Acute Prosthetic Joint Infection Research Articles

Risk Factors of DAIR Failure and Validation of the KLIC Score: A Multicenter Study of Four Hundred Fifty-Five Patients.

Background: Debridement, antibiotic agents, and implant retention (DAIR) is a currently accepted approach for the treatment of early prosthetic joint infections (PJI). The success of a DAIR procedure has shown variable results throughout the published literature. Scoring systems such as the Kidney, Liver, Index surgery, Cemented prosthesis, and C-reactive protein value (KLIC) score for the selection of patients that are likely to benefit from DAIR have proved to be helpful in decision making. Our study aims to further validate the KLIC score using a large external multicentric cohort and to evaluate other risk factors for failure. Patients and Methods: A retrospective analysis of patients with an early acute PJI who were treated with DAIR and recorded in a database of eight Spanish university hospitals was performed. According to pre-operative variables of the KLIC study, patients were categorized into five groups: group A, ≤2 points; group B, 2.5-3.5 points; group C, 4-5 points; group D, 5.5-6.5 points; and group E, ≥7 points. Failure rates were compared between groups at 60 days and after 60 days of DAIR. Further variables for risk of failure were also analyzed. Results: A total of 455 patients with early acute PJI were included in the analyses. At 60 days, patients presenting with pre-operative elevated C-reactive protein serum levels, Staphylococcus aureus, and polymicrobial infections were associated with failure. Failure rates recorded were 12% for group A (n = 210), 18% for group B (n = 83), 26% for group C (n = 89), 24% for group D (n = 66), and 0% for group E (n = 7). Univariable analysis between consecutive groups of the KLIC score showed no differences for failure before 60 days of the DAIR procedure. Scheduled surgery and having the procedure performed by a specialized unit were also identified as important factors for DAIR success. Conclusions: Our results suggest the KLIC score was not useful for predicting failure in our cohort. Furthermore, our results indicate a specialized unit should conduct DAIR procedures.

239. Sex Differences in Prosthetic Joint Infection

BackgroundMale sex has been demonstrated to be a non-modifiable risk factor for prosthetic joint infection (PJI) incidence in multiple studies. Given the known anatomical, genetic, and immunological differences between sexes, we compared the clinical characteristics of PJI among men and women. MethodsA retrospective cohort of total hip and knee arthroplasty PJIs from 2009 to 2019 were identified using a single institution PJI database. Included cases met the 2013 MSIS criteria. Microbiology, acuity (defined by implant age and symptom days), and surgical outcomes were collected. Success was defined as no further PJI surgery at two years. Continuous variables were tested with either Student’s t test or Mann-Whitney U test. Categorical variables were tested with either Chi-squared test or Fisher’s exact test.ResultsWe identified 1052 PJI patients, of whom 463 (44.0%) were women. In univariate analysis of the total cohort, women were younger (68.1 ± 11.2 vs 66.1 ± 11.8 years, p=0.01), had higher BMI (30.8 ± 7.78 vs 29.8 ± 6.0, p=0.04), and had a higher culture-negative rate (14.5% vs 9.0%, p < 0.01) than men, but no difference was noted in Charlson Comorbidity Index (Table 1). Among hip PJIs, women were likelier than men to present with acute PJI (15.9% vs 8.7%, p=0.03). There were no differences in debridement, antibiotics, and implant retention (DAIR) utilization (48.2% vs 44.1%, p=0.067), and overall treatment success (72.1% vs 71.6%, p=0.9), nor in any subanalysis of acute, hip, or knee PJIs. ConclusionAlthough females may present differently when diagnosed with PJI, overall outcomes and outcomes with respect to acuity and type of septic revision did not clearly differ in this single-center cohort. Further research in larger cohorts, including additional biomarkers and socioeconomic variables, may further elucidate relationships between sex and PJI characteristics including culture-negativity and symptom acuity.Disclosures All Authors: No reported disclosures

Chronic Antibiotic Suppression for Nonstaphylococcal Prosthetic Joint Infections Treated with Debridement or Implant Retention

