Plasma Fibrinogen Performs Better Than Plasma d-Dimer and Fibrin Degradation Product in the Diagnosis of Periprosthetic Joint Infection and Determination of Reimplantation Timing

BackgroundThe accurate and timely diagnosis of periprosthetic joint infection (PJI) is challenging, and no single biomarker can definitively confirm infection before revision arthroplasty. The coagulation cascade has been linked closely to infection. This study was performed to determine the value of plasma d-dimer, plasma fibrinogen, and plasma fibrin degradation product (FDP) for the diagnosis of PJI and timing of reimplantation.MethodsWe retrospectively enrolled 136 patients who underwent revision surgery from January 2008 to December 2019. They were assigned to 3 groups: aseptic failure (group A), PJI (group B), and reimplantation (group C). Receiver operating characteristic curves were constructed to estimate the value of plasma fibrinogen, plasma d-dimer, plasma FDP, erythrocyte sedimentation rate (ESR), and serum C-reactive protein (CRP) for PJI diagnosis and reimplantation timing.ResultsAll biomarker levels were significantly higher in group B than in group A (P < .05), and plasma fibrinogen, CRP, and ESR values were significantly higher in group B than in group C (all P < .05). The receiver operating characteristic curves showed that the areas under the curve of plasma fibrinogen, plasma d-dimer, plasma FDP, CRP, and ESR were 0.848, 0.914, 0.728, 0.737, and 0.868, respectively, and the threshold values for plasma fibrinogen, plasma d-dimer, and plasma FDP were 3.61 g/L, 0.41 mg/L, and 3.55 mg/L, respectively.ConclusionPlasma fibrinogen exhibits good value for the diagnosis of PJI and can be an indicator of residual infection before reimplantation in 2-stage arthroplasty. Plasma d-dimer and FDP are of limited value for PJI diagnosis and cannot be used to determine the timing of reimplantation.     

Plasma Fibrinogen and Platelet Count Are Referable Tools for Diagnosing Periprosthetic Joint Infection: A Single-Center Retrospective Cohort Study

BackgroundAlthough the MusculoSkeletal Infection Society has suggested a series of markers to diagnose periprosthetic joint infection (PJI), no single marker can accurately identify infection before revision hip or knee arthroplasty, and exploring promising markers to easily and reliably diagnose PJI is ongoing. The aim of this study was to evaluate the diagnostic value of plasma fibrinogen and platelet count for diagnosing PJI.MethodsWe retrospectively included 439 patients who underwent revision arthroplasty from January 2008 to December 2018; 79 patients with coagulation-related comorbidities were evaluated separately. The remaining 360 patients constituted 153 PJI and 207 non-PJI patients. Receiver operating characteristic curves were used to evaluate the maximum sensitivity and specificity of the tested markers.ResultsThe receiver operating characteristic curves showed that the areas under the curve for plasma fibrinogen, platelet count, and serum C-reactive protein and erythrocyte sedimentation rate were 0.834, 0.746, 0.887, and 0.842, respectively. Based on Youden's index, the optimal predictive cutoffs for fibrinogen and platelet count were 3.57 g/L and 221 × 10⁹/L, respectively. The sensitivity and specificity, respectively, were 68.6% and 86.0% (fibrinogen) and 57.5% and 83.1% (platelet count) for diagnosing PJI. The sensitivity and specificity, respectively, were 76.7% and 72.2% (fibrinogen) and 48.8% and 63.9% (platelet count) for diagnosing PJI in patients with coagulation-related comorbidities.ConclusionPlasma fibrinogen performed well for diagnosing PJI before revision arthroplasty, and its value neared that of traditional inflammatory markers. Although the diagnostic value of the platelet count was inferior to traditional markers, its diagnostic value was fair for diagnosing PJI. Fibrinogen also may be useful for diagnosing PJI in patients with coagulation-related comorbidities.     

