Aims. Debridement, antibiotics, and implant retention (DAIR) is a widely accepted form of surgical treatment for patients with an early periprosthetic joint infection (PJI) after primary arthroplasty. The outcome of DAIR after revision arthroplasty, however, has not been reported. The aim of this study was to report the success rate of DAIR after revision arthroplasty with a follow-up of two years. Methods. This retrospective study, conducted at the Sint Maartenskliniek, Nijmegen, the Netherlands, included 88 patients who underwent DAIR within 90 days of revision total hip or total knee arthroplasty between 2012 and 2019. Details of the surgical procedures and PJI were collected. Univariate analysis and a subgroup analysis of the culture-positive group were performed. Kaplan-Meier survivorship curves were constructed. Results. The overall success rate of DAIR, with respect to the retention of components and the cure of infection, was 68% after two years. DAIR performed with an interval of > 30 days after the index revision procedure (odds ratio (OR) 0.24 (95% confidence interval (CI) 0.08 to 0.72); p = 0.008), a repeated DAIR within 90 days (OR 0.37 (95% CI 0.14 to 0.97); p = 0.040), and the use of an immunosuppressive agent (OR 0.13 (95% CI 0.02 to 0.67); p = 0.012) were associated with a significantly reduced success rate. In the culture-positive group, a mismatch between the antibiotic treatment and the susceptibility of the organism was associated with a significantly lower success rate (OR 0.13 (95% CI 0.03 to 0.62); p = 0.007). Conclusion. DAIR is an acceptable form of surgical treatment for patients with a suspected early PJI after revision arthroplasty of the hip or knee. DAIRs performed after a prolonged interval, multiple DAIRs, and antibiotic mismatches were significantly associated with an increased risk of failure. Optimization of the host immune response and the prevention of antibiotic mismatch are modifiable factors that may improve the outcome. The high rate of mismatches was an important finding, underlining the need for a review of the local microbiological data, which might improve the outcome. Cite this article: Bone Joint J 2022;104-B(4):464–471

Aims. Debridement, antibiotics, and implant retention (DAIR) remains one option for the treatment of acute periprosthetic joint infection (PJI) despite imperfect success rates. Intraosseous (IO) administration of vancomycin results in significantly increased local bone and tissue concentrations compared to systemic antibiotics alone. The purpose of this study was to evaluate if the addition of a single dose of IO regional antibiotics to our protocol at the time of DAIR would improve outcomes. Methods. A retrospective case series of 35 PJI TKA patients, with a median age of 67 years (interquartile range (IQR) 61 to 75), who underwent DAIR combined with IO vancomycin (500 mg), was performed with minimum 12 months' follow-up. A total of 26 patients with primary implants were treated for acute perioperative or acute haematogenous infections. Additionally, nine patients were treated for chronic infections with components that were considered unresectable. Primary outcome was defined by no reoperations for infection, nor clinical signs or symptoms of PJI. Results. Mean follow-up for acute infection was 16.5 months (12.1 to 24.2) and 15.8 months (12 to 24.8) for chronic infections with unresectable components. Overall non-recurrence rates for acute infection was 92.3% (24/26) but only 44.4% (4/9) for chronic infections with unresectable components. The majority of patients remained on suppressive oral antibiotics. Musculoskeletal Infection Society (MSIS) host grade was a significant indicator of failure (p < 0.001). Conclusion. The addition of IO vancomycin at the time of DAIR was shown to be safe with improved results compared to current literature using standard DAIR without IO antibiotic administration. Use of this technique in chronic infections should be applied with caution. While these results are encouraging, this technique requires longer follow-up before widespread adoption. Cite this article: Bone Joint J 2021;103-B(6 Supple A):185–190

Aims. Current treatments of prosthetic joint infection (PJI) are minimally effective against Staphylococcus aureus biofilm. A murine PJI model of debridement, antibiotics, and implant retention (DAIR) was used to test the hypothesis that PlySs2, a bacteriophage-derived lysin, can target S. aureus biofilm and address the unique challenges presented in this periprosthetic environment. Methods. The ability of PlySs2 and vancomycin to kill biofilm and colony-forming units (CFUs) on orthopaedic implants were compared using in vitro models. An in vivo murine PJI model of DAIR was used to assess the efficacy of a combination of PlySs2 and vancomycin on periprosthetic bacterial load. Results. PlySs2 treatment reduced 99% more CFUs and 75% more biofilm compared with vancomycin in vitro. A combination of PlySs2 and vancomycin in vivo reduced the number of CFUs on the surface of implants by 92% and in the periprosthetic tissue by 88%. Conclusion. PlySs2 lysin was able to reduce biofilm, target planktonic bacteria, and work synergistically with vancomycin in our in vitro models. A combination of PlySs2 and vancomycin also reduced bacterial load in periprosthetic tissue and on the surface of implants in a murine model of DAIR treatment for established PJI. Cite this article: Bone Joint J 2020;102-B(7 Supple B):3–10

