Globulin and albumin to globulin ratio precisely diagnose periprosthetic joint infection and determine the timing of second-stage reimplantation

Diagnostic value of neutrophil-to-lymphocyte ratio and albumin-to-globulin ratio for periprosthetic joint infections: a systematic review and meta-analysis

Purpose

Periprosthetic joint infection (PJI) is a serious complication after joint arthroplasty, resulting in high morbidity and mortality. The neutrophil-to-lymphocyte ratio (NLR) and albumin-to-globulin ratio (AGR) are novel diagnostic markers for PJI; however, their diagnostic value remains inconsistent.

Methods

This meta-analysis was conducted using the PubMed, Embase, and MEDLINE databases to determine the diagnostic accuracy of NLR and AGR for PJI in the knee or hip. Data extraction and quality assessment were independently completed by two reviewers. The pooled sensitivity and specificity, diagnostic odds ratio (DOR), summary receiver operating characteristic curve (sROC), and area under the sROC curve (AUC) were assessed using the univariate meta-analysis framework.

Results

Nineteen eligible studies were included in the quantitative analysis. The pooled sensitivity and specificity of NLR for the diagnosis of PJI were 0.73 (95% CI: 0.68-0.77) and 0.72 (95% CI: 0.66-0.77), respectively. Its pooled DOR was 6.89 (95% CI: 5.03-9.43), and AUC was 0.79 (95% CI: 0.75-0.82). The pooled sensitivity and specificity of AGR for the diagnosis of PJI were 0.80 (95% CI: 0.70-0.88) and 0.83 (95% CI: 0.79-0.87), respectively. Its DOR was 17.69 (95% CI: 10.76-29.07), and AUC was 0.88 (95% CI: 0.85-0.91).

Conclusion

NLR and AGR can be individually used as reliable serum biomarkers for the detection of PJI. Future research is warranted to determine the diagnostic value of these markers in combination with C-reactive protein levels and erythrocyte sedimentation rates to improve diagnostic accuracy for PJI in clinical practice.

A comprehensive model to better screen out antiviral treatment candidates for chronic hepatitis B patients

BACKGROUND

Chronic hepatitis B virus (HBV) infection is a serious human health threat given its high morbidity and mortality. Timely and effective antiviral treatment can postpone liver disease progression and reduce the occurrence of HBV-related end-stage liver disease. At present, the antiviral treatment criteria are mainly based on alanine transaminase (ALT) levels, HBV DNA levels and HBV e antigen levels according to the American Association for the Study of Liver Diseases treatment guidelines. However, some chronic hepatitis B (CHB) patients not meeting the above criteria still experience liver disease progression without antiviral treatment. It is urgent to identify a more comprehensive tool to screen out more antiviral treatment candidates as soon as possible.

METHODS

Considering the vital role of the immune response in the development of HBV infection and CHB cure, we collected data from 335 treatment-naïve CHB patients and comprehensively analysed their clinical and immune traits (including innate and adaptive responses). The immune parameters were obtained by flow cytometry. Finally, we established a model that can better distinguished CHB patients who need treatment through machine learning and LASSO regression of serological and immune parameters.

RESULTS

Through a series of analyses, we selected four important clinical parameters (ALT, HBV DNA, the Fibroscan value, and the A/G ratio) and four immune indicators (NKbright + NKp44+, NKbright + NKG2A+, NKT+GranzymeB+, and CD3 + CD107a + ) from more than 200 variables and then successfully established a mathematical model with high sensitivity and specificity to better screen out antiviral treatment candidates from all CHB patients.

CONCLUSIONS

Our results developed a refined model to better screen out antiviral treatment candidates from all CHB patients by combining common clinical parameters and important immune indicators, including innate and adaptive immunity. These findings provide more information for improving treatment guidelines and have potential implications for the timing of antiviral therapy to achieve better virus control and reduce the occurrence of end-stage liver disease.

Construction and validation of predictive models for intravenous immunoglobulin-resistant Kawasaki disease using an interpretable machine learning approach

BACKGROUND

Intravenous immunoglobulin (IVIG)-resistant Kawasaki disease is associated with coronary artery lesion development.

PURPOSE

This study aimed to explore the factors associated with IVIG-resistance and construct and validate an interpretable machine learning (ML) prediction model in clinical practice.

