Septic Revision Research Articles

The anatomical shape of the distal femur is an independent risk factor for aseptic loosening following one-stage septic knee revision using rotating hinge knee prosthesis.

Aseptic loosening (AL) is the second most common reason for failure after one-stage septic knee revision. In this context, the goal of the study is to identify risk factors for AL following one-stage septic knee revision using rotating hinge implants. We aimed to answer the following research question: How does the anatomical shape of the distal femur represent an independent risk factor for AL following one-stage septic knee revision arthroplasty? Patients, who had undergone re-revision surgery due to AL of the rotating hinge knee prosthesis after one-stage septic knee revision arthroplasty between January 2008 and December 2018, were included. For this purpose, 41 patients with AL after one-stage septic knee revision using rotating hinge implants and 37 controls without any revision surgery at latest follow-up were included in this study. Using standardized anteroposterior (AP) views of the knee in all patients, we measured the inner diameter of the femur 20cm proximally from the joint line and at a point 2cm proximally from the adductor tubercle. Among the vast majority of AL cases, we identified an isolated loosening of the femoral component. The AL group showd a high distribution of the Type C according to the Citak classification with 75.7%. Contrary to this, with 24.3% (p < 0.001) the amount of Type C cases was relatively low in the control group. Consequently, Type C configurations of the distal femur represent an independent risk factor for AL with an approximately sevenfold higher risk for AL compareed to Type A and Type B. The novel radiological classification system of the distal femur shows that the Type C subtype is an independent and main risk factor for AL after one-stage septic knee revision using rotating hinge knee implants.

Shoulder Periprosthetic Joint Infection and All-Cause Mortality: A Worrisome Association.

Background:Periprosthetic joint infection (PJI) can be a devastating complication following shoulder arthroplasty. PJI following hip and knee arthroplasties has been found to increase mortality. However, anatomical and bacteriologic differences could potentially result in a different trend after shoulder arthroplasties. Thus, the purpose of the present study was to determine whether there is an association between shoulder PJI and all-cause mortality.Methods:Our institutional Total Joint Registry Database was queried to identify patients who underwent revision shoulder arthroplasty procedures between 2000 and 2018. A total of 1,160 procedures were then classified as either septic (21.8%) or aseptic (78.2%). Septic revisions were further subdivided into (1) debridement, antibiotics, irrigation, and implant retention (9.1%); (2) 2-stage reimplantation for deep infection (61.3%); (3) implant resection without reimplantation (3.6%); and (4) unexpected positive cultures at revision surgery (26.1%). The most common bacterium isolated was Cutibacterium acnes (64.4%). All-cause patient mortality was determined with use of our registry and confirmed with use of a nationwide mortality database. All-cause crude and adjusted mortality rates were then compared between groups.Results:The 1-year crude mortality rate was 1.8% (95% confidence interval [CI], 0.9% to 2.6%) for the aseptic group and 2.8% (95% CI, 0.7% to 4.8%) for the septic group (p = 0.31). Multivariate Cox regression analysis demonstrated an elevated but statistically similar adjusted hazard ratio for 1-year all-cause mortality of 1.9 (95% CI, 0.8 to 4.6) when comparing the septic to the aseptic group (p = 0.17). The risk of 2-year all-cause mortality was significantly higher in the septic group, with a hazard ratio of 2.2 (95% CI, 1.1 to 4.5; p = 0.029). In univariate analyses, increased 5-year mortality in the septic revision group was associated with age, Charlson Comorbidity Index, and methicillin-resistant Staphylococcus aureus infection, whereas C. acnes infection was associated with lower mortality.Conclusions:Shoulder PJI is associated with an adjusted 2-year all-cause mortality rate that is double that of aseptic patients. The results of the present study should be utilized to appropriately counsel patients who are considered to be at risk for infection following shoulder arthroplasty.Level of Evidence:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Favourable outcomes of repeat one-stage exchange for periprosthetic joint infection of the hip.

