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. Two types of national registers surveil infections after primary total hip arthroplasty (THA) in Norway: The National surveillance system for surgical site infections (NOIS) that surveil all primary THAs 30 days postoperatively for surgical site infections (SSI), and the Norwegian Arthroplasty Register (NAR) that follow all THAs until any surgical reoperation/revision or the death of the patient. Since these registers report on the same THAs we assessed correspondence between and time trends for the two registers in period 2013 to 2022. All reported THAs were included. Method. The THAs were matched on a group level according to sex, age and ASA-class. In addition to descriptive statistics, adjusted Cox regression analyses were performed with adjustment for sex, age group (<45, 45-54, 55-64, 65-74, 75-84, >85 years) and ASA-class (1, 2, 3, 4 and missing). Changes in annual incidence and adjusted hazard rate (aHR) was calculated. Endpoints in the NOIS were 30-Days SSI and 30-Days reoperation for SSI. Endpoints in the NAR were 30-Days and 1-Year reoperation for periprosthetic joint infection (PJI). Results. The NOIS had registered 87,923 THAs with 1,393 (1.58%) SSIs and 765 (0.87%) reoperations for SSI within 30 postoperatively. The NAR had registered 91,194 THAs with 725 (0.80%) reoperations for infection after 30 days, and 1,019 (1.21%) reoperations for infections after one year. The distribution of sex, age and ASA-class was near identical in the two registers. There was a mean annual reduction in risk of both SSI (aHR 0.92 (95% CI 0.90-0.93)) and reoperation for SSI (0.95(0.92-0.97)) and PJI (30-Days: 0.96 (0.94-0.99), 1-Year: 0.95-0.99)) over the period 2013-2022. Conclusions. The NOIS and the NAR have excellent completeness and the registrations in both registers may be considered representative for the Norwegian population. Not all SSI are reoperated. The incidence and risk of SSI (NOIS) and reoperation for PJI (NAR) is declining and may reflect a true reduction in incidence of PJI after primary THA

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. Daptomycin plus fosfomycin combination therapy is a valuable strategy for treating staphylococcal osteoarticular infections. Considernig that each gram of fosfomycin contains 330 mg of sodium, electrolytic imbalance due to sodium overload could pose safety issues, especially in the cardiopatic patients and/or in the frail elderly. The aim of this study was to compare the efficacy of using reduced vs. standard daily dose fosfomycin in combination with daptomycin in a cohort of patients with osteoarticular infections. Method. This analysis included adult patients with osteoarticular infections admitted to the Infectious Diseases Unit of our University hospital in the period Nov 2022 – Feb 2024 and who were treated with daptomycin (8-10 mg/kg/daily) plus 24h-continuous infusion (CI) fosfomycin at the standard-dose of 16 g daily (standard-dose group) or at the reduced-dose of 8-12 g daily (reduced-dose group). All the patients underwent therapeutic drug monitoring (TDM) of fosfomycin for granting a pharmacodynamic target attainment of 24h-area under the concentration-time curve over minimum inhibitory concentration (AUC24h/MIC) >95 against Staphylococcus aureus with an MIC value up to 32 mg/L and of 70%t>MIC. Estimated glomerular filtration rate (eGFR) was assessed at each TDM session. Patient clinical outcome was assessed. Results. The standard- and the reduced-dose groups included 43 (29 males, 67.4%) and 21 (11 males, 52.4%) patients, respectively. No differences in median age (54 vs. 63 years, p=36), weight (80 vs. 76 kg, p=0.13) and type of diagnosis [prosthetic joint infections (16 vs. 29, p=0.38), osteomyelitis (2 vs. 9, p=0.72), septic arthritis (3 vs. 3, p=0.39) and spondilodiscitis (0 vs. 2, p=1.0)] were observed between the two groups. Median eGFR was similar in the standard vs. the reduced-dose group (109 vs. 98 mL/min/1.73m2, p=0.004). In the reduced-dose group, CI fosfomycin was administerd at 8 and 12 g/daily in 12 and 9 patients, respectively. There was no difference between the standard- and reduced-dose groups in attainment of the pharmacodynamic targets of AUC24h/MIC>95 (41/43 vs. 20/21, p=1.0), of 70%t>MIC (43/43 vs. 21/21 p=1.0) and of clinical cure (39/43 vs. 19/21, p=1.0). Conclusions. Combination therapy of 8-10 mg/kg/daily daptomycin plus 8-12 g/daily CI fosfomycin may be as effective as that of 8-10 mg/kg/daily daptomycin plus 16 g/daily CI fosfomycin. The fosfomycin reduced-dose strategy allows to decrease the daily sodium load by 25-50% compared to the standard dose, thus reducing the risk of cardiac adverse events. TDM may be a valuable strategy for individualizing fosfomycin dose in patients with osteoarticular infections

