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

Serum and Synovial Markers in the Diagnosis of Periprosthetic Joint Infection of the Hip, Knee, and Shoulder: An Algorithmic Approach

➤ No single test has demonstrated absolute accuracy for the diagnosis of periprosthetic joint infection (PJI).➤ Physicians rely on a combination of serological tests, synovial markers, and clinical findings plus clinical judgment to help to guide preoperative decision-making.➤ Several organizations have proposed criteria for the diagnosis of hip or knee PJI on which we now rely.➤ Given that shoulder arthroplasty has only recently become popular, it is possible that a shoulder-specific definition of PJI will be introduced in the coming years.➤ Although a number of serum and synovial markers have demonstrated high accuracy for the diagnosis of PJI of the hip and knee, further research is needed in order to identify markers that may be more suitable for the diagnosis of shoulder PJI and for the potential development and identification of specific serological tests as screening tools for PJI.

Efficacy and safety of two-stage revision for patients with culture-negative versus culture-positive periprosthetic joint infection: a single-center retrospective study

BACKGROUND

The safety and efficacy of two-stage revision for culture-negative PJI remain controversial. This study analyzed outcomes after two-stage revision in patients with culture-negative and culture-positive periprosthetic joint infection (PJI) during follow-up lasting at least two years.

METHODS

Data were retrospectively analysed patients who underwent hip or knee revision arthroplasty from January 2008 to October 2020 at our medical center. The primary outcome was the re-revision rate, while secondary outcomes were the rates of reinfection, readmission, and mortality. Patients with culture-negative or culture-positive PJI were compared in terms of these outcomes, as well as survival time without reinfection or revision surgery, based on Kaplan‒Meier analysis.

RESULTS

The final analysis included 87 patients who were followed up for a mean of 72.3 months (range, 24-123 months). The mean age was 58.1 years in the culture-negative group (n = 24) and 59.1 years in the culture-positive group (n = 63). The two groups (culture-negative versus culture-positive) did not differ significantly in rates of re-revision (0.0% vs. 3.2%, p > 0.05), reinfection (4.2% vs. 3.2%, p > 0.05), readmission (8.4% vs. 8.0%, p > 0.05), or mortality (8.3% vs. 7.9%, p > 0.05). They were also similar in survival rates without infection-related complications or revision surgery at 100 months (91.5% in the culture-negative group vs. 87.9% in the culture-positive group; Mantel‒Cox log-rank χ2 = 0.251, p = 0.616).

CONCLUSION

The two-stage revision proves to be a well-tolerated and effective procedure in both culture-negative and culture-positive PJI during mid to long-term follow-up.

Comparison of various prediction models in the effect of laparoscopic sleeve gastrectomy on type 2 diabetes mellitus in the Chinese population 5 years after surgery

BACKGROUND

The effect of bariatric surgery on type 2 diabetes mellitus (T2DM) control can be assessed based on predictive models of T2DM remission. Various models have been externally verified internationally. However, long-term validated results after laparoscopic sleeve gastrectomy (LSG) surgery are lacking. The best model for the Chinese population is also unknown.

METHODS

We retrospectively analyzed Chinese population data 5 years after LSG at Beijing Shijitan Hospital in China between March 2009 and December 2016. The independent t -test, Mann-Whitney U test, and chi-squared test were used to compare characteristics between T2DM remission and non-remission groups. We evaluated the predictive efficacy of each model for long-term T2DM remission after LSG by calculating the area under the curve (AUC), sensitivity, specificity, Youden index, positive predictive value (PPV), negative predictive value (NPV), and predicted-to-observed ratio, and performed calibration using Hosmer-Lemeshow test for 11 prediction models.

RESULTS

We enrolled 108 patients, including 44 (40.7%) men, with a mean age of 35.5 years. The mean body mass index was 40.3 ± 9.1 kg/m 2 , the percentage of excess weight loss (%EWL) was (75.9 ± 30.4)%, and the percentage of total weight loss (%TWL) was (29.1± 10.6)%. The mean glycated hemoglobin A1c (HbA1c) level was (7.3 ± 1.8)% preoperatively and decreased to (5.9 ± 1.0)% 5 years after LSG. The 5-year postoperative complete and partial remission rates of T2DM were 50.9% [55/108] and 27.8% [30/108], respectively. Six models, i.e., "ABCD", individualized metabolic surgery (IMS), advanced-DiaRem, DiaBetter, Dixon et al' s regression model, and Panunzi et al 's regression model, showed a good discrimination ability (all AUC >0.8). The "ABCD" (sensitivity, 74%; specificity, 80%; AUC, 0.82 [95% confidence interval [CI]: 0.74-0.89]), IMS (sensitivity, 78%; specificity, 84%; AUC, 0.82 [95% CI: 0.73-0.89]), and Panunzi et al' s regression models (sensitivity, 78%; specificity, 91%; AUC, 0.86 [95% CI: 0.78-0.92]) showed good discernibility. In the Hosmer-Lemeshow goodness-of-fit test, except for DiaRem ( P <0.01), DiaBetter ( P <0.01), Hayes et al ( P = 0.03), Park et al ( P = 0.02), and Ramos-Levi et al' s ( P <0.01) models, all models had a satifactory fit results ( P >0.05). The P values of calibration results of the "ABCD" and IMS were 0.07 and 0.14, respectively. The predicted-to-observed ratios of the "ABCD" and IMS were 0.87 and 0.89, respectively.

CONCLUSION

The prediction model IMS was recommended for clinical use because of excellent predictive performance, good statistical test results, and simple and practical design features.

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.

Can Platelets/Mean Platelet Volume Accurately Diagnose Periprosthetic Joint Infection? Revealing Their Actual Diagnostic Efficacy

Background

Currently, there is no single test indicator for diagnosing periprosthetic joint infection (PJI) with an acceptable level of sensitivity. Therefore, ratio indicators have been introduced to improve the accuracy of diagnostic algorithms. Platelet count /mean platelet volume (PMR) is reported to be a potential PJI diagnostic biomarker, but its clinical value for diagnosing PJI is still uncertain. This study aims to provide additional evidence to support the effectiveness of PMR in accurately diagnosing PJI.

Methods

This study recruited 116 patients with PJI and 137 patients with aseptic loosening, divided them into PJI group and AL group. Collect subjects' preoperative laboratory indicators such as ESR, CRP, PLT, MPV, etc. The area under the curve (AUC) was calculated by plotting the receiver operating characteristic (ROC) curve to determine the diagnostic efficacy of PMR.

Results

ESR, CRP, PLT, and PLT/MPV were significantly increased in the PJI group, while MPV levels were decreased (both P< 0.001). The AUC of the PMR was 0.752, and the optimal cut-off value for diagnosing chronic PJI was determined to be 27.8 based on the Youden index. The sensitivity and specificity for diagnosing PJI were 79.3% and 47.9%, respectively, with a positive predictive value of 68.27%, a negative predictive value of 69.80%, and a diagnostic odds ratio of 4.97. The AUC (0.752) of the ratio biomarker was lower than that of ESR (0.825) and CRP (0.900). After predictive model calculation, the combination of PMR, CRP, and ESR had an AUC value of 0.910, with a sensitivity of 84.5% and a specificity of 84.7%, showing good discriminative ability.

Conclusion

Compared with traditional biomarkers ESR and CRP, the value of the PMR for diagnosing PJI is not significant, but it can be used as an auxiliary indicator for PJI diagnosis in combination with other indicators (P<0.001).

Comparison of various prediction models in the effect of Roux-en-Y gastric bypass on type 2 diabetes in the Chinese population 5 years after surgery

BACKGROUND

Various prediction models of type 2 diabetes (T2D) remission have been externally verified internationally. However, long-term validated results after Roux-en-Y gastric bypass (RYGB) surgery are lacking. The best model for the Chinese population is also unknown.

