Aim. To review the outcome of deep prosthetic infection in patients following hip hemiarthroplasty surgery. Method. A retrospective case-note analysis was performed of deep infection coded hip hemiarthroplasty patients between 2004–2009. Patients were selected when there was proven microbiology from deep wound swabs or tissue specimens. Results. Deep infection developed in 14 of 1428 hemiarthroplasties. The mean age at time of fracture was 83 (71–93). There was a 12:2 female to male ratio. Eleven of the 14 cases had an American Society of Anaesthesiologists (ASA) score of three or four. Eight infections were due to Staphylococcus aureus, of which 6 were due to MRSA, which accounted for 43% of infections overall. There was no significant correlation between pathogen and success of treatment. Eight of the 14 hips were treated with open debridement and washout with implant retention. This was successful in 4 hips (50%). Infection recurred in 4 hips, one of which was revised to total hip replacement. The remaining 3 hips with recurrent infection were treated with excision arthroplasty. Three of the 14 hips were treated initially with excision arthroplasty. One required a further debridement and another required 3 debridements to control infection following implant removal. In 2 hips, a single stage revision to total hip replacement was performed. One of these developed recurrent infection, which was treated successfully with open debridement and washout. In one hip, no further surgery was performed. The 90-day mortality for patients with infected hemiarthroplasty was 36%. Conclusion. Deep infection following hemiarthroplasty of the hip has serious consequences and high mortality at 90 days. In our study sample, recurrence of infection was common and at least half required multiple operations. This study highlights the importance of infection prevention to reduce the morbidity and mortality following hip fracture surgery

The Control of Infection Committee at a specialist orthopaedic hospital prospectively collected data on all episodes of bacteriologically-proven deep infection arising after primary hip and knee replacements over a 15-year period from 1987 to 2001.

There were 10 735 patients who underwent primary hip or knee replacement. In 34 of 5947 hip replacements (0.57%) and 41 of 4788 knee replacements (0.86%) a deep infection developed. The most common infecting micro-organism was coagulase-negative staphylococcus, followed by Staphylococcus aureus, enterococci and streptococci. Of the infecting organisms, 72% were sensitive to routine prophylactic antimicrobial agents.

Of the infections, 29% (22) arose in the first three months following surgery, 35% between three months and one year (26), and 36% (27) after one year. Most cases were detected early and treated aggressively, with eradication of the infection in 96% (72). There was no significant change in the infection rate or type of infecting micro-organism over the course of this study.

These results set a benchmark, and importantly emphasise that only 64% of peri-prosthetic infections arise within one year of surgery. These results also illustrate the advantages of conducting joint replacement surgery in the isolation of a specialist hospital.

Infection after total hip arthroplasty is a rare but potentially devastating complication. The most common pathogens responsible for these infections are gram positive bacteria. Infection caused by fungi is uncommon. There are few reports of prosthetic joint infection caused by Candida species, and there has no report of implant preservation.

We experienced the case of a patient with Candida arthritis who underwent total hip arthroplasty for hip arthrosis, and successfully could preserved prosthetic joint.

A 60 year-old woman underwent total hip arthroplasty in September 2014. She had had the past of sepsis by the Candida after surgery of the duodenal cancer. After four weeks in total hip arthroplasty, she made clinic visits. Her chief complaints were low-grade fever of 1 week's duration and discharge from operative scar for THA. The patient underwent arthrocentesis of the left hip. The culture was positive for Candida tropicalis.

Operation of surgical debridement and liner change was performed as soon as possible. After operation, the patient was treated with fluconazole intravenously for 28 days.

She has continued to taken fluconazole by mouth. Reactivation of infection have not been in her left hip.

We reported the case of a patient with Candida arthritis who underwent total hip arthroplasty. Prosthetic joint could have preserved because of early detection for infection. This is the first report of preservating implant after Candida infection in total hip arthroplasty.