Aim. Orthopedic implants play a tremendous role in fixing bone damages due to aging as well as fractures. However, these implants tend to get colonized by bacteria on the surface, leading to infections and subsequently prevention of healing and osteointegration. Recently, Roupie et al. showed that a nisin layer-by-layer based coating applied on biomaterials has both osteogenic and antibacterial properties. The Galleria mellonella larva is a well-known insect infection model that has been used to test the virulence of bacterial and fungal strains as well as for the high throughput screening of antimicrobial compounds against infections. Recently, we have developed an insect infection model with G. mellonella larvae to study implant-associated biofilm infections using Kirschner (K)-wires as implant material. Here, we would like to test the antibacterial capacity of nisin layer-by-layer based coatings on K-wires against Staphylococcus aureus in the G. mellonella larva implant infection model. Method. Prior to the implantation procedure, G. mellonella larvae are maintained at room temperature on wheat germ in an incubator. The larvae received bare titanium K-wires (uncoated), or either control-coated or nisin-coated K-wires. After one hour, the larvae were injected with 5×10. 5. S. aureus bacteria per larva (i.e., hematogenous implant infection model). Next, the larvae were incubated at 37. o. C in an incubator and the survival of the larvae was monitored for five days. Moreover, the number of bacteria on the implant surface and in the surrounding tissue was determined after 24h of incubation. Further, scanning electron microscopy (SEM) analyses were performed to study the effect of nisin on biofilm formation. Results. The larvae receiving the nisin-coated K-wires showed significantly higher survival rates compared to uncoated titanium K-wires, although not when compared to control-coated K-wires. A more than 1-log reduction in number of bacteria on the implant surface and in the surrounding tissue was observed in larvae receiving the nisin-coated K-wires, when compared to uncoated titanium K-wires SEM analysis showed reduced colonization of the bacteria nisin-coated K-wires compared to the controls. Conclusions. In conclusion, the antimicrobial nisin layer-by-layer based coating applied on titanium surfaces is able to prevent implant-related S. aureus biofilm infection in G. mellonella and is a promising antimicrobial strategy to prevent implant-related infections

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

Aims

Pain is the most frequent complaint associated with osteonecrosis of the femoral head (ONFH), but the factors contributing to such pain are poorly understood. This study explored diverse demographic, clinical, radiological, psychological, and neurophysiological factors for their potential contribution to pain in patients with ONFH.

