Detection Of Prosthetic Joint Infection Research Articles

Comparison of microbial detection rates in microbial culture methods versus next-generation sequencing in patients with prosthetic joint infection: a systematic review and meta-analysis

BackgroundAccurate diagnosis of prosthetic joint infection (PJI) enables early and effective treatment. However, there is currently no gold standard test for microbial detection of PJI and traditional synovial fluid culture is relatively insensitive. Recently, it has been reported that sonicating fluid culture and next-generation sequencing (NGS) improve microbial detection rates. Hence, we performed a systematic review and meta-analysis to compare microbial detection rates in microbial culture methods with and without sonication versus NGS.MethodsWe systematically searched EMBASE, PubMed, Scopus, CINAHL, and Ichushi databases and other sources (previous reviews) until August 2022. We evaluated the detection rates of pathogens in NGS and microbial cultures using samples of synovial or sonicated fluid.ResultsOf the 170 citations identified for screening, nine studies were included. Pooled analysis indicated that NGS had the highest detection rate among the microbial detection methods (NGS vs. sonicated, odds ratios [OR] 5.09, 95% confidential interval [CI] 1.67–15.50; NGS vs. synovial, OR 4.52, 95% CI 2.86–7.16). Sonicated fluid culture showed a higher detection rate than synovial fluid culture (OR 2.11, 95% CI 1.23–3.62).ConclusionNGS might be useful as a screening tool for culture-negative patients. In clinical settings, sonicated fluid culture is a practical method for diagnosing PJI.

Diagnostic Performance of Metagenomic Next⁃Generation Sequencing in the Diagnosis of Prosthetic Joint Infection Using Tissue Specimens.

The purpose of this study was to evaluate the ability of metagenomic next-generation sequencing (mNGS) diagnosing prosthetic joint infection (PJI) using tissue from hip/knee rapidly and precisely, especially in patients who had received antibiotic treatment within the preceding two weeks. From May 2020 to March 2022, 52 cases with suspected PJI were enrolled. mNGS was performed on surgical tissue samples. The sensitivity and specificity of mNGS in diagnosis was evaluated using culture in conjunction with MSIS criteria. This study also looked at how antibiotic use affected culture and mNGS efficacy. According to MSIS criteria, 31 of the 44 cases had PJI, and 13 were classified in the aseptic loosening group. Sensitivity, specificity, positive/negative predictive value (PPV/NPV), positive/negative likelihood ratio (PLR/NLR), and area under the curve (AUC) of mNGS assay were 80.6% (71.9-91.8%), 84.6 (73.7-97.9%), 92.6 (84.2-98.7%), 64.7 (58.6-74.7%), 5.241 (4.081-6.693), 0.229 (0.108-0.482) and 0.826 (0.786-0.967), respectively, with MSIS as a reference. When MSIS was used as a reference, the results of culture assay were 45.2% (40.8-51.5%), 100 (100.0-100.0%), 100 (100.0-100.0%), 43.3 (39.1-49.5%), +∞, 0.548 (0.396-0.617) and 0.726 (0.621-0.864), respectively. The AUC values for mNGS and culture were 0.826 and 0.731, respectively, and the differences were insignificant. mNGS demonstrated higher sensitivity than culture in PJI subjects who had previously received antibiotic treatment within 2 weeks (69.5% vs 23.1%, P =0.03). In our series, mNGS yield a higher sensitivity for diagnosis and pathogen detection of PJI compared to microbiological culture. Additionally, mNGS is less affected by prior antibiotic exposure.

Serum calprotectin: a potential biomarker to diagnose chronic prosthetic joint infection after total hip or knee arthroplasty

The preoperative detection of prosthetic joint infection (PJI) prior to revision of total hip or knee arthroplasty is still a challenge. Serum Calprotectin (CP) is a heterodimer of two calcium-binding proteins present in the cytoplasm of neutrophils that is released in inflammatory processes and infections. The objective of this study is to determine the reliability of serum CP in the diagnosis of chronic PJI. 81 patients (40 women, 41 men) that presented a potential indication for revision arthroplasty of the hip (THA; n = 18) or knee (TKA, n = 63) at a single institution were prospectively evaluated. The joints were diagnosed as chronically infected or aseptic based on the musculoskeletal infection society (MSIS) criteria of 2018. Receiver operating characteristics and the Youden’s index were used to define an ideal cutoff value. The median serum CP level was significantly higher in the group with chronic PJI (15,120 vs. 4980 ng/ml; p < 0.001) compared to the aseptic cases. The calculated optimal cut-off value was 9910 ng/ml (AUC 0.899, 95% CI 0.830–0.968) with a specificity of 91% and sensitivity of 81%. The present investigation suggests that serum CP has a high specificity and good sensitivity to diagnose chronic PJI after TJA of the knee or hip.