Background: Early postoperative and acute prosthetic joint infection (PJI) may be managed with debridement, antibiotics, and implant retention (DAIR). Among patients with nonstaphylococcal PJI, an initial 4–6-week course of intravenous or highly bioavailable oral antibiotics is recommended in the Infectious Diseases Society of America (IDSA) guidelines, with disagreement among committee members on the need for subsequent chronic oral antimicrobial suppression (CAS). We aimed to characterize patients with nonstaphylococcal PJI who received CAS and to compare them to those who did not receive CAS. Methods: This retrospective cohort study included patients admitted to Veterans’ Affairs (VA) hospitals from 2003 to 2017 who had a PJI caused by nonstaphylococcal bacteria, underwent DAIR, and received 4–6 weeks of antimicrobial treatment. PJI was defined by Musculoskeletal Infection Society (MSIS) 2011 criteria. CAS was defined as at least 6 months of oral antibiotics following initial treatment of the PJI. Patients were followed for 5 years after debridement. We used χ2 tests and t tests were used to compare patients who received CAS with those who did not receive CAS. Results: Overall, 561 patients had a nonstaphylococcal PJI treated with DAIR, and 80.6% of patients received CAS. The most common organisms causing PJI were streptococci. We detected no significant differences between patients who received CAS and those who did not receive CAS, except that modified Acute Physiology and Chronic Health Evaluation (mAPACHE) scores were higher among patients who did not receive CAS (Table 1). Conclusion: Patients not on CAS were more severely ill (by mAPACHE) than those on CAS. Otherwise, the 2 groups were not different. This finding was contrary to our hypothesis that patients with multiple comorbidities or higher mAPACHE scores would be more likely to get CAS. A future analysis will be conducted to assess treatment failure in both groups. We hope to find a specific cohort who may benefit from CAS and hope to deimplement CAS in others who may not benefit from it.Funding: NoDisclosures: None

To DAIR or not to DAIR: Decision-making in the management of acute prosthetic joint infection � A narrative review

To DAIR or not to DAIR: Decision-making in the management of acute prosthetic joint infection � A narrative review

Factors Associated With Elevated Inflammatory Markers Prior to Shoulder Arthroplasty.

Background: Preoperative erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) ranges for several shoulder arthroplasty indications are not well understood. Purpose: We sought to compare preoperative ESR and CRP values for a variety of shoulder arthroplasty indications and evaluate risk factors for elevated preoperative ESR and CRP values. Methods: We conducted a retrospective cohort study of shoulder arthroplasty cases performed at a single academic medical institution from 2013 to 2018. Preoperative ESR and CRP values for 235 shoulder arthroplasties with various indications were recorded. Independent risk factors for elevated values (CRP > 10.0 mg/L and ESR > 30.0 mm/h) were determined via multiple variable logistic regression. Results: Patients undergoing shoulder arthroplasty for osteoarthritis had an ESR (mean ± SD) of 22.6 ± 17.8, with 29.8% of patients elevated, and a CRP of 6.5 ± 6.4, with 25.5% of patients elevated. Arthroplasty for acute fracture and prosthetic joint infection (PJI) had higher preoperative ESR and CRP values. Multivariate analysis identified several predictors of elevated ESR, including infection, acute fracture, diabetes, and female sex. It also identified predictors of elevated CRP, including infection, acute fracture, and younger age. Conclusions: Preoperative ESR and CRP values may be elevated in 25% to 30% of patients undergoing primary shoulder arthroplasty. Arthroplasty for both acute fracture and PJI, along with several other patient factors, was associated with elevated preoperative ESR and CRP. Thus, routine collection of ESR and CRP preoperatively may not be of benefit, as elevated values are common. Further study is warranted.