Aim. Debridement Antibiotics and Implant Retention(DAIR) is a procedure to treat a periprosthetic joint infection(PJI) after Total Hip Arthroplasty(THA) or Total Knee Arthroplasty(TKA). The timing between the primary procedure and the DAIR is likely a determinant for its successful outcome. There are few retrospective studies correlating timing of a DAIR with success (1,2). However, the optimal timing of a DAIR and the chance of success still remains unclear. We aimed to assess the risk of re-revision within one year after a DAIR procedure and to evaluate the timing of the DAIR in primary THA and TKA. An estimation of the chance of a successful DAIR will help clinicians and patients in their decision-making process in case of an acute postoperative PJI. Method. We used data from the Dutch Arthroplasty Register(LROI) and selected all primary THA and TKA in the period 2007–2016 who underwent a DAIR within 12 weeks after primary procedure. A DAIR was defined as a revision for infection in which only modular parts were exchanged. A DAIR was successful if not followed by a re-revision within 1 year after DAIR. The analyses were separated for THA and TKA procedures. Results. 207 DAIRs were performed <4 weeks after THA of which 41(20%) received a re-revision within 1 year; 87 DAIRs were performed between 4–8 weeks of which 15(17%) were re-revised and 11 DAIRs were performed >8 weeks and 2(18%) received a re-revision. 126 DAIRs were performed <4 weeks after TKA of which 27(21%) received a re-revision within 1 year; 68 DAIRs were performed between 4–8 weeks of which 14(21%) were re-revised and 15 DAIRs were performed >8 weeks and 3(20%) received a re-revision. Conclusions. There was no difference in 1-year re-revision rate after a DAIR procedure by timing of DAIR procedure for total hip and knee arthroplasty based on Dutch registry data

Aims. Arthroplasty surgery of the knee and hip is performed in two to three million patients annually. Periprosthetic joint infections occur in 4% of these patients. Debridement, antibiotics, and implant retention (DAIR) surgery aimed at cleaning the infected prosthesis often fails, subsequently requiring invasive revision of the complete prosthetic reconstruction. Infection-specific imaging may help to guide DAIR. In this study, we evaluated a bacteria-specific hybrid tracer (. 99m. Tc-UBI. 29-41. -Cy5) and its ability to visualize the bacterial load on femoral implants using clinical-grade image guidance methods. Methods. 99m. Tc-UBI. 29-41. -Cy5 specificity for Stapylococcus aureus was assessed in vitro using fluorescence confocal imaging. Topical administration was used to highlight the location of S. aureus cultured on femoral prostheses using fluorescence imaging and freehand single photon emission CT (fhSPECT) scans. Gamma counting and fhSPECT were used to quantify the bacterial load and monitor cleaning with chlorhexidine. Microbiological culturing helped to relate the imaging findings with the number of (remaining) bacteria. Results. Bacteria could be effectively stained in vitro and on prostheses, irrespective of the presence of biofilm. Infected prostheses revealed bacterial presence on the transition zone between the head and neck, and in the screw hole. Qualitative 2D fluorescence images could be complemented with quantitative 3D fhSPECT scans. Despite thorough chlorhexidine treatments, 28% to 44% of the signal remained present in the locations of the infection that were identified using imaging, which included 500 to 2,000 viable bacteria. Conclusion. The hybrid tracer . 99m. Tc-UBI. 29-41. -Cy5 allowed effective bacterial staining. Qualitative real-time fluorescence guidance could be effectively combined with nuclear imaging that enables quantitative monitoring of the effectiveness of cleaning strategies. Cite this article: Bone Joint Res 2023;12(1):72–79