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. Despite the availability of numerous tests, the diagnosis of periprosthetic infection (PJI) continues to be complex. Although several studies have suggested that coagulation-related markers, such as D-dimer and fibrinogen, may be promising tools in the diagnosis of prosthetic infections, their role is still controversial. The aim of this study is to evaluate the diagnostic accuracy of serum D-dimer and fibrinogen in patients with painful total knee replacement. Method. 83 patients with painful total knee replacement and suspected peri-prosthetic infection were included. All patients underwent pre-operative blood tests to evaluate inflammation indices (ESR and CRP) and serum D-Dimer and Fibrinogen levels. The diagnostic performance of the tests was assessed using the ICM definition as the gold standard. The diagnostic accuracy of the D-dimer and fibrinogen was measured by assessing sensitivity, specificity and by calculating the area under the ROC curve. Results. The definition of prosthetic infection based on the ICM criteria has made it possible to classify 40 peri-prosthetic infections and 43 aseptic failures. The mean value of fibrinogen, D-Dimer, VES and PCR observed in patients with prosthetic infection was significantly higher than in patients with aseptic failure [fibrinogen 468 mg / dl vs 331 mg / dl, p <0.001; D-Dimero 2177 ng/mL vs. 875 ng / mL, p <0.005], ESR 49 mm / hr vs 24 mm/h, p <0.001; PCR 25.5 mg /L vs 8.9 mg/L, p <0.001]. The optimal threshold value of the fibrinogen indicative of the presence of infection was 418 mg/dl, with a sensitivity of 72% and a specificity of 88%. The serum concentration of d-dimer greater than 945 ng / ml showed a sensitivity of 72.5% and a specificity of 76.7%. Conclusions. Although in this multicenter prospective study we found that serum D-dimer may have significantly higher statistical values in PJI than aseptic failures, its diagnostic power appears however limited when compared with other markers including plasma fibrinogen. Fibrinogen is regularly analyzed before surgery, the evaluation of this marker does not involve additional costs. The diagnostic accuracy appears to be similar to that of classic markers such as the level of PCR and VES. Plasma D-dimer may have a limited value in the diagnosis of PJI unlike plasma fibrinogen which has shown moderate sensitivity and excellent specificity. However, in our limited series of cases, both tests cannot be used alone in the diagnosis of infection but could contribute to the diagnosis if contextualized to ves and pcr

Abstract Background. The treatment of bone and joint infections (BJI) involving multi-drug resistant bacteria remains a challenge. MDR Staphylococcus epidermidis (MDRSE) clones, resistant to methicillin, clindamycin, levofloxacin, rifampicin and even linezolid, have been reported worldwide. The interest of delafloxacin (DFX), theoretically active on MRSA, remains to be evaluated with respect to MDRSE. Purpose. Our objective was to evaluate during a retrospective multicenter study the DFX minimal inhibitory concentrations (MICs) and compare its efficacy between ofloxacin-susceptible and ofloxacin-resistant S. epidermidis clinical strains involved in BJI. Methods. In this multicenter retrospective study (Reference centers from the West part of France, CRIOGO), 529 strains were collected mostly from BJI. DFX MICs were determined by using a 0.5 Mc Farland bacterial inoculum on Mueller-Hinton agar plates with gradient strips incubated for 24h at 35°C. For S. aureus, breakpoints differentiate skin and soft tissue infections from other infections. Breakpoints followed 2022 EUCAST criteria, with S. aureus values adopted for S. epidermidis. Results. Of the 529 strains collected, 355 were from prosthetic infections, 159 from synthetic infections and 15 from non-device infections. 152 strains were susceptible to ofloxacin (110 males vs 42 females) and 377 resistant (210 vs 167). As presented in Figure 1, all the ofloxacin-susceptible strains presented a DFX MIC ≤0.006mg/L. Resistant strains presented a double population distribution, with 3.7% categorized susceptible according to skin and soft tissues infections breakpoint, against 88.9% according to other breakpoint infections (0.016 or 0.25mg/L respectively). Conclusion. DFX shows excellent activity against ofloxacine-susceptible strains. Concerning the ofloxacin-resistant strains, more than 80% strains or less than 10% can be considered as DFX-susceptible depending on the breakpoints used. Further clinical studies are needed to validate the real breakpoints that must be used in MDRSE BJI, allowing a microbiological cure and a favourable clinical outcome. For any tables or figures, please contact the authors directly

