Accuracy of blood-tests and synovial fluid-tests in the diagnosis of periprosthetic joint infections

Imaging in Periprosthetic Joint Infection Diagnosis: A Comprehensive Review

Various imaging methods assist in diagnosing periprosthetic joint infection (PJI). These include radiological techniques such as radiography, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US); as well as advanced nuclear medicine techniques including bone scintigraphy (BS), anti-granulocyte antibody imaging (AGS), leukocyte scintigraphy (LS), and fluorodeoxyglucose positron emission tomography (FDG-PET and FDG-PET/CT). Each imaging technique and radiopharmaceutical has been extensively studied, with unique diagnostic accuracy, limitations, and benefits for PJI diagnosis. This review aims to detail and describe the most commonly used imaging techniques and radiopharmaceuticals for evaluating PJI, focusing particularly on knee and hip arthroplasties.

Analysis of Serum and Synovial Inflammatory Markers in Periprosthetic Joint Infections: A Narrative Review

Periprosthetic joint infection (PJI) is considered a rare but devastating complication after total joint arthroplasty (TJA). The problem lies in the fact that there is a paucity of "gold standard" diagnostic tests that make the diagnosis of PJI extremely challenging. Recently, there have been increasing evidence-based guidelines that have been introduced to standardise the approach to a patient with a suspected PJI. Diagnosing a case of PJI traditionally involves initial screening for elevated serum inflammation markers C-reactive protein (CRP) (mg/dL) and erythrocyte sedimentation rate (ESR), and aspiration remains the sole confirmatory investigation. However, several factors would affect the values of the aforementioned markers, such as gender, age, and the presence of inflammatory circumstances. Serum D-dimer that detects fibrinolytic activities during infection has high sensitivity, but the specificity was not persuasive as it would elevate during other conditions, such as venous thromboembolism. Therefore, there is also a need for a simultaneous and secondary marker. There are also several synovial biomarkers, including ESR, CRP, alpha-defensin, and synovial fluid leukocyte count and differential for the detection of PJI. In this narrative review, we want to sum up the serum and inflammatory markers that have been introduced so far for detecting PJI.

Current Status and Perspectives of Diagnosis and Treatment of Periprosthetic Joint Infection

Periprosthetic joint infection (PJI) is a catastrophic complication following joint replacement surgery, posing significant challenges to orthopedic surgeons. Due to the lack of a definitive diagnostic gold standard, timely treatment initiation is problematic, resulting in substantial economic burdens on patients and society. In this review, we thoroughly analyze the complexities of PJI and emphasize the importance of accurate diagnosis and effective treatment. The article specifically focuses on the advancements in diagnostic techniques, ranging from traditional pathogen culture to advanced molecular diagnostics, and discusses their role in enhancing diagnostic accuracy. Additionally, we review the latest surgical management strategies, including everything from debridement to revision surgeries. Our summary aims to provide practical information for the diagnosis and treatment of PJI and encourages further research to improve diagnostic accuracy and treatment outcomes.

Accuracy of Serological Markers, Synovial Fluid, Microbiological Culture, and Histopathological Examination for Diagnosing Periprosthetic Knee Infection

Objective  This study assessed the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of serological tests, synovial fluid markers, microbiological tissue culture, and histopathological examination of the periprosthetic membrane in diagnosing periprosthetic knee infection. Methods  This study is prospective, and it includes patients undergoing total knee arthroplasty revision surgery from November 2019 to December 2021. The analysis consisted of serological tests (erythrocyte sedimentation rate [ESR], C-reactive protein [CRP], and D-dimer), synovial fluid markers (leukocyte and polymorphonuclear cell counts), periprosthetic tissue culture, and histopathological examination of the periprosthetic membrane of all patients. Results  Sixty-two patients had periprosthetic joint infection (PJI) according to the 2018 International Consensus Meeting criteria (infection group), while 22 subjects had no infection. ESR sensitivity and specificity were 83.6% and 45.4%, respectively. CRP sensitivity and specificity were 64.5% and 100%, whereas D-dimer sensitivity and specificity were 78.9% and 25%, respectively. Leukocyte count sensitivity and specificity were 75.6% and 100%, polymorphonuclear cell count sensitivity and specificity were 33% and 100%, respectively. Periprosthetic tissue culture sensitivity and specificity culture were, respectively, 77.4% and 100%. Histopathological examination sensitivity and specificity were 43.7% and 100%, respectively. Conclusions  In our study, the total blood cell count in synovial fluid and microbiological cultures of periprosthetic tissues were the most accurate tests for PJI diagnosis. In contrast, polymorphonuclear cell percentage was the least accurate test for PJI diagnosis.