Saline lavage after a "dry tap".

In patients with a "dry" aspiration during the investigation of prosthetic joint infection (PJI), saline lavage is commonly used to obtain a sample for analysis. The aim of this study was to investigate prospectively the impact of saline lavage on synovial fluid analysis in revision arthroplasty. Patients undergoing revision hip (THA) or knee arthroplasty (TKA) for any septic or aseptic indication were enrolled. Intraoperatively, prior to arthrotomy, the maximum amount of fluid possible was aspirated to simulate a dry tap (pre-lavage) followed by the injection with 20 ml of normal saline and re-aspiration (post-lavage). Pre- and post-lavage synovial white blood cell (WBC) count, percent polymorphonuclear cells (%PMN), and cultures were compared. A total of 78 patients had data available for analysis; 17 underwent revision THA and 61 underwent revision TKA. A total of 16 patients met modified Musculoskeletal Infection Society (MSIS) criteria for PJI. Pre- and post-lavage %PMNs were similar in septic patients (87% vs 85%) and aseptic patients (35% vs 39%). Pre- and post-lavage synovial fluid WBC count were far more disparate in septic (53,553 vs 8,275 WBCs) and aseptic (1,103 vs 268 WBCs) cohorts. At a cutoff of 80% PMN, the post-lavage aspirate had a sensitivity of 75% and specificity of 95%. At a cutoff of 3,000 WBCs, the post-lavage aspirate had a sensitivity of 63% and specificity of 98%. As the post-lavage synovial WBC count increased, the difference between pre- and post-lavage %PMN decreased (mean difference of 5% PMN in WBC < 3,000 vs mean difference 2% PMN in WBC > 3,000, p = 0.013). Of ten positive pre-lavage fluid cultures, only six remained positive post-lavage. While saline lavage aspiration significantly lowered the synovial WBC count, the %PMN remained similar, particularly at WBC counts of > 3,000. These findings suggest that in patients with a dry-tap, the %PMN of a saline lavage aspiration has reasonable sensitivity (75%) for the detection of PJI. Cite this article: Bone Joint J 2020;102-B(6 Supple A):138-144.

High Accuracy of Second Generation Unyvero ITI Automated Multiplex PCR Analysis of Joint Fluid Aspirate in Low-Grade Prosthetic Hip and Knee Joint Infections

Aims and Objectives:A major obstacle for the treatment of prosthetic joint infections (PJIs) is the identification of the organism causing it. While the diagnostic criteria ruling PJIs in or out have become ever more accurate, detecting the causative pathogen(s) still relies mostly on conventional culture. The aim of this study was to evaluate the diagnostic potential of a second generation multiplex PCR assay (Unyvero ITI G2, Curetis AG, Holzgerlingen, Germany) used on synovial fluid specimens.Materials and Methods:Prospectively collected frozen joint fluid specimens from 26 patients undergoing arthroplasty revision surgery of the hip or knee for any reason were tested as per the manufacturer’s protocol. The sensitivity and specificity were calculated using the Chi-squared-test and a combination of the serum CRP level, leukocyte count, erythrocyte sedimentation rate, joint fluid culture, tissue biopsy culture, and tissue biopsy histology served as gold standard.Results:Of the 26 cases included in the study, 15 were infected and 11 aseptic. Conventional joint fluid culture showed a sensitivity 0.67 and a specificity of 0.91. Joint fluid multiplex PCR yielded a sensitivity of 0.8 and a specificity of 1.0.Conclusion:This is the first study to assess the second generation Unyvero ITI cartridge on joint fluid aspirate for the detection of prosthetic joint infection. In our setting, the method achieved a higher diagnostic accuracy than conventional culture. We conclude that, to improve pathogen detection before revision surgery, this method represents a valuable tool.

Improved pre-operative diagnostic accuracy for low-grade prosthetic joint infections using second-generation multiplex Polymerase chain reaction on joint fluid aspirate