Gram-negative prosthetic joint infections (GN-PJI) present unique challenges in management due to their distinct pathogenesis of biofilm formation on implant surfaces. To date, there are no animal models that can fully recapitulate how a biofilm is challenged in vivo in the setting of GN-PJI. The purpose of this study is to establish a clinically representative GN-PJI in vivo model that can reliably depict biofilm formation on titanium implant surface. We hypothesized that the biofilm formation on the implant surface would affect the ability of the implant to be osseointegrated. The model was developed using a 3D-printed, medical-grade titanium (Ti-6Al-4V), monoblock, cementless hemiarthroplasty hip implant. This implant was used to replace the femoral head of a Sprague-Dawley rat using a posterior surgical approach. To induce PJI, two bioluminescent Pseudomonas aeruginosa (PA) strains were utilized: a reference strain (PA14-lux) and a mutant strain that is defective in biofilm formation (DflgK-lux). PJI development and biofilm formation was quantitatively assessed in vivo using the in vivo imaging system (IVIS), and in vitro using the viable colony count of the bacterial load on implant surface. Magnetic Resonance Imaging (MRI) was acquired to assess the involvement of periprosthetic tissue in vivo, and the field emission scanning electron microscopy (FE-SEM) of the explanted implants was used to visualize the biofilm formation at the bone-implant interface. The implant stability, as an outcome, was directly assessed by quantifying the osseointegration using microCT scans of the extracted femurs with retained implants in vitro, and indirectly assessed by identifying the gait pattern changes using DigiGaitTM system in vivo. A localized prosthetic infection was reliably established within the hip joint and was followed by IVIS in real-time. There was a quantitative and qualitative difference in the bacterial load and biofilm formation between PA14 and DflgK. This difference in the ability to persist in the model between the two strains was reflected on the gait pattern and implant osseointegration. We developed a novel uncemented hip hemiarthroplasty GN-PJI rat model. This model is clinically representative since animals can bear weight on the implant. PJI was detected by various modalities. In addition, biofilm formation correlated with implant function and stability. In conclusion, the proposed in vivo GN-PJI model will allow for more reliable testing of novel biofilm-targeting therapetics

Aim. Prosthetic joint replacement is more commonly done in the elderly group of patients due to an increase pathology related to joint degeneration that comes with age. In this age group is also more frequent having underling condition that may predispose to a prosthetic joint infection. Also, the pharmacological intervention in those patients may play an important role as a risk factor for infection after joint replacement surgery. The use of oral anticoagulants seems to be particularly increased in elderly patients but there aren't enough data published to support an association between prosthetic joint infection and the use of oral anticoagulants. Identifying risk factors in elderly patients age >75 years old with a special focus on the oral anticoagulation therapy is the aim of the study. Methods. In a retrospective study from 2011 till 2018 all the patients >75 years old with knee and hip replacement surgery have been review looking for acute prosthetic infection and risk factors that may be predispose to it. Patients with previous surgery or any other mechanical complication that needed intervention on the same area have been excluded. Results. A total of 1220 patients have been included (801 knee replacement surgery and 419 hip replacement surgery). The mean age was 79.5 ± 3.44 years and most of the patients were women (72,6%). The infection rate was 2,5%. Several factors have been identified to be associated with acute infection. (Table.1.). The patients receiving oral anticoagulants had an increased risk of infection (OR 3.63 (1.60–7.74), p=0.002). Conclusions. Even all the risk factors associated with risk infection have been described previously, the relevant aspect is the increased risk of prosthetic joint infection in patients receiving oral anticoagulants

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

Thoracic hyperkyphosis (TH – Cobb angle >40°) is correlated with rotator cuff arthropathy and associated with anterior tilting and protraction of scapula, impacting the glenoid orientation and the surrounding musculature. Reverse total shoulder arthroplasty (RTSA) is a reliable surgical treatment for patients with rotator cuff arthropathy and recent literature suggests that patients with TH may have comparable range of motion after RTSA. However, there exists no study reporting the possible link between patient-reported outcomes, humeral retroversion and TH after RTSA. While the risk of post-operative complications such as instability, hardware loosening, scapular notching, and prosthetic infection are low, we hypothesize that it is critical to optimize the biomechanical parameters through proper implant positioning and understanding patient-specific scapular and thoracic anatomy to improve surgical outcomes in this subset of patients with TH. Patients treated with primary RTSA at an academic hospital in 2018 were reviewed for a two-year follow-up. Exclusion criteria were as follows: no pre-existing chest radiographs for Cobb angle measurement, change in post-operative functional status as a result of trauma or medical comorbidities, and missing component placement and parameter information in the operative note. As most patients did not have a pre-operative chest radiograph, only seven patients with a Cobb angle equal to or greater than 40° were eligible. Chart reviews were completed to determine indications for RTSA, hardware positioning parameters such as inferior tilting, humeral stem retroversion, glenosphere size/location, and baseplate size. Clinical data following surgery included review of radiographs and complications. Follow-up in all patients were to a period of two years. The American Shoulder and Elbow Surgeons (ASES) Shoulder Score was used for patient-reported functional and pain outcomes. The average age of the patients at the time of RTSA was 71 years old, with six female patients and one male patient. The indication for RTSA was primarily rotator cuff arthropathy. Possible correlation between Cobb angle and humeral retroversion was noted, whereby, Cobb angle greater than 40° matched with humeral retroversion greater than 30°, and resulted in significantly higher ASES scores. Two patients with mean Cobb angle of 50° and mean humeral retroversion 37.5° had mean ASES scores of 92.5. Five patients who received mean humeral retroversion of 30° had mean lower ASES scores of 63.7 (p < 0 .05). There was no significant correlation with glenosphere size or position, baseplate size, degree of inferior tilting or lateralization. Patient-reported outcomes have not been reported in RTSA patients with TH. In this case series, we observed that humeral stem retroversion greater than 30° may be correlated with less post-operative pain and greater patient satisfaction in patients with TH. Further clinical studies are needed to understanding the biomechanical relationship between RTSA, humeral retroversion and TH to optimize patient outcomes