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. Antibiotic prophylaxis is central in preventing postoperative spine infections, yet knowledge of clinical spine tissue antibiotic concentrations remains limited. Pooled postoperative spine infection rates are constant (approximately 3%), resulting in severe patient morbidity, mortality, and prolonged hospitalization. Current antibiotic dosing regimens often involve fixed doses based on empirical knowledge, surrogate measures (plasma samples), non-clinical evidence (experimental models), and inferior methodology (tissue specimens). Therefore, personalized antibiotic dosing may be the future of antibiotic prophylaxis to prevent postoperative infections, especially implant infections. The aim was to continuously evaluate intra- and postoperative cefuroxime target spine tissue concentrations in long-lasting spine surgery after personalized dosing by repeated weight-dosed intravenous administrations. Method. Twenty patients (15 female, 5 male) scheduled for long-lasting spine deformity surgery with hypotensive anaesthesia were included; median age (range): 17.5 years (12-74), mean BMI (range): 22.2 (16.2-37.7), and mean surgery time (range): 4h 49min (3h 57min-6h 9min). Weight-dosed cefuroxime (20 mg/kg) was administered intravenously to all patients on average 25 min before incision and repeated after 4 hours. Microdialysis catheters were placed for sampling of cefuroxime concentrations in vertebral bone (only intraoperative sampling), paravertebral muscle, and subcutaneous tissue as soon as possible after surgery start. Upon wound closure, two additional catheters were placed in the profound and superficial part of the wound. Microdialysis and plasma samples were obtained continuously intra- and postoperative for up to 12 hours. The primary endpoint was (based on cefuroxime time-dependent efficacy) the time with cefuroxime concentrations above the clinical breakpoint minimal inhibitory concentration for Staphylococcus aureus of 4 µg/mL in percentage (%fT>MIC4) of. (a). patients’ individual surgery time,. (b). first dosing interval (0-4 hours),. (c). second dosing interval (4-12 hours). Results. Mean cefuroxime %fT>MIC4 (range) of:. (a). patients’ individual surgery time was 100% (100-100%) in all investigated tissues. (b). the first dosing interval was 93% (93-93%) in vertebral bone, paravertebral muscle, subcutaneous tissue, and 99% (99-100%) in plasma. (c). the second dosing interval was 87% (52-100%) in paravertebral muscle, 89% (52-100%) in subcutaneous tissue, 91% (71-100%) in the profound wound, 94% (72-100%) in the superficial wound, and 71% (42-100%) in plasma. Conclusions. Personalized cefuroxime dosing by repeated weight-dosed (20 mg/kg) intravenous administrations provided homogenous and therapeutic spine tissue exposure across all investigated tissues and plasma in long-lasting spine surgery with hypotensive anaesthesia (up to 11 hours). Thus, personalized cefuroxime dosing may decrease the risk of postoperative spine infection, especially in cases with implant insertion

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

Aims. Bone and joint infections cause significant morbidity, often requiring combination medical and surgical treatment. The presence of foreign material reduces the number of organisms required to cause an infection. The aim of this study was to assess whether there was a difference in the species of organism identified on culture in osteomyelitis compared to prosthetic joint infection. Method. This was a retrospective observational cohort study of patients that had surgical intervention for prosthetic joint infection or osteomyelitis with positive microbial culture between 2019 and 2022. Data including patient demographics, site of injury, BACH score for osteomyelitis and JS-BACH score for prosthetic joint infection, organism classification and antibiotic resistance to vancomycin and gentamicin were extracted from the medical record. Logistic and multiple regressions were used to adjust for potential confounding variables. Results. A total of 445 patients were included in the study; 267 patients with osteomyelitis or fracture-related infection and 177 patients with prosthetic joint infection. The patients with prosthetic joint infection were older (Mean age 70 for PJI; IQR 60-77 vs 56 for OM/FRI; IQR 39-64), more likely to be female (55.6% vs 26.2%) and had a higher BMI and ASA compared to those with osteomyelitis. Symptom duration tended to be longer in osteomyelitis/FRI (p<0.001). Staphylococcus aureus was the most common pathogen isolated in both osteomyelitis (155/267 (58.1%)) and prosthetic joint infection (85/177 (48.9%), followed by other Gram negative pathogens with 77/267 (28.8%) in osteomyelitis and 48/177 (27.1%) in prosthetic joint infection. On multivariate analysis, there was no difference between the rate of Staphylococcus aureus infection between the two groups. The rate of polymicrobial infection was higher in patients with osteomyelitis (92/267 (34.5%)) compared to prosthetic joint infection (38/177 (23.7%), however after adjustment for confounders there was no difference, p = 0.842. There was no difference in the presence of gentamicin resistant organisms or vancomycin resistant Gram positive organisms in osteomyelitis compared to prosthetic joint infection. Conclusion. Causative pathogens are similar in these two common forms of bone and joint infection. There was no significant difference in the identification, presence of polymicrobial infection or gentamicin and vancomycin resistance in organisms isolated in osteomyelitis compared to prosthetic joint infection. This may have implications for empiric antibiotic choice and local antibiotic therapy in the management of bone and joint infection