OBJECTIVES

To evaluate the prediction effect of various prediction models on the long-term diabetes remission after RYGB in the Chinese population and to provide reference for clinical use.

SETTING

A retrospective clinical study at a university hospital.

METHODS

We retrospectively analyzed Chinese population data 5 years after RYGB and externally validated 11 predictive models to evaluate the predictive effect of each model on long-term T2D remission after RYGB.

RESULTS

We enrolled 84 patients. The mean body mass index was 41 kg/m2, and the percentage of excess weight loss (%EWL) was 72.3%. The mean glycated hemoglobin level was 8.4% preoperatively and decreased to 5.9% after 5 years. The 5-year postoperative complete and partial remission rates of T2D were 31% and 70.2%, respectively. The ABCD scoring model (sensitivity, 84%; specificity, 76%; area under the curve [AUC], .866) and the Panuzi et al. [34] study (sensitivity, 84%; specificity, 81%; AUC, .842) showed excellent results. In the Hosmer-Lemeshow goodness-of-fit test, calibration values for ABCD and Panuzi et al. [34] were .14 and .21, respectively. The predicted-to-observed ratios of ABCD and Panuzi et al. [34] were .83 and .88, respectively.

CONCLUSIONS

T2D was relieved to varying degrees 5 years after RYGB in patients with obesity. The prediction models in ABCD and the Panuzi et al. [34] studies showed the best prediction effects. ABCD was recommended for clinical use because of excellent predictive performance, good statistical test results, and simple and practical design features.

C-reactive protein/albumin and C-reactive protein/fibrinogen ratios for the diagnosis of periprosthetic joint infection in revision total joint arthroplasty

AIM

Testing for systemic inflammation markers is considered a simpler method for diagnosing periprosthetic joint infection (PJI). Changes in the C-reactive protein/albumin ratio (CRP/Alb ratio) and C-reactive protein/fibrinogen ratio (CRP/Fib ratio) are associated with PJI. This study aimed to evaluate the application of CRP/Alb and CRP/Fib ratios as novel inflammation-based markers for the diagnosis of PJI.

METHODS

We retrospectively evaluated 445 patients who underwent total hip and knee revision arthroplasties between January 2010 and February 2021. Of these, 129 patients were also independently evaluated for PJI with coagulation-related comorbidities. The patients were divided into two groups: the aseptic revision (268 patients) and PJI revision groups (187 patients). Subsequently, we evaluated the diagnostic value of the CRP/Alb and CRP/Fib ratios compared to other inflammation-based diagnoses using the area under the curve (AUC) values.

RESULTS

The AUC values of the CRP/Alb and CRP/Fib ratios were 0.880 and 0.872, respectively, suggesting similar diagnostic potentials for PJI. The CRP/Alb and CRP/Fib ratios were better than the erythrocyte sedimentation rate (ESR), Alb, and Fib, whose AUC values were 0.765, 0.352, and 0.730, respectively, for the diagnosis of PJI. The optimal cut-off for the CRP/Alb ratio was 0.13, with good sensitivity (85.0%) and specificity (78.4%). The optimal cut-off CRP/Fib ratio was 2.04, with good sensitivity (81.3%) and specificity (80.6%). Notably, the CRP/Alb and CRP/Fib ratios had the highest sensitivity, followed by four conventional inflammatory markers, namely, CRP, ESR, Alb, and Fib, which had sensitivities of 80.2%, 67.4%, 50.8%, and 54.0%, respectively. Similar findings were observed in patients with coagulation-related comorbidities.

CONCLUSION

Both the CRP/Alb and CRP/Fib ratios were significantly higher in patients with PJI than in those with aseptic failure and showed better sensitivity and specificity for diagnosing PJI than classical inflammatory markers.

The combined evaluation of fibrinogen and D-dimer levels are a helpful tool to exclude periprosthetic knee infection

This retrospective study was undertaken to (i) define the most appropriate thresholds for serum d-dimer and fibrinogen for differentiating aseptic failure from periprosthetic joint infection (PJI) and (ii) evaluate the predictive value of our d-dimer and fibrinogen threshold compared to previously proposed thresholds. This observational cohort study included consecutive patients who had undergone total knee arthroplasty (TKA) revision between January 2019 and December 2020. International Consensus Meeting diagnostic criteria were used to identify patients affected by the prosthetic infection. Receiver operating characteristic curve analyses assessed the predictive value of the parameters, and the areas under the curves were evaluated. We included 125 patients with a median age of 69 years (53-82) affected by painful TKA. Fifty-seven patients (47%) had PJI. Patients with PJI had higher median d-dimer, fibrinogen, ESR, and CRP when compared to patients believed to be free of PJI. The best threshold values for d-dimer and fibrinogen were 1063 ng/ml (sensitivity 0.72, specificity 0.74) and 420 mg/dl (sensitivity 0.67 and specificity 0.82), respectively. A d-dimer level >1063 ng/ml combined with a fibrinogen level >420 mg/dl had a sensitivity of 0.52, and a specificity of 0.90. We found that an increased d-dimer beyond 1063 ng/ml showed a better predictive value than the previously proposed threshold. The combined determination of d-dimer and fibrinogen displayed high specificity and should be considered an excellent tool to rule out an infection. The accuracy of the proposed cutoffs is more effective than previously reported.

Combination of albumin-to-globulin ratio and plasma fibrinogen is a sensitive tool for preoperative screening of infected nonunion in patients undergoing reoperation after open reduction and internal fixation: a retrospective study

Background

Accurate preoperative diagnosis of infected nonunion remains a challenge. Here, we evaluated the diagnostic potential of novel biomarkers for infected nonunion.

Methods

A cohort of 275 patients who underwent surgery for suspected septic nonunion after open reduction and internal fixation were enrolled. Preoperatively analyzed clinical parameters included white blood cell (WBC) count, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), albumin, globulin, albumin-to-globulin ratio (AGR), plasma D-dimer, plasma fibrinogen, platelet count (PC), monocyte-lymphocyte ratio (MLR), neutrophil–lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR). Receiver operating characteristic (ROC) curves, sensitivity, and specificity were utilized to compare the diagnostic potential of those biomarkers.

Results

The WBC count and levels of CRP, ESR, NLR, MLR, PLR, PC, plasma D-dimer, plasma fibrinogen, and globulin in infected nonunion patients were significantly higher (p < 0.05) than those in aseptic patients. The albumin and AGR levels of the infected nonunion group were significantly lower (p < 0.05) than the aseptic group. The ROC curve analysis showed that the diagnostic accuracy of AGR and plasma fibrinogen was good. The combination of AGR with plasma fibrinogen had the highest area under the curve (AUC) (0.916). The sensitivity and specificity were 70.27% and 91.04% for AGR, and 67.57% and 84.08% for plasma fibrinogen, respectively. The combination of AGR with plasma fibrinogen showed a sensitivity of 86.49% and specificity of 92.54%. In patients with comorbidities, the diagnostic accuracy of the combination of AGR with plasma fibrinogen was also good.

Conclusions

AGR and plasma fibrinogen are promising biomarkers to improve the diagnosis of infected nonunion. The combination of AGR with plasma fibrinogen is a sensitive tool for screening infected nonunion.

