Aim. Haematogenous prosthetic joint infections account for 20-35% of total prosthetic infections. Debridement, antibiotics and implant retention (DAIR) is a well-accepted treatment for these infections and probably the most desired by surgeons, since it tries to maintain a functional and stable implant. However, the risk of DAIR failure is not negligible and some risk factors have been described, and also, different scores, such as CRIME80. Nonetheless, less is known about the impact of positive blood cultures may have on DAIR treatment. The aim of our study is to analyze whether the presence of a positive culture is a risk factor for DAIR failure. Method. A retrospective cohort study of 50 late acute haematogenous TKA infections was performed from 2015 to 2023. DAIR failure was defined as the need of a subsequent intervention either a new DAIR or a revision surgery. So, patients were divided into two groups depending on the surgical outcome: successful (SG) vs failure (FG). Demographic variables including age, gender, affected side and body mass index were collected. Patient's comorbidities were also collected including chronic obstructive pulmonary disease (COPD), diabetes, rheumatoid arthritis (RA), cirrhosis and chronic renal failure, etc. Other variables, such as ones included in CRIME80 (C-reactive protein (CRP) >150mg/dl and polyethylene exchange), were also collected. Results. 30 patients had a successful DAIR outcome (60%). Age and sex do not act as risk factors [OR 0.7 (0.2-2.6) and OR 0.4 (0.1-1.3)]. Neither do COPD [OR 3.3 (0.5-2.0), p=0.2]; RA [OR 0.8 (0.2-3.1), p=0.7]; CRP value [3.2 (0.9-11.2), p=0.06]; and polyethylene exchange [OR 0.4 (0.1-2.5), p= 0.3]. Thirty-five blood cultures (70%) were obtained before surgery (20 SG and 15 FG). Nine of the obtained blood cultures were positive (25.7%), being 7 from FG (46.7%) [OR 7.6 (1.3-4.8), p=0.02]. A logistic regression was performed where positive blood cultures were the only significant variable to predict DAIR failure (OR 12, 95% CI 1.1−18, p=0.049), after adjusting for all CRIME80 variables. Skin and soft tissue origin was described in 5 of the nine positive blood cultures (55.6%). Cardiovascular system was the second most common spread (22.2%), and then followed by urogenital and digestive tract. The most common microorganism in FG was Staphylococcus aureus (57.1%) [OR 6.4 (0.2-18.0), p=0.2]. Conclusions. Positive blood cultures may be another risk factor for DAIR failure. This can be important in diagnosis and it may be taken into account in antibiotic and surgical treatment strategies

Aim. Periprosthetic Joint Infection (PJI) is a devastating complication in hip and knee joint arthroplasty. The “JS BACH” classification system was developed in 2021 to stratify the complexity of PJI, and more importantly, to act as a tool to guide referrals to specialist centers. The “JS BACH” classification has not been validated in an external cohort. This study aimed to do so using a large prospective cohort from Australia and New Zealand. Method. We applied the JS-BACH classification to the Prosthetic Joint Infection in Australia and New Zealand Observational (PIANO) cohort. This prospective study of newly diagnosed PJI collected 2-year outcome data from 653 participants enrolled in 27 hospitals. The definition of PJI treatment failure at 24 months was any of the following: death, clinical or microbiological signs of infection, destination prosthesis removed, or ongoing antibiotic use. Results. Individual cases were classified as per JS-BACH into “1 - uncomplicated” (n = 268), “2 - complex” (n = 330), and “3 - limited options” (n = 55). This cohort was similar to the original JS-BACH population in terms of baseline characteristics. However, there was a difference in complexity, with more DAIR procedures, fewer revision procedures, and a higher proportion of uncomplicated patients in the PIANO cohort. The risk of treatment failure correlated strongly with the JS-BACH category, with odds ratios (95% CI [confidence interval]) for category 2 versus 1 of 1.75 (1.24 to 2.47) and for category 3 versus 1 of 7.12 (3.42 to 16.02). Conclusions. Despite the PIANO study population being less complicated than the original derivation cohort, the JS-BACH classification showed a clear association with treatment failure in this large external cohort