BackgroundA major obstacle for the treatment of prosthetic joint infection (PJI) is the identification of the underlying causative organism. While the diagnostic criteria ruling PJI in or out have become ever more accurate, the detection of the causative pathogen(s) still relies mostly on conventional and time-consuming microbial culture. The aim of this study was to evaluate the diagnostic potential of a second-generation multiplex PCR assay (Unyvero ITI G2, Curetis AG, Holzgerlingen, Germany) used on synovial fluid specimens. Our hypothesis was that the method would yield a higher diagnostic accuracy in the pre-operative workup than synovial fluid culture. Thus, a more precise classification of septic and aseptic prosthesis failure could be achieved before revision surgery.MethodsProspectively collected frozen joint fluid specimens from 26 patients undergoing arthroplasty revision surgery of the hip or knee were tested as per the manufacturer’s protocol. Sensitivities, specificities, positive and negative predictive values as well as positive and negative likelihood ratios with corresponding confidence intervals were estimated using the statistical software R. A combination of the serum C-reactive protein (CRP) level, leukocyte count, erythrocyte sedimentation rate, joint fluid culture, tissue biopsy culture, and tissue biopsy histology served as the gold standard.ResultsOf the 26 patients included in the study, 15 were infected and 11 were aseptic. Conventional joint fluid culture showed a sensitivity of 0.67 and a specificity of 0.91. Joint fluid multiplex PCR yielded a sensitivity of 0.8 and a specificity of 1.0.ConclusionsUsing the second-generation Unyvero ITI cartridge on joint fluid aspirate for the detection of prosthetic joint infection, we were able to achieve a higher diagnostic accuracy than with conventional culture. We conclude that to improve pathogen detection before revision surgery, this method represents a valuable and practicable tool.

2442. Detection of Prosthetic Hip and Knee Joint Infections Using Administrative Databases – A Validation Study

BackgroundForming large cohorts to study prosthetic joint infections (PJIs) is a challenge without an existing surgical registry, as is the case in Canada. Administrative databases are an option, yet PJI diagnostic codes are insensitive. There is a need to improve the detection of PJIs from within administrative databases.MethodsIndividuals who had a primary arthroplasty at four hospitals in Toronto, Canada from 2010 to 2016 were identified using Canadian Classification of Health Intervention codes (based on the International Classification of Disease, Tenth Revision). Each re-admission to the same hospital until December 31, 2016 was reviewed for the presence of a PJI. The performance characteristics (sensitivity, specificity, positive and negative predictive values) of combinations of diagnostic and procedure codes when compared with the gold standard of chart review were calculated. The primary outcome was the algorithm that maximized sensitivity and positive predictive value.Results27,843 primary arthroplasties were performed with 8595 readmissions, of which 572 involved a PJI. Median follow-up was 1258 days (interquartile range (IQR) 614–1891 days), with median time to first re-admission of 352 days (IQR range 166–725 days). PJI codes exhibited a sensitivity of 0.86 (95% confidence interval (95% CI) 0.83–0.89) and positive predictive value (PPV) of 0.89 (95% CI 0.86–0.92). The best performing algorithm is a combination of a PJI code or joint spacer insertion procedure code or insertion of a peripherally inserted central catheter along with an arthroplasty code (sensitivity 0.90, 95% CI 0.88–0.93 and PPV 0.89, 95% CI 0.86–0.91). Using timing from primary arthroplasty, spacer insertion codes and presence of a subsequent arthroplasty procedure code identified 68% (71/105) of first stage and 74% (108/146) of debridement with joint retention procedures during the first re-admission for a PJI.ConclusionCombinations of diagnosis and procedure codes can reliably identify PJIs from administrative databases. Individual orthopaedic procedure codes and timing from primary arthroplasty can inform the surgical procedure performed. This PJI detection algorithm could be used for PJI surveillance and research.Disclosures All authors: No reported disclosures.

Culturing periprosthetic tissue in BacT/Alert\xae Virtuo blood culture system leads to improved and faster detection of prosthetic joint infections

BackgroundBlood culture bottles (BCBs) provide a semiautomated method for culturing periprosthetic tissue specimens. A study evaluating BCBs for culturing clinical samples other than body fluids is needed before implementation into clinical practice. Our objective was to evaluate use of the BacT/Alert® Virtuo blood culture system for culturing periprosthetic tissue specimens.MethodsThe study was performed through the analysis of spiked (n = 36) and clinical (n = 158) periprosthetic tissue samples. Clinical samples were analyzed by the BCB method and the results were compared to the conventional microbiological culture-based method for time to detection and microorganisms identified.ResultsThe BacT/Alert® Virtuo blood culture system detected relevant bacteria for prosthetic joint infection in both spiked and clinical samples. The BCB method was found to be as sensitive (79%) as the conventional method (76%) (p = 0.844) during the analyses of clinical samples. The BCB method yielded positive results much faster than the conventional method: 89% against 27% detection within 24 h, respectively. The median detection time was 11.1 h for the BCB method (12 h and 11 h for the aerobic and the anaerobic BCBs, correspondingly).ConclusionWe recommend using the BacT/Alert® Virtuo blood culture system for analyzing prosthetic joint tissue, since this detect efficiently and more rapidly a wider range of bacteria than the conventional microbiological method.