Development and Validation of an Evidence-Based Algorithm for Diagnosing Periprosthetic Joint Infection

BackgroundThe guidelines for diagnosis of periprosthetic joint infection (PJI) introduced by the American Academy of Orthopaedic Surgeons served the orthopedic community well. However, they have never been validated and do not account for newer diagnostic modalities. Our aim was to update current guidelines and develop an evidence-based and validated diagnostic algorithm.MethodsThis multi-institutional study examined total joint arthroplasty patients from 3 institutions. Patients fulfilling major criteria for infection as defined by Musculoskeletal Infection Society were considered infected (n = 684). Patients undergoing aseptic revision for a noninfective indication and did not show evidence of PJI or undergo reoperation within 2 years served as a noninfected control group (n = 820). The algorithm was validated on a separate cohort of 422 cases.ResultsThe first step in evaluating PJI should include a physical examination, followed by serum C-reactive protein, erythrocyte sedimentation rate, and D-dimer. If at least one of these tests are elevated, or if high clinical suspicion exists, joint aspiration should be performed, sending the fluid for a white blood cell count, leukocyte esterase, polymorphonuclear percentage, and culture. Alpha defensin did not show added benefit as a routine diagnostic test. In inconclusive cases, intraoperative findings including gross purulence, histology, and next-generation sequencing or a single positive culture can aid in making the diagnosis. The proposed algorithm demonstrated a high sensitivity (96.9%) and specificity (99.5%).ConclusionThis validated, evidence-based algorithm for diagnosing PJI should guide clinicians in the workup of patients undergoing revision arthroplasty and improve clinical practice. It also has the potential to reduce cost.     

Comparison of a Comprehensive Set of Fibrinolytic Markers With C-Reactive Protein and Erythrocyte Sedimentation Rate for the Diagnosis of Periprosthetic Joint Infection

BackgroundThe diagnosis of periprosthetic joint infection (PJI), a serious complication after primary total joint arthroplasty, remains challenging. Recently, fibrinolytic activities have been shown to be closely related to infections and inflammation. However, data assessing the value of fibrinolytic markers for the diagnosis of PJI have been sparse until now.MethodsWe retrospectively enrolled 157 patients undergoing revision for aseptic loosening (n = 106, group A) or revision for chronic PJI (n = 51, group B) from January 2014 to August 2019. PJI was defined using the Musculoskeletal Infection Society criteria. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), D-dimer, fibrin degradation product (FDP), and fibrinogen were measured preoperatively. The diagnostic values of each biomarker were analyzed and compared using receiver operating characteristic curves, sensitivity, and specificity.ResultsCompared with group A, group B had significantly higher levels of CRP, ESR, D-dimer, FDP, and fibrinogen (P < .001). The area under the curve of fibrinogen was 0.914, which was slightly lower than that of CRP (0.924). FDP and D-dimer had area under the curve values of 0.808 and 0.784, respectively. The optimal threshold, sensitivity, and specificity were 3.56 g/L, 86.27%, and 83.96% for fibrinogen; 1.22 mg/L, 66.67%, and 85.85% for D-dimer; and 3.98 μg/mL, 72.55%, and 80.19% for FDP, respectively.ConclusionFibrinolytic markers provided promising diagnostic support for PJI, especially fibrinogen, which had a diagnostic efficiency similar to that of CRP and ESR.     

Diagnosing Periprosthetic Joint Infection in Inflammatory Arthritis: Assumption Is the Enemy of True Understanding

Background

Despite concern over the interpretation of serum and synovial fluid tests to screen and diagnose periprosthetic joint infection (PJI) in patients with inflammatory arthritis, only a single study has investigated this area. We aimed to assess accuracy of clinical and laboratory markers for PJI diagnosis in the context of underlying inflammatory arthritis.