Aim. This retrospective study evaluated the outcome of treatment for unhealed fracture-related infections (FRI). Methods. We identified a consecutive, single-centre cohort of patients having treatment for an FRI Consensus confirmed FRI. All fractures were unhealed at the time of treatment. Patients were followed up for at least one year. Successful outcome was a healed fracture without recurrent infection. Lack of union, persistent infection and/or unplanned reoperation defined failure. Results. Demographics: 183 patients (184 FRIs) with mean age 52.1 years (range 17-96) were treated and followed up for a mean of 2.8 years (range 1-9.4). Mean duration of FRI was 1.1 years with 65 (35.5 %) presenting within 6 months of injury. 118 patients had established infected non-union. FRI was most frequent in the tibia (74), femur (48) and humerus (24). 171 patients were BACH Complex. 75.5% of FRIs were culture positive, with Staph. aureus being the most frequent organism. Polymicrobial infection and Gram negative cultures were common (25.5% and 33.6%). Treatment: 98.3% of surgeries were performed in one stage with just 3 planned 2-stage procedures (2 endoprosthetic replacements and 1 free fibular flap). No bone graft was used in any surgery and all wounds were closed at first operation. 48 cases (26%) required flap coverage (29 free flaps and 19 local flaps). Local antibiotics were used in 124 cases (67.4%) of primary surgeries. All patients had sampling, debridement, systemic antibiotics and wound closure. 40 (21.7%) had DAIR, 31 (16.8%) had new internal fixation and 105 (57.1%) had external fixation (including 79 Ilizarov fixators). Outcomes: After primary surgery, 84.6% of all patients were infection-free and 77.2% had united. After further surgery, 98.8% were infection-free and 98.1% had united. External fixation techniques achieved infection eradication in 89.1% compared to 71.7% with any internal fixation (p=0.005). Primary internal fixation achieved union in 81.7% compared to 74.3% with external fixation (p=0.27). Secondary surgery after external fixation was mainly docking site fixation. Conclusion. Unhealed FRIs present a difficult challenge for treatment. This large series demonstrated that single-stage treatment, without bone grafting, gave acceptable results with few reoperations. Primary external fixation gave more certainty of infection eradication but required more reoperations to secure union. However, this difference in reoperation was not statistically significant. We strongly advocate managing these patients with a multidisciplinary team which can treat all aspects of the condition

Aim. The current recommendation in Norway is to use four doses of a first-generation cephalosporin (cefazolin or cephalotin) as systemic antibiotic prophylaxis (SAP) the day of surgery in primary joint arthroplasty. Due to shortage of supply, scientific development, changed courses of treatment and improved antibiotic stewardship, this recommendation has been disputed. We therefore wanted to assess if one dose of SAP was non-inferior to four doses in preventing periprosthetic joint infection (PJI) in primary joint arthroplasty. Method. We included patients with primary hip- and knee arthroplasties from the Norwegian Arthroplasty Register and the Norwegian Hip Fracture Register for the period 2005-2023. We included the most used SAPs (cephalotin, cefazolin, cefuroxime, cloxacillin and clindamycin), administered as the only SAP in 1-4 doses, starting preoperatively. Risk of revision (Hazard rate ratio; HRR) for PJI was estimated by Cox regression analyses with adjustment for sex, age, ASA class, duration of surgery, reason for- and type of arthroplasty, and year of primary arthroplasty. The outcome was 1-year reoperation or revision for PJI. Non-inferiority margins were calculated for 1, 2 and 3 doses versus reference of 4 doses of SAP at the day of surgery, against a predetermined limit of 15% increased risk of PJI. Results. In total 274,188 primary arthroplasties (total hip 133,985, hemi hip 51,442, and total knee 88,761) were included. Of these primary arthroplasties, 2,996 (1.1%) had subsequent revisions for PJI during the first postoperative year. One dose of SAP was given in 9,603 arthroplasties, two doses in 10,068, three doses in 18,351, and four doses in 236,166 arthroplasties. With the recommended four doses as reference, the HRR (95% CI) for 1-year revision for infection was 0.9 (0.7-1.1) for one dose, 1.0 (0.8-1.2) for two doses, and 0.9 (0.8-1.1) for three doses. The corresponding adjusted 1-year revision incidences for PJI was 0.9 (0.7-1.1), 1.0 (0.8-1.2), 0.9 (0. 8-1.1) and 1.0 (1.0-1.1) for one, two, three and four doses respectively, and less than four doses was found to be non-inferior. Conclusions. One preoperative dose of SAP in primary joint arthroplasty surgery seems to be non-inferior to the current recommendation of four doses of a first-generation cephalosporin as PJI-prophylaxis. This finding may simplify the course of treatment for arthroplasty patients, save costs, and improve antibiotic stewardship

Aim. This is the first study to directly compare the clinical outcome of debridement, antimicrobials and implant retention (DAIR) with stabilization using new internal fixation after debridement, for patients with Fracture-related Infection (FRI). Method. Consecutive patients with FRI Consensus confirmed FRI had single-stage surgery with tissue sampling, debridement, stabilization, antimicrobial therapy and skin closure. All cases had FRIs which were unhealed at surgery. When existing implants were stable, the implant was retained but loose implants or fractures with poor reduction had implant removal and refixation with new implants. All patients had the same empiric and definitive antibiotics, the same diagnostic criteria and outcome assessment at least one year after surgery. Failure was defined as infection recurrence, reoperation or lack of fracture consolidation at one year. Results. Seventy-one patients were studied (40 DAIRs and 31 new implants, including 10 exchange nails). The two groups were well matched for age, duration of infection, BACH complexity, microbiology, bone involved and need for flap coverage. Ten patients (13.7%) died before the endpoint. Mortality was similar in both groups (DAIR 14.1% vs New Metalware 12.9%; p=0.801) but DAIR of IM nails had a higher mortality at 40% (p=0.011). Sixty-one patients were followed-up for a mean of 3.32 years (1.04-9.43). Infection was eradicated in 23/34 (67.6%) DAIR patients and 24/27 (88.9%) with new metalware (p=0.049). Overall rates of infection-free union were similar in both groups (58.8% vs 77.8%; p=0.117). DAIR of plates had significantly fewer infection-free unions compared to removal and implantation of new plates (DAIR 57.1% vs NM 91.7%; p=0.033). Conclusion. Implantation of new metalware had better eradication of infection and a strong trend towards better union rates. Treating FRI with retained or new metalware had a substantial mortality (13.7%). Choosing DAIR did not reduce this mortality and these patients more often required further surgery to treat residual infection and secure union