Aims. Our aim was to estimate the total costs of all hospitalizations for treating periprosthetic joint infection (PJI) by main management strategy within 24 months post-diagnosis using activity-based costing. Additionally, we investigated the influence of individual PJI treatment pathways on hospital costs within the first 24 months. Methods. Using admission and procedure data from a prospective observational cohort in Australia and New Zealand, Australian Refined Diagnosis Related Groups were assigned to each admitted patient episode of care for activity-based costing estimates of 273 hip PJI patients and 377 knee PJI patients. Costs were aggregated at 24 months post-diagnosis, and are presented in Australian dollars. Results. The mean cost per hip and knee PJI patient was $64,585 (SD $53,550). Single-stage revision mean costs were $67,029 (SD $47,116) and $80,063 (SD $42,438) for hip and knee, respectively. Two-stage revision costs were $113,226 (SD $66,724) and $122,425 (SD $60,874) for hip and knee, respectively. Debridement, antibiotics, and implant retention in hips and knees mean costs were $53,537 (SD$ 39,342) and $48,463 (SD $33,179), respectively. Suppressive antibiotic therapy without surgical management mean costs were $20,296 (SD $8,875) for hip patients and $16,481 (SD $6,712) for knee patients. Hip patients had 16 different treatment pathways and knee patients had 18 treatment pathways. Additional treatment, episodes of care, and length of stay contributed to substantially increased costs up to a maximum of $369,948. Conclusion. Treating PJI incurs a substantial cost burden, which is substantially influenced by management strategy. With an annual PJI incidence of 3,900, the cost burden would be in excess of $250 million to the Australian healthcare system. Treatment pathways with additional surgery, more episodes of care, and a longer length of stay substantially increase the associated hospital costs. Prospectively monitoring individual patient treatment pathways beyond initial management is important when quantifying PJI treatment cost. Our study highlights the importance of optimizing initial surgical treatment, and informs treating hospitals of the resources required to provide care for PJI patients. Cite this article: Bone Joint J 2024;106-B(10):1084–1092

Aims. The aims of this study were to determine the incidence and factors for developing periprosthetic joint infection (PJI) following hemiarthroplasty (HA) for hip fracture, and to evaluate treatment outcome and identify factors associated with treatment outcome. Methods. A retrospective review was performed of consecutive patients treated for HA PJI at a tertiary referral centre with a mean 4.5 years’ follow-up (1.6 weeks to 12.9 years). Surgeries performed included debridement, antibiotics, and implant retention (DAIR) and single-stage revision. The effect of different factors on developing infection and treatment outcome was determined. Results. A total of 1,984 HAs were performed during the study period, and 44 sustained a PJI (2.2%). Multiple logistic regression analysis revealed that a higher CCI score (odds ratio (OR) 1.56 (95% confidence interval (CI) 1.117 to 2.187); p = 0.003), peripheral vascular disease (OR 11.34 (95% CI 1.897 to 67.810); p = 0.008), cerebrovascular disease (OR 65.32 (95% CI 22.783 to 187.278); p < 0.001), diabetes (OR 4.82 (95% CI 1.903 to 12.218); p < 0.001), moderate-to-severe renal disease (OR 5.84 (95% CI 1.116 to 30.589); p = 0.037), cancer without metastasis (OR 6.42 (95% CI 1.643 to 25.006); p = 0.007), and metastatic solid tumour (OR 15.64 (95% CI 1.499 to 163.087); p = 0.022) were associated with increasing PJI risk. Upon final follow-up, 17 patients (38.6%) failed initial treatment and required further surgery for HA PJI. One-year mortality was 22.7%. Factors associated with treatment outcome included lower preoperative Hgb level (97.9 g/l (SD 11.4) vs 107.0 g/l (SD 16.1); p = 0.009), elevated CRP level (99.1 mg/l (SD 63.4) vs 56.6 mg/l (SD 47.1); p = 0.030), and type of surgery. There was lower chance of success with DAIR (42.3%) compared to revision HA (66.7%) or revision with conversion to total hip arthroplasty (100%). Early-onset PJI (≤ six weeks) was associated with a higher likelihood of treatment failure (OR 3.5 (95% CI 1.2 to 10.6); p = 0.007) along with patients treated by a non-arthroplasty surgeon (OR 2.5 (95% CI 1.2 to 5.3); p = 0.014). Conclusion. HA PJI initially treated with DAIR is associated with poor chances of success and its value is limited. We strongly recommend consideration of a single-stage revision arthroplasty with cemented components. Cite this article: Bone Jt Open 2022;3(12):924–932

Aims

National joint registries under-report revisions for periprosthetic joint infection (PJI). We aimed to validate PJI reporting to the Australian Orthopaedic Association National Joint Arthroplasty Registry (AOANJRR) and the factors associated with its accuracy. We then applied these data to refine estimates of the total national burden of PJI.