Is Fibrinogen a Reliable Biomarker in the Diagnosis of Peri-Prosthetic Joint Infection? A Systematic Review and Meta-Analysis

Background: In recent years, several studies have identified closed correlations between the coagulation cascade and inflammatory mechanisms in infective diseases. Fibrinogen (PF) is emerging as promising biomarker for the diagnosis of peri-prosthetic joint infection (PJI). This study aims to investigate the diagnostic value of PF in diagnosing PJI and to explore potential causes influencing the diagnostic value of PF. Materials and Methods: PubMed, Embase, and Cochrane Library were searched regarding the role of fibrinogen as a biomarker in the diagnosis of PJI. Studies in English were included in the meta-analysis if they determined the diagnostic value of fibrinogen for PJI detection after hip or knee arthroplasty, applying the recognized diagnostic criteria for PJI. A quality evaluation of the studies included was performed. The pooled sensitivity, specificity, likelihood ratios and diagnostic odds ratio (DOR) and the area under the receiver operating characteristic curve (AUROC) were obtained using the statistical software STATA, version 17 (StataCorp, College Station, TX). Results: Ten studies (9 retrospective) were included in the study. Low publication bias was detected, but with high heterogeneity among them. Plasma fibrinogen showed a good diagnostic accuracy and clinical utility in PJI (sensitivity, 0.81 [95% confidence interval {CI}, 0.75-0.86]; specificity, 0.82 [95% CI, 0.76-0.86]; AUROC, 0.88 [95% CI, 0.85-0.91]; DOR, 19 [95% CI, 14-26]). Conclusions: The attempt to find an "ideal" biomarker is crucial to improve the sensitivity and specificity of the current diagnostic algorithms for PJI. The analysis performed in the current study indicates that plasma fibrinogen test is a valid biomarker for PJI diagnosis.

What Is the Normal Trajectory of C-Reactive Protein, Erythrocyte Sedimentation Rate, Plasma Fibrinogen and D-Dimer after Two-Stage Exchange for Periprosthetic Joint Infection?

Objective

C‐reactive protein (CRP), erythrocyte sedimentation rate (ESR), plasma fibrinogen and D‐Dimer are used as diagnostic biomarkers of prosthetic joint infection (PJI) after total joint arthroplasty (TJA). The purpose of the study was to investigate the normal trajectory of CRP, ESR, plasma fibrinogen and D‐Dimer at different time points after two‐stage exchange arthroplasty for PJI.

Methods

We studied 53 patients undergoing two‐stage exchange for PJI at five time points: preoperatively (T0), duration of hospital stays (T1), 30 days (T2), 30–90 days (T3), and 90–180 days (T4) after surgery. The medical records of all patients were well documented and carefully reviewed. The Shapiro–Wilk test was utilized to compare the normal distribution for continuous variables, and the nonnormally distributed data were used for Friedmann's one‐way repeat measures analysis of variances. Post hoc Dunnett's test was used to compare each pair of data to find differences from baseline.

Results

Compare with T0 point, the levels of CRP and ESR increased significantly and reached peak values at T1 point (all P < 0.001), with median values of 56.40 mg/L (range, 5.54–161.0 mg/L) and 49.00 mm/h (range, 13.00–113.0 mm/h), respectively. In addition, the levels of plasma fibrinogen and D‐Dimer increased significantly and reached peak values at T1 point (all P < 0.001), with median values of 4.13g/L (range, 2.27–6.80 mg/L) and 4.00 mg/L (range, 0.19–14.01 mg/L), respectively. CRP and ESR rapidly declined at the T2 point with significantly compared with T0 point (P = 0.001 and P < 0.001). The levels of CRP, ESR, plasma fibrinogen and D‐Dimer returned to preoperative levels of 5.23 mg/L (range, 1.01–21.70 mg/L), 19.00 mm/h (range, 6.00–60.00 mm/h), 3.38g/L (range, 1.71–5.10 g/L) and 2.33 mm/h (range, 0.19–6.87 mg/L) at T4 point, and there was no significant difference compared with T0 point (all P > 0.05).

Conclusions

The study demonstrated the normal trajectory of CRP, ESR, plasma fibrinogen and D‐Dimer at five time points in patients who underwent two‐stage exchange for PJI. Thus, the results have the possibility of providing signs of infection after the patient receives two‐stage exchange arthroplasty for PJI, which can benefit from early treatment.

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.

A deep learning framework for diagnosing periprosthetic joint infections using X-ray images: a discovery and validation study

BACKGROUND

X-ray examination is the first-line imaging test for periprosthetic joint infections (PJIs). Deep learning has the potential to improve the diagnostic performance of X-ray examination for PJIs.

METHODS

A deep learning framework was developed for PJI diagnosis based on 1,062 X-ray images of the index prosthesis from patients who had PJI or aseptic failure. The classification network was constructed based on an ensemble of four deep learning models in a two-channel format for dual-view X-ray images. The interpret network was developed based on gradient weighted class to generate disease probability maps of individual PJI risk. The discrimination performance and disease probability maps were estimated in the validation set.

RESULTS

This PJI deep learning technique achieved an area under the curve (AUC) of 0.913 (95% confidence interval [CI]: 0.840-0.948), sensitivity of 0.844 (95% CI: 0.768-0.861), and specificity of 0.882 (95% CI: 0.851-0.934) for PJI recognition in hip prostheses. The PJI deep learning technique achieved an AUC of 0.931 (95% CI: 0.893-0.978), sensitivity of 0.905 (95% CI: 0.806-0.942), and specificity of 0.889 (95% CI: 0.747-0.944) for PJI recognition in knee prostheses. The high-risk prosthetic regions predicted by PJI deep learning were closely tracked with intraoperative clinical and pathological findings.

CONCLUSIONS

Deep learning provided a clinically applicable strategy for diagnosing PJI with high accuracy and robustness using routinely available X-ray images. However, the finding should be considered preliminary, the diagnosis performance might be partially attributed to prosthesis loosening, and the deep learning method is only helpful in patients already deemed suitable for revision.

Combination of C-reactive protein and fibrinogen is useful for diagnosing periprosthetic joint infection in patients with inflammatory diseases

BACKGROUND

The screening of periprosthetic joint infection (PJI) in patients with inflammatory diseases before revision arthroplasty remains uncertain. Serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), plasma fibrinogen (FIB), monocyte/lymphocyte ratio, and neutrophil/lymphocyte ratio (NLR) can help screening PJI, but their values in patients with inflammatory diseases have not been determined.

METHODS

Patients with inflammatory diseases who underwent revision hip or knee arthroplasty at West China Hospital, Sichuan University, from January 2008 to September 2020 were divided into infected and non-infected groups based on the 2013 International Consensus Meeting criteria. Sensitivity and specificity of the tested biomarkers for diagnosing infection were determined based on receiver operating characteristic (ROC) curves, and optimal cutoffs were determined based on the Youden index. The diagnostic ability of these biomarkers was re-assessed after combining them with each other.

RESULTS

A total of 62 patients with inflammatory diseases were studied; of them 30 were infected. The area under the ROC curve was 0.813 for CRP, 0.638 for ESR, 0.795 for FIB, and 0.656 for NLR. The optimal predictive cutoff of CRP was 14.04 mg/L with a sensitivity of 86.2% and a specificity of 68.7%, while FIB had a sensitivity of 72.4% and a specificity of 81.2% with the optimal predictive cutoff of 4.04 g/L. The combinations of CRP with FIB produced a sensitivity of 86.2% and specificity of 78.1%.

CONCLUSION

CRP with a slightly higher predictive cutoff and FIB are useful for screening PJI in patients with inflammatory diseases, and the combination of CRP and FIB may further improve the diagnostic values.

TRIAL REGISTRATION

ChiCTR.org.cn, ChiCTR2000039989.

The Diagnostic Value of Various Inflammatory Biomarkers for Diagnosing Periprosthetic Joint Infection is Gender-Specific

Objective

Previous studies have suggested that the diagnostic biomarkers of periprosthetic joint infection (PJI) are largely influenced by gender. In the present study, we aimed to evaluate the diagnostic value of traditional inflammatory biomarkers, fibrinolytic biomarkers (fibrinogen and D-dimer), and C-reactive protein (CRP)/albumin for PJI in different genders.