METHODS

Between December 2014 and November 2022, 602 patients were screened and risk factors for IVIG-resistance investigated. Five ML models are used to establish an optimal prediction model. The SHapley Additive exPlanations (SHAP) method was used to interpret the ML model.

RESULTS

Na+, hemoglobin (Hb), C-reactive protein (CRP), and globulin were independent risk factors for IVIG-resistance. A nonlinear relationship was identified between globulin level and IVIG-resistance. The XGBoost model exhibited excellent performance, with an area under the receiver operating characteristic curve of 0.821, accuracy of 0.748, sensitivity of 0.889, and specificity of 0.683 in the testing set. The XGBoost model was interpreted globally and locally using the SHAP method.

CONCLUSION

Na+, Hb, CRP, and globulin levels were independently associated with IVIG-resistance. Our findings demonstrate that ML models can reliably predict IVIG-resistance. Moreover, use of the SHAP method to interpret the established XGBoost model's findings would provide evidence of IVIG-resistance and guide the individualized treatment of Kawasaki disease.

Serum albumin-to-globulin ratio and CRP-to-albumin ratio did not outperform serum CRP in diagnosing periprosthetic joint infections

Aims

Serum inflammatory parameters are widely used to aid in diagnosing a periprosthetic joint infection (PJI). Due to their limited performances in the literature, novel and more accurate biomarkers are needed. Serum albumin-to-globulin ratio (AGR) and serum CRP-to-albumin ratio (CAR) have previously been proposed as potential new parameters, but results were mixed. The aim of this study was to assess the diagnostic accuracy of AGR and CAR in diagnosing PJI and to compare them to the established and widely used marker CRP.

Methods

From 2015 to 2022, a consecutive series of 275 cases of revision total hip (n = 129) and knee arthroplasty (n = 146) were included in this retrospective cohort study. Based on the 2021 European Bone and Joint Infection Society (EBJIS) definition, 144 arthroplasties were classified as septic. Using receiver operating characteristic curve (ROC) analysis, the ideal thresholds and diagnostic performances were calculated. The areas under the curve (AUCs) were compared using the z-test.

Results

AGR, CAR, and CRP were associated with PJI (p < 0.001). Sensitivities were 62.5% (95% CI 54.3 to 70.0), 73.6% (95% CI 65.8 to 80.1), and 71.5% (95% CI 63.6 to 78.3), respectively. Specificities were calculated with 84.7% (95% CI 77.5 to 89.9), 86.3% (95% CI 79.2 to 91.2), and 87.8% (95% CI 80.9 to 92.4), respectively. The AUC of CRP (0.797 (95% CI 0.750 to 0.843)) was significantly higher than the AUC of AGR (0.736 (95% CI 0.686 to 0.786), p < 0.001), and similar to AUC of CAR (0.799 (95% CI 0.753 to 0.846), p = 0.832). Decreased sensitivities were observed in PJIs caused by low-virulence organisms (AGR: 60%, CAR: 78%) compared to high-virulence pathogens (AGR: 80%, p = 0.042; CAR: 88%, p = 0.158). Higher sensitivities were seen in acute haematogenous (AGR: 83%, CAR: 96%) compared to chronic PJIs (AGR: 54%, p = 0.001; CAR: 65%, p < 0.001).

Conclusion

Serum AGR and CAR showed limited diagnostic accuracy (especially in low-grade and chronic infections) and did not outperform the established marker CRP in our study. Hence, neither parameter can be recommended as an additional tool for diagnosing PJI.

Limited value of platelet-related markers in diagnosing periprosthetic joint infection

OBJECTIVE

To evaluate the diagnostic values of serum platelet count (PC), mean platelet volume ratio (MPV), platelet count to mean platelet volume ratio (PVR), platelet to lymphocyte ratio (PLR), platelet to neutrophil ratio (PNR), PC/Albumin-globulin ratio (PC/AGR), and PC/C-reactive protein (PC/ CRP) in the diagnosis of periprosthetic joint infection (PJI).