One-stage exchange for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) is gaining popularity. The outcome for a repeat one-stage revision THA after a failed one-stage exchange for infection remains unknown. The aim of this study was to report the infection-free and all-cause revision-free survival of repeat one-stage exchange, and to investigate the association between the Musculoskeletal Infection Society (MSIS) staging system and further infection-related failure. We retrospectively reviewed all repeat one-stage revision THAs performed after failed one-stage exchange THA for infection between January 2008 and December 2016. The final cohort included 32 patients. The mean follow-up after repeat one-stage exchange was 5.3 years (1.2 to 13.0). The patients with a further infection-related failure and/or all-cause revision were reported, and Kaplan-Meier survival for these endpoints determined. Patients were categorized according to the MSIS system, and its association with further infection was analyzed. A total of eight repeat septic revisions (25%) developed a further infection-related failure, and the five-year infection-free survival was 81% (95% confidence interval (CI) 57 to 92). Nine (28%) underwent a further all-cause revision and the five-year all-cause revision-free survival was 74% (95% CI 52 to 88). Neither the MSIS classification of the host status (p = 0.423) nor the limb status (p = 0.366) was significantly associated with further infection-related failure. Repeat one-stage exchange for PJI in THA is associated with a favourable five-year infection-free and all-cause revision-free survival. Notably, the rate of infection control is encouraging when compared with the reported rates after repeat two-stage exchange. The results can be used to counsel patients and help clinicians make informed decisions about treatment. With the available number of patients, further infection-related failure was not associated with the MSIS host or limb status. Cite this article: Bone Joint J2022;104-B(1):27-33.

Time Required for Planned and Unplanned Episodes of Care in Septic and Aseptic Hip and Knee Revision Surgery

Background: Surgical reimbursement rates are established by the Centers for Medicare and Medicaid Services (CMS). Studies have indicated that revision hip (rTHA) and knee (rTKA) arthroplasties require significantly more work effort, but are reimbursed less than primary procedures. This study quantified planned and unplanned work performed for revision surgeries by the surgeon and/or the surgeon’s team during the episode of care “reimbursement window.” Quantification of time was performed separately for aseptic and septic (two-stage) revisions and compared to allowed reimbursement amounts. &#x0D; &#x0D; Methods: All unilateral rTHA and rTKA procedures performed over a 10-year period by a single surgeon at a single institution were retrospectively reviewed. Time dedicated to planned work was calculated over each episode of care, from surgery scheduling to 90 days postoperatively. Impromptu patient inquiries and treatments after discharge, but within the episode of care, involving the surgeon/surgeon team constituted unplanned work. Planned and unplanned work minutes were summed and divided by the number of patients reviewed to obtain average minutes of work per patient. &#x0D; &#x0D; Results: Calculations demonstrated average per patient work for aseptic rTKA exceeded the reimbursable amount by 31 minutes. Calculated average minutes of work per patient required for aseptic rTHA fell within the number of minutes approved for reimbursement. Average per patient work for septic rTKA and rTHA exceeded the reimbursable amounts by 331 and 166 minutes, respectively, equating to 2.8 to 5.5 hours of uncompensated time. &#x0D; &#x0D; Conclusion: Revision hip and knee procedures are substantially more complex than primary procedures, with many surgeons referring patients to out-of-network care. Financially dis-incentivizing surgeons to care for these patients reduces patient access to care when high quality care is needed the most, especially infection cases susceptible to high sepsis and mortality rates. Study findings will be applied to advocacy efforts for appropriate legislative reform.

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

In-Hospital Mortality Is Associated With Low-Volume Hip Revision Centers After Septic Revision Total Hip Arthroplasty.