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. 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. It still remains unclear whether postoperative antibiotic treatment is advantageous in presumed aseptic revision-arthroplasties of the hip (rTHA) and knee (rTKA) with unexpected-positive-intraoperative-cultures (UPIC). The aim of this study was to evaluate if there is a difference in the septic and/or aseptic re-revision rate in patients with or without postoperative antibiotics. Method. In this retrospective propensity-score (PS) matched cohort-study we compared the re-revision rate and the microbiological spectrum in rTHA and rTKA treated with (AB-Group; n=70) and without (non-AB-Group; n=70) antibiotic treatment in patients with UPIC. Baseline covariates for PS-matching were type of revision, sex, Body-Mass-Index, age, Surgical-Site-Infection-Score, American-Society-of-Anesthesiologists-Classification, serum C-reactive-protein. All patients received routine antibiotic prophylaxis, but empiric AB treatment was started only in patients in the AB-Group. Post-operative treatment was decided on an individual basis according to the preference of the surgeon and the infectious disease specialist for a minimum duration of two weeks. In total, 90 rTHA (45 AB-Group, 45 in non-AB-Group) patients with UPICs and 50 rTKA (25 AB-Group, 25 in non-AB-Group) were included in the study. There was no significant variation in patient demographics. Results. After a median follow-up of 4.1 (IQR: 2.9-5.5) years after rTHA and rTKA, there was no higher re-revision rate (p=0.813) between the AB-group 10/70 (14.3%), and the non-AB-group 11/70 (15.7%). In the AB group, 4.3% (3/70) of patients underwent revision due to septic complications compared to 5.7% (4/70) in the non-AB group (survival log-rank: p=0.691). In total, 30/70 (42.9%) of patients in the AB-group and 23/70 (32.9%) of patients in the non-AB group were diagnosed as having an “infection likely” according to the PJI diagnostic criteria of EBJIS (p=0.223). All UPICs comprised low virulent microorganisms and were considered as a contaminant. In total, 68/70 (97.1%) of the patients in the AB-group received a dual antibiotic treatment for a mean duration of 41 (IQR: 23.5-56.5) days. Conclusion. Postoperative antibiotic treatment did not result in a decreased re-revision rate compared to non-antibiotic treatment in patients with UPIC in presumed aseptic rTHA and rTKA. UPICs with pathogens are likely to be a containment and therefore the classification of “infection likely” according to the EBJIS definition can be safely ignored