METHODS

The medical records were retrospectively analyzed of the 158 patients who had undergone hip or knee revisions from January 2018 to May 2022. Of them, 79 cases were diagnosed with PJI and 79 with aseptic loosening (AL). PJI was defined using the Musculoskeletal Infection Society criteria. The plasma levels of CRP, the erythrocyte sedimentation rate (ESR), PC, MPV, PVR, PLR, PNR, PC/AGR, and PC/CRP in the 2 groups were recorded and analyzed. In addition, tests were performed according to different joint types. The receiver operating characteristic curve was used to calculate the sensitivity and specificity of each indicator. The diagnostic value for each indicator was calculated according to the area under the curve (AUC).

RESULTS

The PC, PVR, PLR and PC/AGR levels in the PJI group were significantly higher than those in the AL group, while PC/CRP levels were significantly lower (P < 0.001). The AUC for PC/CRP, and PC/AGR was 0.804 and 0.802, respectively, which were slightly lower than that of CRP (0.826) and ESR (0.846). ROC analysis for PC/CRP, and PC/AGR revealed a cut-off value of 37.80 and 160.63, respectively, which provided a sensitivity of 73.42% and 84.81% and a specificity of 75.95% and 65.82% for PJI. The area under the curve of PLR and PC was 0.738 and 0.702. The area under the curve values for PVR, PNR, and MPV were 0.672, 0.553, and 0.544, respectively.

CONCLUSIONS

The results of this study suggest that PC, PLR, PC/CRP, and PC/AGR values do not offer significant advantages over ESR or CRP values when employed for the diagnosis of PJI. PVR, PNR, and MPV were not reliable in the diagnosis of PJI.

The Diagnostic Utility of Serum Metal Ion Markers for High-Grade Aseptic Lymphocyte-Dominated Vasculitis-Associated Lesions (ALVALs) in Revision Hip and Knee Arthroplasty: An International Multicenter Study

BACKGROUND

Aseptic lymphocyte-dominated vasculitis-associated lesions (ALVALs) are typically described in the context of metal-on-metal (MoM) hip bearings. This study explores the diagnostic utility of preoperative serum cobalt and chromium ion levels in determining the histological grade of ALVAL in revision hip and knee arthroplasty.

METHODS

This was a multicenter retrospective review of 26 hips and 13 knees assessing the correlation between preoperative ion levels (mg/L (ppb)) and the histological grade of ALVAL from intraoperative specimens. The diagnostic ability of preoperative serum cobalt and chromium levels to determine high-grade ALVAL was assessed using a receiver operating characteristic (ROC) curve.

RESULTS

In the knee cohort, there was a higher serum cobalt level in high-grade ALVAL cases (10.2 mg/L (ppb) versus 3.1 mg/L (ppb)) (P = .0002). The Area Under the Curve (AUC) was 1.00 (95% confidence interval (CI) 1.00 to 1.00). There was a higher serum chromium level in high-grade ALVAL cases (12.25 mg/L (ppb) versus 7.77 mg/L (ppb)) (P = .0002). The AUC was 0.806 (95% CI 0.555 to 1.00). In the hip cohort, there was a higher serum cobalt level in high-grade ALVAL cases (333.5 mg/L (ppb) versus 119.9 mg/L (ppb)) (P = .0831). The AUC was 0.619 (95% CI 0.388 to 0.849). There was a higher serum chromium level in high-grade ALVAL cases (186.4 mg/L (ppb) versus 79.3 mg/L (ppb)) (P = .183). The AUC was 0.595 (95% CI 0.365 to 0.824).

CONCLUSIONS

Histologically, high-grade ALVAL has significantly higher preoperative serum cobalt and chromium ion levels in revision TKA. Preoperative serum ion levels have excellent diagnostic utility in revision TKA. Cobalt levels in revision THA have a fair diagnostic ability and chromium levels had a poor diagnostic ability.

The Albumin to Globulin Ratio Performs Well for Diagnosing Periprosthetic Joint Infection: A Single-Center Retrospective Study

BACKGROUND

Accurate diagnosis of the periprosthetic joint infection (PJI) remains a challenge for surgeons. The purpose of this study was to assess the value of albumin to globulin ratio (AGR) and globulin (GLB) for diagnosing PJI.

METHODS

A total of 182 patients undergoing revision after arthroplasty were included and divided into 2 groups, 61 in knee group (PJI: 38; non-PJI: 23) and 121 in hip group (PJI: 26; non-PJI: 95). We used receiver operating characteristic curves to determine the diagnostic value of AGR, GLB, inflammatory markers (erythrocyte sedimentation rate [ESR] and C-reactive protein [CRP]).