Revision total hip arthroplasty (rTHA) after septic failure is associated with higher morbidity and mortality compared with aseptic revisions. The goals of this study were to characterize (1) the in-hospital mortality rate for patients with septic rTHA, (2) the effect of hospital hip revision surgery volume (HRV) on mortality after septic rTHA, and (3) the independent risk factors associated with in-hospital mortality rates after rTHA with 2-year follow-up. The authors analyzed the Healthcare Cost and Utilization Project State Inpatient Databases of New York and Florida to identify cases of septic rTHA from 2007 to 2012 with International Classification of Diseases, Ninth Revision, codes. The authors included patients with (1) no history of THA for 2 years before the index admission and (2) 2 years of follow-up. Groups with primary THA and aseptic rTHA were identified as control groups. Logistic regression was used to evaluate independent associations. Of 3057 patients with septic rTHA, 5.2% (n=160) had in-hospital mortality vs 2.9% of those with primary THA (n=3525, P=.0001) and 2.1% of those with aseptic rTHA (n=252, P=.0001). Octogenarian status, medium-risk Elixhauser comorbidity score, and high-risk Elixhauser comorbidity score were independent risk factors for mortality (adjusted odds ratio [AOR]=1.587, 95% CI=1.103-2.282, P=.0128; AOR=2.439, 95% CI=1.680-3.541, P<.0001; and AOR=6.367, 95% CI=4.134-9.804, P<.0001, respectively). Undergoing rTHA in a high-HRV hospital was associated with lower odds of in-hospital mortality (AOR=0.539, 95% CI=0.332-0.877, P=.0127). Receiving care in a low-HRV hospital increased the risk of 2-year postoperative patient mortality. Similarly, older age and a higher comorbidity burden were independently associated with increased 2-year postoperative mortality. [Orthopedics. 2022;45(1):57-63.].

The role of serum D-dimer in the diagnosis of periprosthetic joint infection and timing of reimplantation.

D-dimer is a fibrin degradation product formed by the destruction of the cross-linked fibrin clot by activation of the coagulation system. Many studies have shown that systemic and local infections cause fibrinolytic activities. The purpose of this study was to determine the role of serum D-dimer in the diagnosis of periprosthetic joint infection (PJI) and the timing of reimplantation. The patients who underwent primary and revision knee or hip arthroplasty between July 2018 and May 2019 were prospectively evaluated. All surgeries were performed by the same surgeon. 60 of 71 patients who met our criteria were included in the study, comprising of 27 primary arthroplasties (PA), 21 two-stage septic revision (SR) and 12 aseptic revision (AR). We analyzed D-dimer, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels. The values of the septic group were evaluated as two groups; Group 1 (before the first stage) and Group 2 (before the second stage) to investigate the role of D-dimer in determining the timing of reimplantation. D-dimer level was significantly higher in the SR group compared to PA and AR groups (p<0.001 and p=0.045). CRP and ESR levels were significantly higher in the SR group compared to PA and AR groups. There was no statistically significant difference between preoperative D-dimer levels of Group 1 and Group 2 (p=0.2). Serum D-dimer level can be used as an easy and inexpensive test to support the diagnosis of PJI. But the D-dimer level is not useful to determine the timing of reimplantation.

Management of bone loss in revision total knee arthroplasty: therapeutic options and results.

The treatment of small to moderate size defects in revision total knee arthroplasty (rTKA) has yielded good results with various techniques (cement and screws, small metal augments, impaction bone grafting and modular stems). However, the treatment of severe defects remains problematic.Severe defects have typically been treated with large allograft and metaphyseal sleeves. The use of structural allograft has decreased in recent years due to increased long-term failure rates and the introduction of highly porous metal augments (cones and sleeves).A systematic review of level IV evidence studies on the outcomes of rTKA metaphyseal sleeves found a 4% rate of septic revision, and a rate of septic loosening of the sleeves of 0.35%. Aseptic re-revision was required in 3% of the cases. The rate of aseptic loosening of the sleeves was 0.7%, and the rate of intraoperative fracture was 3.1%. The mean follow-up was 3.7 years.Another systematic review of tantalum cones and sleeves found a reoperation rate of 9.7% and a 0.8% rate of aseptic loosening per sleeve. For cones, the reoperation rate was 18.7%, and the rate of aseptic loosening per cone was 1.7%.The reported survival of metal sleeves was 99.1% at three years, 98.7% at five years and 97.8% at 10 years. The reported survival free of cone revision for aseptic loosening was 100%, and survival free of any cone revision was 98%. Survival free of any revision or reoperation was 90% and 83%, respectively. Cite this article: EFORT Open Rev 2021;6:1073-1086. DOI: 10.1302/2058-5241.6.210007

Septic revision arthroplasty: how to confirm diagnosis, plan surgery and manage follow-up treatment

Septic revision arthroplasty represents an interdisciplinary challenge in terms of diagnosis as well as surgical and follow-up treatment. The implementation of astandardized diagnostic algorithm including anamnesis, clinic, imaging, blood sampling and joint aspiration is essential. Depending on the duration of the symptoms acute (< 3weeks) and chronic (> 3weeks) infections are distinguished. While acute infections show an immature biofilm and can usually be addressed surgically via debridement and changing the mobile parts, chronic infections almost always require acomplete change of the implant. This can be done in one or two stages, depending on the general condition of the patient, the pathogen, its resistances as well as the wound conditions. The surgical revision is always followed by aresistance-based antibiotic treatment.