Aim. Decubitus ulcers are found in approximately 4.7% of hospitalized patients, with a higher prevalence (up to 30%) among those with spinal cord injuries. These ulcers are often associated with hip septic arthritis and/or osteomyelitis involving the femur. Girdlestone resection arthroplasty is a surgical technique used to remove affected proximal femur and acetabular tissues, resulting in a substantial defect. The vastus lateralis flap has been employed as an effective option for managing this dead space. The aim of this study was to evaluate the long-term outcomes of this procedure in a consecutive series of patients. Method. A retrospective single-center study was conducted from October 2012 to December 2022, involving 7 patients with spinal cord injuries affected by chronic severe septic hip arthritis and/or femoral head septic necrosis as a consequence of decubitus ulcers over trochanter area. All patients underwent treatment using a multidisciplinary approach by the same surgical team (orthopedic and plastic surgeons) along with infectious disease specialists. The treatment consisted of a one-stage procedure combining Girdlestone resection arthroplasty with unilateral vastus lateralis flap reconstruction, alongside targeted antibiotic therapy. Complications and postoperative outcomes were assessed and recorded. The mean follow-up period was 8 years (range 2-12). Results. Of the 7 patients, 5 were male and 2 were female, with a mean age of 50.3 years at the time of surgery. Minor wound dehiscence occurred in 28.6% of the flap sites, and 2 patients required additional revisional procedures—one for hematoma and the other for bleeding. There were no instances of flap failure, and complete wound healing was achieved in an average of 32 days (range 20-41), with the ability to load over the hip area. No cases of infection recurrence or relapse were observed. Conclusions. An aggressive surgical approach is strongly recommended for managing chronic hip septic arthritis or proximal femur osteomyelitis in patients with spinal cord injuries. A single-stage procedure combining Girdlestone resection arthroplasty with immediate vastus lateralis muscle flap reconstruction proves to be an effective strategy for dead space management and localized antibiotic delivery through the vastus muscle, giving reliable soft tissue coverage around the proximal femur to avoid the recurrence of pressure ulcers. The implementation of a standardized multidisciplinary protocol contributes significantly to the success of reconstruction efforts

Aim. There is limited data on the frequency and impact of untoward events such as glove perforation, contamination of the surgical field (drape perforation, laceration, detachment), the unsterile object in the surgical field (hair, sweat droplet…), defecation, elevated air temperature…that may happen in the operating theatre. These events should influence the surgical site infection rate but it is not clear to what extent. We wanted to calculate the frequency and measure the impact of these events on the infection and general revision rate. Method. In our institution, scrub nurses prospectively and diligently record untoward events in the theatres. We have an institutional implant registry with close to 100% data completion since 2001, and surgeons register complications before discharge. We analysed the respective databases and compared the revision and infection rate in the group with untoward events with the outcome of all arthroplasty patients within the same period. Two-tailed Z statistical test was used for analysis. Results. Between 1.1.2012 and 31.12.2018 we operated 13574 prosthetic joints: 6232 primary THR (total hip replacement) and 5466 primary KR (total and partial knee replacement) and 1245 and 631 revisions respectively. During this period, we recorded 372 events (2.74%) including 20 (0.15 %) defecations, 40 (0.29 %) unsterile object in the surgical field, 73 (0.54%) field sterility violations, 45 (0.33 %) glove perforations, 45 (0.33 %) occasions with elevated air temperature, 106 (0.78%) with guests in the OR, 11 (0.08%) with wound near the surgical field, and 32 (0.24%) with other events. We followed the patients till 1.1.2022, in this time we recorded 27 (7.26%) reoperations in the cohort with untoward events. There were 9 (2.42%) infections and 18 (4.84%) aseptic revisions in the group with unwanted events. The infection rate for all TJR (total joint replacement) from the period 2012-2018, followed till 1.1.2022 was 2.23%, the revision rate for any reason was 4.37%. For all THR (primary and revision) the infection rate was 0.84%, the overall revision rate was 3.18% and for the KR (primary and revision) 1.71% and 5,82% respectively. The difference is significant at p>0.05 for infection rate. Conclusions. The potentially serious sterility disruptive events in the operative rooms did result in an increased infection rate but not an increase in revision rate. There is no data about the rate and the impact of these events besides for perforated surgical gloves with higher reported incidences than in our study influencing infection rate if perioperative antibiotic prophylaxis was not used. Ours is the first study reporting the impact of these unwanted events in the operating theatre. Key words. orthopaedic surgery, unwanted events, revision rate