The Topical Tranexamic Acid Have Potential Hazard of Promoting Biofilm Formation of Staphylococcus aureus in Microenvironment of the Prosthetic Joint

Background. Perioperative topical tranexamic acid as antifibrinolytic agent is often used for total joint replacement to reduce bleeding currently. Staphylococcus aureus was the most common isolates from perioperative infection of prosthetic joint. The influence of topical application with tranexamic acid on the incidence of acute prosthetic joint infection of Staphylococcus aureus has not been clarified. Methods. Mouse model of Staphylococcus aureus knee prosthesis infection was constructed. Tranexamic acid was intra-articular injected during the perioperative period. CFU counting from tissue and implant sample was evaluated 3 days and 7 days after inoculating of Staphylococcus aureus. Bacterial growth curve, biofilm formation, aggregation, and plasmin inhibition of Staphylococcus aureus were tested with tranexamic acid added to the synovial culture medium. Results. There were no significant differences of CFU counting from tissue and implant samples in knee prosthesis infection after a single local injection of tranexamic acid at the postoperative 3 or 7 days. The amount of bacterial colonization on the surface of implant increased after 3 days’ continuous local injection of tranexamic acid. Tranexamic acid has no effect on bacterial growth at the concentration (10 mg/ml) of clinical application, but it can inhibit bacterial aggregation and mildly inhibit biofilm formation. Plasmin can significantly inhibit biofilm formation which can be revised by adding tranexamic acid. Conclusion. Although continuous local injection of tranexamic acid can promote the biofilm formation of Staphylococcus aureus on the surface of articular implant, it has clinical safety for using one single local injection of tranexamic acid during the perioperative period.

Implant Removal in the Management of Prosthetic Joint Infection by Staphylococcus aureus: Outcome and Predictors of Failure in a Large Retrospective Multicenter Study.

Objectives: To compare the characteristics and outcomes of cases with acute prosthetic joint infection (PJI; early post-surgical or hematogenous) by Staphylococcus aureus managed with implant removal (IRm) or debridement and retention (DAIR). To analyze the outcomes of all cases managed with IRm (initially or after DAIR failure). Methods: Retrospective, multicenter, cohort study of PJI by S. aureus (2003–2010). Overall failure included mortality within 60 days since surgery and local failure due to staphylococcal persistence/relapse. Results: 499 cases, 338 initially managed with DAIR, 161 with IRm. Mortality was higher in acute PJI managed initially with IRm compared to DAIR, but not associated with the surgical procedure, after propensity score matching. Underlying conditions, hemiarthroplasty, and methicillin-resistant S. aureus were risk factors for mortality. Finally, 249 cases underwent IRm (88 after DAIR failure); overall failure was 15.6%. Local failure (9.3%) was slightly higher in cases with several comorbidities, but independent of previous DAIR, type of IRm, and rifampin treatment. Conclusions: In a large multicenter study of S. aureus PJI managed with IRm, failure was low, but mortality significant, especially in cases with acute PJI and underlying conditions, but not associated with the IRm itself. Rifampin efficacy was limited in this setting.

Is DAIR Still an Effective Way to Eradicate Acute Prosthetic Joint Infections? Our Experience in the Jordanian Royal Medical Services.

Background:Prosthetic joint infections is estimated to occur in 1–2% of primary total joint arthroplasty. Debridement, antibiotics, irrigation and retention of prosthesis (DAIR) is the traditional treatment for acute prosthetic joint infections.Objective:To determine risk factors of treatment failure in subjects managed with debridement, antibiotics, irrigation and retention of prosthesis for acute prosthetic joint infections.Methods:Our prospective, double blind and randomized investigation included 70 subjects, of both sexes, aged 63-72 years, who were managed with debridement, antibiotics, irrigation and retention of prosthesis for total hip or total knee arthroplasty acute prosthetic joint infections at Prince Hashim military hospital and Queen Alia military hospital, Jordan, during the period October 2017-October 2020. The observation period was 3 years. Therapy success was defined as absence of infection following 3 years, retention of the prosthesis and no further antibiotics therapy. Prosthetic joint infection was defined based on one or more of: a) growth of the same microorganism in minimum 2 cultures; b) one positive culture and a purulent synovial fluid upon debridement; c) negative culture and minimum 2 of purulent synovial fluid upon debridement. A successful outcome was defined as no clinical and laboratory evidence of infection (serum C-reactive protein less than 10 mg/L) at 3 years. Subjects with chronic, suppressive antibiotics or with prosthesis removal were considered therapy failure. Parameters statistically and remarkably discrepant between success and failure groups were investigated with logistic regression. P less than 0.05 were considered statistically significant.Results:Amount of 46 subjects (65.7%) had no infection during the period of observation. Factors correlated with therapy failure were: history of Rheumatoid Arthritis, delayed infection (more than 1.5 years following arthroplasty), ESR at presentation of more than 50 mm/h and infection induced by coagulase-negative Staphylococcus. Symptoms duration of less than 5 days was associated with a better outcome. The use of Gentamicin sponges was statistically remarkably more in the success group and the use of beads was more in the failure group in the univariate but not in the logistic regression. Less surgical interventions were needed in the group managed with sponges than in the group managed with beads. Prosthetic joint infection induced by coagulase-negative Staphylococcus was associated with a less success rate and streptococcal infections were associated with an increased success rate.Conclusion:Rheumatoid arthritis, duration of symptoms of more than 5 days, ESR of more than 50 mm/h, delayed infection (more than 1.5 years following the index arthroplasty) and coagulase-negative Staphylococcus infections reduce the rate of a successful debridement, antibiotics, irrigation and retention of prosthesis therapy.

