Query: Diagnostic criteria of infection after knee arthroplasty

title: The diagnostic value of routine preliminary biopsy in diagnosing late prosthetic joint infection after hip and knee arthroplasty.
abstract: Biopsy of the periprosthetic tissue is an important diagnostic tool for prosthetic joint infection (PJI) as it enables the detection of the responsible microorganism with its sensitivity to antibiotics. We aimed to investigate how often the bacteria identified in the tissue analysis differed between samples obtained from preoperative biopsy and intraoperative revision surgery in cases of late PJI; and whether there was a therapeutic consequence.  A total of 508 patients who required revision surgery of total hip arthroplasty (THA) (n 231) or total knee arthroplasty (TKA) (n 277) because of component loosening underwent biopsy before revision surgery. The tissue samples collected at biopsy and during revision surgery were analyzed according to the criteria of the Musculoskeletal Infection Society (MSIS) RESULTS In total, 178 (113 THA, 65 TKA) were classified as infected. The biopsy procedure had a sensitivity of 93.8% a specificity of 97.3% a positive predictive value (PPV) of 94.9% a negative predictive value (NPV) of 96.7% and an accuracy of 96.1% Of the 178 infected patients, 26 showed a difference in the detected bacteria from the biopsy and the revision surgery (14.6% This difference required a change to antibiotic therapy in only two cases (1.1% CONCLUSION Biopsy is a useful tool to diagnose PJI, but there may be a difference in the detected bacteria between the biopsy and revision surgery. However, this did not affect the choice of antibiotic therapy in most cases, rendering the clinical relevance of this phenomenon as low.

title: Diagnostic Utility of a Novel Point of Care Test of Calprotectin for Periprosthetic Joint Infection After Total Knee Arthroplasty: A Prospective Cohort Study.
abstract: Despite several synovial fluid biomarkers for the diagnosis of periprosthetic joint infection (PJI) having been investigated, point of care (POC) tests using these biomarkers are not widely available. Synovial calprotectin has recently been reported to effectively exclude the diagnosis of PJI. Thus, the objective of this study was to test the value of a calprotectin POC test for PJI diagnosis in patients undergoing total knee arthroplasty (TKA) using the 2013 Musculoskeletal Infection Society (MSIS) PJI diagnosis criteria as the gold standard.  Synovial fluid samples were prospectively collected from 123 patients who underwent revision TKA at 2 institutions within the same health care system from October 2018 to January 2020. The study was conducted under institutional review board approval. Data collection comprised demographic, clinical, and laboratory data in compliance with the MSIS criteria. Synovial fluid samples were analyzed by calprotectin POC tests in accordance with the manufacturer's instructions. Revisions were categorized as septic or aseptic using MSIS criteria by 2 independent reviewers blinded to the calprotectin results. Calprotectin test performance characteristics with sensitivities, specificities, positive predictive values, negative predictive values, and areas under the receiver operating characteristic curve (AUC) were calculated for 2 different PJI diagnosis scenarios: (1) a threshold of =50 mg/L, and (2) a threshold of =14 mg/L.  According to the MSIS criteria, 53 revision TKAs were septic and 70 revision TKAs were aseptic. In the =50 mg/mL threshold scenario, the calprotectin POC performance showed a sensitivity of 98.1% a specificity of 95.7% a positive predictive value of 94.5% a negative predictive value of 98.5% and an AUC of 0.969. In the =14 mg/mL threshold scenario, the sensitivity was 98.1% the specificity was 87.1% the positive predictive value was 85.2% the negative predictive value was 98.4% and the AUC was 0.926.  The calprotectin POC test has excellent PJI diagnostic characteristics, including high sensitivity and specificity in patients undergoing revision TKA. This test could be effectively implemented as a rule out test. However, further investigations with larger cohorts are necessary to validate these results.