Aim. Bone infections often manifest with soft tissue complications such as severe scarring, fistulas, or ulcerations. Ideally, their management involves thorough debridement of infected bone and associated soft tissues, along with achieving stable bone structure, substantial tissue coverage, and long-term antibiotic therapy. The formation of a multidisciplinary team comprising orthopedic surgeons, plastic surgeons, and infectious disease specialists is essential in addressing the most complex cases. Method. We conducted a retrospective study during six years (2018-2023) at our university center. Focusing on the most challenging cases, we included patients with bone infections in the leg and/or foot requiring free flap reconstruction. Each patient underwent simultaneous bone debridement and reconstruction by the orthopedic team, alongside soft tissue debridement and free flap reconstruction by the plastic surgery team. Targeted antibiotic therapy for either 6 weeks (acute) or 12 weeks (chronic osteitis) was initiated based on intraoperative cultures. Additional procedures such as allografts, arthrodesis, or autografts were performed if necessary. We analyzed the rates of bone union, infection resolution, and limb preservation. Results. Forty-five patients were enrolled. Twenty-four patients (53.3%) had urgent indications (e.g., open infected fractures, osteitis, acute osteoarthritis, or wound dehiscence), while 21 (46.7%) underwent elective surgery (e.g., septic pseudarthrosis or chronic osteitis). Two patients underwent amputation due to flap failure (4.4%), and one patient was lost to follow-up. Follow-up of the remaining 42 patients averaged 28 months (range: 6–60 months). During this period, 35 patients (83.4%) experienced no recurrence of infection. Similarly, 35 patients (83.4%) achieved bone union. Overall, the rate of lower limb preservation was 93.3%. Conclusions. Managing bone infection coupled with soft tissue defects brings significant challenges. Although the majority of patients treated here belong to a complex framework based on the BACH classification, the outcomes achieved here appear to align with those of the simpler cases, thanks to optimal care with a dedicated septic ortho-plastic team. Our study demonstrates a notable success rate in treating infection, achieving bone consolidation, and preserving lower limb function

Aim. Cutibacterium acnes is a major skin commensal that may also act as an opportunistic pathogen. Findings of C. acnes in tissue cultures obtained during arthroplasty revision surgery are difficult to interpret, since they may represent true infection or contamination. This study investigated whether C. acnes isolates obtained from prosthetic joint infections (PJIs) were related and shared common genomic traits that might correlate with clinical courses and patient outcomes. Method. C. acnes isolates from revision surgery of patients with PJIs of the hip, shoulder, and knee were characterized using molecular methods to determine sequence type (ST) and the presence of virulence determinants (CAMP factors, dermatan sulfate-binding adhesion 1, hyaluronidase lyase, and linear plasmid). A standardized review of the patients’ medical charts was performed. Results. The study included 37 patients with C. acnes culture-positive tissue samples where multiple isolates of C. acnes belonged to the same ST. Most of the isolates belonged to phylotype IA. 1. Phylogenetic analysis of virulence determinants revealed no shared pattern among PJI isolates. Seven patients had a polymicrobial infection. Exchange revision was performed in 70% of the patients, and >50% of all patients received antibiotic treatment for ≥3 months. Failure was noted in seven patients, all of whom had shoulder PJIs. Conclusions. No specific ST or any identifiable unique feature among virulence determinants were found among C. acnes isolated from PJIs of hips and shoulders. The majority of all included patients had low inflammatory markers and were treated successfully, even when the infection consisted of a polymicrobial infection

Aim. Efficacious antibiotic treatment is crucial for managing and preventing orthopedic infections due to their complexity and associated risk of treatment failure. Previous reviews on antibiotic target tissue concentrations have primarily focused on static measurements, which may not accurately reflect the dynamic pharmacokinetic/pharmacodynamic (PK/PD) changes encountered in clinical settings. This review aimed to summarize the current literature on antibiotic distribution in orthopedically relevant tissues and settings using dynamic sampling methods. Method. In accordance with PRISMA guidelines, a literature search was conducted with a scientific librarian's assistance. PubMed and Embase databases were systematically searched using relevant MeSH terms, entries, and keywords. English-published studies between 2004 and 2023 involving systemic antibiotic administration and dynamic measurements were included. 4467 titles were identified. After title and abstract screening, 77 eligible studies remained. Results. The studies covered clinical and pre-clinical studies on both healthy and infected tissue. Dynamic measurements were obtained from various tissues including bone, intervertebral discs, joints, muscles, and subcutaneous tissue. Microdialysis was the predominant sampling method (98.70%, 76/77). Antibiotics like cefuroxime, linezolid, and vancomycin were extensively studied. Fluoroquinolones, tetracyclines, and most beta-lactams typically presented good tissue penetration in relation to relevant PK/PD-targets. In contrast, glycopeptides, macrolides, and flucloxacillin exhibited poorer penetration. Conclusions. This review provides valuable insights of antibiotic distribution in orthopedically relevant target tissues and settings, which may help improve dosing recommendations and treatment outcomes. Our findings are limited to the investigated dosing regimens and administration methods and depend on the chosen PK/PD target. Many antibiotics still require further research to address the significant knowledge gaps, such as the lack of dynamic evaluations for certain antibiotic types and further investigation across various orthopedic settings and tissues