Aim. Analysis of microbiological spectrum and resistance patterns as well as the clinical outcome of patients who underwent a Debridement, antibiotics and implant retention (DAIR) procedure in the early phase following failed two-stage exchange arthroplasty of the knee and hip. Method. Of 312 patients treated with two-stage exchange arthroplasty between January 2011 and December 2019, 16 (5.1%) patients (9 knee, 7 hip) underwent a DAIR procedure within 6 months following second stage. We retrospectively analyzed the microbiological results as well as changes in the microbiological spectrum and antibiotic resistance patterns between stages of two-stage exchange arthroplasties and DAIR procedures. Patient's re-revision rates after a minimum follow-up of 12 months following DAIR procedure were evaluated. Moreover, differences between knee and hip and between infected primary total joint replacement (TJRs) and infected revision TJRs as well as patient's host factors and microbiological results regarding the outcome of DAIR were analyzed. Results. In 7/16 (43.8%) patients the first and second stage procedure was culture positive, in 5/16 (31.2%) patients the first and second stage procedure was culture negative and in 4/16 (25%) patients the first stage procedure was culture positive, and the second stage procedure was culture negative. Moreover, 6 (37.5%) out of 16 DAIR procedures showed a positive microbiological result. In 5/7 (71.4%) patients with culture positive second stage procedure a different microorganism compared to first stage procedure was detected. In 6/6 (100%) patients with culture positive DAIR procedure, the isolated microorganisms were not detected during first or second stage procedure. An additional re-revision surgery was necessary in 4/16 (25%) patients after a median time of 31 months (range, 12 to 138 months) at a mean follow up of 63.1 ± 32 months following DAIR procedure. Highest re-revision rates were found in patients with culture positive second stage procedures (3/7 [42.9%]) and patients with culture positive DAIR procedures (2/6 [33.3%]). Conclusions. DAIR procedure seems to be a useful early treatment option following failed two-stage exchange arthroplasty. The re-revision rates were independent of different combinations of culture positive and culture negative first and second stage procedures. The high number of changes in the microbiological spectrum needs to be considered in the treatment of PJI

Aims. Fracture-Related Infection (FRI) is a severe complication caused by microbial infection of bone. It is imperative to gain more insight into the potentials and limitations of Debridement, Antibiotics and Implant Retention (DAIR) to improve future FRI treatment. The aims of this study were to: 1) determine how time to surgery affects the success rate of DAIR procedures of the lower leg performed within 12 weeks after the initial fracture fixation operation and 2) evaluate whether appropriate systemic antimicrobial therapy affects the success rate of a DAIR procedure. Methods. This multinational retrospective cohort study included patients of at least 18-years of age who developed an FRI of the lower leg within 12 weeks after the initial fracture fixation operation, between January 1st 2015 to July 1st 2020. DAIR success was defined by the absence of recurrence of infection, preservation of the affected limb and retention of implants during the initial treatment. The antimicrobial regimen was considered appropriate if the pathogen(s) was susceptible to the given treatment at the correct dose as per guideline. Logistic regression modelling was used to assess factors that could contribute to the DAIR success rate. Results. A total of 120 patients were included, of whom 70 DAIR patients and 50 non-DAIR patients. Within a median follow-up of 35.5 months, 21.4% of DAIR patients developed a recurrent FRI compared to 12.0% of non-DAIR patients. The DAIR procedure was successful in 45 patients (64.3%). According to the Willenegger and Roth classification, DAIR success was achieved in 66.7% (n=16/24) of patients with an early infection (<2 weeks), 64.4% (n=29/45) of patients with a delayed infection (2–10 weeks) and 0.0% (0/1) of patients with a late infection (>10 weeks). Univariate analysis showed that the duration of infection was not associated with DAIR success in this cohort (p=0.136; OR: 0.977; 95%CI: [0.947–1.007]). However, an appropriate antimicrobial regimen was associated with success of DAIR (p=0.029; OR: 3.231; 95%CI: [1.138–9.506]). Conclusions. Although the results should be interpreted with caution, an increased duration of infection was not associated with a decreased success rate of a DAIR procedure in patients with FRI of the lower leg. The results of this study highlight the multifactorial contribution to the success of a DAIR procedure and emphasize the importance of adequate antimicrobial treatment. Therefore, time to surgery should not be the only key-factor when considering a DAIR procedure to treat FRI