title: Diagnostic Value of Synovial White Blood Cell Count and Serum C Reactive Protein for Acute Periprosthetic Joint Infection After Knee Arthroplasty.
abstract: The diagnosis of periprosthetic joint infection (PJI) remains difficult, particularly in acute postoperative stage. The purpose of this study was to investigate the optimal cutoff value of synovial white blood cell (WBC) count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and C reactive protein (CRP) for diagnosing early postoperative infection after knee joint arthroplasty.  We retrospectively reviewed primary total knee arthroplasties and unicompartmental knee arthroplasties, with a knee aspiration within 3 weeks of surgery, from January 2006 to November 2016. Twelve infected cases and 185 uninfected cases met the inclusion criteria of our study. We compared the laboratory parameters (synovial WBC count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and CRP levels) between the 2 groups. Receiver operating characteristic curves were constructed to determine the optimal cutoff values for each parameter. Each parameter was studied to determine its sensitivity, specificity, and positive and negative predictive values (PPV and NPV) in diagnosing acute PJI.  There were 2 optimal cutoff values for synovial WBC count and CRP levels. With the cutoff value of synovial WBC set at 11,200 cells/mL, acute PJI could be diagnosed with the highest sensitivity (100% and specificity (98.9% with the cutoff value set at 16,000 cells/mL, the best PPV and NPV were found (100% and 99.5% respectively) Similarly, the CRP level >34.9 mg/L had the best sensitivity (100% and specificity (90.3% whereas the CRP level >74.5 mg/L had the best PPV (100% and NPV (99.2% CONCLUSION Synovial WBC count and CRP levels are useful in diagnosing acute PJI between 1 and 3 weeks after primary knee arthroplasty.

title: Synovial neutrophilic gelatinase associated lipocalin in the diagnosis of periprosthetic joint infection after total knee arthroplasty
abstract: Periprosthetic joint infection (PJI) is one of the most serious complications following total knee arthroplasty (TKA) However, the diagnosis remains a challenge for clinicians. In 2011, the muscoskeletal infection society (MSIS) criteria provided a consensus which has been updated in 2013, but these criteria are complex and contain tests that are time consuming. The same is applicable to the pro Implant guidelines. Therefore, a simpler diagnostic test is desirable.  The value of neutrophil gelatinase associated lipocalin (NGAL) leucocyte esterase (LE) levels, and the white blood cell (WBC) count in synovial fluid to diagnose PJI after TKA was evaluated.  In a retrospective cohort study, we analyzed 89 synovial fluid samples from 86 patients with suspected PJI after TKA. Thirteen and 23 of those samples were classified as PJI according to the MSIS and pro Implant criteria, respectively. Subsequently, NGAL, LE levels, and the WBC count were determined, the former one using an immunoassay. Using either the MSIS or pro Implant criteria as the golden standard for PJI, sensitivity and specificity of those markers were determined with ROC curves, and medians were compared with Mann Whitney U and Pearson Chi square tests.  When applying the MSIS criteria, NGAL revealed 92% sensitivity and 83% specificity. WBC count showed similar sensitivity (92% and specificity (84% whereas sensitivity and specificity for LE were 39% and 88% respectively. When applying the pro Implant criteria, sensitivity was 95% and specificity was 95% for NGAL. Sensitivity and specificity for WBC count were 100% and 97% and for LE 39% and 92% respectively.  NGAL and WBC count in synovial fluid has high accuracy in the diagnosis of PJI after TKA and should seriously be considered as part of PJI diagnostics. Leucocyte esterase can serve as rule in criterion peroperatively. These conclusions are independent of which criteria set was used as golden standard.

title: Evolution of Diagnostic Definitions for Periprosthetic Joint Infection in Total Hip and Knee Arthroplasty.
abstract: Various definitions and biomarkers have been developed in an unsuccessful attempt to obtain a "gold standard" for periprosthetic joint infection (PJI) diagnosis. The development of the 2011 Musculoskeletal Infection Society criteria facilitated further research and advances by allowing the use of a consistent PJI definition across studies. The newly proposed 2018 criteria do not rely at all on expert opinions/consensus. In this review, we describe the most relevant definitions developed throughout recent time, their rationale, characteristics, and supportive evidence for their clinical implementation. In the opinion of the authors, the orthopedic community should consider a probability and likelihood paradigm to create a PJI diagnostic definition. Probably not a single definition might be suited for all situations; the inclusion of serological findings could be the next step moving forward.