Aim. Predicting success of a Debridement, Antibiotics and Implant Retention (DAIR) procedure for Periprosthetic Joint Infection (PJI) remains a challenge. A failed DAIR might adversely affect the outcome of any future revision surgery for PJI. Hence, the ability to identify and optimise 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. Method. A retrospective review of our prospective Bone Infection Group database was performed to identify all patients who underwent a DAIR of their hip or knee arthroplasty. Diagnosis of PJI was confirmed using the Musculoskeletal Infection Society (MSIS) 2013 and the European Bone and Joint Infection Society (EBJIS) 2021 classification systems. DAIR surgery was grouped into “successful” or “unsuccessful” outcomes as per the MSIS working group outcome-reporting tool. Results. Sixty-Four consecutive patients with an acute PJI underwent a DAIR procedure between 2009 and 2020. Treatment was successful in 44 (69%). The chance of a successful DAIR was significantly greater if performed 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]). The chances of a successful DAIR 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%; followed by Coagulasenegative Staphylococci 71% and Methicillin-susceptible Staphylococcus Aureus 65%. Polymicrobial infection had the worst outcome with a success rate of 47%. Conclusions. In our experience DAIR surgery performed within one week of symptom onset, significantly increased chances of successful infection eradication. Collaborative work is required to ensure arthroplasty patients access prompt appropriate surgical decision-making, remove barriers to early assessment and minimise delays to surgery

Aim. Determine therapeutic and prognostic value of three different prosthetic joint infections (PJI) staging systems – JS-Bach, McPherson and PJI-TNM. Method. Retrospective analysis of patients who received surgery for PJI between 2011 and 2022 at one single institution, including DAIR, 1-stage revision and 2-stage revision. We applied three staging systems - JS-Bach, McPherson, PJI-TNM – and categorize the results into A (less severe), B (intermediate) and C (most severe). Demographic data and comorbidities, anatomic location, type of treatment, recurrency of infection, final outcome and antibiogram were analyzed. Results. 186 patients were included, 112 (60%) were woman. Median age was 70 years old. 51% were submitted to DAIR, 10% to 1-stage revision and 39% to 2-stage revision. Recurrence of infection was found on 27% of patients after initial treatment. 10% died with complication related to PJI. Final status at last follow-up showed 96% of cases were ultimately free of infection at last follow-up. JS-BACH was associated with recurrence. All three staging systems were associated with final outcome. Conclusions. Despite all existing knowledge around risk factors for treatment failure of PJI, there is still a lack of a generally accepted classification system to accurately predict patient outcome. JS-BACH, McPherson and PJI-TNM are three different proposed classifications developed to predict clinical outcomes. To the best of our knowledge there are no studies directly comparing their performance. We retrospectively evaluated our cohort and found that all three correlated with final patient outcome but JS-BACH was the only who significantly correlated with infection recurrence after initial treatment

Aim. This study aimed to evaluate the impact of intraoperative direct sonication on the yield of traditional culture and the time to positivity (TTP) of cultures obtained for periprosthetic joint infection (PJI), thereby assessing its potential to improve diagnostic efficiency and reduce contamination risk. Method. A prospective cohort study was conducted at a tertiary care center, involving 190 patients undergoing revision surgery for PJI from August 2021 to January 2024. Patients were included based on the 2018 International Consensus Meeting definition of PJI. The study utilized a novel sonication protocol, which involved direct intraoperative sonication of the implant and tissue, followed by incubation in a BACT/ALERT 3D system. The primary outcomes measured were the number and percentage of positive culture samples, identified microorganisms, and the TTP of each culture. Statistical analysis was performed using R software, with various tests applied to assess the significance of findings. Results. The study included 510 positive cultures from 190 patients, demonstrating that sonication significantly improved the positivity rate for both tissue and prosthesis specimens (p < 0.05). The median TTP for all samples was 3.13 days, with sonicated samples showing a significantly shorter TTP compared to non-sonicated samples (p < 0.05). Specifically, the shortest median TTP was observed in prosthesis post-sonication samples. Furthermore, the study found that Gram-positive organisms had a shorter TTP than gram-negative organisms, and specific microorganisms like Staphylococcus aureus and MRSE showed the fastest TTP. The analysis also revealed higher positivity rates in chronic PJIs compared to acute PJIs for sonicated tissue samples. Conclusions. The study demonstrates that intraoperative direct sonication combined with the BACT/ALERT 3D system can significantly enhance the diagnostic yield of cultures and reduce the TTP for common PJI pathogens. This novel technique not only improves pathogen detection, facilitating the tailoring of antibiotic therapy, but also potentially reduces the risk of contamination associated with sonication. These findings suggest that direct intraoperative sonication could be a valuable addition to the current diagnostic protocols for PJI, contributing to more effective management and treatment of this complex condition. Further research is necessary to explore the clinical significance of TTP and its correlation with patient outcomes in PJI