It can be unnecessary to combine common synovial fluid analysis and alpha-defensin tests for periprosthetic joint infection diagnosis

BACKGROUND

Periprosthetic joint infection is a serious complication after total joint arthroplasty. Despite that alpha-defensin was used as diagnostic test in the 2018 ICM (international consensus meeting) criteria, its position in the PJI diagnostic pipeline was controversial. Therefore, we performed a retrospective pilot study to identify whether synovial fluid alpha-defensin test was necessary when corresponding synovial fluid analysis (WBC count, PMN% and LE tests) was performed.

METHODS

Between May 2015 and October 2018, a total of 90 suspected PJI patients who underwent revisions after TJA were included in this study. Based on the 2018 ICM criteria, the interobserver agreements between preoperative diagnostic results and postoperative diagnostic results and the interobserver reliability between preoperative diagnostic results and postoperative diagnostic results with or without synovial fluid alpha-defensin tests were calculated. After that, the ROC analysis, and the direct cost-effectiveness of adding alpha-defensin was performed.

RESULTS

There were 48,16 and 26 patients in the PJI group, inconclusive group and non-PJI group, respectively. Adding the alpha-defensin tests into 2018 ICM criteria can't change the preoperative diagnostic results, postoperative diagnostic results, and the concordance between preoperative and postoperative diagnostic results. Moreover, the Risk-benefit Ratio is over 90 per changed decision and the direct cost-effectiveness of alpha-defensin was more than $8370($93*90) per case.

CONCLUSIONS

Alpha-defensin assay exhibit high sensitivity and specificity for PJI detection as a standalone test based on the 2018 ICM criteria. However, the additional order of Alpha-defensin can't offer additional evidence for PJI diagnosis when corresponding synovial fluid analysis was performed (synovial fluid WBC count, PMN% and LE strip tests).

EVIDENCE LEVEL

Level II, Diagnostic study.

The Diagnostic and Prognostic Value of Synovial Fluid Analysis in Joint Diseases

Liquid biopsy is an emergent test method for the diagnosis and prognosis in the clinic. Joint fluid, also known as synovial fluid, contains a variety of bioactive constituents that can be selectively detected and further evaluated in a convenient fashion. Therefore, synovial fluid analysis functions as a specific form of liquid biopsy and plays a vital role in numerous joint diseases. In spite of the component analysis of aspirated synovial fluid beingconsidered as the gold standard for diagnosis of joint infections, biopsy of joint fluid benefits the initial diagnosis and long-term prognosis of degenerative, inflammatory, autoimmune, traumatic, congenital, and even neoplastic joint diseases. The convenience and accuracy for disease evaluation are significantly elevated as a result of the combination of synovial fluid analysis and other novel clinical technologies. In this review, we shed light on the latent role of synovial fluid in the diagnosis and prognosis of articular diseases and proposed future prospects for relevant research in this field.

Synovial calprotectin for the diagnosis of periprosthetic joint infection: a diagnostic meta-analysis

Background

Periprosthetic joint infections (PJI) are a rare but severe complication of total joint arthroplasty (TJA). However, the diagnosis of PJI remains difficult. It is one of the research that focuses about diagnosis for PJI for majority researchers to discover a novel biomarker. This meta-analysis tried to evaluate diagnostic value of synovial calprotectin for PJI.

Methods

This meta-analysis search of the literature was conducted in PubMed, EMBASE, Web of Science, and the Cochrane Library. Literature quality was appraised using Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) based on RevMan (version 5.3). The diagnostic value of calprotectin for PJI was evaluated by calculating sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), diagnostic score and area under SROC (AUC) based on the Stata version 14.0 software. We conduct subgroup analysis according to the study design, cutoff values, the country of study, and gold standard.