D-Dimer,Erythrocyte Sedimentation Rate,and C-Reactive Protein Sensitivities for Periprosthetic Joint Infection Diagnosis

BackgroundThere is contradicting evidence on the diagnostic value of inflammatory biomarkers for periprosthetic joint infection (PJI). We sought to quantify the sensitivity of D-dimer for acute and chronic PJI diagnosis and evaluate D-dimer lab values in the 90-day postoperative window in a control cohort of primary joint arthroplasty patients for comparison.MethodsAn institutional database was queried for patients undergoing revision procedures for PJI after total hip arthroplasty (THA) and total knee arthroplasty (TKA) from 2014 to present. CRP, ESR, and D-dimer were collected within 90 days pre and postoperatively and sensitivities for the diagnosis of PJI were calculated. The control group included patients who underwent a negative diagnostic workup for deep venous thrombosis (DVT) or pulmonary embolus (PE) and had a D-dimer lab collected within 90 days postoperatively from primary total joint arthroplasty (TJA).ResultsA total of 604 PJI patients were identified, and 81 patients had D-dimer, ESR, and CRP collected. There were 50/81 acute PJI patients and 31/81 chronic PJI patients who had median D-dimer values of 2,136.5 ng/mL [interquartile range (IQR): 1,642-3,966.5] and 3,336 ng/mL [IQR: 1,976-5,594]. Only the chronic PJI group had significantly higher D-dimer values when compared to the control cohort (P = .009). The sensitivity of D-dimer was calculated to be 92% and 93.5% in the acute and chronic PJI groups, respectively.ConclusionSerum D-dimer may not have high diagnostic utility for acute PJI, especially in the setting of recent surgery; however, it still may be useful for patients who have chronic PJI.     

External Validation Demonstrates Limited Clinical Utility of a Preoperative Prognostic Calculator for Periprosthetic Joint Infection

BackgroundPreoperative calculation of treatment failure risk in patients undergoing surgery for periprosthetic joint infection (PJI) is imperative to allow for medical optimization and targeted prevention. A preoperative prognostic model for PJI treatment failure was previously developed, and this study sought to externally validate the model.MethodsA retrospective review was performed of 380 PJIs treated at two institutions. The model was used to calculate the risk of treatment failure, and receiver operating characteristic curves were generated to calculate the area under the curve (AUC) for each institution.ResultsWhen applying this model to institution 1, an AUC of 0.795 (95% confidence interval [CI]: 0.693-0.897) was found, whereas institution 2 had an AUC of 0.592 (95% CI: 0.502-0.683). Comparing all institutions in which the model had been applied to, we found institution 2 represented a significantly sicker population and different infection profile.ConclusionIn this cohort study, we externally validated the prior published model for institution 1. However, institution 2 had a decreased AUC using the prior model and represented a sicker and less homogenous cohort compared with institution 1. When matching for chronicity of the infection, the AUC of the model was not affected. This study highlights the impact of comorbidities and their distributions on PJI prognosis and brings to question the clinical utility of the algorithm which requires further external validation.     

The Utility of Frozen Section Histology in Diagnosing Periprosthetic Joint Infection in Revision Total Joint Arthroplasty

BackgroundSurgeons utilize a combination of preoperative tests and intraoperative findings to diagnose periprosthetic joint infection (PJI); however, there is currently no reliable diagnostic marker that can be used in isolation. The purpose of our study is to evaluate the utility of frozen section histology in diagnosis of PJI.MethodsRetrospective analysis of 614 patients undergoing revision total joint arthroplasty with frozen section histology from a single institution was performed. Discriminatory value of frozen section histology was assessed using univariate analysis and evaluation of area under the curve (AUC) of a receiver operating characteristic curve comparing frozen section histology results to the 2018 International Consensus Meeting (ICM) PJI criteria modified to exclude the histology component.ResultsThe sensitivity of the frozen section histology was 53.6% and the specificity was 95.2%. There was 99.2% concordance between the permanent section and frozen section results. The receiver operating characteristic curve for frozen section yielded an AUC of 0.744 (95% confidence interval 0.627-0.860) and the modified ICM score yielded an AUC of 0.912 (95% confidence interval 0.836-0.988) when compared to the full score. The addition of frozen section histology changed the decision to infected in 20% of “inconclusive” cases but less than 1% of total cases.ConclusionIn comparison to the modified ICM criteria, intraoperative frozen section histology has poor sensitivity, strong specificity, and acceptable overall discrimination for diagnosing PJI. This test appears to be of particular value for patients deemed “inconclusive” for infection using the remaining ICM criteria.     