Periprosthetic joint infection is a serious complication of primary total hip replacement (THR) with significant associated morbidity. In acute infection, Debridement, Antibiotics and Implant Retention (DAIR) may be considered. Current national guidelines recommend a DAIR should be performed by “an experienced arthroplasty surgeon┕ but do not specify the need for this to be a revision arthroplasty surgeon. We investigated outcomes in our NHS Trust of DAIR procedures performed by revision and non-revision arthroplasty surgeons. Infection registry data and patient records were analysed for all DAIR procedures of infected primary THRs between 2017 and 2021. Data collected included details of the primary surgery, the presentation with infection, the DAIR procedure and any subsequent complications including return to theatre at any time point. Routinely collected pre- and post-operative patient reported outcome measures (PROMs) were reviewed. 54 periprosthetic joint infections of primary THRs received a DAIR procedure. 41 DAIRs were performed by a revision surgeon and 13 by non-revision surgeons. There was no significant difference in time from primary THR to presentation with infection, time from presentation to DAIR or pre-operative C-reactive protein between the two groups. In 21 (38.9%) patients the DAIR procedure was classed as a treatment failure; 17 patients (31.5%) returned to theatre for further revision surgery, one (2.4%) died related to infection and three (5.6%) had persistent infection but did not receive further surgery. Treatment failure was significantly higher in the non-revision surgeon group (9/13 (69.2%)) than in the revision surgeon group (12/41 (29.3%)) (p = 0.02). Overall, improvement in PROMs after DAIR was seen at both six and 12 months. The overall success rate of DAIR was 61.1% and there was a sustained improvement in PROMs after surgery. However, there was a significant difference in failure rates between revision surgeons and non-revision surgeons

Aims. To compare the functional outcome, health-related quality of life (HRQoL), and satisfaction of patients who underwent primary total hip arthroplasty (THA) and a single debridement, antibiotics and implant retention (DAIR) procedure for deep infection, using either the transgluteal or the posterior surgical approach for both procedures. Methods. The study was registered at clinicaltrials.gov (ID: NCT03161990) on 15 May 2017. Patients treated with a single DAIR procedure for deep infection through the same operative approach as their primary THA (either the transgluteal or the posterior approach) were identified in the Norwegian Arthroplasty Register and given a questionnaire. Median follow-up after DAIR by questionnaire was 5.5 years in the transgluteal group (n = 87) and 2.5 years in the posterior approach group (n = 102). Results. Patients in the posterior approach group were less likely to limp after the DAIR procedure (17% vs 36% limped all the time; p = 0.005), had a higher mean Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function score (80 vs 71; p = 0.013), and were more likely to achieve a patient acceptable symptom state for the WOMAC function score (76% vs 55%; p = 0.002). In a multivariable analysis, the point estimate for the increase in WOMAC function score using the posterior approach was 10.2 (95% CI 3.1 to 17.2; p = 0.005), which is above the minimal clinically important improvement. The patients in the posterior approach group also reported better mean HRQoL scores and were more likely to be satisfied with their hip arthroplasty (77% vs 55%; p = 0.001). Conclusion. In patients treated with a single, successful DAIR procedure for deep infection of a primary THA, the use of the posterior approach in both primary surgery and DAIR was associated with less limping, better functional outcome, better HRQoL, and higher patient satisfaction compared with cases where both were performed using the transgluteal approach. The observed differences in functional outcome and patient satisfaction were clinically relevant. Cite this article: Bone Joint J 2020;102-B(12):1662–1669