title: 310. Assessment of MSIS Diagnostic Criteria as Predictors of Treatment Success in Total Knee Arthroplasty (TKA) Infections Treated With Two Stage Exchange
abstract: Prosthetic joint infection (PJI) is a grave complication of total knee arthroplasty (TKA) predicting outcome is difficult. Musculoskeletal Infection Society (MSIS) criteria are sensitive and specific for the diagnosis of PJI. In prior work, we systematically studied the value of each MSIS criterion as a prognostic marker among a large cohort of patients with infected hip and knee arthroplasty treated with debridement, antibiotics, and implant retention (DAIR) at our specialized orthopedic hospital. We found that sinus tract drainage and culture positivity predicted explantation within two years of DAIR; the minor MSIS criteria were not predictive. Here, we sought to evaluate the utility of MSIS criteria in predicting outcomes of infected TKR PJI treated with two stage exchange arthroplasty. We sought to evaluate whether MSIS criteria can predict the outcome of infected TKR PJI treated with two stage exchange arthroplasty.  A retrospective cohort of TKA PJI treated with two stage exchange was identified by query of hospital coding records from 2009 to 2014, with subsequent chart review. Collected data included demographics and comorbidities, duration of symptoms, implant age, and pathogen. All cases met Musculoskeletal Infection Society International Consensus criteria for PJI. The primary endpoint was defined as prosthesis retention for 2 years from reimplantation. Descriptive statistics were completed using the Fisher's exact test for categorical variables and the Mann Whitney U test for continuous variables.  159 patients who underwent 2 stage exchange for TKA PJI meeting MSIS criteria were identified. 116 patients (73% remained infection free after two years of observation. Neither of the major criteria [presence of sinus drainage (P 0.6) >1 positive culture (P 1.0) nor any of the minor criteria (individually or in composite) reached statistically significant association with treatment outcome.  Individual MSIS diagnostic criteria, which have prognostic utility in TKA PJI treated with DAIR, are not powerful predictors of outcome of TKA PJI after two stage exchange.  No reported disclosures.

title: Acute pseudogout presenting as an exception to Musculoskeletal Infection Society criteria in total knee arthroplasty: a case report.
abstract: In this case, a 78 year old female with no previous medical history of crystalline arthropathy presented with pain, effusion, and erythema about a total knee arthroplasty (TKA) performed 13 years prior. Implementation of a novel synovial fluid alpha defensin assay ruled out periprosthetic joint infection (PJI) despite a positive 2018 Musculoskeletal Infection Society (MSIS) minor criteria score of 8 points, a significant diagnostic differentiation which prevented secondary invasive debridement or joint irrigation intervention. Confirmatory histologic study was positive for calcium pyrophosphate crystals, indicative of acute pseudogout inflammation rather than PJI or septic arthritis manifestation. The patient was then conservatively managed medically for a pseudogout flare and had no evidence of infection with normal physical exam and laboratory study at one and two years post treatment, respectively. Given the predominantly clinical nature of current PJI assessment in clinic coupled with notable risks associated with aggressive re intervention in the setting of suspected infection, critical need exists for the maturation of sensitive, reliable empiric measures which may assist in guiding orthopaedic surgeon evaluation of patients presenting with inflammatory symptomology around a previous surgical site. In this case, we conclude that patients with a negative alpha defensin assay alongside crystalline arthropathy on histology may be cautiously yet successfully treated non operatively despite clinical MSIS criteria concerning for PJI.

title: Diagnostic accuracy of alpha defensin enzyme linked immunosorbent assay in the clinical evaluation of painful hip and knee arthroplasty with possible prosthetic joint infection: a prospective study of 202 cases.
abstract: The aim of this study was to evaluate the diagnostic accuracy of the synovial alpha defensin enzyme linked immunosorbent assay (ELISA) for the diagnosis of prosthetic joint infection (PJI) in the work up prior to revision of total hip (THA) and knee arthroplasty (TKA)  Inclusion criteria for this prospective cohort study were acute or chronic symptoms of the index joint without specific exclusion criteria. Synovial fluid aspirates of 202 patients were analyzed and semiquantitative laboratory alpha defensin ELISA was performed. Final diagnosis of PJI was established by examination of samples obtained during revision surgery.  Sensitivity and specificity of the alpha defensin ELISA for PJI were 78.2% (95% confidence interval (CI) 66.7 to 88.5) and 96.6% (95% CI 93.0 to 99.3) Positive and negative predictive values were 89.6% (95% CI 80.6 to 97.8) and 92.2% (95% CI 87.5 to 96.1) The test remained false negative in 22% of septic revisions, most of which were due to coagulase negative staphylococci all occurring in either late chronic or early postoperative PJI.  The routine use of synovial fluid alpha defensin laboratory ELISA in the preoperative evaluation of symptomatic THAs and TKAs is insufficient to accurately diagnose PJI. Particularly in cases involving low virulence organisms, such as coagulase negative staphylococci, there remains a need for tests with a higher sensitivity.

