Cite this article: Bone Joint Res 2024;13(12):790–792.

Aims

This cross-sectional study aimed to investigate the in vivo ankle kinetic alterations in patients with concomitant chronic ankle instability (CAI) and osteochondral lesion of the talus (OLT), which may offer opportunities for clinician intervention in treatment and rehabilitation.

Aims. Cutibacterium acnes (C. acnes; previously known as Propionibacterium acnes or P. acnes) periprosthetic hip and knee infections are under-reported. While culture contamination with C. acnes occurs, true infections are important to recognize and treat. We sought to describe the demographics and treatment outcomes of patients with C. acnes periprosthetic joint infections (PJIs) of the hip and knee. Methods. Patients with C. acnes PJI between January 2005 and December 2018 were retrospectively reviewed utilizing the institutional total joint registry. Patients with monomicrobial PJI and two or more positive cultures were considered to have true C. acnes PJI. Patients with polymicrobial infection or with only one positive culture were excluded. This resulted in 35 PJIs (21 hips and 14 knees); the patients’ mean age was 63 years (35 to 84) and 15 (43%) were female. Mean follow-up was five years (1 to 14). Results. The median time to positive culture was five days (IQR 5 to 6) and median synovial fluid cell count was 22,583 cells (IQR 15,200 to 53,231). The median ESR was 25 mm/hr (IQR 7 to 37), and CRP was 15 mg/l (IQR 3 to 29). Of the 35 PJIs, 18 (51%) were treated with chronic antibiotic suppression without surgical intervention, and the remainder were treated with two-stage exchange arthroplasty. The two-year survival free of any revision was 94%. Four patients failed treatment due to symptomatic infection, with three treated with two-stage exchange and one treated with irrigation and debridement with modular component exchange for a survival rate of 89% and 83% at two and five years, respectively. Conclusion. Laboratory evidence of C. acnes PJI in this cohort was typical compared to more conventional organisms. Cultures grew more quickly than previously thought in patients with C. acnes PJI. Treatment with two-stage exchange or chronic antibiotic suppression alone both had few treatment failures at mid-term follow-up. Cite this article: Bone Joint J 2024;106-B(12):1426–1430

Periprosthetic joint infection (PJI) represents a complex challenge in orthopaedic surgery associated with substantial morbidity and healthcare expenditures. The debridement, antibiotics, and implant retention (DAIR) protocol is a viable treatment, offering several advantages over exchange arthroplasty. With the evolution of treatment strategies, considerable efforts have been directed towards enhancing the efficacy of DAIR, including the development of a phased debridement protocol for acute PJI management. This article provides an in-depth analysis of DAIR, presenting the outcomes of single-stage, two-stage, and repeated DAIR procedures. It delves into the challenges faced, including patient heterogeneity, pathogen identification, variability in surgical techniques, and antibiotics selection. Moreover, critical factors that influence the decision-making process between single- and two-stage DAIR protocols are addressed, including team composition, timing of the intervention, antibiotic regimens, and both anatomical and implant-related considerations. By providing a comprehensive overview of DAIR protocols and their clinical implications, this annotation aims to elucidate the advancements, challenges, and potential future directions in the application of DAIR for PJI management. It is intended to equip clinicians with the insights required to effectively navigate the complexities of implementing DAIR strategies, thereby facilitating informed decision-making for optimizing patient outcomes. Cite this article: Bone Joint J 2024;106-B(12):1377–1384

The December 2024 Foot & Ankle Roundup³⁶⁰ looks at: Tibiotalar sector and lateral ankle instability; Isolated subtalar fusion and correction of progressive collapsing foot deformity; Diabetic control and postoperative complications following ankle fracture fixation; Are insoles of any benefit for plantar fasciitis?; Postoperative foot shape and patient-reported outcome following surgery for progressing collapsing foot deformity; Calcaneo-stop procedure for symptomatic flexible flatfoot in children.

Aims

Calcaneal osteomyelitis remains a difficult condition to treat with high rates of recurrence and below-knee amputation, particularly in the presence of severe soft-tissue destruction. This study assesses the outcomes of single-stage orthoplastic surgical treatment of calcaneal osteomyelitis with large soft-tissue defects.