Combined Measurement of D-Dimer and C-Reactive Protein Levels: Highly Accurate for Diagnosing Chronic Periprosthetic Joint Infection

BackgroundDiagnosis of chronic periprosthetic joint infection (PJI) can be challenging and elusive in the absence of a gold standard. D-dimer plays an important role in inflammation that occurs during infections and therefore could be a valuable biomarker for PJI. This study aims to investigate the sensitivity and specificity of D-dimer in detecting chronic PJI and to improve the accuracy of chronic PJI diagnosis through combined measurement of serum D-dimer with C-reactive protein (CRP)/erythrocyte sedimentation rate.MethodsOne hundred twenty-two patients presenting with a painful knee or hip after total hip or total knee arthroplasty for surgical revision were included in this prospective trial. Our cohort consisted of 55 patients undergoing revision for chronic PJI and 67 patients undergoing revision for aseptic failure. PJI was defined using the Musculoskeletal Infection Society criteria. Receiver operating characteristic curves and area under the curve were analyzed for each biomarker.ResultsThe area under the curve for D-dimer was 0.915 and was more accurate than serum erythrocyte sedimentation rate 0.719 and CRP 0.761. 1170 ng/mL was determined to be the optimal threshold value of D-dimer for the diagnosis of chronic PJI, with a sensitivity of 92.73% and a specificity of 74.63% in the diagnosis of chronic PJI. The combination of D-dimer and CRP tests demonstrated a sensitivity of 98.11% and negative predictive value of 96.55% for the diagnosis of chronic PJI.ConclusionThe present study identified the D-dimer is a valuable biomarker in detecting chronic PJI. The combinations of serum D-dimer and CRP led to the improvement of sensitivity compared with those of the single-index test.     

Mortality During Total Knee Periprosthetic Joint Infection

Background

Periprosthetic joint infections (PJIs) are fraught with multiple complications including poor patient-reported outcomes, disability, reinfection, disarticulation, and even death. We sought to perform a systematic review asking the question: (1) What is the mortality rate of a PJI of the knee undergoing 2-stage revision for infection? (2) Has this rate improved over time? (3) How does this compare to a normal cohort of individuals?

Synovial Fluid Calprotectin for the Preoperative Diagnosis of Chronic Periprosthetic Joint Infection

BackgroundThe diagnosis of periprosthetic joint infection (PJI) represents a challenge in clinical practice and the analysis of synovial fluid is a useful diagnostic tool. Calprotectin is an inflammatory biomarker widely used in the evaluation of chronic inflammatory diseases; however, little is known about its role in PJI. The purpose of this study is to determine the reliability of synovial calprotectin in the diagnosis of PJI.MethodsSeventy-six patients with painful knee arthroplasty were included in this prospective observational study. Synovial fluid was analyzed for cell count, percentage of polymorphonuclear neutrophils, microbiological culture, leukocyte esterase strip test, alpha-defensin rapid test, and calprotectin immunoassay dosage. The 2018 Consensus Statements criteria for PJI were used as standard reference to define the presence of infection. Sensitivity, specificity, positive and negative likelihood ratio, and receiver-operation characteristic curve were calculated for calprotectin immunoassay test.ResultsBy 2018 Consensus Statements criteria for PJI, 28 patients were considered infected, 44 patients were considered not infected, and 4 patients were classified as inconclusive. The calprotectin synovial fluid test resulted in 2 false-positive results and no false-negative results. The calprotectin synovial fluid test demonstrated a sensitivity of 100% (95% confidence interval [CI] 99.96-100) and specificity of 95% (95% CI 89.4-100) for the diagnosis of PJI. The positive likelihood ratio was 22 (95% CI 5.680-85.209) and the negative likelihood ratio was 0 (95% CI 0-0.292). The area under the receiver-operation characteristic curve was 0.996 (95% CI 94.3-100).ConclusionThe present study suggests that synovial calprotectin immunoassay test has a high sensitivity and specificity in the diagnosis of knee PJI. Moreover, it is easily applied, quick and valuable in clinical practice.     