An elderly female with adult-onset Still\u2019s disease initially misdiagnosed as prosthetic joint infection after total knee arthroplasty: lessons in differential diagnosis and treatment

BackgroundHigh fever, knee swelling and pain after knee arthroplasty are often considered as symptoms of acute prosthetic joint infection. However, similar symptoms can also present as primary manifestations of adult-onset Still’s disease, which creates some interference in differential diagnosis. To our knowledge, this is the first published case of misdiagnosis of adult Still’s disease after total knee arthroplasty, who was initially misdiagnosed as an prosthetic joint infection due to the above-mentioned symptoms. The symptoms of the knee infection was not relieve after several revisions and continous antibiotic treatment. Finally, after several consultations and repeated evaluation it was diagnosed as adult-onset Still’s disease.Case presentationA 77-year-old female who underwent bilateral total knee arthroplasty 6 years ago was admitted to our hospital with high fever, right knee effusion and painful knee. Based on the results of joint fluid aspiration and culture, we treated the right knee as acute hematogenous prosthetic joint infection. After three debridement and revision surgeries, the patient’s symptoms continued to persist. Subsequent manifestations of other symptoms such as typical rash and sore throat and laboratory examination suggested the possibility of adult-onset Still’s disease. So she underwent diagnostic steroid hormone therapy at the recommendation of a rheumatologist, and a final revision was performed after symptom was controlled. At the one-year follow-up, the patient’s symptoms completely resolved and the knee revision was functioning well.ConclusionsWhen joint swelling and pain occurs after knee arthroplasty, the possibility of joint infection should not only be considered, but rheumatic autoimmune diseases should also be differentiated. Because the manifestations of joint infection and rheumatic immune disease sometimes overlap highly, when reasonable treatment over a period of time fails to relieve symptoms and signs, we should notice subtle differences in symptoms and laborotary tests and look for other diagnostic possibilities in time.

Clorpactin: An Alternative Irrigation Method for Total Knee Arthroplasty Joint Infection Revisions.

Different combinations of irrigation solutions have been used in attempt to eradicate microorganisms for the prevention and treatment of prosthetic joint infections (PJIs). Clorpactin WCS-90 was evaluated as an alternative irrigation intraoperative technique for the treatment of PJI using both debridement, antibiotics, and implant retention (DAIR) and 2-stage total knee arthroplasty (TKA) procedures. We retrospectively reviewed PJIs irrigated with Clorpactin between January 2015 and January 2020. We found 13 patients who underwent a DAIR procedure for an acutely infected primary TKA, 18 patients underwent a 2-stage procedure for a chronically infected primary TKA, two patients underwent a DAIR procedure for an acutely infected revision TKA, and 18 patients underwent a 2-stage procedure for a chronically infected revision TKA. The odds of reinfection and need for additional surgery were analyzed at a mean follow-up of 20 to 26 months between groups. Only one patient (7.69%) became reinfected in the acute infected primary TKA group, three patients (16.67%) in the chronic infected primary TKA group, 0 patients (0%) in the acute infected revision TKA group, and six patients (33.33%) in the chronic infected revision TKA group. When the acute primary TKA infection group was compared with the chronic revision TKA infection group, the odds of reinfection (Chi-square test [χ2] = 21.7, df 3, p < 0.001) and odds of additional surgery (χ2 = 13.6, df 3, p < 0.003) were significantly higher for the chronic revision TKA infection group. Overall, the reinfection rate for DAIR revisions was 6.67% (range = 0-7.69) and 2-stage revisions was 25.00% (range = 16.67-33.33). The use of Clorpactin WCS-90 irrigation prior to wound closure is a useful option for the treatment of acute and chronic knee PJIs. Our study provides evidence that infection eradication with the use of Clorpactin is comparable to other irrigation methods and surgical techniques in reported literature.