RESULTS

The receiver operating characteristic curves showed the areas under the curve of AGR, GLB, ESR, and CRP in the knee group were 0.940, 0.928, 0.867, and 0.848, respectively, and they were 0.855, 0.831, 0.886, and 0.912 in the hip group. The optimal predictive cut-off values for AGR in knee and hip groups were 1.375 and 1.295, respectively. The sensitivity and specificity of AGR, respectively, were 94.7% and 87.0% (knee group) and 84.6% and 75.8% (hip group) for diagnosing PJI. The sensitivity of "AGR or ESR" and specificity of "AGR and GLB" in the knee group were 99.6% and 98.9%, respectively.

CONCLUSION

For knee or hip groups, the AGR exhibits good value for the diagnosis of PJI comparable with ESR and CRP. The AGR and GLB, together with CRP and ESR, should be used as the preferred indicators for diagnosing PJI. The "AGR or ESR" and "AGR and GLB" in the knee group have an excellent diagnostic value in sensitivity and specificity, respectively.

Accuracy of Albumin, Globulin, and Albumin-Globulin Ratio for Diagnosing Periprosthetic Joint Infection: A Systematic Review and Meta-Analysis

Periprosthetic joint infection (PJI) is one of the most intractable orthopedic diseases, partly because of the difficulty in differentiating septic from aseptic conditions. We aimed to evaluate and consolidate the diagnostic accuracy of the quantitative assessment of serum albumin (Alb), globulin (Glb), and albumin-globulin ratio (AGR), alone or in combination with the inflammatory marker, C-reactive protein (CRP), for PJI. We searched the PubMed, CINAHL, and Cochrane Library databases for studies that quantitatively measured Alb, Glb, or AGR for the diagnosis of PJI up until the 30 April 2023. A total of 2339 patients were included from 10 studies, including 845 patients with a definitive diagnosis of PJI and 1494 with non-PJI. The pooled sensitivity, specificity, and area under the curve (AUC) in the summary receiver-operating characteristic curve were as follows: 0.625, 0.732, and 0.715 for Alb; 0.815, 0.857, and 0.887 for Glb; 0.753, 0.757, and 0.875 for AGR; 0.788, 0.837, and 0.876 for CRP; 0.879, 0.890, and 0.917 for the CRP-Alb ratio; and 0.845, 0.855, and 0.908 for the CRP-AGR ratio. Serum Alb, Glb, and AGR levels are feasible and accurate diagnostic markers for PJI, and the combination of these markers with CRP levels may potentially improve preoperative serum diagnostic accuracy. Future prospective studies are required to verify these findings because of the small numbers of included studies.

Interpretations of the Role of Plasma Albumin in Prognostic Indices: A Literature Review

This review assesses how publications interpret factors that influence the serum or plasma albumin (PA) level in prognostic indices, focusing on inflammation and nutrition. On PubMed, a search for "albumin AND prognosis" yielded 23,919 results. From these records, prognostic indices were retrieved, and their names were used as search strings on PubMed. Indices found in 10 or more original research articles were included. The same search strings, restricted to "Review" or "Systematic review", retrieved yielded on the indices. The data comprised the 10 latest original research articles and up to 10 of the latest reviews. Thirty indices had 294 original research articles (6 covering two indices) and 131 reviews, most of which were from recent years. A total of 106 articles related the PA level to inflammation, and 136 related the PA level to nutrition. For the reviews, the equivalent numbers were 54 and 65. In conclusion, more publications mention the PA level as a marker of nutrition rather than inflammation. This is in contrast to several general reviews on albumin and nutritional guidelines, which state that the PA level is a marker of inflammation but not nutrition. Hypoalbuminemia should prompt clinicians to focus on the inflammatory aspects in their patients.

Fibrinogen, albumin-to-globulin ratio, and fibrinogen to albumin-to-globulin ratio may be potential diagnostic biomarkers for infected tibial nonunion

AIM

The accurate preoperative diagnosis of infected tibial nonunion remains challenging. Hence, we evaluated the diagnostic potential of novel biomarkers for infected tibial nonunion.

