacteria, biofilms, persister cells, intracellular bacteria, and small colony variants (SCVs). Moreover, microbial-mediated dysregulation of the bone immune microenvironment impedes the bone regeneration process, leading to impaired bone defect repair. Despite advances in surgical strategies and drug applications for the treatment of bone infections within the last decade, challenges remain in clinical management. The development and application of tissue engineering materials have provided new strategies for the treatment of bone infections, but a comprehensive review of their research progress is lacking. This review discusses the critical pathogenic mechanisms of microbes in the skeletal system and their immunomodulatory effects on bone regeneration, and highlights the prospects and challenges for the application of tissue engineering technologies in the treatment of bone infections. It will inform the development and translation of antimicrobial and bone repair tissue engineering materials for the management of bone infections.

An Advanced Human Bone Tissue Culture Model for the Assessment of Implant Osteointegration In Vitro

In the field of biomaterials for prosthetic reconstructive surgery, there is the lack of advanced innovative methods to investigate the potentialities of smart biomaterials before in vivo tests. Despite the complex osteointegration process being difficult to recreate in vitro, this study proposes an advanced in vitro tissue culture model of osteointegration using human bone. Cubic samples of trabecular bone were harvested, as waste material, from hip arthroplasty; inner cylindrical defects were created and assigned to the following groups: (1) empty defects (CTRneg); (2) defects implanted with a cytotoxic copper pin (CTRpos); (3) defects implanted with standard titanium pins (Ti). Tissues were dynamically cultured in mini rotating bioreactors and assessed weekly for viability and sterility. After 8 weeks, immunoenzymatic, microtomographic, histological, and histomorphometric analyses were performed. The model was able to simulate the effects of implantation of the materials, showing a drop in viability in CTR+, while Ti appears to have a trophic effect on bone. MicroCT and a histological analysis supported the results, with signs of matrix and bone deposition at the Ti implant site. Data suggest the reliability of the tested model in recreating the osteointegration process in vitro with the aim of reducing and refining in vivo preclinical models.

Antibiotic-Loaded Ultrahigh Molecular Weight Polyethylenes

The occurrence of periprosthetic joint infections (PJI) after total joint replacement constitutes a great burden for the patients and the healthcare system. Antibiotic-loaded polymethylmethacrylate (PMMA) bone cement is often used in temporary spacers during antibiotic treatment. PMMA is not a load-bearing solution and needs to be replaced by a functional implant. Elution from the ultrahigh molecular weight polyethylene (UHMWPE) bearing surface for drug delivery can combine functionality with the release of clinically relevant doses of antibiotics. In this study, the feasibility of incorporating a range of antibiotics into UHMWPE is investigated. Drug stability is assessed by thermo-gravimetric analysis and nuclear magnetic resonance spectroscopy. Drug-loaded UHMWPEs are prepared by compression molding, using eight antibiotics at different loading. The predicted intra-articular concentrations of drugs eluted from UHMWPE are above minimum inhibitory concentration for at least 3 weeks against Staphylococci, which are the major causative bacteria for PJI. The antibacterial efficacy is confirmed for samples covering 2% of a representative knee implant in vitro over 72 h, showing that a small fraction of the implant surface loaded with antibiotics may be sufficient against Staphylococci.

International Delphi Study on Wound Closure and Dressing Management in Joint Arthroplasty: Part 1: Total Knee Arthroplasty

BACKGROUND

The purpose of this modified Delphi study was to obtain consensus on wound closure and dressing management in total knee arthroplasty (TKA).

METHODS

The Delphi panel included 20 orthopaedic surgeons from Europe and North America. There were 26 statements identified using a targeted literature review. Consensus was developed for the statements with up to three rounds of anonymous voting per topic. Panelists ranked their agreement with each statement on a five-point Likert scale. An a priori threshold of ≥ 75% was required for consensus.