Reply to Scheper and deBoer's comment on "Duration of rifampin therapy is a key determinant of improved outcomes in early-onset acute prosthetic joint infection due to Staphylococcus treated with a debridement, antibiotics and implant retention (DAIR): a retrospective multicenter study in France" by Becker et al.(2020).

Reply to Scheper and deBoer's comment on "Duration of rifampin therapy is a key determinant of improved outcomes in early-onset acute prosthetic joint infection due to Staphylococcus treated with a debridement, antibiotics and implant retention (DAIR): a retrospective multicenter study in France" by Becker et al.(2020).

Local delivery of tobramycin and vancomycin in primary total knee arthroplasty achieves minimum inhibitory concentrations for common bacteria causing acute prosthetic joint infection.

The aim of this study was to determine if the local delivery of vancomycin and tobramycin in primary total knee arthroplasty (TKA) can achieve intra-articular concentrations exceeding the minimum inhibitory concentration thresholds for bacteria causing acute prosthetic joint infection (PJI). Using a retrospective single-institution database of all primary TKAs performed between January 1 2014 and May 7 2019, we identified patients with acute PJI that were managed surgically within 90 days of the initial procedure. The organisms from positive cultures obtained at the time of revision were tested for susceptibility to gentamicin, tobramycin, and vancomycin. A prospective study was then performed to determine the intra-articular antibiotic concentration on postoperative day one after primary TKA using one of five local antibiotic delivery strategies with tobramycin and/or vancomycin mixed into the polymethylmethacrylate (PMMA) or vancomycin powder. A total of 19 patients with acute PJI after TKA were identified and 29 unique bacterial isolates were recovered. The mean time to revision was 37 days (6 to 84). Nine isolates (31%) were resistant to gentamicin, ten (34%) were resistant to tobramycin, and seven (24%) were resistant to vancomycin. Excluding one Fusobacterium nucleatum, which was resistant to all three antibiotics, all isolates resistant to tobramycin or gentamicin were susceptible to vancomycin and vice versa. Overall, 2.4 g of tobramycin hand-mixed into 80 g of PMMA and 1 g of intra-articular vancomycin powder consistently achieved concentrations above the minimum inhibitory concentrations of susceptible organisms. One-third of bacteria causing acute PJI after primary TKA were resistant to the aminoglycosides commonly mixed into PMMA, and one-quarter were resistant to vancomycin. With one exception, all bacteria resistant to tobramycin were susceptible to vancomycin and vice versa. Based on these results, the optimal cover for organisms causing most cases of acute PJI after TKA can be achieved with a combination of tobramycin mixed in antibiotic cement, and vancomycin powder. Cite this article: Bone Joint J 2020;102-B(6 Supple A):163-169.

Duration of rifampin therapy is a key determinant of improved outcomes in early-onset acute prosthetic joint infection due to Staphylococcus treated with a debridement, antibiotics and implant retention (DAIR): a retrospective multicenter study in France.