Methods

A single-center retrospective analysis was performed on revision total hip or knee arthroplasty between June 2013 to June 2021, and the study included 80 patients in the PJI group and 136 patients in the non-PJI group. PJI was diagnosed based on the International Consensus Meeting (ICM) in 2018. The levels of CRP, fibrinogen, erythrocyte sedimentation rate (ESR), D-dimer, and albumin count were determined. Receiver operating characteristic (ROC) curves and Youden's index were used to evaluate the diagnostic ability of various biomarkers.

Results

The levels of CRP, fibrinogen, D-dimer, ESR, and CRP/albumin were significantly higher in the PJI group (P < 0.001). In PJI of females, the predictive value of CRP was the highest among the five biomarkers, with the area under the curve (AUC) of 0.98. The optimal predictive cut-off for CRP was 8.86 mg/L, with a sensitivity and specificity of 90.2% and 95.7%, respectively. When combined with the other four biomarkers, the AUC of CRP was 0.98, 0.99, 0.98, and 0.99, respectively. In PJI of males, the predictive value of ESR was the highest among the five biomarkers, with an AUC of 0.92. The optimal predictive cut-off for ESR was 14.50 mm/h, with a sensitivity and specificity of 84.6% and 86.6%, respectively. When combined with the other four biomarkers, the AUC of ESR was 0.95, 0.94, 0.93, and 0.97, respectively.

Conclusion

CRP and ESR were excellent biomarkers for diagnosing PJI in female and male patients, respectively, and their combined use with CPR/albumin could provide higher diagnostic value in different genders.

Poor performance of monocyte-to-lymphocyte ratio, neutrophil-to-lymphocyte ratio, and fibrinogen when screening for occult infection among patients with sequelae of suppurative hip arthritis before total hip arthroplasty

BACKGROUND

Total hip arthroplasty (THA) is considered the best treatment for sequelae of suppurative hip arthritis, but such patients are more likely to have occult infection and therefore to suffer post-operative periprosthetic joint infection. Our study examined (1) the occult infection rate among patients with sequelae of suppurative hip arthritis, and whether (2) neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), or fibrinogen levels can be used to screen such patients for occult infection before THA.

METHODS

We retrospectively enrolled 428 patients who underwent primary THA at our hospital between 2010 and 2021, of whom 31 had occult infection and 397 did not. The maximum sensitivity and specificity were determined for the three indicators using receiver operating characteristic curves, and positive and negative predictive values were calculated.

RESULTS

Patients with occult infection showed significantly higher erythrocyte sedimentation rate (ESR) and higher levels of C-reactive protein (CRP) and fibrinogen than those without occult infection. The various potential indicators gave the following areas under the receiver operating characteristic curves: ESR, 0.586; CRP, 0.599; interleukin-6, 0.651; NLR, 0.506; MLR, 0.600; and fibrinogen, 0.589. Sensitivity and specificity were as follows: ESR, 30.8% and 92.5%; CRP, 50.0% and 70.2%; interleukin-6, 57.7% and 67.5%; NLR, 46.7% and 62.9%; MLR, 60.0% and 61.7%; and fibrinogen, 43.3% and 81.7%.

CONCLUSION

The rate of occult infection was 7.24% among our patients. ESR, NLR, MLR, and levels of CRP, interleukin-6, and fibrinogen may be unreliable for screening such patients for occult infection before THA according to sensitivity and specificity.

Plasma fibrinogen: a sensitive biomarker for the screening of periprosthetic joint infection in patients undergoing re-revision arthroplasty

Background

Although serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), plasma fibrinogen and neutrophil–lymphocyte ratio (NLR) are promising biomarkers for screening PJI in patients undergoing revision arthroplasty, their efficacy with respect to re-revision arthroplasty remains unclear.

Methods

We included patients who underwent re-revision arthroplasty at our hospital during 2008–2020, and stratified them into two groups whether they had been diagnosed with PJI (infected) or aseptic failure (non-infected) according to the 2013 International Consensus Meeting criteria. We evaluated the diagnostic performance of CRP, ESR, fibrinogen and NLR, both individually and in combinations, based on sensitivity, specificity, and area under the receiver operating characteristic curve.

Results

Of the 63 included patients, 32 were diagnosed with PJI. The area under the ROC curve was 0.821 for CRP, 0.794 for ESR, 0.885 for fibrinogen and 0.702 for NLR. CRP gave a sensitivity of 87.5% and specificity of 74.2% with an optimal predictive cut-off of 8.50 mg/mL. ESR gave a sensitivity of 81.3% and specificity of 71.0% with an optimal predictive cut-off of 33 mm/h. Plasma fibrinogen gave a comparatively higher sensitivity of 93.8% and specificity of 77.4% with an optimal predictive cut-off of 3.55 g/L, while NLR gave a moderate sensitivity of 84.4% but low specificity of 54.8% with an optimal predictive cut-off of 2.30. The combination of fibrinogen and CRP gave a high AUC of 0.897, an acceptable sensitivity of 75% and a high specificity 93.5%.

Conclusions

Plasma fibrinogen is a cost-effective, convenient biomarker that can be used to rule out PJI in patients scheduled for re-revision arthroplasty. In combination with CRP, it may be effective in diagnosing PJI in such patients.

The Screening of Fixation-Related Infection in Patients Undergoing Conversion Total Hip Arthroplasty after Failed Internal Fixation of Hip Fractures: A Single-Central Retrospective Study

Objective

To evaluate the diagnostic values of preoperative plasma fibrinogen and platelet count for screening fixation‐related infection (FRI) in patients undergoing conversion total hip arthroplasty (cTHA) after failed internal fixation of hip fractures.

Method

This was a single‐center retrospective study. Data were retrospectively analyzed for 435 patients who underwent cTHA in our hospital from January 2008 to September 2020. They were divided into infected (n = 30) and non‐infected groups (n = 405) according to the 2013 International Consensus Meeting (ICM) criteria. The diagnostic sensitivity and specificity of plasma fibrinogen and platelet count were determined using receiver operating characteristic (ROC) curves. Optimal predictive cutoffs of these two markers were determined based on the Youden index. In addition, the diagnostic value of preoperative serum C‐reactive protein (CRP) and erythrocyte sedimentation rate (ESR) for screening FRI were also evaluated based on the cutoffs recommended by the 2013 ICM Criteria. Finally, the diagnostic ability of various combinations of the plasma fibrinogen and platelet count as well as serum CRP and ESR was re‐assessed.

Results

The numbers of patients with and without FRI were 30 (6.9%) and 405 (93.1%), respectively. Areas under the ROC curves were 0.770 for fibrinogen, 0.606 for platelet, 0.844 for CRP and 0.749 for ESR. The optimal predictive cutoff of fibrinogen was 3.73 g/L, which gave sensitivity of 60.0% and specificity of 90.5%. The optimal predictive cutoff for platelet was 241.5 × 10⁹/L, which gave sensitivity of 46.7% and specificity of 83.7%. The CRP gave sensitivity of 66.7% and specificity of 92.5% with the predetermined cutoff of 10 mg/L, while the ESR gave sensitivity of 67.5% and specificity of 72.4% % with the predetermined cutoff of 30 mm/h. The combination of CRP and ESR showed high specificity of 93.2% but low sensitivity of 66.7%, while the corresponding values for CRP with fibrinogen were satisfied both for sensitivity of 80.0% and specificity of 78.7%. The combination of these four biomarkers gave sensitivity of 73.3% and specificity of 85.7%.

Conclusion

Preoperative serum CRP, ESR, plasma fibrinogen and platelet count have low sensitivity on their own for screening FRI in patients, but the combination of CRP with fibrinogen shows promise for that.