Results

Seven studies were included in this meta-analysis. The pooled sensitivity of synovial calprotectin for the diagnosis of PJI was 0.94 (95% CI, 0.87–0.98), and the specificity was 0.93 (95% CI, 0.87–0.96). The pooled AUC, PLR, and NLR for synovial calprotectin were 0.98 (95% CI, 0.96–0.99), 13.65 (95% CI, 6.89–27.07), and 0.06 (95% CI, 0.02–0.15), respectively. The pooled diagnostic score and DOR were 5.4 (95% CI, 3.96–6.85) and 222.32 (95% CI, 52.52–941.12), respectively.

Conclusion

In summary, this meta-analysis indicates that synovial calprotectin is a promising biomarker of assistant diagnosis for PJI, as well as recommended test for excluding diagnostic tool.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02746-2.

Leukocyte Esterase Versus ICM 2018 Criteria in the Diagnosis of Periprosthetic Joint Infection

BACKGROUND

A leukocyte esterase (LE) test is inexpensive and provides real-time information about patients suspected of periprosthetic joint infections (PJIs). The 2018 International Consensus Meeting (ICM) recommends it as a diagnostic tool with a 2+ cutoff. There is still a lack of data revealing LE utility versus the ICM 2018 criteria for PJI.

METHODS

This is a retrospective study of patients who underwent revision total hip and total knee arthroplasty at a single institution between March 2009 and December 2019. All patients underwent joint aspiration before the arthrotomy, and the LE strip test was performed on aspirated joint fluid. PJI was defined using the 2018 ICM criteria.

RESULTS

As per the 2018 ICM criteria, 78 patients were diagnosed with chronic PJI and 181 were not infected. An LE test with a cutoff of ≥1+ had a sensitivity of 0.744, a specificity of 0.906, a positive predictive value of 0.773, an accuracy of 0.825 (95% confidence interval 0.772-0.878), and a negative predictive value of 0.891. The positive likelihood ratio (LR+) was 7.917. Using an LE cutoff of 2 + had a sensitivity of 0.513, a specificity of 1.000, and an accuracy of 0.756 (95% confidence interval-0.812).

CONCLUSION

LE is a rapid and inexpensive test which can be performed at the bedside. Its performance is valuable as per ICM criteria. Based on the findings of this study and the given cohort, we suggest using the cutoff of LE1+ (result = negative or trace) as a point of care test to exclude infection, whereas LE at 2 + threshold has near absolute specificity for the diagnosis.

The impact of sonication cultures when the diagnosis of prosthetic joint infection is inconclusive

BACKGROUND

In the absence of a gold standard criterion for diagnosing prosthetic joint infections (PJI), sonication of the removed implant may provide superior microbiological identification to synovial fluid and peri-implant tissue cultures. The aim of this retrospective study was to assess the role of sonication culture compared to tissue cultures for diagnosing PJI, using different consensus and international guidelines for PJI definition.

METHODS

Data of 146 patients undergoing removal of hip or knee arthroplasties between 2010 and 2018 were retrospectively reviewed. The International Consensus Meeting (ICM-2018), Musculoskeletal Infection Society (MSIS), Infectious Diseases Society of America (IDSA), the European Bone and Joint Infection Society (EBJIS), and a modified clinical criterion, were used to compare the performance of microbiological tests. McNemar´s test and proportion comparison were employed to calculate p-value.

RESULTS

Overall, 56% (82/146) were diagnosed with PJI using the clinical criteria. Out of these cases, 57% (47/82) tested positive on tissue culture and 93% (76/82) on sonication culture. Applying this clinical criterion, the sensitivity of sonication fluid and tissue cultures was 92.7% (95% CI: 87.1%- 98.3%) and 57.3% (95% CI: 46.6%-68.0%) (p<0.001), respectively. When both methods were combined for diagnosis (sonication and tissue cultures) sensitivity reached 96.3% (95% CI: 91.5%-100%). Sonication culture and the combination of sonication with tissue cultures, showed higher sensitivity rates than tissue cultures alone for all diagnostic criteria (ICM-18, MSIS, IDSA and EBJIS) applied. Conversely, tissue culture provided greater specificity than sonication culture for all the criteria assessed, except for the EBJIS criteria, in which sonication and tissue cultures specificity was 100% and 95.3% (95% CI: 87.8-100%), respectively (p = 0.024).

CONCLUSIONS

In a context where diagnostic criteria available have shortcomings and tissue cultures remain the gold standard, sonication cultures can aid PJI diagnosis, especially when diagnostic criteria are inconclusive due to some important missing data (joint puncture, histology).