title: Infection After Unicompartmental Knee Arthroplasty: A High Risk of Subsequent Complications
abstract: Unicompartmental knee arthroplasty restores function and improves pain in appropriately selected patients. Scant evidence exists regarding the treatment of periprosthetic joint infection (PJI) after unicompartmental knee arthroplasty (UKA) Questions/purposes (1) What was the overall survivorship free from reinfection? (2) What is the survivorship free of all cause revision? (3) What are the Knee Society scores (KSS) and complications after surgical treatment of UKA PJI?  This retrospective study with data drawn from a longitudinally maintained institutional registry identified 15 UKA PJIs between 1992 and 2014. The median age at PJI diagnosis was 58 years (range, 41 82 years) nine of 15 were men, and the median body mass index was 29 kg/m2 (range, 23 36 kg/m2) Ten patients (10 of 15) satisfied major Musculoskeletal Infection Society diagnostic criteria. There were five patients (five of 15) with early postoperative infections, five (five of 15) with acute hematogenous infections, and five (five of 15) with chronic PJIs. Two stage exchange was performed in four patients with PJIs (four of 15) and debridement, antibiotics, and implant retention (DAIR) was performed in 11 patients (11 of 15) with PJIs. We performed Kaplan Meier survivorship analysis for reinfection and revision procedures. Thirteen patients had a minimum of 2 years' followup and were included in the clinical analysis. Median followup was 4 years (range, 2 6 years) We calculated KSS.  Infection free survivorship was 71% at 5 years (95% confidence interval [CI] 46% 96% Treatment success was higher for patients undergoing two stage exchange (100% at 5 years; 95% CI, 100% 100% versus DAIR (61% at 5 years; 95% CI, 31% 92% Four of 11 patients undergoing DAIR had developed a reinfection at final followup. Survivorship free of any revision was 49% at 5 years (95% CI, 19% 79% One patient from the two stage exchange cohort underwent femoral component revision for aseptic loosening 5 years after PJI treatment, and two patients from the DAIR group were converted to TKA for disease progression at a mean of 4 years. In patients with a minimum of 2 years' followup, median KSS improved from 73 (range, 50 93) before index UKA to 94 (range, 55 100; p 0.016) Conclusions Treatment of UKA PJI with DAIR was associated with a lower infection free survivorship at 5 years compared with two stage exchange with conversion to TKA. Among those patients who were infection free, a number needed reoperations for disease progression (in the DAIR group) or component loosening (in both groups) UKA PJI results in substantial morbidity, and patients with these infections should be followed closely for aseptic causes of failure in addition to infection recurrence.

title: Diagnostic Criteria and Treatment of Acute and Chronic Periprosthetic Joint Infection of Total Ankle Arthroplasty
abstract: Prosthetic joint infection (PJI) after total ankle arthroplasty (TAA) is a serious complication that results in significant consequences to the patient and threatens the survival of the ankle replacement. PJI in TAA may require debridement, placement of antibiotic spacer, revision arthroplasty, conversion to arthrodesis, or potentially below the knee amputation. While the practice of TAA has gained popularity in recent years, there is some minimal data regarding wound complications in acute or chronic PJI of TAA. However, of the limited studies that describe complications of PJI of TAA, even fewer studies describe the criteria used in diagnosing PJI. This review will cover the current available literature regarding total ankle arthroplasty infection and will propose a model for treatment options for acute and chronic PJI in TAA.  A review of the current literature was conducted to identify clinical investigations in which prosthetic joint infections occurred in total ankle arthroplasty with associated clinical findings, radiographic imaging, and functional outcomes. The electronic databases for all peer reviewed published works available through January 31, 2018, of the Cochrane Library, PubMed MEDLINE, and Google Scholar were explored using the following search terms and Boolean operators: "total ankle replacement" OR "total ankle arthroplasty" AND "periprosthetic joint infection" AND "diagnosis" OR "diagnostic criteria." An article was considered eligible for inclusion if it concerned diagnostic criteria of acute or chronic periprosthetic joint infection of total ankle arthroplasty regardless of the number of patients treated, type of TAA utilized, conclusion, or level of evidence of study.  No studies were found in the review of the literature describing criteria for diagnosing PJI specific to TAA.  Literature describing the diagnosis and treatment of PJI in TAA is entirely reliant on the literature surrounding knee and hip arthroplasty. Because of the limited volume of total ankle arthroplasty in comparison to knee and hip arthroplasty, no studies to our knowledge exist describing diagnostic criteria specific to total ankle arthroplasty with associated reliability. Large multicenter trials may be required to obtain the volume necessary to accurately describe diagnostic criteria of PJI specific to TAA.