Potential Blood Biomarkers for Diagnosing Periprosthetic Joint Infection: A Single-Center, Retrospective Study

Background: Blood biomarkers are first-line tools for identifying periprosthetic joint infection (PJI). C-reactive protein (CRP) is currently recognized as the standard biomarker for PJI diagnosis. Other recently reported novel biomarkers, including plasma fibrinogen, platelet count, monocyte/lymphocyte ratio (MLR), neutrophil/lymphocyte ratio (NLR), and platelet count/lymphocyte ratio (PLR), have also shown promise in diagnosing PJI. This study aimed to evaluate whether these biomarkers were superior to CRP for identifying PJI. Methods: Patients who underwent revision hip or knee arthroplasty at our hospital from January 2008 to September 2020 were included consecutively and divided into infected and non-infected groups according to the 2013 International Consensus Meeting Criteria. Blood samples were collected preoperatively, and erythrocyte sedimentation rate (ESR), CRP, interleukin-6, fibrinogen, platelet count, MLR, NLR, and PLR were analyzed. The diagnostic values of the tested biomarkers and their combinations were compared with CRP based on the area under the receiver operating characteristic curve (AUC) using the z-test. Classification trees were constructed to explore more accurate combinations of the tested markers for identifying PJI. Results: A total of 543 patients were included, of whom 245 had PJI. Among the tested biomarkers, CRP with a cutoff of 7.39 mg/L showed the highest AUC, which gave a sensitivity of 79.1% and specificity of 86.0%. The AUCs of pairwise combinations of tested markers including CRP also were inferior to CRP itself, as were combinations derived from classification trees. Conclusions: Preoperative serum CRP with a low cutoff may be the best reliable blood biomarker for identifying PJI, and those traditional or novel available blood biomarkers could not further improve the diagnostic ability on the basis of CRP.

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.

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

Background

Periprosthetic joint infection (PJI) is one of the most challenging complications of total joint arthroplasty (TJI). An early and accurate diagnosis of PJI is associated with better treatment outcomes. However, whether the platelet-related markers and globulin-related markers can be used to assist the diagnosis of PJI remains elusive.

Methods

A total of 206 patients who underwent revision hip or knee arthroplasty in our institution were divided into two groups: 79 patients in PJI group and 127 patients in aseptic failure group. The levels of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), platelet-related markers including platelet count (PLT), mean platelet volume (MPV), plateletcrit (PCT) and PLT to MPV ratio (PMR) and globulin-related markers such as globulin (GLB), albumin to globulin ratio (AGR) and PLT to AGR ratio were compared. The diagnostic value was measured using area under the curve (AUC) after constructing receiver operating characteristic (ROC) curves. The potential of each marker for determining the timing of second-staged reimplantation was also evaluated.

Results

Significantly increased levels of ESR, CRP, PLT, PCT, PMR, GLB and PLT to AGR ratio were identified in PJI group, while decreased levels of MPV and AGR were also found. The diagnostic values of all platelet-related markers and GLB were considered as fair, and good diagnostic values of AGR and PLT to AGR ratio were found, which were comparable to those of ESR and CRP. The levels of GLB and AGR can also be used to predict negative culture result and the timing of second-stage reimplantation.

Conclusions

Globulin and albumin to globulin ratio were found to have good diagnostic values for PJI, and they can precisely predict the culture results and persistent infection.

The Potential Value of Monocyte to Lymphocyte Ratio, Platelet to Mean Platelet Volume Ratio in the Diagnosis of Periprosthetic Joint Infections

Objective

To explore the possibility of obtaining more accurate information from routine blood tests for the diagnosis of periprosthetic joint infection (PJI).

Methods

This is a retrospective study. Between 2017 and 2018, a total of 246 patients who underwent total hip or knee revision surgery were included in this study. There were 146 females and 100 males, and the mean age of the patients was 62.1 ± 12.75 years. Laboratory parameters erythrocyte sedimentation rate (ESR), C‐reactive protein (CRP), D‐dimer, plasma fibrinogen, serum white blood cell (WBC), and calculable ratio markers were collected. Based on leukocytes (monocyte count, neutrophil count, lymphocyte count), platelet count, and mean platelet volume Inflammation‐related ratio markers were calculated, which including monocyte to lymphocyte ratio (MLR), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and platelet to mean platelet volume ratio (PMR). Follow‐up of all studied cases for at least 1 year. The diagnostic value of the markers based on the receiver operating characteristic (ROC) analysis. The most optimal combinations of blood markers were selected by the prediction models. Statistical analyses and prediction models were performed using R software.

Results

Of the 246 patients, 125 were diagnosed with PJI and 121 with aseptic loosening. A higher rate of patients underwent revision surgery due to hip prosthesis loosening in the aseptic loosening group (74.4%) compared to the PJI group (45.6%, P < 0.001). ROC curves showed that the area under the curve (AUC) for classical markers, fibrinogen was 0.853 (95% confidence interval [CI], 0.805–0.901), ESR was 0.836 (95% CI, 0.785–0.887) and CRP was 0.825 (95% CI, 0.773–0.878). Followed by the PMR, PLR, NLR and MLR, which showed promising diagnostic performance with AUCs of 0.791, 0.785, 0.736, and 0.733. The AUCs of the ratio markers were higher than those of D‐dimer (0.691;95% CI, 0.6243–0.7584) and serum WBC (0.622; 95% CI, 0.552–0.691). After the predictive model calculation, AUC was up to 0.923 (95% CI, 0.891–0.951) when plasma fibrinogen combined with MLR and PMR and interpreted excellent discriminatory capacity with a sensitivity of 86.40% and a specificity of 84.17%. The new combination significantly increases the accuracy and reliability of the diagnosis of PJI (P < 0.001). The AUC increased to 0.899 (95% CI, 0.861–0.931; P = 0.007) and 0.916 (95% CI, 0.880–0.946; P < 0.001), followed by CRP and ESR, respectively. All plasma fibrinogen, ESR, and CRP combined with both PMR and MLR achieved the highest specificity (89.17%) and PPV (85.34%).

Conclusion

The diagnostic performance greatly improved when plasma fibrinogen, ESR, and CRP combined with ratio markers.

CRP/Albumin Has a Promising Prospect as a New Biomarker for the Diagnosis of Periprosthetic Joint Infection

Purpose

In the present study, we aimed to identify more effective biomarkers for the diagnosis of periprosthetic joint infection (PJI) by comparing the diagnostic ability of C-reactive protein (CRP)/albumin, systemic immune-inflammation index (SII), and existing biomarkers.

Methods

In this single-center retrospective analysis, 216 patients who underwent revision knee or hip arthroplasty from June 2013 to June 2021 and met the inclusion and exclusion criteria were analyzed, including 80 patients in the PJI group and 136 patients in the non-PJI group. The following information was collected for analysis, including CRP, fibrinogen, erythrocyte sedimentation rate (ESR), D-dimer, platelet count (PC), neutrophil count (N), lymphocyte count (Lym), and albumin count on the second day of admission. The receiver operating characteristic (ROC) curve was used to compare the diagnostic ability of various biomarkers, and further subgroup analysis was carried out in the PJI group.

Results

Compared with the non-PJI group, CRP, fibrinogen, D-dimer, ESR, CRP/albumin, and SII in the PJI group were significantly increased (P < 0.001), and their area under the curve (AUC) was 0.937, 0.878, 0.777, 0.914, 0.941, and 0.765, respectively. In the three subgroup analyses, there was no significant difference in appeal biomarker (P > 0.05) based on PJI culture results, infection time, and infection site.

Conclusion

CRP/albumin had a promising prospect as a new biomarker for the diagnosis of PJI, while it had insufficient predictive ability in the PJI subgroup analysis. However, SII had insufficient ability to diagnose PJI. Therefore, SII was not suitable to be used as a diagnostic biomarker.

Plasma levels of D-dimer and fibrin degradation product are unreliable for diagnosing periprosthetic joint infection in patients undergoing re-revision arthroplasty

Background

The preoperative diagnosis of periprosthetic joint infection (PJI) in patients undergoing re-revision arthroplasty is crucial, so we evaluated whether plasma levels of D-dimer and fibrin degradation product (FDP) could aid such diagnosis.