Aim. The incidence of prosthetic joint infections can be severe to monitor, as they are rare events. Recent publications from National registries points toward a significant underestimation of reported infections. The aim of this project was to develop a complication register that could report the “true” and momentaneous incidence of prosthetic infections after total knee and hip arthroplasty. Method. All patients operated with total hip arthroplasty (THA) or total knee arthroplasty (TKA) at our hospital were included in a local quality registry. All complications were reported at follow-up at 2 and 3 months for total knee and hip arthroplasties respectively, and at 1-year follow up. Both primary and revision surgeries were included. In order to monitor complications of special interest, such as deep postoperative infections, key variables were presented in a g-chart. This chart shows the number of uncomplicated surgeries between each complication (such as infection) in a bar diagram. This diagram is easily read as high bars indicate a low incidence of complications and low bars indicate a high incidence. The diagram is updated and distributed for information every month. Results. From September 2010 till December 2015 we included 2093 primary total hip arthroplasties and 272 hip revisions. The overall incidence for prosthetic infection after primary THA within 1 year after surgery was 1.8% and for hip revisions 3.4%. The momentaneous incidence in December 2015 was 3% for both primary and revision THA together. In the same period 1555 total knee arthroplasties and 155 knee revisions were included. The overall incidence of prosthetic infection after primary TKA within 1 year after surgery was 1.2% and for knee revisions 2.2%. The momentaneous incidence in December 2015 was 2.5% for primary and revision TKA together. Conclusions. Reporting the number of uncomplicated surgeries between every unwanted event or complication, such as postoperative infections, is a good method for describing rare events. This method will reveal changes in the trend at an earlier stage and can be an important tool in the work on preventing postoperative infections. A local quality register can be important in order to report a “true” incidence of postoperative infections, as the risk of underestimation is lower than in a national registry

The diagnosis of infection following shoulder arthroplasty is notoriously difficult. The prevalence of prosthetic shoulder infection after arthroplasty ranges from 3.9 – 15.4% and the most common infective organism is Cutibacterium acnes. Current preoperative diagnostic tests fail to provide a reliable means of diagnosis including WBC, ESR, CRP and joint aspiration. Fluoroscopic-guided percutaneous synovial biopsy (PSB) has previously been reported in the context of a pilot study and demonstrated promising results. The purpose of this study was to determine the diagnostic accuracy of percutaneous synovial biopsy compared with open culture results (gold standard). This was a multicenter prospective cohort study involving four sites and 98 patients who underwent revision shoulder arthroplasty. The cohort was 60% female with a mean age was 65 years (range 36-83 years). Enrollment occurred between June 2014 and November 2021. Pre-operative fluoroscopy-guided synovial biopsies were carried out by musculoskeletal radiologists prior to revision surgery. A minimum of five synovial capsular tissue biopsies were obtained from five separate regions in the shoulder. Revision shoulder arthroplasty was performed by fellowship-trained shoulder surgeons. Intraoperative tissue samples were taken from five regions of the joint capsule during revision surgery. Of 98 patients who underwent revision surgery, 71 patients underwent both the synovial biopsy and open biopsy at time of revision surgery. Nineteen percent had positive infection based on PSB, and 22% had confirmed culture positive infections based on intra-operative tissue sampling. The diagnostic accuracy of PSB compared with open biopsy results were as follows: sensitivity 0.37 (95%CI 0.13-0.61), specificity 0.81 (95%CI 0.7-0.91), positive predictive value 0.37 (95%CI 0.13 – 0.61), negative predictive value 0.81 (95%CI 0.70-0.91), positive likelihood ratio 1.98 and negative likelihood ratio 0.77. A patient with a positive pre-operative PSB undergoing revision surgery had an 37% probability of having true positive infection. A patient with a negative pre-operative PSB has an 81% chance of being infection-free. PSB appears to be of value mainly in ruling out the presence of peri-prosthetic infection. However, poor likelihood ratios suggest that other ancillary tests are required in the pre-operative workup of the potentially infected patient