Aim. Antimicrobial peptides occur naturally in our intrinsic immune system. PLG0206 is a novel, engineered, 24-amino acid peptide which has broad-spectrum antimicrobial activity, including in biofilm and against multi-drug resistant pathogens (1,2). This is the first clinical study to evaluate the safety and tolerability of PLG0206 when administered via an irrigation solution in patients with periprosthetic joint infections (PJI) following total knee arthroplasty (TKA) during debridement, antibiotics, and implant retention (DAIR). Secondary objectives were to evaluate pharmacokinetics (PK), biomarkers and initial clinical efficacy at one year post-DAIR procedure. Method. This prospective, multicenter, open-label, interventional study assessed two dose levels of PLG0206. Fourteen patients underwent revision for PJI after TKA. At the end of debridement, they received a single intra-articular irrigation of PLG0206 into the wound cavity lasting 15 minutes at concentrations of 3 mg/mL (n=7) or 10 mg/mL (n=7). Patients received post-operative care and intravenous/oral antimicrobial therapy as per their institutional guidelines. Patients were monitored for safety and signs of relapse or persistent infection for 12 months post study drug administration and PK and blood biomarkers were assessed. Results. All patients completed their final study assessment at Day 365. Over the 1-year follow-up, only one recurrence (7%) was noted at Day 169 in the low-dose cohort. Following dosing, nine patients (64.3%) had limited systemic exposure; maximum plasma concentration occurred 1-hour post-administration and declined rapidly to undetectable levels by 24 hours following treatment in all patients. The incidence of drug related treatment-emergent adverse events (TEAEs) was low. Two patients, both in the higher dose cohort, experienced a transient drug related TEAE; one of hypertransaminasaemia and one of neuralgia. Both events were moderate in severity and resolved within two weeks of onset. Conclusions. A single 15-minute irrigation of PLG0206 into the wound cavity of patients undergoing a DAIR procedure for PJI following TKA, is safe and well tolerated by patients. This new antimicrobial peptide offers a promising therapeutic option in musculoskeletal infection. The initial clinical efficacy is encouraging but now needs to be investigated in a much larger clinical trial

Aim. Arthroscopic interventions have revolutionized the treatment of joint pathologies. The appropriate diagnostics and treatment are required for infections after ligament reconstructions using non-resorbable material such as tendon grafts, anchors, and sutures, prone to biofilm formation. The infection rate is around 1% for knee and shoulder, while up to 4% for Achilles tendon reconstructions. Despite high number of these procedures worldwide, there is limited evidence about the best treatment protocol. Our study aimed to provide a general protocol for the treatment of small implants for soft tissue reconstruction. Method. Between 2019 and 2023, we treated 48 infections of ligament, meniscus, and tendon reconstructions out of 7291 related procedures performed in the same time period. Early infection (<30 days) were treated with an arthroscopic debridement and implant retention (DAIR), except Achilles tendons had open DAIR, while those with delayed or chronic infection (>30 days) were treated with extensive debridement and lavage combined with one-stage exchange (OSE) or implant removal. During surgery, at least 5 microbiological s and samples for histopathology were obtained. The removed material was sonicated. After surgery, all patients were one week on iv. antibiotics, followed by oral antibiofilm antibiotics for 6 weeks including rifampicin and/or a quinolone. All patients were followed for at least 1 year. Failure was defined as the need for additional revision surgery after finished iv. antibiotic treatment. Results. Among 48 patients, 38 were early and 10 were late acute or chronic infections. The incidence of infection for our cohort was 0.7%. We observed 27 infections after ligament reconstruction of the knee, 15 of the shoulder, 5 of the ankle, and 1 infection of the elbow joint. 40 patients were treated with DAIR, 5 with OSE, and 3 with implant removal. We had 11 C. acnes, 10 S. aureus, 6 S. epidermidis, 2 P. aeruginosa, 2 S. lugdunensis, 10 mixed flora, and 3 culture-negative infections. 12 patients received antibiotics before surgery, and all culture-negative infections were related to this subgroup. We observed 2 failures, both in a combination of proximal tibial osteotomy and ligament reconstruction of the knee joint. The success rate of our protocol was 96%. Conclusions. Prompt surgical treatment followed by 6 weeks of antibiotic treatment cured 96% of infections of small implants after reconstruction procedures of knee, shoulder, and ankle joints. Our study is the first to provide a treatment protocol for infections of small implants after ligament reconstruction procedures