Methods

We retrospectively analyzed data on patients who underwent re-revision hip or knee arthroplasty at our institute during 2008–2020. Patients were stratified into those who experienced PJI or not, based on 2013 International Consensus Meeting Criteria. Plasma levels of D-dimer and FDP as well as levels of the traditional inflammatory biomarkers C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and interleukin-6 were compared between the groups. The ability of these biomarkers to diagnose PJI was assessed based on the area under the receiver operating characteristic (AUC) curve, for which predictive cut-offs were optimized based on the Youden index.

Results

Based on a cut-off of 0.80 mg/L, D-dimer gave an AUC of 0.595, high sensitivity of 85.7% but poor specificity of 47.8%. Based on a cut-off of 2.80 mg/L, FDP gave an AUC of 0.550, poor sensitivity of 56.5% and poor specificity of 52.9%. CRP, ESR and interleukin-6 showed much better diagnostic ability, with AUCs > 0.82. The combination of CRP and interleukin-6 gave an AUC of 0.877, high sensitivity of 91.7% and acceptable specificity of 78.3%.

Conclusions

Plasma levels of D-dimer and FDP may be inappropriate for diagnosing PJI in patients undergoing re-revision arthroplasty, whereas the combination of serum CRP and interleukin-6 may be effective.

Thromboelastography parameters in diagnosing periprosthetic joint infection and predicting reimplantation timing

BACKGROUND

Coagulation-related biomarkers are drawing new attention in the diagnosis of periprosthetic joint infection (PJI). The thromboelastography (TEG) assay provides a comprehensive assessment of blood coagulation; therefore, it could be a promising test for PJI. This study aims to assess the value of TEG in diagnosing PJI and to determine the clinical significance of TEG in analysing reimplantation timing for second-stage revision.

METHODS

From October 2017 to September 2020, 62 patients who underwent revision arthroplasty were prospectively included. PJI was defined by the 2011 Musculoskeletal Infection Society criteria, in which 23 patients were diagnosed with PJI (Group A), and the remaining 39 patients were included as having aseptic loosening (Group B). In group A, 17 patients completed a two-stage revision in our centre. C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), D-dimer, and TEG parameters (clotting time, α-angle, MA [maximum amplitude], amplitude at 30 min, and thrombodynamic potential index) were measured preoperatively in all included patients. In addition, receiver operating characteristic curves were used to evaluate the diagnostic value of these biomarkers.

RESULTS

ESR (area under curve [AUC], 0.953; sensitivity, 81.82; specificity, 94.87) performed best for PJI diagnosis, followed by MA (AUC, 0.895; sensitivity, 82.61; specificity, 97.44) and CRP (AUC, 0.893; sensitivity, 82.61; specificity, 94.74). When these biomarkers were combined in pairs, the diagnostic value improved compared with any individual biomarker. The overall success rate of the two-stage revision was 100%. Furthermore, ESR and MA were valuable in determining the time of reimplantation, and their values all decreased below the cut-off values before reimplantation.

CONCLUSION

TEG could be a promising test in assisting PJI diagnosis, and a useful tool in judging the proper timing of reimplantation.

Combination of CRP with NLR is a sensitive tool for screening fixation-related infection in patients undergoing conversion total hip arthroplasty after failed internal fixation for femoral neck fracture

AIMS

Monocyte-lymphocyte ratio (MLR) or neutrophil-lymphocyte ratio (NLR) are useful for diagnosing periprosthetic joint infection (PJI), but their diagnostic values are unclear for screening fixation-related infection (FRI) in patients for whom conversion total hip arthroplasty (THA) is planned after failed internal fixation for femoral neck fracture.

METHODS

We retrospectively included 340 patients who underwent conversion THA after internal fixation for femoral neck fracture from January 2008 to September 2020. Those patients constituted two groups: noninfected patients and patients diagnosed with FRI according to the 2013 International Consensus Meeting Criteria. Receiver operating characteristic (ROC) curves were used to determine maximum sensitivity and specificity of these two preoperative ratios. The diagnostic performance of the two ratios combined with preoperative CRP or ESR was also evaluated.

RESULTS

The numbers of patients with and without FRI were 19 (5.6%) and 321 (94.4%), respectively. Areas under the ROC curve for diagnosing FRI were 0.763 for MLR, 0.686 for NLR, 0.905 for CRP, and 0.769 for ESR. Based on the Youden index, the optimal predictive cutoffs were 0.25 for MLR and 2.38 for NLR. Sensitivity and specificity were 78.9% and 71.0% for MLR, and 78.9% and 56.4% for NLR, respectively. The combination of CRP with MLR showed a sensitivity of 84.2% and specificity of 94.6%, while the corresponding values for the combination of CRP with NLR were 89.5% and 91.5%, respectively.

CONCLUSION

The presence of preoperative FRI among patients undergoing conversion THA after internal fixation for femoral neck fracture should be determined. The combination of preoperative CRP with NLR is sensitive tool for screening FRI in those patients. Cite this article: Bone Joint J 2021;103-B(9):1534-1540.

Ability of plasma-based or serum-based assays of D-dimer and FDP for diagnosing periprosthetic joint infection: protocol for a prospective single-centre, parallel comparative study

INTRODUCTION

Several studies have evaluated the diagnostic values of D-dimer and fibrin degradation product (FDP) for detecting periprosthetic joint infection (PJI), but their conclusions have been inconsistent. More importantly, whether the diagnostic value of these two biomarkers differs depending on whether they are assayed in plasma or serum is unclear.

METHODS AND ANALYSIS

This prospective single-centre, parallel comparative study will involve patients planning to undergo revision hip or knee arthroplasty due to an aseptic mechanical failure or PJI. After the patients provide written informed consent, their serum and plasma will be sampled and assayed for D-dimer and FDP. The diagnostic value of these two biomarkers in plasma and serum will be compared with one another and with the value of two traditional inflammatory markers (C reactive protein and erythrocyte sedimentation rate) used to diagnose PJI according to the 2013 International Consensus Meeting criteria. Diagnostic value will be assessed in terms of area under receiver operating characteristic curves, sensitivity, specificity, as well as positive and negative predictive values, all calculated based on the optimal cut-off determined from the Youden index.

ETHICS AND DISSEMINATION

This study was approved by the Ethics Committee of our hospital (approval no. 2020-859). Written informed consent will be obtained from all patients before enrollment. Study findings will be disseminated widely through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

This study was registered in the Chinese Clinical Trial Registry (ChiCTR2000038547), and it is ongoing.

Globulin, the albumin-to-globulin ratio, and fibrinogen perform well in the diagnosis of Periprosthetic joint infection

Background

Although periprosthetic joint infection (PJI) is a severe complication of total joint arthroplasty (TJA), the diagnosis of PJI remains challenging. Albumin (ALB), globulin (GLB), the albumin-to-globulin ratio (AGR), and fibrinogen could be indicators of the body’s inflammatory state. This study aimed to compare the diagnostic accuracy of these biomarkers with that of other inflammatory biomarkers in PJI patients.

Methods

We conducted a retrospective cohort study that included a consecutive series of patients undergoing debridement antibiotic irrigation and implant retention (DAIR), one-stage or the first stage of a two-stage revision total knee arthroplasty (TKA) or total hip arthroplasty (THA) for acute (n = 31) or chronic (n = 51) PJI, or revision TKA or THA for aseptic failures (n = 139) between January 2017 and December 2019 in our hospital. The 2013 criteria of the Musculoskeletal Infection Society (2013 MSIS) were used as the reference standard for the diagnosis of PJI. The preoperative ALB, GLB, AGR, fibrinogen, D-dimer, platelet count, fibrin degradation product (FDP), platelet-to-lymphocyte (PLR), platelet count to mean platelet volume ratio (PVR), neutrophil-to-lymphocyte ratio (NLR), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels were assessed. The receiver operating characteristic curve (ROC), sensitivity, and specificity were utilized to compare different biomarkers.