Understanding the 30-day mortality burden after revision total knee arthroplasty.

BackgroundIn revision total knee arthroplasty (TKA), information regarding perioperative mortality risk is essential for careful decision-making. This study aimed to elucidate the (1) overall 30-day mortality rate and (2) 30-day mortality rate stratified by age, comorbidity, and septic vs aseptic failure after revision TKA.MethodsThe American College of Surgeons National Surgical Quality Improvement Program was reviewed for all patients undergoing revision TKA from 2011 to 2019. A total of 32,354 patients who underwent TKA were identified and categorized as mortality (n = 115) or mortality-free (n = 32,239). Patient characteristics were compared between cohorts and further stratified by septic and aseptic failure.ResultsThe overall 30-day mortality rate was 0.36%. The percentage of deaths per age group (normalized per 1000) was 0% (18-29 years), 0% (30-39 years), 0.18% (40-49 years), 0.13% (50-59 years), 0.14% (60-69 years), 0.40% (70-79 years), 1.25% (80-89 years), and 6.93% (90+ years). The percentage of deaths per American Society of Anesthesiologists (ASA) class was 0.30% (ASA 1), 0.06% (ASA 2), 0.39% (ASA 3), 2.41% (ASA 4), and 14.29% (ASA 5). Septic revision (P < .001), general anesthesia (P < .001), body mass index ≤ 24.9 (P < .001), and insulin-dependent diabetes (P = .039) were associated with an increased risk of mortality.ConclusionsIncreasing age, greater comorbidity burden, underweight or normal body mass index, insulin-dependent diabetes, septic revision, and general anesthesia were all associated with an increased risk of mortality after revision TKA. Notably, 1 in 80 patients aged 80-89 years died after revision TKA compared to 1 in 720 patients aged 60-69 years. Patients who underwent septic revision had a 4-fold increase in mortality compared to aseptic revision. Our stratified assessment of mortality provides a more individualized estimation of risk that can be used for patient counseling in revision TKA.

The Future is Non-cemented Total Knee Arthroplasty: Volume Trends at the Hospital for Special Surgery.

IntroductionThe optimal fixation method for total knee arthroplasty (TKA) is still a debate. Cemented fixation has excellent long-term results and is the gold standard. However, longevity in the younger, heavier, and more active population is suboptimal. Cementless TKA offers the opportunity to gain biological fixation and overcome these shortcomings.MethodsThis is a retrospective review of all consecutive cementless TKA procedures performed at a single academic institution from 2016 until 2020. Demographics, aseptic revisions, and septic revisions were pulled from the electronic medical record. The number of yearly implanted cementless TKA prosthesis was determined to analyze utilization trends.ResultsEight-hundred and two patients were identified with a mean age of 61.57 ± 7.78 years, and a mean of BMI 32.12 ± 5.98 kg/m2. The mean time to revision was 12.31 ± 13.91 months. There were four septic failures and nine aseptic failures during the study period. Of these nine aseptic failures only five were due to mechanical loosening. There was a yearly linear increase in the use of cementless fixation.ConclusionCementless fixation is here to stay, and its use will continue to increase. Early and mid-term outcomes have been excellent thus far. Changing clinical practice takes time but we have already seen this transition take place in total hip arthroplasty. As technology and design continue to evolve, we believe it is a possibility.