Aim. A substantial portion of periprosthetic joint infections (PJI) literature is comprised of observational studies. The Strengthening the Reporting of Observational Studies in Epidemiology guidelines emphasize the importance of clearly defining variables and providing diagnostic criteria. Well-defined variables in these studies play a crucial role in ensuring data consistency, fostering comparability among studies, and laying a robust foundation for evidence-based decision-making. We aimed to determine the definition of these variables and determine the objectivity of the definitions. Method. We reviewed observational studies on hip or knee PJI that focused on variables and their association with treatment outcomes. The inclusion criteria comprised studies from Jan 2017 to Jan 2023. We focused on 13 variables that were possibly subjective. These were smoking, alcohol use, diabetes mellitus, hypertension, lung disease, rheumatoid arthritis, liver diseases, kidney diseases, cardiovascular diseases, malignancy, immunosuppression, use of antibiotics, and type of infection. The reviewers examined the text of the articles, along with any available online supplements or protocols, for definitions of the selected variables. We classified a definition as objective if there was the presence of time element, severity, staging, frequencies, laboratory cut-off, medication dependence, among others. Chart review was deemed subjective. Results. We included 75 studies in the analysis. The most common factors studied were diabetes mellitus (79%), cardiovascular disease, smoking history, and rheumatoid arthritis (47% each). The variables that were objectively defined most often were antibiotic use (100%) and type of infection (95%). Smoking history (16%) and alcohol use (20%) were the least frequently objectively defined variables. Further analysis revealed that a considerable number of studies incorporated variables into their primary analyses without clear definitions. For instance, out of the 59 studies where diabetes was considered a variable, 41 studies (70%) included diabetes in their main analyses as a factor for PJI treatment outcomes, despite only 34 studies having defined this variable. Moreover, of the 34 provided definitions of diabetes mellitus, only 12 provided objective criteria for diagnosis. The rest of the provided definitions relied on “chart review” without further specification. Table 1 outlines the proportion of studies with variables defined and included in their analysis. Conclusions. Study variables were not clearly defined in most of the observational studies raising concerns about the reproducibility and reliability of findings. Our study underscores the vital need for standardized variable definitions in PJI research. Professional societies may play a crucial role in setting standards for the definition of variables. For any tables or figures, please contact the authors directly

Aim. To report outcomes of soft tissue reconstruction using free tissue transfer for the treatment of tibial osteomyelitis as part of a single-stage, ortho-plastic procedure. Method. Patients who underwent ortho-plastic reconstructive surgery to excise tibial osteomyelitis in combination with free tissue transfer in one stage were included. Patients underwent surgery between 2015 and 2024 in a single specialist centre within the UK. Baseline patient information, demographics, and infection information was recorded. Adverse outcomes were defined as (i) flap salvage required, (ii) flap failure and (iii) recurrence of infection. Patient reported quality of life was measured using the EuroQol EQ-5D-5L index score. Pre-operative QoL was compared to QoL at 1 year with a control group of 53 similar patients who underwent surgical treatment for tibial osteomyelitis without a free flap (local flap or primary closure). Results. Ninety-three patients were eligible for inclusion, with a mean age of 52 years (range 18–90). 77/93 (82.8%) had a free muscle flap with the remainder (17.2%) receiving a fasciocutaneous flap. The donor tissue was defined as 57 gracilis, 6 latissimus dorsi, 14 hemi-latissimus dorsi, and 16 anterolateral thigh. The recipient area of the tibia was distal 1/3 in 52 cases, middle 1/3 in 27 cases and proximal 1/3 in 12 cases. The average flap ischaemic time was 70 minutes (range 28 to 125). Seven patients (7.5%) required urgent flap salvage at a median time of 1.0 day (range 0.5 – 4.0). Of these, 4 (4.3%) went on to have total flap failure, of which 2 patients underwent below knee amputation subsequently. Flap failure was due to either arterial (n=2) or venous (n=2) anastomotic thrombus. There were 3 (3.2%) episodes of confirmed infection recurrence within the first year after the index procedure. EQ-index scores at 1-year post-operatively were significantly improved when compared to pre-operative scores (p=0.008). At 1-year post-operatively, EQ-index scores in patients who underwent free flap was similar compared to local flaps (p=0.410) and in those who underwent primary closure for tibial osteomyelitis (p=0.070). Conclusions. Microsurgical single stage surgery can achieve high flap survival rate (95.7%). Free flaps fail early due to anastomotic thrombus with no late failures seen. Free tissue transfer does not appear to give inferior QoL compared to matched patients with local flaps or direct closure in tibial osteomyelitis