METHODS

This single-center retrospective study was conducted in 252 patients divided into two groups: infected tibial nonunion (67 patients) and aseptic tibial nonunion (185 patients). The preoperative clinical biomarkers included D-dimer, fibrinogen, albumin, globulin, total protein, and C-reactive protein (CRP) levels; albumin-to-globulin ratio (AGR); erythrocyte sedimentation rate (ESR); and white blood cell (WBC) count. Receiver operating characteristic (ROC) curves, sensitivity, and specificity were utilized to compare the biomarkers' diagnostic potential.

RESULTS

The area under the curve (AUC) values for fibrinogen and AGR were 0.829 and 0.821, respectively, suggesting similarly good diagnostic potentials for infected tibial nonunion. Fibrinogen and AGR were better diagnostic biomarkers for infected tibial nonunion than the WBC count; ESR; D-dimer, albumin, globulin, CRP, and total protein levels, whose AUC values were 0.623, 0.684, 0.741, 0.797, 0.765, 0.715, and 0.554, respectively. The sensitivity and specificity of fibrinogen with a cut-off value of 3.35 g/L were 71.64% and 84.86%, respectively. The corresponding values for AGR with a cut-off value of 1.33 were 73.13% and 86.49%. Moreover, the fibrinogen-AGR (FAGR), i.e., the combination of fibrinogen and AGR, had the highest diagnostic accuracy for infected tibial nonunion (AUC = 0.906). The optimal FAGR cut-off was 2.69, with fair sensitivity (74.63%) but the highest specificity (94.59%).

CONCLUSION

Fibrinogen, AGR, and FAGR are promising biomarkers for the diagnosis of infected tibial nonunion.

The superiority of immune-inflammation summary index for diagnosing periprosthetic joint infection

BACKGROUND

Accurate and rapid diagnosis of periprosthetic joint infections (PJI) is particularly challenging. This study aimed to evaluate the diagnostic value of a newly developed immune-inflammation summary index (IISI) for PJI.

METHODS

Our study enrolled 171 aseptic loosening (AL) and 172 PJI cases. Based on a biological-driven approach, the IISI was formulated as C-reaction protein (CRP) × globulin × neutrophil / [lymphocyte × albumin]. Receiver operating characteristic (ROC) curves were constructed to compare the diagnostic performance of IISI with other known serum markers. Subgroup analysis was also performed to explore the robustness of IISI. Restricted cubic splines were used to evaluate the dose-response association. Additionally, changes in IISI levels prior to reimplantation were investigated.

RESULTS

The levels of all tested biomarkers were significantly different between the PJI and AL groups (all P < 0.05). ROC analysis revealed that IISI outperformed any other marker in diagnosing PJI with an area under the curve (AUC) value of 0.890. The diagnostic performance of IISI was also optimal in the hip (0.898), knee (0.903), low-grade infection (0.841), and culture-negative (0.919) subgroups. The optimal cut-off value is stabilized at around 1.6. The nonlinear association between IISI scores and PJI was also confirmed (P < 0.001). The levels of IISI before reimplantation demonstrated a significant decrease (P < 0.001) and were comparable to those of the AL group (P = 0.143).

CONCLUSION

IISI can improve the utilization of serum indicators and is superior to other well-known biomarkers in diagnosing PJI. Further studies should evaluate its specific role in different infectious and inflammatory diseases.

Globulin and Albumin/Globulin Ratios as Potential Biomarkers for the Diagnosis of Acute and Chronic Peri-Prosthetic Joint Infections: A Retrospective Study