A Novel Adjunct Indicator of Periprosthetic Joint Infection: Platelet Count and Mean Platelet Volume

BackgroundDiagnosing a periprosthetic joint infection (PJI) is difficult and often requires a combination of objective findings. The purpose of this study is to determine whether platelets, a known acute phase reactant, would be able to further aid in the diagnosis of PJI.MethodsA single-institution retrospective review study was performed on all revision total hip and knee arthroplasties done between 2000 and 2016 (n = 4939). PJI was defined by Musculoskeletal Infection Society criteria (n = 949). Platelet count and mean platelet volume were assessed from each patient’s preoperative complete blood count. These values were then assessed as a ratio via receiver operating characteristic (ROC) curve analysis.ResultsThe platelet count to mean platelet volume ratio for PJI patients was 33.45 compared to 25.68 for patients in the aseptic revision cohort (P < .001). ROC curve analysis demonstrates that a ratio of 31.70 has a sensitivity of 48.10 (95% confidence interval 44.9-51.4) and a specificity of 80.85 (95% confidence interval 79.6-82.1). This specificity was higher than that of both estimated sedimentation ratio (ESR) and C-reactive protein (CRP) for the same cohorts using optimal values determined via ROC curve analysis. When used in conjunction with ESR and CRP, there was a statistically significant increase in the diagnostic performance of the model used to assess PJI relative to the model that just employed ESR and CRP (P < .05).ConclusionOur study demonstrates that platelets and their associated serum biomarkers are associated with PJI and warrant consideration in patients who are being evaluated for potential PJI.     

Fungal Periprosthetic Joint Infection: A Review of Demographics and Management

BackgroundPeriprosthetic joint infection (PJI) is one of the most feared complications of total joint arthroplasty (TJA). Although commonly the result of colonization by Staphylococcal species, a growing number of cases of PJI with fungal pathogens have been reported within the last decade. Although standard treatment with two-stage exchange mirrors that of bacterial PJI, the variability in virulence between fungal species makes for an unpredictable and challenging treatment course.MethodsA review of Pubmed and Scopus from years 2009 to 2019 was conducted with the search terms fungal, infection, Candida, arthroplasty, periprosthetic, and prosthesis. Publications were reviewed and screened, yielding data for 286 patients with fungal PJI in the hip, knee, shoulder, and elbow prosthetics.ResultsPatient comorbidities generally included conditions impairing wound healing and immune response such as diabetes mellitus. Candida species were the most common fungal pathogens identified (85%); 30% had a concomitant bacterial infection. A two-stage exchange was most utilized, with a mean success rate of 65%. Antifungal impregnated spacers were utilized in 82 cases, with a comparatively high success rate (81%). Attempts at debridement with implant retention had substantially lower cure rates (15%).ConclusionsTwo-stage exchange is the favored approach to treating fungal PJI. Debridement with implant retention does not appear adequate to control infection, and retrieval of implanted materials should be prioritized. The use of antifungal impregnated spacers is an important area of ongoing research, with uncertainty regarding the type and quantity of antifungal agent to incorporate, although recent reports support the use of these agents.     