Evaluation of the standard procedure for treatment of periprosthetic joint infections of total knee and hip arthroplasty: a comparison of the 2015 and 2020 census in total joint replacement centres in Germany

BackgroundThere are different procedures for both, the diagnosis and the therapy of a periprosthetic joint infection (PJI), however, national or international guidelines for a standardised treatment regime are still lacking. The present paper evaluates the use of the predominant treatment protocols for PJI in certified total joint replacement centres (EPZ) in Germany based on an EndoCert questionnaire.Materials and methodsThe questionnaire was developed in cooperation with the EndoCert Certification Commission to survey the treatment protocols for septic revision arthroplasties in EPZ. Questions targeted the various treatment options including prosthesis preserving procedures (DAIR - Debridement, antibiotics, irrigation, and retention of the prosthesis), one-stage revision, two-stage revision, removal of the endoprosthesis and diagnostic sampling prior to re-implantation. All certified EPZ participated (n = 504) and the results from the current survey in 2020 were compared to data from a previous analysis in 2015.ResultsThe number of centres that performed DAIR up to a maximum of 4 weeks and more than 10 weeks after index surgery decreased since 2015, while the number of centres that provided a one-stage revision as a treatment option increased (hip: + 6.3%; knee: + 6.6%). The majority of the centres (73.2%) indicated a 4–8 week period as the preferred interval between prosthesis removal and re-implantation in two-stage revision in hip as well as knee revisions. Centres with a higher number of revision surgeries (> 200 revisions/year), opted even more often for the 4–8 week period (92.3%). In two-stage revision the use of metal-based spacers with/without reinforcement with antibiotic-containing cement as an interim placeholder was significantly reduced in 2020 compared to 2015. There was also a clear preference for cemented anchoring in two-stage revision arthroplasty in the knee in 2020, whereas the majority of hip replacements was cementless. Additionally, in 2020 the number of samples for microbiological testing during the removal of the infected endoprosthesis increased and 72% of the centres took five or more samples. Overall, the number of EPZ with a standardised protocol for the procedure expanded from 2015 to 2020.ConclusionWhile there was a trend towards standardised therapeutic algorithms for PJI with more uniform choices among the centres in 2020 compared to 2015, the treatment often remains an individual decision. However, since a consistent treatment regime is of vital importance with an expected rise of total numbers of revision arthroplasties, uniform definitions with regard to comparability and standardisation are necessary for the further development of the EndoCert system.

New Technique for Custom-Made Spacers in Septic Two-Stage Revision of Total Hip Arthroplasties.

The choice of spacer in the interim phase of two-stage revision hip arthroplasty is crucial. Conventional concepts like a Girdlestone situation, handformed or preformed bone cement spacers show complications like soft-tissue contractions, abrasion of bone cement particles, dislocation, breakage and a low level of mobility in the interim phase. To address these disadvantages, the senior author developed a new technique for custom-made spacers in septic two-stage revision of total hip arthroplasties using prosthetic implants with individualized antibiotic mixture in the cement applying a mechanical inferior cementation method. The aim of this study was to evaluate the results of these spacers with respect to their non-inferiority in terms of reinfection and survival-rate of the new implant and to describe the complications associated with this procedure. Our collective consisted of 130 patients with a median follow-up of nearly five years. With a reinfect-free rate of 92% and a spacer-related complication rate of 10% (8% articular dislocation, 1% periprosthetic joint fracture, 1% breakage), this procedure seems to be safe and superior regarding complications compared to conventional concepts. Further studies are necessary to show the clinical benefit of this procedure.

Cost of septic and aseptic revision total knee arthroplasty: a systematic review

BackgroundThe increasing incidence of primary total knee arthroplasty (TKA) has led to an increase in both the incidence and the cost burden of revision TKA procedures. This study aimed to review the literature on the cost of revision TKA for septic and aseptic causes and to identify the major cost components contributing to the cost burden.MethodsWe searched MEDLINE (OvidSp), Embase, Web of Science, Cochrane Library, EconLit, and Google Scholar to identify relevant studies. Selection, data extraction and assessment of the risk of bias and cost transparency within the studies were conducted by two independent reviewers, after which the cost data were analysed narratively for 1- or 2-stage septic revision without re-revision; 2-stage septic revision with re-revision; and aseptic revision with and without re-revision, respectively. The major cost components identified in the respective studies were also reported.ResultsThe direct medical cost from the healthcare provider perspective for high-income countries for 2-stage septic revision with re-revision ranged from US$66,629 to US$81,938, which can be about 2.5 times the cost of 1- or 2-stage septic revision without re-revision, (range: US$24,027 – US$38,109), which can be about double the cost of aseptic revision without re-revision (range: US$13,910 – US$29,213). The major cost components were the perioperative cost (33%), prosthesis cost (28%), and hospital ward stay cost (22%).ConclusionsSeptic TKA revision with re-revision for periprosthetic joint infection (PJI) increases the cost burden of revision TKA by 4 times when compared to aseptic single-stage revision and by 2.5 times when compared to septic TKA revision that does not undergo re-revision. Cost reductions can be achieved by reducing the number of primary TKA that develop PJI, avoidance of re-revisions for PJI, and reduction in the length of stay after revision.Trial registrationPROSPERO; CRD42020171988.