Aim. Propionibacterium acnes is an emerging pathogen especially in orthopedic implant infection. Interestingly, we previously reported a difference in the distribution of the clades involved in spine versus hip or knee prosthetic infection. To date, no study has previously explored the direct impact and close relationship of P. acnes on bone cells according to their own genetic background. The aim of this study was to investigate this interaction of P. acnes clinical strains involved in spine material infections, arthroplasty infections and acne lesions with bone cells. Method. From a large collection of 88 P. acnes clinical isolates collected between January 2003 and December 2014, a subset of 11 isolates was studied. Four isolates were recovered from spine infections, two from prosthetic infections (knee and hip), three from acne lesions and two reference strains (ATCC11827 and ATCC6919). Implant-associated infections were confirmed according to Infectious Diseases Society of America guidelines for bone and joint infections. Multi-Locus Sequence Typing (MLST) was carried out on all isolates as described by Lomholt et al. PLoS ONE 2010. Bacterial internalization experiments with MG63 osteosarcoma cells were adapted from Crémet et al. Pathog Dis 2015. Results. Among the nine clinical isolates, three isolates belonged to clonal complexes (CCs) 18; three to CC28 and three to CC36. ATCC isolates belonged to CC18. Bacterial internalization experiments revealed that CC36 P. acnes strains were less invasive than CC18 and CC28 P. acnes strains towards osteoblasts (mean percentage of internalized bacteria (< 0.01% for the CC36 P. acnes strains versus more than 1% for the CC18 and CC28 P. acnes strains). Surprisingly, the ATCC11827 CC18 P. acnes strain exhibited invasiveness similar to CC36 isolates. Conclusions. Evasion mechanism observed for CC36 P. acnes isolates could allow this clade to leave the site of infection, disseminate into deeper tissue layers and beget arthroplasty infection. Inside the deeper tissue, close to the material, the local immune defect fosters the low-grade infections observed with P. acnes clinical strains. On the another hand, for CC18 et CC28 clades, mostly involved in spine infection, the internalization process observed could allow these clades to escape from the numerous immune cells located under the skin and generate an infection locally, favored by the spine instrumentation close to the skin, especially during long spine surgeries

The inmate population is a unique cohort with several healthcare-related challenges. International studies have demonstrated higher rates of infectious diseases, chronic diseases and psychiatric disorders in inmates when compared to general population. However, little is known about the outcomes following total joint arthroplasty in this population. This retrospective chart review aims to outline the differences in clinical outcomes after hip and knee total joint arthroplasty in the Kingston inmate population compared to the national population standard. A list of all inmate inpatient hospital visits with diagnostic/procedure codes pertaining to total joint arthroplasty within the last ten years was obtained through a computer-based search of the Kingston General Hospital Discharge Abstract Database(DAD). The patient charts were reviewed and demographic and outcome data pertinent to our study was collected. Data was compiled using Excel and imported into IBM SPSS for descriptive analysis. Twenty male inmate patients underwent 24 primary Total Hip Arthroplasties(THA) or Total Knee Arthroplasties(TKA) and one medial unicompartmental knee arthroplasty from May 2003 to January 2013. The average age was 58 with mean Body Mass Index(BMI) of 34. Median American Society of Anesthesiologist(ASA) score was 3 and mean Charlston Comorbidity Index was 3.92. The rates of HCV and HIV were 35%(n=5) and 0%, respectively. Average length of stay from time of initial procedure was 4.2 days. The overall revision rate was 24% (n=6). Reasons for revision included deep prosthetic infection (50%, n=3), aseptic loosening (17%, n=1), arthrofibrosis (17%, n=1) and late periprosthetic fracture (17%, n=1). Infection rates were reported at 16% (n=4); 75% of which were deep prosthetic infections requiring revision surgery. Other complications included ST-elevation myocardial infarction(STEMI) (n=1), and postoperative knee stiffness requiring manipulation under anesthesia(MUA) (n=1). Compared to Correctional Services Canada(CSC) data on male inmate health in 2012, our study population demonstrated a higher rate of HCV (35% vs. 9.4%), diabetes (30% vs. 4.2%) and overall cardiovascular and respiratory comorbidities. This may reflect the higher rate of comorbidities associated with osteoarthritis, such as BMI>25, which was evident in 95% of our study population vs. 64.5% in Canadian inmates. Total joint revision rates in our inmate study population was 24%, which is higher than the 2014 Canadian Joint Replacement Registry's yearly revision rate of 8.7% in THA and 5.2% in TKA. Our study population also demonstrated infection as the leading cause for revision at 50%, compared to 14.5% for THA and 19.6% for TKA in the general Canadian population. Further study of the complex biopsychosocial risk factors in the inmate population is warranted to better define pre-surgical risk assessment criteria