Abstract. Background. Infections are rare and poorly studied complications of unicompartmental knee athroplasty (UKA) surgery. They are significantly less common compared to infections after total knee arthroplasties (TKAs). Optimal management of periprosthetic joint infections (PJIs) after a UKA is not clearly defined in the literature. We present the results of a multicentre retrospective series of UKA PJIs treated with Debridement, Antibiotics and Implant Retention (DAIR). Methodology. Patients presenting between January 2016 and December 2019 with early UKA infection were identified at three specialist centres using the Musculoskeletal Infection Society (MSIS) criteria. All patients underwent a standardized treatment protocol consisting of the DAIR procedure and antibiotic therapy comprising two weeks of intravenous (IV) antibiotics followed by six weeks of oral therapy. The main outcome measure was overall survivorship free from reoperation for infection. Results. A total of 3225 UKAs (2793 (86.2%) medial and 432 (13.8%) lateral UKAs) were performed between January 2016 and December 2019. Nineteen patients had early infections necessitating DAIR. The mean follow-up period was 32.5 months. DAIR showed an overall survivorship free from septic reoperation of 84.2%, with an overall survivorship free from all-cause reoperation of 78.95%. The most common bacteria were Coagulase-negative Staphylococci, Staphylococcus aureus and Group B Streptococci. Three patients required a second DAIR procedure but remained free from re-infection at follow-up obviating the need for more demanding, staged revision surgery. Conclusions. In infected UKAs, the DAIR procedure produces a high rate of success, with a high survivorship of the implant

Aim. To date, the value of culture results after a debridement, antibiotics and implant retention (DAIR) for early (suspected) prosthetic joint infection (PJI) as risk indicators in terms of prosthesis retention is not clear. At one year follow-up, the relative risk of prosthesis removal was determined for culture-positive and culture-negative DAIRs after primary total hip or knee arthroplasty. The secondary aim was to explore differences in patient characteristics, infection characteristics and outcomes between these two groups. Methods. A retrospective regional registry study was performed in a group of 359 patients (positive cultures: n = 299, negative cultures n = 60) undergoing DAIR for high suspicion of early PJI in the period from 2014 to 2019. Differences in patient characteristics, deceased patients and number of subsequent DAIRs between the positive and negative DAIR groups were analyzed using independent t-tests, Mann-Whitney, Pearson's Chi-square tests and Fisher's Exact tests. Results. Overall implant survival rate following DAIR was 89%. The relative risk for prosthesis removal was 7.4 times higher (95% confidence interval (CI) 1.0–53.1) in the positive DAIR group (37/299, 12.4%) compared to the negative DAIR group (1/60, 1.7%). The positive group had a higher body mass index (p = 0.034), rate of wound leakage of >10 days (p = 0.016) and more subsequent DAIRs (p = 0.006). Conclusion. Since implant survival results after DAIR are favorable, the threshold to perform a DAIR procedure in early PJI should be low in order to retain the prosthesis. A DAIR procedure in case of negative cultures does not seem to have unfavorable results in terms of prosthesis retention

Background. Acute soft tissue defects (wound dehiscence or necrosis) after a total knee arthroplasty (TKA) may be the cause of the devasting complication of deep infection. When a medium (4–6cm) defect is present, in patellar or infra-patellar localization, a medial hemi-gastrocnemius flap is widely used to cover it, because of its low morbidity and high functional results. Normally, this coverage is not associated to a debridement, antibiotics and implant retention surgery (DAIR). When facing this situation, we should consider associating to the coverage treatment, like muscle flap, a DAIR procedure, in order to treat the possible acute infection, even when the diagnosis of infection is not clear. We could not find any studies comparing the benefice of this association in the same surgical act to isolated treatment of soft tissue defects. Our hypothesis was that when a TKA surgical wound defect is present, the risk of an acute infection is elevated and the patient would benefit from a muscle flap with DAIR procedure and polyethylene exchange. Methods. We performed a retrospective study to compare TKA infection clearance in patients with DAIR and flap in the same surgical act against those who received an isolated flap procedure for soft tissue coverage after an acute surgical wound defect. Patients were identified from a prospectively collated TKA database. Between 2005 and 2021, 19 patients met our inclusion criteria. A medial hemi-gastrocnemius flap was performed in 15 patients (78%). Healing or TKA infection clearance was defined as the presence of the original prosthesis after soft tissue coverage intervention, no need of DAIR after soft tissue coverage or no suppressive antibiotic treatment. Results. We obtained two groups. The first one, included those patients who had received the association of DAIR with polyethylene exchange and Flap (n=12). The other group included those who had received an isolated flap (n=7). We did not find differences in comorbidities and risk factors between both groups. In the combination treatment group 66,6% patients healed after treatment. In the other group, these favourable results decrease to 42,9%. Even though results were better in the combination treatment group, no significant differences were found. Conclusion. Although no significant statistical differences were found, probably due to small sample, the association of DAIR with polyethylene exchange and muscle flap is recommended in the coverage over an acute dehiscence or necrosis after TKA. More studies, with bigger sample are needed to extrapolate results in general population