Aim. Candida species are uncommon pathogens causing prosthetic joint infection (PJI). This study evaluated the surgical management and outcome of Candida PJI. Methods. Patients with EBJIS Definition confirmed PJI, due to Candida species, from 19 medical centres were assessed. Demographic, diagnostic, medical and surgical treatment and outcome data were collected. Results. 269 patients were recruited with follow-up for at least one year. Mean age was 70.2 years (+/- 12.4) with 10.8% being immunocompromised. The most common fungal species were C. albicans (55.8%), C. parapsilosis (29.4%), C. glabrata (7.8%) and C. tropicalis (5.6%). Co-infection with bacteria occurred in 138 (51.3%) cases. DAIR was performed in 96 (36.2%) cases, with 169 (63.8%) having implant exchange or removal (76 one-stage, 78 two-stage, 11 removal/Girdlestone arthroplasty, 2 amputation). Patient demographics and antifungal therapy were similar in all surgical groups. Overall, treatment was successful in 156 (58%) cases. Failure was more likely in older patients (>70 years; p=0.008) and those who had DAIR (OR 1.945; 1.156-3.279; p=0.004). Failure was less likely with C. parapsilosis infection compared to C. albicans (31.6% vs 48%; p=0.037). DAIR patients had more co-infection with bacteria (63.5% vs 47.4%; p=0.013) and more previous surgeries (median 4 vs 3; p=0.007), but multivariate analysis showed that these were not independent risk factors for failure. There was no difference in mortality between DAIR patients and those with other surgery (13.5% vs 17.7%; p=0.372). DAIR was successful in 45/96 (46.9%) cases compared to 110/169 (65.1%) cases with other surgery (p<0.004). Early DAIR (surgery performed <I month from implantation/infection onset) was not more effective than late DAIR (surgery performed after 1 month)(early DAIR 44.4% cure vs 63.9% cure in late DAIR; p=0.004). Two-stage revision was successful in 54/78 (69.2%), which was significantly better than DAIR (p=0.003). One-stage revision was successful in 51/76 (67.1%) patients; also significantly better than DAIR (p=0.002), but equivalent to two-stage revision (p=0.777). Conclusion. DAIR was successful in less than half of patients with Candida PJI. We could not identify any subgroup which might have better outcomes with this surgical option. Interestingly, almost 90% of our patients with Candida PJI had no immunocompromise. One or two-stage revision offer a better option, if possible, and do not increase mortality

Aim. There is controversy regarding the use of Antibiotic-loaded cement (ALBC) as compared to non-antibiotic-loaded cement (NALBC) to reduce the overall infection rate without affecting implant survival or adding additional risks on fixation for primary total knee arthroplasty (TKA). Method. To conduct the analysis, we utilized the Catalan Arthroplasty Registry (RACat) for the TKAs implanted between 2005 and 2017. The primary variable recorded was the use of cement with or without antibiotics. Other recorded variables included were age, sex, diabetes mellitus, obesity, Charlson index and type of hospital. We analyzed the effect of ALBC vs. NALBC in reducing the risk of prosthetic infection at 3, 6, 12, and 24 months as well as prosthetic survival due to mechanical causes at 1, 5, and 10 years. Univariate and multivariable analyses of risk factors were conducted. Thereby, an interactive predictive model that determines the risk of prosthetic infection based on each patient's characteristics was created. Results. A total of 28,287 TKAs from the RACat were analyzed. In that total, there were 19,788 NALBC and 8,499 ALBC. The infection rates for TKAs with NALBC vs. those with ALBC at 3, 6, 12, and 24 months were respectively: 1.69% vs. 1.39% (p=0.132); 1.81% vs. 1.56% (p=0.147); 2.14% vs. 1.73% (p=0.030); 2.51% vs. 1.86% (p=0.001). A statistically significant reduction in periprosthetic infection rate was observed in the ALBC group at 12 and 24 months. No differences were observed between the two groups in terms of prosthetic mechanical survival. Being younger, male and having had previous knee surgery or having a high comorbidity index all led to a higher risk of prosthetic revision due to infection. Conclusions. The use of ALBC as a fixation method for TKA leads to a reduction in the risk of prosthetic infection without altering the mechanical survival of the implant. The creation of a predictive model helps determine the individualized risk of prosthetic infection based on the patient's characteristics