Unicompartmental Knee Replacement in Obese Patients: A Systematic Review and Meta-Analysis.

Thanks to modern surgical techniques and implants, traditional exclusion criteria for unicompartmental knee arthroplasty (UKA) are no longer considered contraindications. The aim of this study is to clarify the impact of obesity on functional outcomes and revision rates of UKA. We performed a comprehensive systematic review using PubMed–Medline, Google Scholar and Cochrane Central. Then, we extracted data related to body mass index (BMI), age and follow-up, functional outcome scores and rate of revisions (all-cause, aseptic and septic). Patients were stratified according to BMI into two groups: non-obese (BMI < 30) and obese (BMI ≥ 30). We identified 22 eligible studies, of which 13 were included in the meta-analysis. Patients with a BMI > 30 had a significantly higher likelihood for revision (p = 0.02), while the risk of septic revision was similar (p = 0.79). The clinical outcome measures showed a significant difference in favor of patients with a BMI < 30 (p < 0.0001). The improvements in Oxford Knee Score and Knee Society Score were significant in both obese and non-obese patients, although the latter showed inferior results. The results of this systematic review and meta-analysis show that BMI is not a contraindication to UKA. However, obese patients have a higher risk for aseptic failure and lower improvement in clinical scores compared to non-obese patients.

Adherence to a reliable PJI diagnostic protocol minimizes unsuspected positive cultures rate

BackgroundThe aim of the present study was to evaluate the incidence of unsuspected PJI when prosthetic revisions are thoroughly evaluated by PJI dedicated orthopedic surgeon before surgery. The hypothesis is that the incidence of unsuspected PJI is reduced by applying this protocol.MethodsThis is a historical cohort study carried out in one university hospital. The prosthetic revision assessment was carried out in January 2019. From that date on, all patients that were programmed for hip or knee revision (either by an orthopedic surgeon specialized or not in septic revisions) were scheduled for a preoperative visit with the same orthopedic surgeon specialized in septic revisions. The diagnostic algorithm applied was based on the Pro-Implant Foundation diagnostic criteria. Prior to the revision assessment, the indication for joint aspiration was done at the surgeons’ discretion (non-specialized in septic revisions) and the preoperative identification of PJI was also done by a hip or knee surgeon (not specialized in septic surgery).ResultsBased on the PIF criteria, there were 15 infections among the revisions in group 1 and 18 PJI in group 2 (p > 0.05). The most interesting finding was that there were 7 patients with unsuspected positive cultures in group 1. That represents 11% of all revisions. No patient in group 2 was found with unsuspected positive cultures (p < 0.001).ConclusionA thorough PJI diagnostic algorithm should be implemented before prosthetic revision to avoid unsuspected positive cultures.

Implementation of astandardized clinical test kit for diagnostics of periprosthetic infections in the clinical routine.