Aim. This study seeks to outline the clinical, laboratory, and imaging features of patients with pyogenic spondylitis. It aims to define a novel imaging sign that could indicate the severity of suppurative spondylitis, aiding in its early diagnosis and treatment. Method. This retrospective study included 137 patients from 2013 to 2023. Through the analysis and summary of imaging characteristics among all patients, we identified a distinct MRI sign known as ‘the Disc Penetration sign’ (DP). This sign is defined as an image finding on sagittal MRI depicting the anterior and posterior penetration of an abscess through the intervertebral disc space, affecting both the anterior margin of the vertebrae and the structures within the spinal canal. Observational parameters included WBC, ESR, CRP, hemoglobin, and albumin levels. Documentation of the study included location and segment of the lesion, presence or absence of spinal cord compression, and paravertebral abscesses. Results. 56 patients presented with the Disc Penetration sign(DP) and 81 did not. In both groups, there were no significant differences in gender ratio or age (P > 0.05). However, significant differences were observed in the presence of comorbid diabetes and chronic kidney disease (p < 0.05). The DP group had a significantly greater ESR level (74.30±33.79 mm/h vs. 51.46±30.46 mm/h, P < 0.001) and CRP level (47.28 mg/L vs. 26.18 mg/L, P = 0.003). Additionally, the DP group had a significantly lower Hb (100.66±19.82 g/L vs. 116.99±19.99g/L,P < 0.001) and the serum albumin level (28.81±6.59 g/L vs. 34.09±6.17 g/L,P < 0.001). Imaging results showed no significant differences in affected spinal segments or parts (p>0.05). Patients in the DP group showed a higher likelihood of developing paravertebral abscesses compared to those in the non-DP group (n = 54 [96.4%] vs. n = 33 [40.7%], P < 0.001), and also exhibited a higher incidence of spinal cord compression(n = 32 [57.1%] vs. n = 17 [21.0%], P < 0.001). Conclusions. The study suggests that the Disc Penetration sign in pyogenic spondylitis patients correlates with more severe inflammation and higher incidence of paraspinal abscess, pointing to worse stability of the spine, longer bone restructuring time, and potentially poorer prognosis. These findings enable clinicians to rapidly assess the severity of the disease and prognosticate outcomes more effectively We emphasize the need for early, pathogen-specific diagnosis and treatment, particularly considering surgical intervention for patients demonstrating substantial paraspinal abscesses or spinal instability

Aim. Periprosthetic joint infection (PJI) is a complication of total joint arthroplasty that typically requires revision surgery for treatment. Systemic antibiotics are usually held prior to surgery to improve yield of intraoperative cultures. However, recent studies suggest that preoperative aspirations have a high concordance with intraoperative cultures, which may allow surgeons to initiate antibiotic treatment earlier. The purpose of the study was to investigate the effect of Pre-surgical systemic antibiotic therapy on the bacterial burden within the periprosthetic space and systemic immune reaction. Method. PJI was induced with MSSA (Xen36) S. aureus in the right knee of 16-week old, female, C57BL6 mice using a previously validated murine model. Mice were randomized to three groups (n=8, each): control; Vanc, receiving systemic vancomycin (110mg/kg, SQ, twice daily); or VancRif receiving vancomycin same as in Vanc group, plus rifampin (12mg/kg dose, IV, once daily). Following 2 weeks of treatment, mice were euthanized and periprosthetic bone, soft tissue and the implant were harvested. Bacterial burden, colony forming units (CFUs), was quantified in soft tissue, tibial bone, and on the implant. Specifically, tissues were homogenized and serially plated for CFUs, while the implant was sonicated and then plated for CFUs. The host immune response was analysed through weighing inguinal and iliac lymph nodes and through measuring serum amyloid A (SAA). Non-parametric pairwise group comparisons of the three outcome measures were performed using a Mann-Whitney U test. Results. VancRif, the combined treatment significantly reduced bacterial burden in the periprosthetic soft tissue, bone, and implant compared to control (p<0.001) and Vanc alone (p<0.001). While not significant, Vanc alone did reduce bacterial load as compared to control. The ipsilateral weight of the iliac lymph nodes was significantly reduced in Vanc and VancRif mice compared to controls (p<0.001), was well as in VancRif versus Vanc alone (p<0.001). Interestingly, SAA levels did not significantly differ among all groups. During tissue harvesting, minimal purulence was observed in antibiotic treatment groups, unlike controls. Conclusions. Treating active PJI with vancomycin alone decreases periprosthetic bacterial loads and reduces the local immunological response. This effect is significantly enhanced with the combined rifampin use. These findings could suggest that when culture positive PJI is diagnosed, pre-surgical treatment with antibiotics may decrease immunosuppression and soft tissue infiltration, leading to a better chance of infection cure with subsequent surgical debridement. Histological investigations and repeat experiments involving subsequent surgical treatment are underway. Acknowledgements. Funding comes from internal institutional grants

Aim. Local antibiotics, delivered to the site of infection, achieve high tissue concentrations and are used as an adjunct to systemic therapy. Local gentamicin provides levels well above the minimum inhibitory concentration and may be sufficient on its own, however, the efficacy of single or combination local antibiotics has not been studied. This retrospective study evaluated the effect of combination aminoglycoside and vancomycin local antibiotic treatment compared to aminoglycoside alone in the surgical management of bone infection. Method. We studied patients with microbiologically confirmed osteomyelitis and fracture-related infection, who had implantation of antibiotic carriers as part of their surgical management. Data including patient demographics, type of surgery, microbiological characteristics, BACH score, duration of antibiotic treatment and clinical outcomes were collected. Failure of therapy was a composite of recurrence of infection, continued or new antimicrobial therapy, or reoperation with suspected or confirmed infection at one year after index surgery. Results. There were 266 patients who met the inclusion criteria. Nine patients died before the outcome endpoint at 12 months and five patients were lost to follow up so were excluded. 252 patients were included in the final analysis and were well matched with regard to demographics, BACH score and microbiology. 113 patients had treatment with aminoglycoside alone and 139 patients had combination aminoglycoside and vancomycin. There was no difference in the failure rate between groups; 10/113 (8.8%) in the aminoglycoside alone and 12/139 (8.6%) in the combination group, p = 0.934. There was no difference for reoperation, ongoing suppressive antibiotic use, or clinical suspicion of infection. Multivariate analysis showed that there was no added benefit of combination therapy (OR 1.54: 95%CI 0.59-4.04, p=0.38). BACH score and low BMI were associated with increased risk of failure (BACH OR 3.49: 95%CI 1.13-10.76, p=0.03; Low BMI OR 0.91: 95%CI 0.84-0.99, p-0.037). The form of the carrier material (pellets or injectable paste) had no effect on failure rate (p=0.434). Aminoglycoside resistance (confirmed and presumed) occurred in 39/113 (34.5%) of the aminoglycoside only group and 36/139 (25.9%) of the combination group (p=0.137). The presence of aminoglycoside resistance had no effect on failure rate (OR 0.39: 95%CI 0.05-3.01, p=0.37). Conclusions. Clinical outcome was not improved by the addition of vancomycin to aminoglycoside alone as local therapy for the management of osteomyelitis and FRI. Laboratory measured resistance, using currently accepted breakpoints, may not be relevant in local therapy