Aims. Fracture-related infection (FRI) is commonly classified based on the time of onset of symptoms. Early infections (< two weeks) are treated with debridement, antibiotics, and implant retention (DAIR). For late infections (> ten weeks), guidelines recommend implant removal due to tolerant biofilms. For delayed infections (two to ten weeks), recommendations are unclear. In this study we compared infection clearance and bone healing in early and delayed FRI treated with DAIR in a rabbit model. Methods. Staphylococcus aureus was inoculated into a humeral osteotomy in 17 rabbits after plate osteosynthesis. Infection developed for one week (early group, n = 6) or four weeks (delayed group, n = 6) before DAIR (systemic antibiotics: two weeks, nafcillin + rifampin; four weeks, levofloxacin + rifampin). A control group (n = 5) received revision surgery after four weeks without antibiotics. Bacteriology of humerus, soft-tissue, and implants was performed seven weeks after revision surgery. Bone healing was assessed using a modified radiological union scale in tibial fractures (mRUST). Results. Greater bacterial burden in the early group compared to the delayed and control groups at revision surgery indicates a retraction of the infection from one to four weeks. Infection was cleared in all animals in the early and delayed groups at euthanasia, but not in the control group. Osteotomies healed in the early group, but bone healing was significantly compromised in the delayed and control groups. Conclusion. The duration of the infection from one to four weeks does not impact the success of infection clearance in this model. Bone healing, however, is impaired as the duration of the infection increases. Cite this article: Bone Joint Res 2024;13(3):127–135

Aims. Although low-intensity pulsed ultrasound (LIPUS) combined with disinfectants has been shown to effectively eliminate portions of biofilm in vitro, its efficacy in vivo remains uncertain. Our objective was to assess the antibiofilm potential and safety of LIPUS combined with 0.35% povidone-iodine (PI) in a rat debridement, antibiotics, and implant retention (DAIR) model of periprosthetic joint infection (PJI). Methods. A total of 56 male Sprague-Dawley rats were established in acute PJI models by intra-articular injection of bacteria. The rats were divided into four groups: a Control group, a 0.35% PI group, a LIPUS and saline group, and a LIPUS and 0.35% PI group. All rats underwent DAIR, except for Control, which underwent a sham procedure. General status, serum biochemical markers, weightbearing analysis, radiographs, micro-CT analysis, scanning electron microscopy of the prostheses, microbiological analysis, macroscope, and histopathology evaluation were performed 14 days after DAIR. Results. The group with LIPUS and 0.35% PI exhibited decreased levels of serum biochemical markers, improved weightbearing scores, reduced reactive bone changes, absence of viable bacteria, and decreased inflammation compared to the Control group. Despite the greater antibiofilm activity observed in the PI group compared to the LIPUS and saline group, none of the monotherapies were successful in preventing reactive bone changes or eliminating the infection. Conclusion. In the rat model of PJI treated with DAIR, LIPUS combined with 0.35% PI demonstrated stronger antibiofilm potential than monotherapy, without impairing any local soft-tissue. Cite this article: Bone Joint Res 2024;13(7):332–341

Aim. The number of periprosthetic joint infections (PJI) is increasing due to ageing population and increasing numbers of arthroplasty procedures and treatment is costly. Aim of the study was to analyze the direct healthcare costs of PJI in Europe for total hip arthroplasties (THA) and total knee arthroplasties (TKA). Method. A systematic review in PubMed with search of direct costs of PJI in European countries was performed. Thereby the term cost* AND (infection OR PJI) AND (prosthesis OR knee OR hip OR “TKA” OR “THA” OR arthroplast*) was combined with each European country to detect relevant publications. Publications with definition of performed procedure and joint localization were included into further analysis. The mean value of direct healthcare cost was calculated for the respective joint and the respective operation performed. Results. Screening revealed 1,274 eligible publications. After review of abstracts and full-texts n=11 manuscripts were included into final analysis (Figure 1). The mean combined direct hospital costs for revision for PJI after TKA and THA was 26,311€. Mean costs for revision procedures for PJI after TKA were 24,617€. Direct costs for TKA-PJI treated with debridement, antibiotics and implant retention (DAIR) were on average 10,121€. For two-stage revisions in knee arthroplasties total average costs were 30,829€. Referring to revision surgery for PJI in THA, the mean hospital costs in Europe were 28,005€. For a DAIR procedure direct healthcare costs of 5,528€ were identified. Two-stage revision cost on average 31,217€. Conclusions. PJIs are associated with significant direct healthcare costs. The financial burden of up to 30,000 € per case underlines the impact of the disease for European health care system. However, the number of detailed reports on PJI costs is limited and the quality of the literature is limited. There is a strong need for more detailed financial data on the costs of PJI treatment. For any tables or figures, please contact the authors directly