Introduction: In patients undergoing a « debridement, antibiotics, and implant retention » (DAIR) procedure for acute staphylococcal prosthetic joint infection (PJI), post-operative treatment with rifampin has been associated with a higher probability of success.(1,2) However, it is not known whether it is the total dose, delay of introduction or length of therapy with rifampin that is most strongly associated with the observed improved outcomes.Methods: A multicentric, retrospective cohort study of patients with acute staphylococcal hip and knee PJI treated with DAIR between January 2011 and December 2016. Failure of the DAIR procedure was defined as persistent infection, need for another surgery or death. We fitted logistic and Cox regression multivariate models to identify predictors of DAIR failure. We compared Kaplan-Meier estimates of failure probability in different levels of the 3 variables of interest - total dose, delay of introduction or length of therapy with rifampin - with the log-rank test.Results: 79 patients included (median age 71 years [63.5-81]; 55 men [70%]), including 54 (68%) DAIR successes and 25 (32%) DAIR failures. Patients observed for a median of 435 days [IQR 107.5-834]. Median ASA score significantly lower in DAIR successes than in DAIR failures (2 vs. 3, respectively p = 0.011). Bacterial cultures revealed 65 (82.3%) S. aureus and 16 (20.3%) coagulase negative staphylococci, with 2 patients being infected simultaneously with S. aureus and CNS. Among S. aureus isolates, 7 (10.8%) resistant to methicillin; 2 (3.1 %) resistant to rifampin. Median duration of antimicrobial therapy was 85 days [IQR 28.5-97.8]. Fifty-eight patients (73.4%) received rifampin at a median dose of 14.6 mg/kg/day |IQR 13-16.7], started at a median delay of 8.5 days [IQR, 4-7.5] after debridement surgery. Twenty-one patients (26.6%) developed a drug-related adverse event, leading to rifampin interruption in 6 of them (7.6% of total cohort). Determinants of DAIR failure were rifampin use (HR 0.17, IC [0.06, 0.45], p-value <0.001), association of rifampin with a fluoroquinolone (HR 0.19, IC [0.07, 0.53], p-value = 0.002) and duration of rifampin therapy (HR 0.97, IC [0.95, 1], p-value = 0.022). We did not observe a significant difference between DAIR successes and failures in rifampin use, dose and delay of introduction. In a multivariate Cox model, only duration of rifampin therapy was significantly associated with DAIR failure. Kaplan Meier estimate of DAIR failure probability was significantly higher in patients receiving less than 14 days of rifampin in comparison with those receiving more than 14 days of rifampin (p = 0.0017).Conclusion: Duration of rifampin therapy is a key determinant of improved outcomes in early-onset acute prosthetic joint infection due to Staphylococcus treated with DAIR.

Streptococcus bovis Hip and Knee Periprosthetic Joint Infections: A Series of 9 Cases.

Introduction: Prosthetic joint infection (PJI) due to Streptococcus bovis group (SBG), specifically S. bovis biotype I (S. gallolyticus), is rare and associated with colorectal carcinoma. Little has been published regarding SBG PJI. We analyzed nine cases of SBG PJI at our institution, the largest series to date.Methods: The medical records of patients diagnosed with SBG PJI between 2000-2017 were reviewed. Patients were followed until death, failure, or loss to follow-up. Mean follow-up was 37 months (range 0.5-74 months).Results: Nine PJI in 8 patients with mean prosthesis age at diagnosis of 8 years (range 4 weeks-17 years) were identified. The median duration between symptom onset and treatment was 38 weeks (range 0.3 weeks-175 weeks). 8/9 had their PJI eradicated with treatment based on acuity of symptoms. Acute PJI (2) was treated with DAIR, and chronic PJI (7) was treated with 2-stage revision arthroplasty. 1 PJI with chronic PJI developed recurrent infection after initial treatment. All patients received post-operative IV antibiotics. 7/8 patients received Ceftriaxone. Three patients received lifelong oral antibiotics. 7/8 patients underwent colonoscopy. 5/7 patients were found to have polyps following PJI diagnosis with one carcinoma and two dysplastic polyps. The two patients without polyps had identifiable gastrointestinal (GI) mucosal abnormality: tooth extraction prior to symptom onset and diverticulosis on chronic anticoagulation.Conclusion: SBG PJI is typically due to hematologic seeding. Colonoscopy should be pursued for patients with SBG PJI. Surgical treatment dictated by infection acuity and 6-week course of Ceftriaxone seems sufficient to control infection.

The use of negative pressure wound therapy increases failure rate in debridement and implant retention for acute prosthetic joint infection.