Aim. Rifampicin and fluoroquinolone based therapy is generally considered as first-choice targeted oral antimicrobial therapy for staphylococcal prosthetic joint infections (PJI) treated with debridement, antibiotics and implant retention (DAIR). Alternative equally effective antimicrobial strategies are urgently needed due to toxicity and drug-drug interactions that frequently occur with this strategy. Data from recent clinical studies suggests equipoise for other antimicrobial treatment regimens. The objective of the Rifampicin Combination Therapy versus Targeted Antimicrobial Monotherapy in the Oral Antimicrobial Treatment Phase of Staphylococcal Prosthetic Joint Infection (RiCOTTA)-trial is to evaluate whether monotherapy with clindamycin is non-inferior to rifampicin/fluoroquinolone combination therapy in patients with staphylococcal PJI that are treated with DAIR. Method. The RiCOTTA-trial is a multicenter, non-inferiority, open-label, randomized controlled trial evaluating clindamycin versus rifampicin/fluoroquinolone combination therapy in the oral treatment phase in patients with staphylococcal PJI managed with DAIR. The trial is performed in 16 hospitals in the Netherlands. Eligible patients are adults with staphylococcal knee or hip PJI managed by DAIR. Patients are included one to six days before antibiotic treatment is switched from intravenous to oral therapy. Patients with a contraindication for rifampicin, with a megaprosthesis or who receive intravenous antibiotics for more than three weeks after initial debridement are excluded. Primary outcome is treatment success one year after finishing antimicrobial treatment. Success is defined as the absence of: i. Infection related re-surgery, ii. New episode of antibiotic treatment for infection of the index joint after the initial treatment phase of 12 weeks, iii. Ongoing use of antibiotics for the index joint at the end of follow-up, iv. Death. The estimated treatment success of rifampicin combination therapy is 85% and the monotherapy strategy is considered not inferior when the difference in treatment success will be less than 10%. Enrolment of 158 patients per group (316 in total) is needed to confirm non-inferiority of monotherapy with a power of 80%. The trial is currently open for enrolment. The study is approved by the Medical Ethics Committee Leiden, the Hague, Delft, the Netherlands and registered under EU trial number 2022-501620-26-00 in Clinical Trial Information System. Conclusions. Currently, the RiCOTTTA study is the largest randomised clinical trial that compares targeted oral monotherapy with rifampicin combination treatment for staphylococcal PJI. Noninferiority of monotherapy would result in a change in national PJI guidelines and enable clinicians to use a more patient-tailored approach when considering antibiotics for patients during the oral treatment phase of PJI

Aim. People awaiting surgery for bone and joint infection may be recommended to stop smoking to improve anaesthetic and surgical outcomes. However, restricting curative surgical treatment to non-smokers on the basis of potentially worse surgical outcomes is not validated for functional outcomes or quality of life differences between patients who do and do not smoke. This study used secondary analysis of trial data to ask: do peri-operative non-smokers have a greater improvement in their quality of life 12 months after surgery for bone and joint infection, compared with non-smokers?. Method. Participants in the SOLARIO and OVIVA clinical trials who had complete baseline and 12 month EQ-5D-5L or EQ-5D-3L scores were included. Smoking status was ascertained at baseline study enrolment from participant self-report. Normalised quality of life scores were calculated for participants at baseline and 12 months, based on contemporaneous health state scores for England. Baseline and 12 month scores were compared to calculate a post-operative increment in quality of life. Results. Mean quality of life increment over 12 months was +0.17 for people who reported smoking peri-operatively (95% confidence interval −0.55 to +0.89), compared to +0.23 for people who did not report smoking peri-operatively (95% confidence interval −0.48 to +0.94). Linear regression analysis found no significant difference between the improvement in quality of life for smokers and non-smokers (p>0.1). Mean increments for both groups were greater than estimates of Minimal Clinically Important Difference in quality of life in musculoskeletal conditions. [1,2]. Conclusions. People who smoke peri-operatively still experience an improvement in quality of life after surgery for orthopaedic infections, commensurate with the improvement experienced by non-smokers. Surgery should not be denied to people on the basis of reported smoking status alone