Aim. This study aims to evaluate the effectiveness of a pre-formulated irrigation solution. 1. (containing ethanol, acetic acid, sodium acetate, benzalkonium chloride, and sterile water) compared to saline solution in managing acute periprosthetic joint infections (A-PJI) during Debridement, Antibiotic, and Implant Retention (DAIR) surgeries. The primary objective is to assess the healing rate using this solution. 1. versus saline in A-PJI patients, with “cure” defined by a set of criteria including no recurrence, wound issues, or need for ongoing suppressive antibiotics after 1 year. Principio del formularioFinal del formulario. Method. This single-center, randomized controlled trial will involve patients with acute periprosthetic infections undergoing standard DAIR surgery, divided into two groups: one receiving saline solution and the other receiving pre-formulated solution. 1. The study is single-blinded, with patients unaware of their group assignment. The study is registered at ISRCTN: https://doi.org/10.1186/ISRCTN10873696. Inclusion criteria include patients over 18 with hip or knee prostheses suffering from acute or hematogenous periprosthetic infections, while exclusion criteria include a history of prior debridement or multiple infected implants, among others. Principio del formularioFinal del formulario A total of 50 subjects are needed for statistical significance, with a 5% dropout rate anticipated. An interim safety analysis will assess early effectiveness and adverse effects, and the results are presented in this study. Data will be managed in online databases and analyzed using SPSS software, with a significance level of p<0.05. Results. Twenty-four patients were eligible for analysis, twelve in each group. The overall average age was 75 years, and the gender distribution was predominantly female (9 F and 3 M in each group). No significant differences were found at the baseline characteristics level between the two groups (p>0.05). The minimum follow-up of 1 year was achieved in all cases except three due to deaths not related to periprosthetic infection. Regarding efficacy, a non-statistically significant difference was observed (p>0.05), with 58% in the serum group and 42% in the pre-formulated irrigation solution. 1. group (X. 2. = 0.17, p=0.683). The average hospital stay was 38.42 days (SD 26.32) in the pre-formulated irrigation solution group. 1. and 24.42 days (SD 18.72) in the serum group, with this difference being not significant (t=1.5, p=0.148). Conclusions. While the current analysis indicates no significant differences between both groups in terms of efficacy, the study's ongoing progress and the inclusion of a larger sample size could potentially yield more definitive results

Aim

An instrumented blood culture system automatically flags when growth within the culture medium has been detected (‘work in progress’), and subsequently when the organism has been identified.

We explore using this data to switch patients to oral therapy within 72 hours post-surgery, reducing costs and improving antimicrobial stewardship.

Aim. Successful management of native Joint septic arthritis (SA) hinges on the timely initiation of appropriate antibiotic therapy coupled with thorough joint debridement. Since 2018 we have implemented a protocol for empirical antibiotic in patients with suspected SA recommending amoxicillin/clavulanate (and cotrimoxazole in cases of beta-lactams allergy) based on local flora. Nevertheless we have recently found that institutional compliance to the protocol is only about 50% and many physicians are still choosing alternative wider spectrum regimens. The aim of this study is to assess whether current clinical and epidemiological characteristics of patients treated for this condition justify an update or whether previous recommendations are still valid. Method. All adult patients admitted to our institution with suspected SA between 2018-2022 were retrospectively reviewed. Data was collected from electronic medical records and then compared to similar data previously collected concerning the 2009-2017 period (that served as a basis for the aforementioned protocol). Results. A summary of available data from both time periods can be found in table 1. Overall, among the 35 patients with positive microbiology treated between 2018-2022, amoxicillin/clavulanate is appropriate for 30 (86%) of isolates (vs 88% in historic control). Analysing the whole cohort, we found that previous contact with healthcare services (hospital admission or prolonged ER stay) (p=0.0044) and antibiotic treatment for any infection (p= 0.0213) in the previous six months correlate with resistance to amoxicillin/clavulanate. In these patients, the proposed alternative cotrimoxazole is effective in 77% of cases. Conclusions. The institutional guideline for empirical antibiotic therapy in native joint SA remains adequate and there seems to be no justification to deviate from protocol except in cases of patients admitted to the hospital or antibiotic treatment in the previous six months. In these cases methicillin-resistance coverage is probably appropriate. Pseudomonal coverage is seldom required in SA. For any tables or figures, please contact the authors directly

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. 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