Aim. Debridement, antibiotics and implant retention (DAIR) are considered as an optimal curative treatment option for prosthetic joint infection (PJI) when the biofilm is still immature and radical debridement is achievable. There are two main groups of patients suitable for DAIR. Those with an early acute PJI and patients with acute hematogenous PJI. However, there is also a third group of early PJI resulting from a wound healing problem or leaking hematoma. These may be either high or low grade depending on the microorganisms that infected the artificial joint “per continuitatem”. Methods. We retrospectively analysed 100 successive DAIR procedures on prosthetic hip and knee joints performed between January 2010 and January 2022, from total of 21000 primary arthroplasties implanted within the same time period. We only included PJI in primary total replacements with no previous surgeries on the affected joint. Patients data (demographics, biochemical, microbiological, histopathological results, and outcomes) were collected from hospital bone and joint infection registry. The aim of surgery was radical debridement and the mobile parts exchange. The standardized antibiotic regime based on antibiofilm antibiotics. Results. The mean age of patients was 70 years (60% women, 43 hips, 57 knees) with a mean follow-up of 3 years. 45 cases were early acute or related to wound healing problems, 55 were hematogenous PJI. 25 patients received preoperative antibiotics. 6 of these were culture negative. The mean symptom duration was 7 days. Mean age of the prosthesis was 30 days for early, and 1064 days for the hematogenous group. Conclusions. In our cohort the success rate of DAIR is 94% which indicates that the protocol is highly successful in PJI with short-lasting symptoms and “debridable” joints. Antibiotic protocol violation and duration of symptoms may have a role in failures

Aim. The time to onset of symptoms after fracture fixation is still commonly used to classify fracture-related infections (FRI). Early infections (<2 weeks) can often be treated with debridement, systemic antibiotics, irrigation, and implant preservation (DAIR). Late infections (>10 weeks) typically require implant removal as mature, antibiotic-tolerant biofilms have formed. However, the recommendations for delayed infections (2–10 weeks) are not clearly defined. Here, infection healing and bone healing in early and delayed FRI is investigated in a rabbit model with a standardized DAIR procedure. Method. Staphylococcus aureus was inoculated into 17 rabbits after plate osteosynthesis in a humerus osteotomy. The infection developed either one week (early group, n=6) or four weeks (delayed group, n=6) before a standardized DAIR procedure and microbiological analysis were performed. Systemic antibiotics were administered for six weeks (two weeks: Nafcillin+Rifampin, four weeks: Levofloxacin+Rifampin). A control group (n=5) also underwent a revision operation (debridement and irrigation) after four weeks, but received no antibiotic treatment. Rabbits were euthanized seven weeks after the revision operation. Bone healing was assessed using a modified radiographic union score for tibial fractures (mRUST). After euthanasia, a quantitative microbiological examination of the entire humerus, adjacent soft tissues, and implants was performed. Results. All animals were infected at the time of revision surgery, with the bacterial load in the early group (especially in soft tissues) being greater than in the delayed group and control group. This indicates infiltration of bacteria into areas that are more difficult to reach after four weeks of debridement. The infection was eradicated in all animals in both the early and delayed groups at euthanasia, but not in the control group (CFU median (IQR): 2.1×10. 7. (1.3×10. 7. -2.6×10. 7. ). The osteotomy healed in the early group, while bone healing was significantly impaired in both the delayed group and control group (mRUST median (IQR): early group: 16 (14–16), delayed group: 7.5 (6–10), control: 7 (5.5–9); early vs. delayed: p=0.0411, early vs. control p=0.0065). Conclusion. The maturation of the infection between the first and fourth week does not affect the success of infection eradication in this rabbit FRI model. However, bone healing appears to be impaired with increasing duration of infection