Cefazolin Prophylaxis for Total Joint Arthroplasty: Obese Patients Are Frequently Underdosed and at Increased Risk of Periprosthetic Joint Infection

Background

One of the most effective prophylactic strategies against periprosthetic joint infection (PJI) is administration of perioperative antibiotics. Many orthopedic surgeons are unaware of the weight-based dosing protocol for cefazolin. This study aimed at elucidating what proportion of patients receiving cefazolin prophylaxis are underdosed and whether this increases the risk of PJI.

Concomitant Hip and Knee Periprosthetic Joint Infection in Periprosthetic Fracture: Diagnostic Utility of Serum and Synovial Fluid Markers

BackgroundDiagnosing periprosthetic joint infection (PJI) in patients with a periprosthetic fracture can be challenging due to concerns regarding the reliability of commonly used serum and synovial fluid markers. This study aimed at determining the diagnostic performance of serum and synovial fluid markers for diagnosing PJI in patients with a periprosthetic fracture of a total joint arthroplasty.MethodsA total of 144 consecutive patients were included: (1) 41 patients with concomitant PJI and periprosthetic fracture and (2) 103 patients with periprosthetic fracture alone. Serum markers erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), and synovial markers white blood cell (WBC) count and polymorphonuclear percentage were assessed.ResultsESR demonstrated 87% sensitivity and 48% specificity at the Musculoskeletal Infection Society threshold, area under the curve (AUC) of 0.74, and optimal threshold of 45.5 mm/h (76% sensitivity, 68% specificity). CRP showed 94% sensitivity and 40% specificity, AUC of 0.68 with optimal threshold of 16.7 mg/L (84% sensitivity, 51% specificity). Synovial WBC count demonstrated 87% sensitivity and 78% specificity, AUC of 0.90 with optimal threshold of 4552 cells/μL (86% sensitivity, 85% specificity). Polymorphonuclear percentage showed 79% sensitivity and 63% specificity, AUC of 0.70 with optimal threshold of 79.5% (74% sensitivity, 63% specificity). The AUC of all combined markers was 0.90 with 84% sensitivity and 79% specificity.ConclusionThe diagnostic utility of the serum and synovial markers for diagnosing PJI was lower in the setting of concomitant periprosthetic fracture compared to PJI alone. Using the Musculoskeletal Infection Society thresholds, ESR, CRP, and WBC count showed high sensitivity, yet low specificity, thus higher thresholds and utilizing all serum and synovial markers in combination should be considered.     

Prevention of Periprosthetic Joint Infection: Examining the Recent Guidelines

Background

The global rise in infectious disease has led the Center for Disease Control and Prevention and the World Health Organization to release new guidelines for the prevention of surgical site infection.

Diagnostic and Invasive Colonoscopy Are Not Risk Factors for Revision Surgery Due to Periprosthetic Joint Infection

BackgroundColonoscopy is routinely performed for colorectal cancer screening in patients who have a preexisting unicompartmental knee arthroplasty (UKA), total knee arthroplasty (TKA), or total hip arthroplasty (THA) prostheses. However, colonoscopy is theorized to provoke transient bacteremia, providing a potential nidus for periprosthetic joint infection. This study aimed to investigate the risk of aseptic and septic revision surgery in patients who underwent diagnostic colonoscopy or invasive colonoscopy within one year following UKA, TKA, or THA.MethodsA retrospective cohort analysis was performed using a national database. Patients were identified using Current Procedural Terminology. In total, 52,891 patients underwent UKA, 1,049,218 underwent TKA, and 526,296 underwent THA. Data were analyzed with univariate analysis preceding multivariable logistic regressions to investigate outcomes of interest at 2 and 3 years from the index procedure.ResultsDiagnostic colonoscopy resulted in no increase in odds of all-cause or septic revision surgery for any prostheses. At both time points, invasive colonoscopy resulted in lower odds of all-cause revision (P < .05) for patients with UKA, decreased odds of septic revision (P < .001) for patients with TKA, and decreased odds of both all-cause and septic revision (P < .05) for patients with THA.ConclusionOur results show that diagnostic colonoscopy was not a significant risk factor for revision following UKA, TKA, or THA. Paradoxically, invasive colonoscopy was protective against revision, even with very minimal use of antibiotic prophylaxis observed. This study addresses the theory that colonoscopy procedures may threaten an existing joint prosthesis via transient bacteremia and shows no increase in revision outcomes following colonoscopy.Level of EvidenceLevel III.     