The number of primary arthroplasties is increasing and the proportion of revision arthroplasties is becoming increasingly more important. The need for standardized and guideline-based diagnostics for the safe detection of a periprosthetic joint infection (PJI) is becoming apparent. In the past 10 years various organizations have published definitions and diagnostic guidelines. The implementation of an inhouse standard test kit could help to simplify the process and could improve the diagnostic quality. In 2016 a test kit was compiled in a monocentric prospective study, taking the International Consensus Meeting (ICM) criteria 2014 and the Infectious Diseases Society of America (IDSA) criteria into account, which also fulfils the definitions of the ICM criteria 2018 and criteria of the European Bone and Joint Infection Society 2021. The test kit was implemented in the clinical setting of a special department for aseptic and septic revision arthroplasty. The usability and accuracy of the test kit were examined. The test kit was implemented using blood samples (leukocyte count; C‑reactive protein, CRP), samples for examining the synovial fluid (white blood cell count, PMN cell differentiation, microbiological culture for incubation over 14 days, alpha-defensin enzyme-linked immunosorbent assay, ELISA, leukocyte esterase test strips) together with information and request forms. Between April 2016 and February 2020 a total of 405 patients were investigated. Within 3 calendar years, the use of the test kit increased from 59% initially to 86%, and finally to 96% of cases in the third calendar year. The leukocyte esterase test strip was reliable in only 72%, due to undifferentiated readability or blood contamination. The costs increased by the only commercially available alpha-defensin ELISA test by approx. 52€ per puncture. The best individual test showed a sensitivity/specificity of 92.8%/95.2% with alpha-defensin. It was calculated which combinations showed a similar test quality and different combinations, such as CRP+ cell count+ microbiology showed a sensitivity/specificity both of around 90%. Metallosis is a challenge for preoperative PJI diagnostics. In a prospective study it was shown, that the implementation of the standardized test kit lead to a guideline based PJI diagnostic in all cases and thus to a significantly increase of the diagnostic quality. There is currently no single test that reliably excludes or proves an infection. The alpha-defensin laboratory ELISA test showed the best test accuracy, whereby the consideration of test combinations is obligatory and at the same time safe.

Assessment of Racial Disparities in the Risks of Septic and Aseptic Revision Total Knee Replacements

Black patients are at higher risk of revision total knee replacement (TKR) than White patients, but whether racial disparities exist for both septic and aseptic revision TKR and the reason for any disparities are unknown. To assess the risk of septic and aseptic revision TKR in Black and White patients and to examine interactions among race and socioeconomic and hospital-related variables that are associated with revision TKR risk. This cohort study included residents of New York, California, and Florida who underwent TKR. Patient-level data were obtained from the New York Statewide Planning and Research Cooperative System, California's Office of Statewide Health Planning and Development Patient Discharge Database, and Florida's Healthcare Utilization Project State Inpatient Database from January 1, 2004, to December 31, 2014. Community characteristics were calculated from the US Census and linked to discharges by patient zip code. American Hospital Association Annual Survey data were linked to discharges using hospital identifiers. The analyses were performed from March 1 to October 30, 2020, with subsequent analyses in April 2021. Cox proportional hazards regression modeling was used to measure the association of race with septic and aseptic revision TKR. A total of 722 492 patients underwent primary TKR, of whom 445 616 (61.68%) were female and 61 092 (8.46%) were Black. Black patients were at higher risk of septic (hazard ratio [HR], 1.11; 95% CI, 1.03-1.20) and aseptic (HR, 1.39; 95% CI, 1.33-1.46) revision TKR compared with White patients. Other risk factors for septic revision TKR were diabetes (HR, 1.24; 95% CI, 1.17-1.30), obesity (HR, 1.13; 95% CI, 1.17-1.30), kidney disease (HR, 1.42; 95% CI, 1.29-1.57), chronic obstructive pulmonary disease (HR, 1.22; 95% CI, 1.15-1.30), inflammatory arthritis (HR, 1.53; 95% CI, 1.39-1.69), surgical site complications during the index TKR (HR, 2.19; 95% CI, 1.87-2.56), Medicaid insurance (HR, 1.17; 95% CI, 1.04-1.31), and low annual TKR volume at the hospital where the index TKR was performed (HR, 1.54; 95% CI, 1.41-1.68). Risk factors for aseptic revision TKR were male sex (HR, 1.03; 95% CI, 1.00-1.06), workers' compensation insurance (HR, 1.61; 95% CI, 1.51-1.72), and low hospital TKR volume (HR, 1.14; 95% CI, 1.07-1.22). Patients with obesity had a lower risk of aseptic TKR revision (HR, 0.81; 95% CI, 0.77-0.84). In an analysis within each category of hospital TKR volume, the HR for aseptic revision among Black vs White patients was 1.20 (95% CI, 1.04-1.37) at very-low-volume hospitals (≤89 TKRs annually) compared with 1.68 (95% CI, 1.48-1.90) at very-high-volume hospitals (≥645 TKRs annually). In this cohort study, Black patients were at significantly higher risk of aseptic revision TKR and, to a lesser extent, septic revision TKR compared with White patients. Racial disparities in aseptic revision risk were greatest at hospitals with very high TKR volumes.