To date only scanty data exist regarding the effect of failed debridement, antibiotics, irrigation and retention of the prostheses (DAIR) and negative pressure wound therapy (NPWT) on the outcome of a subsequent exchange arthroplasty. The objective of this study was to determine the success rate of a two- or multi-stage procedure after initial failed DAIR/NPWT in patients with an acute periprosthetic joint infection (PJI) and to evaluate the influence of possible risk factors for treatment failure. Nineteen consecutive patients with a persisting PJI and ongoing NPWT after treatment of an acute PJI with DAIR of the hip or knee joint from October 2010 to June 2017 were included. All patients were treated according to a structured treatment algorithm after referral to our hospital. The endpoint was a successful reimplantation with absence of signs of infection two years after replantation ("replantation group") or treatment failure ("treatment failure group") in terms of a permanent girdlestone arthroplasty, fistula, amputation or death. A risk factor analysis was performed between the two groups. Explantation was performed in 15 cases, amputation in one case, and DAIR/establishment of a fistula in three cases. The treatment success rate after reimplantation in terms of "definitively free of infection" two years after surgery according to Laffer was 36.85% (seven out of 19 patients). Statistical analysis revealed the number of surgeries until wound consolidation (p= 0.007), number of detected bacterial strains (p= 0.041), a polymicrobial PJI (p= 0.041) and detection of a difficult-to-treat organism (p= 0.005) as factors associated with treatment failure. After failed DAIR/NPWT we could detect a significant higher number of different bacterial strains (p= 0.001). The treatment success rate after failed DAIR and NPWT with 36% is low and associated with a high treatment failure rate (permanent girdlestone arthroplasty, fistula or amputation, death). Thus, the definition of risk factors is crucial. We found that the number of revisions until wound consolidation, a polymicrobial PJI and detection of a difficult-to-treat organisms were risk factors for treatment failure. Furthermore, after failed DAIR/NPWT we could detect a significant higher number of different bacterial strains, with a possible adverse effect on a consecutive exchange.

The Right Time to Safely Re-Evaluate Empirical Antimicrobial Treatment of Hip or Knee Prosthetic Joint Infections.

Currently, no guideline provides recommendations on the duration of empirical antimicrobial treatment (EAT) in prosthetic joint infection (PJI). The aim of our study was to describe the time to growth of bacteria involved in PJI, rendering possible decreased duration of EAT. Based on a French multicentre prospective cohort study, culture data from patients with confirmed hip or knee PJI were analysed. For each patient, five samples were processed. Time to positivity was defined as the first positive medium in at least one sample for virulent pathogens and as the first positive medium in at least two samples for commensals. Definitive diagnosis of polymicrobial infections was considered the day the last bacteria were identified. Among the 183 PJIs, including 28 polymicrobial infections, microbiological diagnosis was carried out between Day 1 (D1) and D5 for 96.7% of cases. There was no difference in the average time to positivity between acute and chronic PJI (p = 0.8871). Microbiological diagnosis was given earlier for monomicrobial than for polymicrobial infections (p = 0.0034). When an optimized culture of peroperative samples was carried out, almost all cases of PJI were diagnosed within five days, including polymicrobial infections. EAT can be re-evaluated at D5 according to microbiological documentation.

Mini Review on the Impact of Mobile Parts' Exchange During the DAIR Procedure (Debridement, Antibiotics, Irrigation, Retention) for Infected Total Joint Arthroplasties

A prosthetic joint infection (PJI) requires a combined approach (infectiology and surgery). The therapeutic DAIR approach (debridement, antibiotics, irrigation, and retention) is an option for acute and stable PJI yielding remission incidences that oscillate between 70% and 90%; in a literature mostly composed of retrospective single-center trials. DAIR can be performed with or without mobile part’s exchange during debridement. Scientific data proving the necessity of mobile part exchanges (by leaving other infected components in situ) remain scarce. In this narrative mini review, we evaluate the existing literature that analyses the benefit of exchanging mobile parts with at least ten own cases. We moreover discuss the optimal duration of concomitant targeted systemic antibiotic therapy and reveal some insights in the surgical difficulties in performing DAIR. Our conclusion tends to favor of the mobile part’s exchange whenever feasible.