Background: Peri-prosthetic joint infection (PJI) is the most serious complication after prosthetic joint replacement. However, the diagnosis of PJI remains challenging for clinicians because of the lack of a gold standard. The purpose of this study was to investigate the diagnostic significance of serum globulin, albumin/globulin, and other biomarkers in acute and chronic periprosthetic infections. Patients and Methods: A retrospective study of 162 patients with PJI and aseptic loosening between January 2016 and March 2021 at our institution was performed in three groups. There were 20 patients with acute infection in group A, 36 patients with chronic infection in group B, and 106 patients with aseptic loosening in group C. Globulin, albumin/globulin, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), platelet count (PLT), mean platelet volume (MPV), d-dimer, and platelet count/mean platelet volume ratio (PMR) levels were recorded. The area under the curve (AUC) was used to measure the diagnostic value of globulin and albumin/globulin with other biomarkers for PJI. Results: Compared with the aseptic loosening group, the acute and chronic PJI group had higher levels of CRP, ESR, d-dimer, globulin, PLT, and PMR (p < 0.01) and lower levels of albumin/globulin and MPV (p < 0.01). The optimal cutoff, AUC, sensitivity, and specificity of CRP, albumin/globulin, ESR, and globulin were: CRP, 8.3 mg/L, 0.903, 78.57%, and 88.68%; albumin/globulin, 1.31, 0.899, 91.07%, and 73.58%; ESR, 32 mm/h, 0.888, 75.%, and 85.85%; globulin, 29.5 g/L, 0.880, 91.07%, and 72.64%. Conclusions: Globulin and albumin/globulin have excellent diagnostic value for acute and chronic PJI and are promising potential biomarkers for the diagnosis of PJI. The diagnostic performance of albumin/globulin is superior to that of ESR and similar to that of CRP.

Diagnostic Utility and Thresholds for Commonly Obtained Serum and Synovial Markers Prior to Reimplantation in Periprosthetic Joint Infection

BACKGROUND

Accurate diagnosis of persistent periprosthetic joint infection (PJI) during 2-stage exchange remains a challenge. This study evaluated the diagnostic performance and thresholds of several commonly obtained serum and synovial markers to better guide reimplantation timing.

METHODS

This was a retrospective review of 249 patients who underwent 2-stage exchange with antibiotic spacers for PJI. Serum and synovial markers analyzed included white blood cell (WBC) count, polymorphonuclear percentage (PMN%), neutrophil-to-lymphocyte ratio (NLR), and absolute neutrophil count (ANC). Serum markers analyzed were erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), as well as percentage change in ESR and CRP from initial diagnosis to reimplantation. Area under the curve (AUC) analyses were performed to determine diagnostic accuracy of detecting PJI.

RESULTS

In TKAs, synovial ANC and WBC had the highest AUCs (0.76), with thresholds of 2,952 and 3,800 cells/μL, respectively. The next best marker was serum CRP (0.73) with a threshold of 5.2 mg/dL. In THAs, serum CRP had the highest AUC (0.84) with a threshold of 4.3 mg/dL, followed by synovial PMN% (0.80) with a threshold of 77%. Percentage change in serum ESR or CRP provided low diagnostic value overall.

CONCLUSION

Regarding serum markers, CRP consistently performed well in detecting persistent PJI in patients with antibiotic spacers. Absolute values of serum CRP and ESR had better diagnostic value than trends for guiding reimplantation timing. Diagnostic performance differed with joint type; however, synovial markers outperformed serum counterparts. No marker alone can be utilized to diagnose residual PJI in these patients, and further work is needed in this domain.

Reliable Diagnostic Tests and Thresholds for Preoperative Diagnosis of Non-Inflammatory Arthritis Periprosthetic Joint Infection: A Meta-analysis and Systematic Review

Objective

The current diagnostic criteria for periprosthetic joint infection (PJI) are diverse and controversial, leading to delayed diagnosis. This study aimed to evaluate and unify their diagnostic accuracy and the threshold selection of serum and synovial routine tests for PJI at an early stage.

Methods

We searched the MEDLINE and Embase databases for retrospective or prospective studies which reported preoperative‐available assays (serum, synovial, or culture tests) for the diagnosis of chronic PJI among inflammatory arthritis (IA) or non‐IA populations from January 1, 2000 to June 30, 2022. Threshold effective analysis was performed on synovial polymorphonuclear neutrophils (PMN%), synovial white blood cell (WBC), serum C‐reactive protein (CRP), and erythrocyte sedimentation rate (ESR) to find the relevant cut‐offs.

Results

Two hundred and sixteen studies and information from 45,316 individuals were included in the final analysis. Synovial laboratory‐based α‐defensin and calprotectin had the best comprehensive sensitivity (0.91 [0.86–0.94], 0.95 [0.88–0.98]) and specificity (0.96 [0.94‐0.97], 0.95 [0.89–0.98]) values. According to the threshold effect analysis, the recommended cut‐offs are 70% (sensitivity 0.89 [0.85–0.92], specificity 0.90 [0.87–0.93]), 4100/μL (sensitivity 0.90 [0.87–0.93], specificity 0.97 [0.93–0.98]), 13.5 mg/L (sensitivity 0.84 [0.78–0.89], specificity 0.83 [0.73–0.89]), and 30 mm/h (sensitivity 0.79 [0.74–0.83], specificity 0.78 [0.72–0.83]) for synovial PMN%, synovial WBC, serum CRP, and ESR, respectively, and tests seem to be more reliable among non‐IA patients.