RESULTS

All 26 statements achieved consensus after three rounds of anonymous voting. Wound closure-related interventions that were recommended for use in TKA included: 1) closing in semi-flexion versus extension (superior range of motion); 2) using aspirin for venous thromboembolism prophylaxis over other agents (reduces wound complications); 3) barbed sutures over non-barbed sutures (lower wound complications, better cosmetic appearances, shorter closing times, and overall cost savings); 4) mesh-adhesives over other skin closure methods (lower wound complications, higher patient satisfaction scores, lower rates of readmission); 5) silver-impregnated dressings over standard dressings (lower wound complications, decreased infections, fewer dressing changes); 6) in high-risk patients, negative pressure wound therapy over other dressings (lower wound complications, decreased reoperations, fewer dressing changes); and 7) using triclosan-coated over non-antimicrobial-coated sutures (lower risks of surgical site infection).

CONCLUSIONS

Using a modified Delphi approach, the panel achieved consensus on 26 statements pertaining to wound closure and dressing management in TKA. This study forms the basis for identifying critical evidence supported by clinical practice for wound management to help reduce variability, advance standardization, and ultimately improve outcomes during TKA. The results presented here can serve as the foundation for knowledge, education, and improved clinical outcomes for surgeons performing TKAs.

BENEFITS OF A CLINICAL PATHWAY IN TOTAL KNEE ARTHROPLASTY

Objective

Demonstrate whether a multiprofessional Clinical Pathway Program in Total Knee Arthroplasty (CPPA) contributesto optimizing hospital care.

Method

Retrospective study of medical data of care indicators in 310 patients divided into two groups: A- who underwent arthroplasty in the last biennium before the introduction of the CPPA (n=144) and group B- who underwent TKA in the biennium after the introduction of the CPPA (n=166).

Results

Postoperative showed a significant difference in favor of group B over group A for hospitalization time in days 4.33 ± 2.79 and 5.4 ± 1.67 (p<0.001), time of prophylactic antibiotic in hours 28.13 ± 33.77 and 81.49 ± 40.91 (p<0.001), referral to the intensive care unit 40.9% and 73.4% (p<0.001), initiation of thromboprophylaxis within 24 hours 97.9% and 82.5% (p<0.001), use of elastic stockings and/or intermittent compression prescribed for thromboprophylaxis 89.5% and 31.2% (p<0.001), initiation of rehabilitation within 24 hours 90.1% and 66.1% (p<0.001), readmissions within 30 days 4.1% and 3% (p = 0.76), readmissions 90 days 2.7% and 6.6% (p = 0.183), transfusions 5.5% and 15.2% (p = 0.033).

Conclusion

The implementation of a multiprofessional CPPA contributed to the implementation of care protocols, favoring greater patient safety. Level of Evidence III; Retrospective Comparative Study.

The 2023 Orthopaedic Research Society's International Consensus Meeting on musculoskeletal infection: Summary from the host immunity section

Musculoskeletal infections (MSKI), which are a major problem in orthopedics, occur when the pathogen eludes or overwhelms the host immune system. While effective vaccines and immunotherapies to prevent and treat MSKI should be possible, fundamental knowledge gaps in our understanding of protective, nonprotective, and pathogenic host immunity are prohibitive. We also lack critical knowledge of how host immunity is affected by the microbiome, implants, prior infection, nutrition, antibiotics, and concomitant therapies, autoimmunity, and other comorbidities. To define our current knowledge of these critical topics, a Host Immunity Section of the 2023 Orthopaedic Research Society MSKI International Consensus Meeting (ICM) proposed 78 questions. Systematic reviews were performed on 15 of these questions, upon which recommendations with level of evidence were voted on by the 72 ICM delegates, and another 12 questions were voted on with a recommendation of "Unknown" without systematic reviews. Two questions were transferred to another ICM Section, and the other 45 were tabled for future consideration due to limitations of available human resources. Here we report the results of the voting with internet access to the questions, recommendations, and rationale from the systematic reviews. Eighteen questions received a consensus vote of ≥90%, while nine recommendations failed to achieve this threshold. Commentary on why consensus was not achieved on these questions and potential ways forward are provided to stimulate specific funding mechanisms and research on these critical MSKI host defense questions.