Implementation of astandardized clinical test kit for diagnostics of periprosthetic infections in the clinical routine. German version

The number of primary arthroplasties is increasing and the proportion of revision arthroplasties is becoming increasingly more important. The need for standardized and guideline-based diagnostics for the safe detection of a periprosthetic joint infection (PJI) is becoming apparent. In the past 10 years various organizations have published definitions and diagnostic guidelines. The implementation of an inhouse standard test kit could help to simplify the process and could improve the diagnostic quality. In 2016 a test kit was compiled in a monocentric prospective study, taking the International Consensus Meeting (ICM) criteria 2014 and the Infectious Diseases Society of America (IDSA) criteria into account, which also fulfils the definitions of the ICM criteria 2018 and criteria of the European Bone and Joint Infection Society 2021. The test kit was implemented in the clinical setting of a special department for aseptic and septic revision arthroplasty. The usability and accuracy of the test kit were examined. The test kit was implemented using blood samples (leukocyte count; C‑reactive protein, CRP), samples for examining the synovial fluid (white blood cell count, PMN cell differentiation, microbiological culture for incubation over 14 days, alpha-defensin enzyme-linked immunosorbent assay, ELISA, leukocyte esterase test strips) together with information and request forms. Between April 2016 and February 2020 a total of 405 patients were investigated. Within 3 calendar years, the use of the test kit increased from 59% initially to 86%, and finally to 96% of cases in the third calendar year. The leukocyte esterase test strip was reliable in only 72%, due to undifferentiated readability or blood contamination. The costs increased by the only commercially available alpha-defensin ELISA test by approx. 52€ per puncture. The best individual test showed a sensitivity/specificity of 92.8%/95.2% with alpha-defensin. It was calculated which combinations showed a similar test quality and different combinations, such as CRP+ cell count+ microbiology showed a sensitivity/specificity both of around 90%. Metallosis is a challenge for preoperative PJI diagnostics. In a prospective study it was shown, that the implementation of the standardized test kit lead to a guideline based PJI diagnostic in all cases and thus to a significantly increase of the diagnostic quality. There is currently no single test that reliably excludes or proves an infection. The alpha-defensin laboratory ELISA test showed the best test accuracy, whereby the consideration of test combinations is obligatory and at the same time safe.

Intraoperative blood loss as indicated by haemoglobin trend is a predictor for the development of postoperative spinal implant infection\u2014a matched-pair analysis

BackgroundWith a reported rate of 0.7–20%, postoperative spinal implant infection (PSII) is one of the most common complications after spine surgery. While in arthroplasty both haematoma formation and perioperative blood loss have been identified as risk factors for developing periprosthetic joint infections and preoperative anaemia has been associated with increased complication rates, literature on the aetiology of PSII remains limited.MethodsWe performed a matched-pair analysis of perioperative haemoglobin (Hb) and haematocrit (Hct) levels in aseptic and septic spine revision surgeries. 317 patients were included, 94 of which were classified as septic according to previously defined criteria. Patients were matched according to age, body mass index, diabetes, American Society of Anesthesiologists score and smoking habits. Descriptive summaries for septic and aseptic groups were analysed using Pearson chi-squared for categorical or Student t test for continuous variables.ResultsFifty patients were matched and did not differ significantly in their reason for revision, mean length of hospital stay, blood transfusion, operating time, or number of levels operated on. While there was no significant difference in preoperative Hb or Hct levels, the mean difference between pre- and postoperative Hb was higher in the septic group (3.45 ± 1.25 vs. 2.82 ± 1.48 g/dL, p = 0.034).ConclusionsWe therefore show that the intraoperative Hb-trend is a predictor for the development of PSII independent of the amount of blood transfusions, operation time, number of spinal levels operated on and hospital length of stay, which is why strategies to reduce intraoperative blood loss in spine surgery need to be further studied.