Introduction. Since the expanded war in Ukraine in 2022, explosives, mines, debris, blast waves, and other factors have predominantly caused injuries during artillery or rocket attacks. These injuries, such as those from shelling shrapnel, involve high-energy penetrating agents, resulting in extensive necrosis and notable characteristics like soft tissue defects and multiple fragmentary fractures with bone tissue defects and a high rate of infection complications caused by multi resistant gram-negative (MRGN) pathogens. Material and Methods. We conducted a prospective study at our center between March 2022 and December 2023. Out of the 56 patients from Ukraine, 21 met the inclusion criteria who had severe war injuries were included in the study. Each of these patients presented with multiple injuries to both bones and soft tissues, having initially undergone treatment in Ukraine involving multiple surgeries. The diagnosis of infection was established based on the EBJIS criteria. Prior to our treatment patients had undergone multiple revision surgeries, including debridement, biopsies, implant and fixator replacement. Additionally, soft tissue management required previously VAC therapy and flap reconstruction for successful treatment. Results. All 21 infections manifested as bone infections (11; 52%), followed by implant-associated infections (5; 24%), soft tissue infections (4; 19%), and septic arthritis (1; 5%). In all patients, the infection was polymicrobial, caused by 3- and 4-MRGN pathogens, as Klebsiella pneumonia 4MRGN, Proteus mirabilis 4MRGN, Enterobacter cloacae 4MRGN etc. Upon admission, all patients carried a diagnosis and exhibited signs indicative of chronic infection. 19 (90.5%) patients required complex antibiotic regimens combined with multiple wound revisions and debridements, changes of fixators and combination of systemic and local antibiotic therapy. In 6 patients (28%) high dosages of local antibiotics such as gentamycin, vancomycin and meropenem were incorporated into a carrier of bio-absorbable calcium sulfate, calcium sulfate/hydroxyapatite which were introduced into the hip joint, femoral canal or bone defect for dead space management during the surgery. When local antibiotics were administered at intervals, the microbiology results at implantation showed negative results. 2 (9%) patients had new infections (different site, different pathogens), 1 (4.8%) is still under the treatment. In 17 (81%) patients infection complications were treated successfully with no recurrence of infection. Conclusion. War injuries result in complex bone and soft-tissue infections caused by 3-, 4-MRGN pathogens. Addressing this challenge necessitates multidisciplinary approach with multiple, thorough surgical debridements, effective local, and systemic antimicrobial therapy. As for the outlook we can see potential in local antibiotic carriers

Aim. Periprosthetic joint infection (PJI) and periprosthetic fracture (PF) are one of the most devastating complications in arthroplasty. Each complication by itself is challenging to solve. Yet, simultaneously, both complications are inconceivably complex to deal with, while the treatment regimen of PJI and PF are contradictory. Chronic PJI most often requires implant removal, while PF requires stability, regularly achieved by stable osteosynthesis. This study aims to (1) analyse the success rate of PJI with following concomitant PF during the treatment course in total hip arthroplasties (THA) and (2) to determine the risk factors for reinfection and subsequent revision surgery after treatment of PJI and PF. Method. This restrospective study analyzed 41 patients with concomitant PJI and PF during the PJI treatment period from 2013 to 2022 involving THA. Patients were divided in two cohorts termed success and failure and were statistically compared. The median follow-up time was 66 months (>12 months). All patients were considered individually and treated according to their individual needs in fracture and infection treatment. Re-arthroplasty survival was analyzed using the Kaplan-Meier method. Relevant risk factors were analyzed using the Mann-Whitney test or Chi-square, depending on the variable's scale. Results. The overall success rate of our cohort was 70,7%. Twelve patients required re-operation due to reinfection, resulting in a cumulative 12-month-reinfection rate of 19,5%. The estimated cumulative reinfection free survival rate was 68,3%. Significance in risk factors for failure were found in pathogen virulence grade, Difficult to treat pathogen and number of debridement during interval. On average the Harris Hip score was 66 in the group of reinfection compared to 77 in the group of success. Conclusions. Reoperation and re-infection rate remains high in patients with simultaneous PJI and PF in THA. Due to the heterogeneity of the fractures, soft tissue conditions and pathogens found, treatment must be individualised to salvage the limb. However, small cohorts impact the statistical strength negatively due to instances of two rare complications