Aim. Periprosthetic joint infection (PJI) is a devastating complication that develops after total joint arthroplasty (TJA) whose incidence is expected to increase over the years. Traditionally, surgical treatment of PJI has been based on algorithms, where early infections are preferably treated with debridement, antibiotics, and implant retention (DAIR), while late infections with two-stage revision surgery. Two-stage revision is considered the “gold standard” for treatment of chronic PJI. In this observational retrospective study, we investigated the potential role of inflammatory blood markers (neutrophil-to- lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), systemic inflammatory index (SII)], systemic inflammatory response index (SIRI), and aggregate index of systemic inflammation (AISI)) as prognostic factors in two-stage exchange arthroplasty for PJI. Method. A single-center retrospective analysis was conducted, collecting clinical data and laboratory parameters from patients submitted to prosthetic explantation for chronic PJI. Laboratory parameters (PCR, NLR, MLR, PLR, SIRI, SII and AISI) were evaluated at the explantation time, at 4, 6, 8 weeks after surgery and at reimplantation time. Correlation between laboratory parameters and surgery success was evaluated, defined as infection absence/resolution at the last follow up. Results. 57 patients with PJI were evaluated (62% males; average age 70 years, SD 12.14). Fifty-three patients with chronic PJI were included. Nineteen patients completed the two-stage revision process. Among them, none showed signs of re-infection or persistence of infection at the last available follow up. The other twenty-three patients did not replant due to persistent infection: among them, some (the most) underwent spacer retention; others were submitted to Girdlestone technique or chronic suppressive antibiotic therapy. Of the patients who concluded the two-stage revision, the ones with high SIRI values (mean 3.08 SD 1.7, p-value 0.04) and MLR values (mean 0.4 SD 0.2, p-value 0.02) at the explantation time were associated with a higher probability of infection resolution. Moreover, higher variation of SIRI and PCR, also defined respectively delta-SIRI (mean −2.3 SD 1.8, p-value 0.03) and delta-PCR (mean −46 SD 35.7, p-value 0.03), were associated with favorable outcomes. Conclusions. The results of our study suggest that, in patients with PJI undergoing two-stage, SIRI and MLR values and delta-SIRI and delta-PCR values could be predictive of favorable outcome. The evaluation of these laboratory indices, especially their determination at 4 weeks after removal, could therefore help to determine which patients could be successfully replanted and to identify the best time to replant

Background and purpose. Previous publications have reported an increased but levelling out risk of revision for infection after total hip arthroplasty (THA) in Norway. We assessed the changes in risk of major (cup and/or stem, 1- or 2-stage) and minor revisions (debridement, exchange of modular parts, antibiotics and implant retention (DAIR)) for infection after primary THAs reported to the Norwegian Arthroplasty Register (NAR) over the period 2005-2022. Patients and methods. Primary THAs reported to the NAR from 2005 to 2022 were included. Time was stratified into time periods (2005-2009, 2010-2018, 2019-2022) based on a previous publication. Cox regression analyses, adjusted for sex, age and ASA-classification, with the first revision for infection were performed. Results. 140,338 primary THAs met the inclusion criteria. 1.3% (1,785) were revised for infection during the study period. 0.5% (638) had major revisions, whereas 0.8% (1,147) had DAIRs for infection. The risk of revision for infection was 1.2 (95%CI 1.1-1.4) for 2010-2018 and 1.0 (0.8-1.1) for 2019-2022 compared to 2005-2009. Compared to 2010-2018, the risk of revision for infection was 0.8 (0.7-0.9) for 2019-2022. The risk of DAIR for infection was 1.5 (1.3-1.9) for 2010-2018 and 1.2 (1.0-1.4) for 2019-2022 compared to 2005-2009. Compared to 2010-2018, the risk of DAIR for infection was 0.8 (0.7-0.9) for 2019-2022. The risk of major revision for infection was 0.8 (0.7-1.0) for 2010-2018 and 0.8 (0.6-1.0) for 2019-2022 compared to 2005-2009. Interpretation. The overall risk of revision for infection after THA, in Norway, has decreased in the period 2019-2022. The risk for DAIR initially increased in the period 2005-2009, levelled out 2010-2018 before starting to decrease in 2019-2022. The risk of major revision for infection was reduced in the period 2005-2009 before levelling out. This shows changes in revision strategies, but may also reflect a true decrease in periprosthetic joint infection