Aim. Infection is one of the worst complications following total joint arthroplasty, which is often associated with significant morbidity and increased medical costs. Although Gram–positive bacteria remains the most prevalent causative agents, an increase in prosthetic joint infections (PJI) due to gram-negative bacteria (GNB) has been reported. Additionally, the emergence of multidrug resistant resistance (MDR) in GNB impacts the therapeutic options and may increase the rate of treatment failure and drug toxicity adverse effects due the prescription of harmful and toxics antimicrobial schemes. The purpose of the present study was to describe the predisposing factors associated to PJI caused by MDR-GNB in a specialized orthopedic reference hospital in Brazil from 2014 through 2018. Method. Retrospective case-control analysis of patients treated for MDR-GNB PJI over a four-year period (2014–2018). Data were collected from medical, surgical and laboratory records. PJI were defined according the criteria of MSIS. MDR was defined as non-susceptibility to at least one agent in three or more antimicrobial categories. Patients with prosthetic infection with at least two positive tissue cultures for MDR-GNB were selected. Univariate and multivariate logistic regression models were used to determine the independent risk factors associated with MDR-GNB PJI. Controls: patients with PJI with at least two positive tissue culture for non MDR- GNB. Results. A total of 104 patients were selected, 59 patients in the MDR-GNB PJI group and 44 in the control. Patients with MDR-GNB PJI were elderly (mean age of 68.36), distribution among sex was similar (49.2% female and 50.8% male) and 72.3% had one or more comorbidities. Most frequently identified comorbidities were diabetes (10.2%), malnutrition (5.5%), hypertension (4.7 %) and obesity (3.9%). Hip replacement accounted for 91.5% of the cases and 59.3% were revision arthroplasty. The mean time between the placement of the prothesis and the onset of PJI signs and symptoms was 438 days. In the univariate regression, the significant risk factors for MDR-GNB PJI were revision arthroplasty, alcoholism, nonelective arthroplasty, prior antimicrobial use, presence of concomitant infection and blood transfusion. However, in the multivariate analysis, prior use of antimicrobials (OR 9.31, CI95% 3.02–28.64) and the nonelective arthroplasty (OR 6.29, CI95% 1.75–22.6) remained as independent risk factors for MDR-GNB PJI. Conclusions. Previous use of antimicrobial and nonelective arthroplasty are important risk factors for PJI by GNB MDR