Periprosthetic Joint Infection in Patients with Inflammatory Joint Disease: a Review of Risk Factors and Current Approaches to Diagnosis and Management

Background

Prevention, early identification, and effective management of periprosthetic joint infection (PJI) in patients with inflammatory joint disease (IJD) present unique challenges for physicians. Discontinuing disease-modifying anti-rheumatoid drugs (DMARDs) perioperatively may reduce immunosuppression and infection risk at the expense of increasing disease flares. Interpreting traditional diagnostic markers of PJI can be difficult due to disease-related inflammation.

Purposes

This review is designed to answer how to (1) manage immunosuppressive/DMARD therapy perioperatively, (2) diagnose PJI in patients with IJD, and (3) treat PJI in this population.

Methods

The PubMed database was searched for relevant articles with subsequent review by independent authors.

Results

While there is evidence to support the use of methotrexate perioperatively in RA patients, it remains unclear whether using anti-tumor necrosis factor medications perioperatively increases the risk of surgical site infections. Serum erythrocyte sedimentation rate and C-reactive protein can be useful for diagnosis of PJI in this population, but only as part of comprehensive workup that ultimately relies upon sampling of joint fluid. Management of PJI depends on several clinical factors including duration of infection and the likelihood of biofilm presence, the infecting organism, sensitivity to antibiotic therapy, and host immune status. The evidence suggests that two-stage revision or resection arthroplasty is more likely to eradicate infection, particularly when MRSA is the pathogen.

Conclusion

Immunosuppression and baseline inflammatory changes in the IJD population can complicate the prevention, diagnosis, and treatment of PJI. Understanding the increase in risk associated with IJD and its treatment is essential for proper management when patients undergo lower extremity arthroplasty.

Electronic supplementary material

The online version of this article (doi:10.1007/s11420-013-9338-8) contains supplementary material, which is available to authorized users.     

Variation in Inflammatory Biomarkers Among Demographic Groups Significantly Affects Their Accuracy in Diagnosing Periprosthetic Joint Infection

BackgroundDiagnosis of periprosthetic joint infection (PJI) is a multistep process that involves performing various tests including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). The latter two tests, despite being used at all times for PJI diagnosis, are known to be nonspecific and substantially affected by demographic characteristics, including age, gender, race, and body mass index. It is unknown how these variations affect the diagnostic utility of serological markers for PJI.MethodsInstitutional databases were queried to identify patients undergoing revision arthroplasty between 2010 and 2018, in whom preoperative serum ESR and CRP was performed. Patient demographics were collected, and patients were cross-referenced with an internal database to determine their infection status. Analyses were performed to determine how ESR and CRP varied with respect to demographic factors, including age, gender, race, and infection status. Given that patient infection status was known at the time of revision, conclusions were drawn about the effect of these variations in inflammatory markers on the diagnostic utility of ESR and CRP.ResultsThe value of ESR increased by age was higher in females and African American race. No significant differences were observed in the value of CRP among the demographic factors, although a slight positive trend was observed with respect to age. The variation in inflammatory markers significantly affected the sensitivity, specificity, and accuracy of ESR and CRP for PJI diagnosis.ConclusionUnderstanding how the accuracy of diagnostic tests varies with respect to demographic factors can help physicians avoid subjecting patients to unnecessary additional testing and reach more accurate diagnoses of PJI.