The 2023 Orthopaedic Research Society International Consensus Meeting on musculoskeletal infection

The Orthopaedic Research Society's Research Interest Group completed its international consensus meeting (ICM) on musculoskeletal infections (MSKI) following the 2023 Annual Meeting. The work products from this ICM include the 65 questions with recommendation and rationale, and the voting results from the 72 delegates. There are also five Consensus Articles in this issue of the Journal of Orthopaedic Research from the ICM Sections: Host Immunity, Established Infection-Treatment, Clinical Questions not addressed by the prior MSKI ICMs, In Vitro, and Animal Models. This Introduction summarizes the 3-year Delphi process used by the ICM with timelines and critical milestones. It also highlights several challenges that had to be addressed, and a large body of work that remains.

Longitudinal intravital imaging of the bone marrow for analysis of the race for the surface in a murine osteomyelitis model

Critical knowledge gaps of orthopedic infections pertain to bacterial colonization. The established dogma termed the Race for the Surface posits that contaminating bacteria compete with host cells for the implant post-op, which remains unproven without real-time in vivo evidence. Thus, we modified the murine longitudinal intravital imaging of the bone marrow (LIMB) system to allow real-time quantification of green fluorescent protein (GFP+) host cells and enhanced cyan fluorescent protein (ECFP+) or red fluorescent protein (RFP+) methicillin-resistant Staphylococcus aureus (MRSA) proximal to a transfemoral implant. Following inoculation with ~105 CFU, an L-shaped metal implant was press-fit through the lateral cortex at a 90° angle ~0.150 mm below a gradient refractive index (GRIN) lens. We empirically derived a volume of interest (VOI) = 0.0161 ± 0.000675 mm3 during each imaging session by aggregating the Z-stacks between the first (superior) and last (inferior) in-focus LIMB slice. LIMB postimplantation revealed very limited bacteria detection at 1 h, but by 3 h, 56.8% of the implant surface was covered by ECFP+ bacteria, and the rest were covered by GFP+ host cells. 3D volumetric rendering of the GFP+ and ECFP+ or RFP+ voxels demonstrated exponential MRSA growth between 3 and 6 h in the Z-plane, which was validated with cross-sectional ex vivo bacterial burden analyses demonstrating significant growth by ~2 × 104 CFU/h on the implant from 2 to 12 h post-op (p < 0.05; r2  > 0.98). Collectively, these results show the competition at the surface is completed by 3 h in this model and demonstrate the potential of LIMB to elucidate mechanisms of bacterial colonization, the host immune response, and the efficacy of antimicrobials.

2023 International Consensus Meeting on musculoskeletal infection: Summary from the treatment workgroup and consensus on treatment in preclinical models

In vitro and in vivo studies are critical for the preclinical efficacy assessment of novel therapies targeting musculoskeletal infections (MSKI). Many preclinical models have been developed and applied as a prelude to evaluating safety and efficacy in human clinical trials. In performing these studies, there is both a requirement for a robust assessment of efficacy, as well as a parallel responsibility to consider the burden on experimental animals used in such studies. Since MSKI is a broad term encompassing infections varying in pathogen, anatomical location, and implants used, there are also a wide range of animal models described modeling these disparate infections. Although some of these variations are required to adequately evaluate specific interventions, there would be enormous value in creating a unified and standardized criteria to animal testing in the treatment of MSKI. The Treatment Workgroup of the 2023 International Consensus Meeting on Musculoskeletal Infection was responsible for questions related to preclinical models for treatment of MSKI. The main objective was to review the literature related to priority questions and estimate consensus opinion after voting. This document presents that process and results for preclinical models related to (1) animal model considerations, (2) outcome measurements, and (3) imaging.

International Delphi Study on Wound Closure and Incision Management in Joint Arthroplasty Part 2: Total Hip Arthroplasty

BACKGROUND

This modified Delphi study aimed to develop a consensus on optimal wound closure and incision management strategies for total hip arthroplasty (THA). Given the critical nature of wound care and incision management in influencing patient outcomes, this study sought to synthesize evidence-based best practices for wound care in THA procedures.