Results

Compared with the aseptic patients, the GLB, D-dimer, fibrinogen, FDP, platelet count, PVR, PLR, NLR, ESR, and CRP levels of PJI patients were significantly higher (P < 0.01); however, the ALB and AGR levels were significantly lower (P < 0.01). The area under the curve (AUC), sensitivity and specificity were 0.774, 67.50, 77.54% for ALB; 0.820, 57.50, 89.86% for GLB; 0.845, 66.25, 93.48% for AGR; 0.832, 78.48, 78.95% for fibrinogen; 0.877, 81.48, 85.07% for ESR; 0.909, 83.95, 88.89% for CRP; 0.683, 55.22, 75.83% for D-dimer; 0.664, 38.81, 88.33% for FDP; 0.678, 52.44, 79.86% for platelet count; 0.707, 48.78, 86.33% for PVR; 0.700, 51.22, 80.58% for PLR; and 0.678, 52.44, 81.30% for NLR, respectively. In the clinic, GLB, AGR and fibrinogen could be used for diagnosis of patients suspected of having PJI.

Conclusion

Our study demonstrated that GLB, AGR, and fibrinogen were promising biomarkers in the diagnosis of PJI.

The change of coagulation profile in two-staged arthroplasty for periprosthetic joint infection patients: a retrospective cohort study

Aims

Periprosthetic joint infection (PJI) is a serious complication of total joint arthroplasty. We performed a retrospective cohort study to evaluate (1) the change of coagulation profile in two-staged arthroplasty patients and (2) the relationship between coagulation profile and the outcomes of reimplantation.

Method

Between January 2011 and December 2018, a total of 202 PJI patients who were operated on with two-staged arthroplasty were included in this study initially. This study continued for 2 years and the corresponding medical records were scrutinized to establish the diagnosis of PJI based on the 2014 MSIS criteria. The coagulation profile was recorded at two designed points, (1) preresection and (2) preimplantation. The difference of coagulation profile between preresection and preimplantation was evaluated. Receiver operating characteristic curves (ROC) were used to evaluate the diagnostic efficiency of the coagulation profile and change of coagulation profile for predicting persistent infection before reimplantation.

Results

The levels of APTT, INR, platelet count, PT, TT, and plasma fibrinogen before spacer implantation were significantly higher than before reimplantation. No significant difference was detected in the levels of D-dimer, ACT, and AT3 between the two groups. The AUC of the combined coagulation profile and the change of combined coagulation profile for predicting persistent infection before reimplantation was 0.667 (95% CI 0.511, 0.823) and 0.667 (95% CI 0.526, 0.808), respectively.

Conclusion

The coagulation profile before preresection is different from before preimplantation in two-staged arthroplasty and the coagulation markers may play a role in predicting infection eradication before reimplantation when two-stage arthroplasty is performed.

Level of evidence

Level III, diagnostic study.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02477-4.

A retrospective comparison of thromboelastography and conventional coagulation parameters for periprosthetic joint infection diagnosis and reimplantation timing

PURPOSE

The diagnostic significance of coagulation parameters in periprosthetic joint infection (PJI) is currently attracting increasing attention. We assessed the diagnostic accuracy of thromboelastography (TEG) for PJI and compared the values of various coagulation indicators for PJI diagnosis and reimplantation timing.

METHODS

We enrolled 250 patients undergoing revision for aseptic failure (Group A), revision for PJI (Group B), or reimplantation (Group C) during 2013-2020. C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), representative coagulation-related indicators (reaction time [R], clotting time [K], angle and maximum amplitude [MA]) of TEG and routine coagulation indicators, including fibrinogen, D-dimer, fibrin degradation product (FDP), platelets count (PC), mean platelet volume (MPV), distribution width (PDW) and plateletcrit (PCT) as well as PC/MPV ratio(PVR)were measured preoperatively. Receiver operating characteristic (ROC) curves were used to evaluate the utility of all tested indicators for assessing infection.

RESULTS

All the indicators showed significant differences between groups A and B (P < 0.05) and, except for D-dimer, FDP, MPV and R, between groups B and C (P < 0.05). Similar differences were also observed in biomarkers before first-stage revision and second-stage reimplantation. ROC curves showed that fibrinogen, K, angle and MA outperformed the other coagulation indicators, with areas under the curve of 0.864 to 0.893 and threshold values of 3.55 g/L, 1.2 min, 72.4 deg and 69.1 mm, respectively. The multiple tests of TEG indices (K, angle and MA) and traditional inflammatory markers (CRP and ESR) or conventional coagulation indicators (fibrinogen, PC and PVR) had good sensitivity and specificity for PJI diagnosis, and the diagnostic values of TEG and platelet-associated indicators (PC and PVR) varied in the different subgroups.

CONCLUSION

TEG was closely related to PJI and could serve as a valuable technique for identifying residual infection before reimplantation. Fibrinogen showed high diagnostic accuracy for PJI and effectively guided the timing of reimplantation.

Role of D-dimer and Fibrinogen in the Diagnosis of Periprosthetic Joint Infection: A Systematic Review and Meta-Analysis

The diagnostic potential of D-dimer and fibrinogen to detect periprosthetic joint infection (PJI) of the hip and knee is not well-understood. The aim of this study was to determine whether D-Dimer and fibrinogen can be used as effective biomarkers to screen PJI. A systematic review of the literature indexed in Web of Science, PubMed, Cochrane Library, Embase, and Google Scholar databases was performed. All studies using D-dimer levels in serum or plasma, or fibrinogen levels in plasma, for the diagnosis of PJI were included. Meta-analysis estimates, including sensitivity, specificity, diagnostic odds ratios (DOR), and the area under the summary receiver operating characteristic curve (AUSROC), were calculated using a random-effects model, and used to assess the diagnostic accuracy of these biomarkers. A total of nine studies were analyzed, and their quality was considered to be acceptable. D-dimer gave a limited diagnostic value if serum and plasma combined: sensitivity (0.77, 95% confidence interval [CI] [0.63 to 0.87]), specificity (0.67, 95% CI [0.54 to 0.78]), DOR (6.81, 95% CI [2.67 to 17.37]), and AUSROC (0.78, 95% CI [0.74 to 0.82]). Plasma D-dimer levels were associated with less satisfactory sensitivity (0.65, 95% CI 0.57 to 0.71), specificity (0.58, 95% CI 0.50 to 0.66), DOR (2.52, 95% CI 1.64 to 3.90), and AUSROC (0.65, 95% CI 0.61 to 0.69). Serum D-dimer levels showed higher corresponding values of 0.89 (95% CI 0.79 to 0.94), 0.76 (95% CI 0.55 to 0.89), 24.24 (95% CI 10.07 to 58.32), and 0.91 (95% CI 0.88 to 0.93). Plasma fibrinogen showed acceptable corresponding values of 0.79 (95% CI 0.70 to 0.85), 0.73 (95% CI 0.57 to 0.85), 10.14 (95% CI 6.16 to 16.70), and 0.83 (95% CI 0.79 to 0.86). Serum D-dimer may be an effective marker for the diagnosis of PJI in hip and knee arthroplasty patients, and it may show higher diagnostic potential than plasma fibrinogen. Plasma D-dimer may have limited diagnostic potential.

Fibrinogen performs better than D-dimer for the diagnosis of periprosthetic joint infection: a meta-analysis of diagnostic trials

Purpose

D-dimer and fibrinogen, both belonging to coagulation parameters, are controversial for the diagnosis of periprosthetic joint infection (PJI). This meta-analysis was conducted to compare their diagnostic accuracies for PJI by synthesizing currently available evidence.