Periprosthetic infection involving TKR has been projected to rise as the burden of implanted TKR continues to grow. A study by Kurtz et al. found a significant increase in the annual incidence of TKR infection, 2001 (2.05%) to 2.18% in 2009. Thus, deep prosthetic infection around a TKR remains a significant problem that has not been solved, even as technologies improve and the operation is more commonly performed. The economic hospital cost of periprosthetic TKR infection is approximately $100,000 US for a two-stage removal and reimplantation; by the year 2020, it is estimated that 48,000 of these operations will be necessary. The total annual hospital cost for PJI treatment is expected to be over $1 billion by 2020, and does not include the doctor, pharmacologic, and physical therapy fees. Many factors have been found to be associated with an increased risk of PJI. This lecture will focus upon the peri-, intra-, and post-operative factors that have been found historically to carry an increased or decreased risk of infection. Preoperative factors that have been found to affect the risk of infection include: perioperative administration of intravenous antibiotics, patient nutrition, weight, and hemoglobin A1C in diabetic patients. Intraoperative factors include the duration of surgery, the use of antibiotic impregnated cement, and the use of dilute povidone/iodine solution irrigation. Postoperatively, wound care with antimicrobial agents, and a resistance to transfusing blood seem to lower the risk of infection. Yang et al. found that diabetes mellitus carried a 1.6x greater risk of TKR infection, in a meta-analysis of 11 cohort studies. In a registry study of over 32,000 TKA, increasing BMI from 25 kg/m2 to 35 kg/m2 was found to be associated with a greater risk of wound infection in TKR patients, increasing from 3 to 4.1%. Preoperative colonization with MRSA has been found by several investigators to be a risk for surgical site infection, despite attempts at eradication. Operatively, a wash of the surgical site for 3 minutes with a dilute solution of betadine has been found by Brown et al. to have decreased the incidence of periprosthetic joint infection from 0.97% to 0.15%. Postoperatively, the type of dressing placed over the incision may play a role; Grosso et al. found a significantly reduced rate of PJI (0.33% vs. 1.58%) when a silver impregnated, antimicrobial, dressing was used as compared to standard xeroform gauze. Finally, patients who received an allogeneic blood transfusion were found to have a higher risk of PJI (1.67%) than those who did not (0.72%)

Aim. As the populations of patients who have multiple prosthetic joints increase these years, the fate of a single joint periprosthetic joint infection in these patients is still unknown. Risk factors leading to a subsequent infection in another prosthetic joint are unclear. Our goal is to identify the risk factors of developing a subsequent infection in another prosthetic joint and describe the organism profile to the second prosthetic infection. Method. We performed a retrospective cohort study of all PJI cases underwent surgical intervention at our institute, a tertiary care referral center over 11 years, during January 2006 to December 2016. We identified 96 patients with periprosthetic joint infection who had another prosthetic joint in place at the time of presentation. The comorbidity, number of prosthetic joints, date and type of each arthroplasty, times of recurrent infection at each prosthetic joint with subsequent debridement or 2-stage resection arthroplasty, organisms from every infection episode, the outcome of each periprosthetic joint infection in these patients were analyzed. Results. During January 2006 to May 2017, we retrospective collected 294 PJI cases (159 hips, 135 knees) in our institute. Patients with single prosthetic joint were excluded and finally 96 patients were included. Of the 96 patients, 19 (19.79%) developed a periprosthetic joint infection in a second joint. The type of organism was the same as the first infection in 12 (63.16%) of 19 patients. The time to developing a second infection averaged 2.16 years (range, 0–9.3 years). The risk factors leading to a subsequent infection in another prosthetic joint are albumin level (< 3.5 mg/dl), long-term steroid usage (> 5mg/day, > 3 months), history of necrotizing fasciitis, history of invasive dental procedure (> Grade IV procedure), 3-stage resection arthroplasty or more, and PJI caused by vacomycin-resistent enterococcus (VRE). Conclusions. A PJI might predispose patients to subsequent PJI in another prosthesis. Patients and surgeons must be aware of the risk factors contribute to this devastating complication. Most organisms in the second PJI are identical to the first one, and we believe the bacteremia may be the pathogenesis, but need further proved. The preventive policy may be needed in the future for this population who has multiple prosthetic joints