METHODS

An international panel of 20 orthopedic surgeons from Europe, Canada, and the United States evaluated a targeted literature review of 18 statements (14 specific to THA and 4 related to both THA and total knee arthroplasty). There were 3 rounds of anonymous voting per topic using a modified 5-point Likert scale with a predetermined consensus threshold of ≥ 75% agreement necessary for a statement to be accepted.

RESULTS

After 3 rounds of voting, consensus was achieved for all 18 statements. Notable recommendations for THA wound management included (1) the use of barbed sutures over non-barbed sutures (shorter closing times and overall cost savings); (2) the use of subcuticular sutures over skin staples (lower risk of superficial infections and higher patient preferences, but longer closing times); (3) the use of mesh-adhesives over silver-impregnated dressings (lower rate of wound complications); (4) for at-risk patients, the use of negative pressure wound therapy over other dressings (lower wound complications and reoperations, as well as fewer dressing changes); and (5) the use of triclosan-coated sutures (lower risk of surgical site infection) over standard sutures.

CONCLUSIONS

Through a structured modified Delphi approach, a panel of 20 orthopedic surgeons reached consensus on all 18 statements pertaining to wound closure and incision management in THA. This study provides a foundational framework for establishing evidence-based best practices, aiming to reduce variability in patient outcomes and to enhance the overall quality of care in THA procedures.

Management of septic arthritis and prosthetic joint infection

Management of joint infection is an evolving topic. This article reviews the literature on the management of native and prosthetic joint infection and suggests some areas of improvement in short- and long-term management which could lead to better patient outcomes. Surgical management is the mainstay of treatment for native or prosthetic knee infection and aspiration should only be used for diagnostic purposes. A multidisciplinary team approach and compliance with national guidelines, alongside referral networks and pooling of expertise, should be mandatory to improve patient outcomes.

Evaluating ChatGPT responses to frequently asked patient questions regarding periprosthetic joint infection after total hip and knee arthroplasty

Background

Patients access relevant information concerning their orthopaedic surgery resources through multiple information channels before presenting for clinical treatment. Recently, artificial intelligence (AI)-powered chatbots have become another source of information for patients. The currently developed AI chat technology ChatGPT (OpenAI LP) is an application for such purposes and it has been rapidly gaining popularity, including for patient education. This study sought to evaluate whether ChatGPT can correctly answer frequently asked questions (FAQ) regarding periprosthetic joint infection (PJI).

Methods

Twelve FAQs about PJI after hip and knee arthroplasty were identified from the websites of fifteen international clinical expert centres. ChatGPT was confronted with these questions and its responses were analysed for their accuracy using an evidence-based approach by a multidisciplinary team. Responses were categorised in four groups: (1) Excellent response that did not require additional improvement; (2) Satisfactory responses that required a small amount of improvement; (3) Satisfactory responses that required moderate improvement; and (4) Unsatisfactory responses that required a large amount of improvement.

Results

From the analysis of the responses given by the chatbot, no reply received an 'unsatisfactory' rating; one did not require any correction; and the majority of the responses required low (7 out of 12) or moderate (4 out of 12) clarification. Although a few responses required minimal clarification, the chatbot responses were generally unbiased and evidence-based, even when asked controversial questions.

Conclusions

The AI-chatbot ChatGPT was able to effectively answer the FAQs of patients seeking information around PJI diagnosis and treatment. The given information was also written in a manner that can be assumed to be understandable by patients. The chatbot could be a valuable clinical tool for patient education and understanding around PJI treatment in the future. Further studies should evaluate its use and acceptance by patients with PJI.

Next-generation Sequencing Results Require Higher Inoculum for Cutibacterium acnes Detection Than Conventional Anaerobic Culture

BACKGROUND

Cutibacterium acnes has been described as the most common causative microorganism in prosthetic shoulder infections. Conventional anaerobic culture or molecular-based technologies are usually used for this purpose, but little to no concordance between these methodologies (k = 0.333 or less) has been observed.