Methods

Cochrane Library, MEDLINE, Web of Science, and Embase up to March 1, 2020, and other relevant articles were searched. Five hundred and eighty-one articles were identified after initial research, and 11 studies were included finally. No threshold effects were found between studies. The pooled sensitivity, specificity, and positive and negative likelihood ratio were reported to evaluate the diagnostic performance with heterogeneity analysis. Z test statistics was used to analyze the difference of diagnostic performance between D-dimer and fibrinogen.

Results

The pooled sensitivity, specificity, and positive and negative likelihood ratio of D-dimer for PJI were 0.79 (95% [CI], 0.72–0.85), 0.77 (0.67–0.84), 3.38 (2.21–5.18), and 0.27 (0.18–0.41), respectively. As for fibrinogen, the pooled sensitivity, specificity, and positive and negative likelihood ratio for PJI were 0.75 (0.68–0.80), 0.85 (0.82–0.88), 5.12 (4.22–6.22), and 0.30 (0.23–0.37), respectively. Great heterogeneity was found in studies for D-dimer, and univariate meta-regression analysis revealed that number of involved joints, disease spectrum, comorbidities influencing D-dimer, and sample sources were the source of heterogeneity. Z test found that the pooled specificity of fibrinogen was significantly higher than D-dimer (0.85 ± 0.01 versus 0.77 ± 0.04, p = 0.03). The pooled positive likelihood ratio of fibrinogen was significantly higher than D-dimer (5.12 ± 0.51 versus 3.38 ± 0.74, p = 0.03).

Conclusion

Based on currently available evidence, the meta-analysis suggests that fibrinogen performs better than D-dimer as a rule-in diagnostic tool for its higher specificity. However, more prospective trials with larger size are still needed to provide further confirmation.

Trial registration

This meta-analysis was prospectively registered on PROSPERO (International prospective register of systematic reviews), and the registering number was CRD42020177176.

Reliability of circulating fibrinogen in the diagnosis of prosthesis-related infections: a systematic review and meta-analysis

Background

Fibrinogen (FIB) has recently been used as a biomarker to diagnose periprosthetic joint infection (PJI), but its reliability is still questionable. The aim of this study was to investigate the accuracy of FIB in the diagnosis of PJI after joint replacement.

Methods

We searched for literatures published in PubMed, EMBASE, and the Cochrane Library from the time of database inception to September 2020 and screened the studies according to the inclusion criteria. Then, we calculated the diagnostic parameters of FIB, including the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), area under the curve (AUC), and diagnostic odds ratio (DOR). In addition, we implemented subgroup analyses to identify the sources of heterogeneity.

Results

Seven studies including 1341 patients were selected in our meta-analysis. The pooled sensitivity, specificity, PLR, NLR, and DOR of FIB for PJI diagnosis were 0.78 (95% confidence interval [CI], 0.73–0.82), 0.83 (95% CI, 0.81–0.86), 4.60 (95% CI, 3.30–6.42), 0.24 (95% CI, 0.18–0.34), and 20.13 (95% CI, 14.80–27.36), respectively, while the AUC was 0.896.

Conclusion

The present study indicated that FIB was a reliable detection method and might be introduced into the diagnostic criteria for PJI. However, more robust studies are still needed to confirm the current findings, because most of the included studies were retrospective and had small sample sizes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-020-02171-x.

Plasma Fibrinogen as a Diagnostic Marker of Infection in Patients with Nonunions

Background

The timely and accurate diagnosis of infected nonunion is challenging, and there is a need for more efficient biomarkers. Previous studies have shown that fibrinogen plays an important role in mediating inflammation in bacterial infections and, therefore, could be a valuable biomarker for infected nonunion. The purpose of this study was to evaluate and compare the performance of plasma fibrinogen and other traditional blood markers for the diagnosis of infected nonunion.

Materials and Methods

We retrospectively studied 146 patients who underwent surgery for primary nonunion between January 2018 and January 2020. The patients were divided into those with infected nonunion (n = 55) and those with aseptic nonunion (n = 91). The preoperatively analyzed parameters were plasma fibrinogen, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, and white blood cell (WBC) count. Receiver operating characteristic (ROC) curve analysis was used to assess the sensitivity and specificity of the biomarkers, and Youden's index was calculated to determine their optimal cut-off values.

Results

The plasma fibrinogen values were significantly higher (p < 0.001) in the patients with infected nonunion than in those with aseptic nonunion. ROC curve analysis showed that plasma fibrinogen had a high value of area under the curve (0.816), which indicated that it had good diagnostic ability. Further, at the optimal threshold value of 2.75 g/L, plasma fibrinogen had the highest sensitivity (78.2%; 95% CI = 64.6-87.8) and good specificity (82.4%; 95% CI, 72.7-89.3).

Conclusion

In comparison to the traditional markers of infection, plasma fibrinogen showed good diagnostic ability for the detection of infected nonunion. It may have potential as a practical and cost-efficient biomarker for the diagnosis of infected nonunion.

Serum globulin and albumin to globulin ratio as potential diagnostic biomarkers for periprosthetic joint infection: a retrospective review

Background

Periprosthetic joint infection (PJI) has been increasingly documented; however, its preoperative accurate diagnosis remains challenging. Furthermore, there is a dire need to identify appropriate and effective biomarkers. We aimed to evaluate the relationship between globulin, albumin to globulin (A/G) ratio, and development of PJI in patients undergoing revision total joint arthroplasty (TJA).

Methods

A retrospective study was conducted on patients who had undergone revision TJA between 2011 and 2018 (89 with aseptic mechanic failure and 38 with PJI). The serum proteins were explored using univariate analysis followed by multivariate logistic regression. The diagnostic performance of these proteins was assessed by the receiver operating characteristic (ROC) curve.

Results

Higher globulin levels (odds ratio [OR], 1.239; P < 0.001) and lower A/G ratio (OR, 0.007; P < 0.001) were strongly associated with the risk of PJI. ROC curve analysis demonstrated reasonable diagnostic performance for globulin (area under the curve [AUC], 0.77; sensitivity, 78.95%; and specificity, 69.66%) and A/G ratio (AUC, 0.779; sensitivity, 65.79%; and specificity, 78.65%).

Conclusions

Both globulin and A/G ratio were associated with PJI and may serve as potential adjuvant biomarkers in the diagnosis of PJI.

Normal trajectory of Interleukin-6 and C-reactive protein in the perioperative period of total knee arthroplasty under an enhanced recovery after surgery scenario

Background

We designed the current study to understand the normal trajectories of interleukin-6 (IL-6) and C-reactive protein (CRP) in the immediate hours and days after primary total knee arthroplasty (TKA) under the management of an enhanced recovery after surgery (ERAS) protocol and examined whether one or the other returned to normal more quickly.

Methods

In this prospective cross-sectional study, we examined the plasma IL-6 and CRP levels in 100 patients undergoing primary TKA at the following time points: 12 h preoperatively as well as postoperatively 12 h, 48 h, 3 days and 2 weeks. Patients were followed up for 1 year to monitor the postoperative complications, especially the infection.

Results

IL-6 peaked at 48 h postoperatively. Then IL-6 started to decline at 3 days postoperatively and went back to baseline level at 2 weeks (p = 0.950). CRP peaked at 3 days postoperatively. At 2 weeks, CRP declined to a normal range, without being significantly different from the baseline level (p = 0.816).

Conclusion

We found that under the ERAS scenario, the postoperative peak of IL-6 and CRP was deferred compared with previous studies. Compared to IL-6, CRP showed a gradual rise after surgery. Both of these two biomarkers returned to normal under the ERAS scenario. Future multiple-center studies with larger sample size can help define the thresholds of IL-6 and CRP for periprosthetic joint infection (PJI) early diagnosis. With these reference data, a clinician can make a quicker decision to perform aspiration to diagnose early PJI and benefits more patients.