Aim. Bacterial biofilms play a key role in prosthetic infection (PI) pathogenesis. Establishment of the biofilm phenotype confers the bacteria with significant tolerance to systemic antibiotics and the host immune system meaning thorough debridement and prosthesis removal often remain the only possible course of treatment. Protection of the prosthesis and dead-space management may be achieved through the use of antibiotic loaded cements and beads to release high concentrations of antibiotics at the surgical site. The antibacterial and antibiofilm efficacy of these materials is poorly understood in the context of mixed species models, such as are often encountered clinically. Methods. A P. aeruginosa and S. aureus in vitro co-culture biofilm model was grown using 1/5th BHI supplemented with 20 µM hemin. The ability of beads made from a synthetic calcium sulfate (CaSO4) loaded with vancomycin, tobramycin and vancomycin & tobramycin in combination to prevent biofilm formation and kill established co-culture biofilms were assessed using viable cell counts and confocal scanning laser microscopy (CSLM) over a 7 day time course. To assay for genetic changes to the individual species as a result of their presence together within a biofilm, mutation rates were measured using fluctuation analysis following growth as planktonic and biofilm cultures, alone or in co-culture. Mutants were determined based on their ability to grow on agar plates containing an inhibitory concentration of rifampicin. Mutation rates were calculated using the Ma-Sandri-Sarkar Maximum Likelihood Estimator and 94% confidence intervals compared for significance. Results. Mixed species biofilms displayed differential sensitivity to vancomycin alone and tobramycin alone CaSO4-loaded beads relative to single species biofilms. Preliminary data suggests 10- and 100-fold increase in mutation rates of P. aeruginosa and S. aureus, respectively, when in a co-culture relative to monospecies biofilm which, while further work is needed, may directly or indirectly contribute to the differing antibiotic sensitivities observed. A broad-spectrum intervention of CaSO4-loaded vancomycin & tobramycin beads was able to prevent bacterial colonisation and attenuate P. aeruginosa and S. aureus mixed species biofilm formation for multiple days. Conclusions. Synthetic antibiotic-loaded CS beads, with a broad-spectrum antibiotic combination, have potential to reduce or eliminate mixed species biofilm formation on implant material by providing locally high concentrations over sufficient time periods to aid in the management of PIs. * Stimulan, Biocomposites Ltd

Presence of superficial wound infection following total joint replacement (TJR) increases risk of deep prosthetic infection and revision surgery. Early identification and management are advocated. We conducted an audit to identify the number of suspected wound infections, treatment received, and whether diagnosis was supported by microbiological evidence. Early complication data were collected for all TJRs completed in a 12-month period (2012, n=314). Medical records were reviewed for all complications and summarised data were compared with data from 2010/11. Forty-nine complications were recorded (47 in 2010/11) with increase in number of bacteriologically confirmed wound infections (from 2 to 6) and in number of serious wound infections (n=3). Review of medical records showed that patients were treated in the community with antibiotics despite lack of objective microbiological evidence. Two of three serious wound infections were preceded by prolonged antibiotic prescription in the community. Analysis of these results led to a new system for management of suspected wound infection in TJR patients. A ‘wound care card’ is issued at time of discharge and early assessment by a specialist orthopaedic nurse is available. Early results indicate a beneficial effect with potential to improve patient experience and long-term outcome, and to reduce overuse of antibiotics

Aim. When treating periprosthetic joint infections with a two-stage procedure, antibiotic-impregnated spacers are used in the interval between removal of prosthesis and reimplantation. The spacer provides local antibiotics; however, it may also act as foreign-body that can be colonized by microorganisms. According to our experience, cultures of sonicated spacers are most often negative. The objective of our study was to investigate whether PCR analysis would improve the detection of bacteria in the spacer sonication fluid. Method. A prospective monocentric study was performed at Lausanne University Hospital from September 2014 until January 2016. Inclusion criteria were two-stage procedure for prosthetic infection and agreement of the patient to participate in the study. For a two-stage procedure the interval before reimplantation ranged between 2 and 8 weeks. Spacers were made of cement impregnated with gentamycin, tobramycin and vancomycin. Cultures of intraoperative deep tissues samples from first and second stage procedures, prosthesis sonication and spacer sonication were analyzed. Multiplex-PCR. *. , pan-bacterial PCR (16S), and a Staphylococcus-specific PCR analysis were performed on the sonicated spacer fluid. Results. 23 patients were identified (12 hip, 10 knee and 1 ankle replacements). Initial infection was caused by Staphylococcus aureus (27%), Streptococcus epidermidis (27%), S. dysgalactiae (13%), S. milleri (9%), S. pneumoniae (4%), S. capitis (4%), S. salivarus (4%), P. acnes (4%), E. faecalis (4%) and C. fetus (4%). At reimplantation, cultures of tissue samples and spacer sonication fluid were all negative. Of culture-negative samples, the PCR analyses were negative except for 5 cases. 4 cases of infection recurrence were observed, with bacteria different than for the initial infection in 3 cases. For these cases, no germs were detected in the spacer sonication fluid by neither cultures nor PCR. Conclusions. The 3 different PCR analyses performed did not detect any bacteria in spacer sonication fluid that was culture-negative. In our study, PCR did not improve the bacterial detection and did not help to predict whether the patient will present a recurrence of infection. Prosthetic 2-stage exchange with short interval and antibiotic-impregnated spacer is an efficient treatment to eradicate infection as both culture- and molecular-based methods were unable to detect bacteria in spacer sonication fluid after reimplantation