Conclusions

The laboratory‐based synovial α‐defensin and synovial calprotectin are the two best independent preoperative diagnostic tests for PJI. A cut off of 70% for synovial PMN% and tighter cut‐offs for synovial WBC and serum CRP could have a better diagnostic accuracy for non‐IA patients with chronic PJI.

C-reactive protein (CRP)/albumin-to-globulin ratio (AGR) is a valuable test for diagnosing periprosthetic joint infection: a single-center retrospective study

Background

The diagnosis of periprosthetic joint infection (PJI) is challenging for clinicians, and the commonly used methods are too complicated and expensive for many clinical practices. The neutrophil-to-lymphocyte ratio (NLR), the platelet-to-lymphocyte ratio (PLR), the platelet–to-mean-platelet-volume ratio (PVR), globulin (GLB), the albumin-to-globulin ratio (AGR), and the C-reactive protein (CRP)/AGR ratio are simple biomarkers for infection and can be easily determined from routine blood tests. Due to their low cost and ready availability in clinical practice, many clinicians have considered the diagnostic value of these biomarkers for PJI. The aim of our study is to determine the value of NLR, PLR, PVR, GLB, AGR, and CRP/AGR for the diagnosis of PJI.

Materials and methods

One hundred sixty-four patients who received revision surgery after total knee or total hip replacements were enrolled, 47 in a PJI group and 117 in an aseptic failure group. Receiver operating characteristic (ROC) analysis was used to evaluate the performance of NLR, PLR, PVR, GLB, AGR, and CRP/AGR for the diagnosis of PJI, and their performance levels were then compared with those of CRP and the erythrocyte sedimentation rate (ESR).

Results

The levels of all tested biomarkers were significantly higher in patients with PJI (all P < 0.05). ROC analysis showed that CRP/AGR performed best in diagnosing PJI, with an area under curve (AUC) value of 0.902, and the AUCs of NLR (0.740), PLR (0.721), PVR (0.668), GLB (0.719), and AGR (0.767) were all lower than those for CRP (0.896) and ESR (0.829).

Conclusion

CRP/AGR was a valuable test for diagnosing PJI, but other novel biomarkers had only limited diagnostic value.

Level of Evidence

Level III

Diagnostic value of platelet indices in infected nonunion: a retrospective study

BACKGROUND

The diagnostic value of platelet indices has been evaluated in various infectious diseases but not in infected nonunion. The purpose of this study was to assess the usefulness of platelet indices for diagnosis of infected nonunion after open reduction and internal fixation.

METHODS

This retrospective study was performed in patients who underwent primary fracture nonunion revision surgeries from January 2016 to December 2021. A total of 297 patients were included in the study: 96 with infected nonunion (group A) and 201 with aseptic nonunion (group B). Receiver operator characteristic (ROC) curve analysis was performed to evaluate diagnostic value of each index. Area under the curve (AUC), sensitivity, specificity, and positive and negative predictive values were calculated and compared.

RESULTS

Demographic characteristics were comparable between the two groups. White blood cell (WBC) count, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), plasma fibrinogen, plasma D-dimer, platelet count (PC), plateletcrit, and ratio of platelet count to mean platelet volume (PC/MPV) were significantly higher, and MPV and platelet distribution width (PDW) significantly lower, in group A than in group B (P < 0.05). ROC analysis showed PC/MPV and plasma fibrinogen to have better diagnostic value than the other coagulation indicators (AUC of 0.801 and 0.807, respectively). The combination of ESR, plasma fibrinogen, and PC/MPV had good sensitivity and specificity for diagnosis of infected nonunion. PC/MPV had better diagnostic value than ESR and plasma fibrinogen in the subgroup of patients with coagulation-related comorbidities.

CONCLUSIONS

Plasma fibrinogen and PC/MPV ratio might be useful parameters for early diagnosis of infected nonunion.