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. 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. 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. Irrigation and debridement with an irrigation solution are essential components of the surgical management of acute and chronic periprosthetic joint infection (PJI). Nevertheless, there is a lack of agreement regarding the most effective solution to use. The aim of the study was to perform a systematic review and meta-analysis of the current literature concerning the efficacy of different irrigation solutions over bacterial biofilm. Method. This study was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analysis extension for Network meta-analysis (PRISMA-NMA) checklist for systematic reviews and meta-analyses. A comprehensive literature search of PubMed, Cochrane Library, Web of Science and Scopus databases from inception to September 1, 2023. We combined terms related to PJI, biofilm and irrigation solutions studied in vitro. We performed a network meta-analysis to analyze which irrigation solution achieved a higher reduction of colony forming units (CFU) after specific exposure times, always with a maximum of five minutes, replicating intraoperative conditions. Effect-size was summarized with logarithmic response ratio (logRR) and 95% confidence intervals (95% CI). The rank probability for each treatment was calculated using the p-scores. Results. We screened 233 potential sources. Following deduplication, screening and full-text review, four studies with ten irrigation solutions for different duration of exposures were included, always less than five minutes, replicating intraoperative conditions. Solutions were studied over mature biofilms of most frequent bacteria grown over metal, bone cement or polyethylene surfaces. The highest effect was achieved with povidone iodine 10% during 5 minutes (logRR: −12.02; 95% CI: −14.04, −9.99). The best ranked solutions were povidone iodine 10% during five, three and one minute (respective p-scores: 0.977, 0.932, 0.887) and its combination with hydrogen peroxide for 3 minutes (p-score: 0.836). Povidone iodine 0.3% acting for 5 minutes completed the top 5 best ranked solutions in this study (p-score: 0.761). We assumed that there were no inconsistencies in our network because after examining both scenarios, with and without inconsistencies, the results were not significantly different. Conclusions. Our results show that 10% povidone-iodine is the best antiseptic solution when studied in vitro in the context of prosthetic joint infection. However, the included studies did not evaluate the possible cytotoxic effects of these solutions. This should also be taken into account before choosing the most appropriate antiseptic solution

Aim. Periprosthetic joint infection (PJI) is one of the most devastating complications after joint replacement. It is associated with high morbidity and economic burden when misdiagnosed as an aseptic failure. Among all cases of PJI, up to 25% could yield negative cultures. Conversely, among cases of aseptic failures, up to 30% may actually be undiagnosed PJIs. In PJIs microbiological diagnosis is a key step for successful treatment. Sonication of the removed prosthesis is more sensitive than conventional periprosthetic-tissue culture, especially in patients who received antimicrobial therapy before surgery. This study aimed to compare the diagnostic value of classic sonication fluid cultures (SF-C) and sonication fluid incubation in blood culture bottle (SF-BCB). Method. Between 2016 and 2018 we analysed 160 revision procedures of joint arthroplasties. For each procedure, at least 5 microbiological and multiple histopathological samples were harvested, and explant sonication was performed which was further analysed by SF-C and SF-BCB. For SF-C classical cultivation of sonication fluid was performed. While for SF-BCB, 10 mL of sonication fluid was inoculated into aerobic and anaerobic lytic blood culture bottles. The definite diagnosis of PJI was based on the EBJIS definition. Results. Among 160 revisions, 59 PJIs were identified, 15 patients were treated with the debridement and implant retention, 7 patients with the one-stage and 35 with the two-stage exchange, remaining 2 were partial revisions. The sensitivity of SF-C and SF-BCB were 81.5% and 94.9%, respectively. The mismatch of microbe identification was observed in 5 cases. We observed positive SF-C while negative SF-BCB in 4 cases, among them having 2 positive histology. While 12 patients have negative SF-C and positive SF-BCB, among them 3 have positive and 6 negative histology. Among these 12 patients, typical low-grade microbes were identified in 9 cases (5 cases of C. acnes, 3 cases of S. epidermidis, and 1 case of S. capitis). Conclusions. The weakest point in all PJI diagnostic criteria is their sensitivity. SF-BCB demonstrates higher sensitivity in diagnosing PJI compared to SF-C. Therefore, it appears prudent to incorporate SF-BCB into the diagnostic protocol for all patients exhibiting either low-grade PJI symptoms or experiencing undiagnosed, presumably aseptic failures, where the likelihood of misdiagnosing infection is greatest