QUESTIONS/PURPOSES

(1) Is the minimum C. acnes load for detection higher for next-generation sequencing (NGS) than for anaerobic conventional culture? (2) What duration of incubation is necessary for anaerobic culture to detect all C. acnes loads?

METHODS

Five C. acnes strains were tested for this study: Four strains were causing infection and were isolated from surgical samples. Meanwhile, the other was a reference strain commonly used as a positive and quality control in microbiology and bioinformatics. To create inoculums with varying degrees of bacterial load, we began with a standard bacterial suspension at 1.5 x 10 8 colony-forming units (CFU)/mL and created six more diluted suspensions (from 1.5 x 10 6 CFU/mL to 1.5 x 10 1 CFU/mL). Briefly, to do so, we transferred 200 µL from the tube with the highest inoculum (for example, 1.5 x 10 6 CFU/mL) to the following dilution tube (1.5 x 10 5 CFU/mL; 1800 µL of diluent + 200 µL of 1.5 x 10 6 CFU/mL). We serially continued the transfers to create all diluted suspensions. Six tubes were prepared per strain. Thirty bacterial suspensions were tested per assay. Then, 100 µL of each diluted suspension was inoculated into brain heart infusion agar with horse blood and taurocholate agar plates. Two plates were used per bacterial suspension in each assay. All plates were incubated at 37°C in an anaerobic chamber and assessed for growth after 3 days of incubation and daily thereafter until positive or Day 14. The remaining volume of each bacterial suspension was sent for NGS analysis to identify bacterial DNA copies. We performed the experimental assays in duplicate. We calculated mean DNA copies and CFUs for each strain, bacterial load, and incubation timepoint assessed. We reported detection by NGS and culture as a qualitative variable based on the identification or absence of DNA copies and CFUs, respectively. In this way, we identified the minimum bacterial load detected by NGS and culture, regardless of incubation time. We performed a qualitative comparison of detection rates between methodologies. Simultaneously, we tracked C. acnes growth on agar plates and determined the minimum incubation time in days required for CFU detection in all strains and loads examined in this study. Growth detection and bacterial CFU counting were performed by three laboratory personnel, with a high intraobserver and interobserver agreement (κ > 0.80). A two-tailed p value below 0.05 was considered statistically significant.

RESULTS

Conventional cultures can detect C. acnes at a load of 1.5 x 10 1 CFU/mL, whereas NGS can detect bacteria when the concentration was higher, at 1.5 x 10 2 CFU/mL. This is represented by a lower positive detection proportion (73% [22 of 30]) for NGS than for cultures (100% [30 of 30]); p = 0.004). By 7 days, anaerobic cultures were able to detect all C. acnes loads, even at the lowest concentrations.

CONCLUSION

When NGS is negative and culture is positive for C. acnes , there is likely a low bacterial load. Holding cultures beyond 7 days is likely unnecessary.

CLINICAL RELEVANCE

This is important for treating physicians to decide whether low bacterial loads necessitate aggressive antibiotic treatment or whether they are more likely contaminants. Cultures that are positive beyond 7 days likely represent contamination or bacterial loads even below the dilution used in this study. Physicians may benefit from studies designed to clarify the clinical importance of the low bacteria loads used in this study at which both methodologies' detection differed. Moreover, researchers might explore whether even lower C. acnes loads have a role in true periprosthetic joint infection.

Accuracy of Serological Markers, Synovial Fluid, Microbiological Culture, and Histopathological Examination for Diagnosing Periprosthetic Knee Infection