Optimization of the empirical antibiotic choice during the treatment of acute prosthetic joint infections: a retrospective analysis of 91 patients

Background and purpose — The preferred treatment of an acute prosthetic joint infection (PJI) is debridement, antibiotics, irrigation and retention of the prosthesis (DAIR). The antibiotic treatment consists of an empirical and targeted phase. In the empirical phase, intravenous antibiotics are started after surgery before micro-organisms are determined in microbiological cultures. Which empirical antibiotic is used differs between hospitals, partly reflecting geographic differences in susceptibility spectrums. We investigated whether flucloxacillin should remain the antibiotic of choice in our hospital for empiric treatment of acute PJI with DAIR.Patients and methods — We retrospectively analyzed 91 patients treated for PJI with DAIR between 2012 and 2016. The susceptibility of micro-organisms was determined in multiple cultures of periprosthetic tissue and synovial fluid for 3 antibiotics: amoxicillin/clavulanic acid, cefazolin, and flucloxacillin.Results — Positive microbiological cultures from 68 patients were analyzed. Staphylococcus aureus was the predominant pathogen, cultured in half of the patients. In one-third of patients more than 1 micro-organism was found. On a patient level, the data showed that 65% were responsive to flucloxacillin, 76% to amoxicillin/clavulanic acid, and 79% to cefazolin.Interpretation — Flucloxacillin appeared to be a suboptimal choice in our patient population treated with DAIR. We therefore changed our practice to cefazolin as the preferred antibiotic in the empirical treatment of acute PJI with DAIR.

First results of a uniform regional treatment protocol and registration for acute prosthetic join infection in the South-East of the Netherlands.

Introduction: Prosthetic joint infection (PJI) is a relatively uncommon (average incidence 0.5-2%) but devastating complication, with significant morbidity and leading to tremendously increased health care costs. In 2013, delegates from nine hospitals covering a large region in the South-East Netherlands composed one combined treatment protocol for acute PJI of total hip and knee arthroplasty (THA and TKA). This protocol was based on the definition of acute PJI according to Workgroup of the American Musculoskeletal Infection Society (MSIS) and the principles of debridement, antibiotics, irrigation and retention (DAIR).Methods: Patients with a THA or TKA treated with DAIR because of suspicion of PJI were selected from the online PJI database. PJI was defined as at least two phenotypically identical pathogens, isolated in cultures from at least two separate tissues, obtained from the affected prosthetic joint. Acute PJIs, occurring within 90 days after primary implantation, between January 2014 and December 2016, were analyzed. We analyzed the PJI incidence rate, patient clinical and microbiological characteristics of PJI, outcome of the DAIR treatment and adherence to the regional protocol.Results: A total of 310 primary THA or TKA with a suspected PJI were registered in the regional PJI database, 236 met the definition of acute PJI, representing overall incidence of 1.12%. Following the regional treatment protocol replacement of exchangeable parts took place in 45% in 2014 to 70% in 2016. After 12 months follow-up, prosthesis retention was achieved in 87% and 3% of the patients died within one year after the primary surgery.Conclusion: Results of the regional cohort are in line with the available literature. Regional collaboration and regular feedback on registered data resulted in better adherence to the combined treatment protocol. Despite our attempts to improve PJI care, PJI remains a serious complication of THA and TKA with a significant mortality rate and burden for the patient.

Metallurgical Gallium Additions to Titanium Alloys Demonstrate a Strong Time-Increasing Antibacterial Activity without any Cellular Toxicity.

Orthopedic metallic devices are often related with devasting complications due to acute prosthetic joint infections. Gallium (Ga) antibacterial activity has been demonstrated by the evidence that Ga in solution ionizes in a Ga3+ trivalent form that replace Fe3+ thus arresting metabolism. However, it is not clear whether such effect is restricted only to Ga3+ release laps. Accordingly, here we investigated Ga addition into titanium alloys using metallurgical methods, thus realizing intermetallides of a very high stability that contain Ga in the range of 1, 2, 20, and 23% wt. ICP-OES analysis confirmed that Ga ions were not released from the specimens regardless of the Ga amount. These alloys ensured long-lasting Ga effect toward multidrug resistant Staphylococcus aureus, whose metabolic activity was reduced of >80% in comparison with controls. Finally, specimens cytocompatibility was confirmed by direct and indirect contact evaluations with mature osteoblasts and preosteoblasts progenitor cells.