Objective  This study assessed the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of serological tests, synovial fluid markers, microbiological tissue culture, and histopathological examination of the periprosthetic membrane in diagnosing periprosthetic knee infection. Methods  This study is prospective, and it includes patients undergoing total knee arthroplasty revision surgery from November 2019 to December 2021. The analysis consisted of serological tests (erythrocyte sedimentation rate [ESR], C-reactive protein [CRP], and D-dimer), synovial fluid markers (leukocyte and polymorphonuclear cell counts), periprosthetic tissue culture, and histopathological examination of the periprosthetic membrane of all patients. Results  Sixty-two patients had periprosthetic joint infection (PJI) according to the 2018 International Consensus Meeting criteria (infection group), while 22 subjects had no infection. ESR sensitivity and specificity were 83.6% and 45.4%, respectively. CRP sensitivity and specificity were 64.5% and 100%, whereas D-dimer sensitivity and specificity were 78.9% and 25%, respectively. Leukocyte count sensitivity and specificity were 75.6% and 100%, polymorphonuclear cell count sensitivity and specificity were 33% and 100%, respectively. Periprosthetic tissue culture sensitivity and specificity culture were, respectively, 77.4% and 100%. Histopathological examination sensitivity and specificity were 43.7% and 100%, respectively. Conclusions  In our study, the total blood cell count in synovial fluid and microbiological cultures of periprosthetic tissues were the most accurate tests for PJI diagnosis. In contrast, polymorphonuclear cell percentage was the least accurate test for PJI diagnosis.

Hematoma-like dynamic hydrogelation through natural glycopeptide molecular recognition for infected bone fracture repair

Infected bone fractures remain a major clinical challenge for orthopedic surgeons. From a tissue regeneration perspective, biomaterial scaffolds with antibacterial and osteoinductive activities are highly desired, while advanced materials capable of mimicking the pathological microenvironment during the healing process of infected tissues remain an area deserving more research. Hematoma, the gel-like blood coagulum, plays an essential role in bone fracture repair because of its ability to serve as a dynamic and temporary scaffold with cytokines for both pathogen elimination and tissue healing. In light of this, we designed a dynamic hydrogel with hematoma-like antimicrobial or reparative performance for infected bone fracture repair in this study. The proposed dynamic hydrogel network was based on the reversible recognition of a natural glycopeptide antibiotic vancomycin (Van) and its target dipeptide D-Ala-D-Ala (AA), which could serve as a hematoma-like scaffold for obliterating bacteria in the fracture region and promoting bone repair by introducing an endogenous osteogenic peptide (OGP). In vivo experiments demonstrated that the hydrogel could rapidly eradicate bacteria, improve bone regeneration and restore the local inflammatory microenvironment. Together, findings from this study imply that the use of hematoma-like dynamic hydrogel could lead to a biomimetic revolution in surgical strategies against susceptible bone fractures.

Early Staphylococcal Periprosthetic Joint Infection (PJI) Treated with Debridement, Antibiotics, and Implant Retention (DAIR): Inferior Outcomes in Patients with Staphylococci Resistant to Rifampicin

It is unknown how rifampicin resistance in staphylococci causing a periprosthetic joint infection (PJI) affects outcomes after debridement, antibiotics, and implant retention (DAIR). We thus aimed to compare the risk of relapse in DAIR-treated early PJI caused by staphylococci with or without rifampicin resistance. In total, 81 patients affected by early PJI were included, and all patients were treated surgically with DAIR. This was repeated if needed. The endpoint of relapse-free survival was estimated using the Kaplan-Meier method, and Cox regression models were fitted to assess the risk of infection relapse for patients infected with rifampicin-resistant bacteria, adjusted for age, sex, type of joint, and type of index surgery. In patients with rifampicin-resistant staphylococci, relapse was seen in 80% after one DAIR procedure and in 70% after two DAIR procedures. In patients with rifampicin-sensitive bacteria, 51% had an infection relapse after one DAIR procedure and 33% had an infection relapse after two DAIR procedures. Patients with rifampicin-resistant staphylococcal PJI thus had an increased adjusted risk of infection relapse of 1.9 (95% CI: 1.1-3.6, p = 0.04) after one DAIR procedure compared to patients with rifampicin-sensitive bacteria and a 4.1-fold (95% CI: 1.2-14.1, p = 0.03) increase in risk of infection relapse after two DAIR procedures. Staphylococcal resistance to rifampicin is associated with inferior outcomes after DAIR. These findings suggest that DAIR may not be a useful strategy in early PJI caused by rifampicin-resistant staphylococci.