Polymerase Chain Reaction Assay Using the Restriction Fragment Length Polymorphism Technique in the Detection of Prosthetic Joint Infections: A Multi-Centered Study

BackgroundPCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) techniques have been used for the diagnosis of bacteria in some infections. In this study, we aimed to evaluate the diagnostic accuracy of PCR for the diagnosis of prosthetic joint infections (PJI) and to identify isolated microorganisms, using the RFLP method. MethodsDuring January 2015 to January 2018, patients who were suspected of having PJI after arthroplasty surgery or were candidates for revision surgery due to loosening of implant entered the study. Patients who had 1 major criterion or 3 minor criteria for PJI based on the Philadelphia Consensus Criteria (PCC) on Periprosthetic Joint Infection were considered as cases of PJI. Both culture results and PCR findings, were cross compared with results of the PCC (as the gold standard criteria). ResultsOverall, 76 samples were included in the study. Mean (standard deviation) age of patients was 66.72 ± 11.82 years. Overall, 57.9% of patients were females. Prevalence of PJI was 50% based on the PCC. Sensitivity, specificity, positive predictive value, negative predictive value, and general efficacy of PCR for detection of PJI was 97.4%, 100%, 100%, 97.4%, and 98.7%, respectively. Sensitivity, specificity, positive predictive value, negative predictive value, and general efficacy of culture was 31.6%, 100%, 65.7%, 100%, and 59.4%, respectively.We isolated a broad range of bacteria using PCR-RFLP including Gram-positive cocci such as Staphylococcus sp., Streptococcus sp., and Enterococcus sp., and Gram-negative bacilli such as Enterobacteriaceae sp., Pseudomonas sp. Citrobacter sp., as well as Chlamydophila pneumonia, Stenotrophomonas maltophilia, Brucella melitensis, non-gonococcal Neisseria, Kingella kingae, Bacteroides ovatus, and Proteus mirabilis from PJI patients. ConclusionInhere, for the first time, we showed that PCR-RFLP is a powerful tool for identifying the type of bacteria involved in PJI, and can be used for follow-up of patients suspected of PJI and those with a history of antibiotic use. PCR-RFLP may be able to substantially decrease detection time of PJI among PCR-based methods, while allowing more accurate identification of the bacteria involved.

Serum IL-6 in combination with synovial IL-6/CRP shows excellent diagnostic power to detect hip and knee prosthetic joint infection.

BackgroundThe diagnosis of prosthetic joint infection (PJI) is still a challenge in some patients after total joint replacement. Interleukin-6 (IL-6) strongly participates in the arrangement of the host-bacteria response. Therefore, increased levels of IL-6 should accompany every PJI.PurposeThe aim of the study was to show diagnostic characteristics of serum IL-6 for the diagnosis of prosthetic joint infection (PJI). We also compared the diagnostic values of serum IL-6 with synovial IL-6 (sIL-6) and synovial C-reactive protein (sCRP).Study designWe performed a prospective study of 240 patients in whom serum IL-6 was determined before total hip (n = 124) or knee (n = 116) reoperations. The PJI diagnosis was based on the MSIS (Musculoskeletal Infection Society) criteria (2011). Receiver operating characteristic plots were constructed for IL-6, sIL-6, and sCRP.ResultsPJI was diagnosed in 93 patients, and aseptic revision was diagnosed in 147 patients. The AUC (area under curve) for IL-6 was 0.938 (95% CI; 0.904–0.971). The optimal IL-6 cut-off value for PJI was 12.55 ng/L. Positive and negative likelihood ratios for IL-6 were 8.24 (95% CI; 4.79–14.17) and 0.15 (95% CI; 0.09–0.26), respectively. The optimal sIL-6 and sCRP cut-off values were 20,988 ng/L and 8.80 mg/L, respectively. Positive and negative likelihood ratios for sIL-6 were 40.000 (95% CI; 5.7–280.5) and 0.170 (95% CI; 0.07–0.417), respectively. Negative likelihood ratio for sCRP was 0.083 (95% CI; 0.022–0.314).ConclusionsThe present study identified the cut-off values for serum/synovial IL-6 and synovial CRP for diagnostics of PJI at the site of THA and TKA and separately for each site. The diagnostic odds ratio for serum/synovial IL-6 and synovial CRP is very good. Simultaneous positivity of serum IL-6 either with synovial IL-6 or synovial CRP almost excludes false negative detection of PJI at the site of interest.

Excellent Diagnostic Characteristics for Ultrafast Gene Profiling of DEFA1-IL1B-LTF in Detection of Prosthetic Joint Infections.

ABSTRACTThe timely and exact diagnosis of prosthetic joint infection (PJI) is crucial for surgical decision-making. Intraoperatively, delivery of the result within an hour is required. Alpha-defensin lateral immunoassay of joint fluid (JF) is precise for the intraoperative exclusion of PJI; however, for patients with a limited amount of JF and/or in cases where the JF is bloody, this test is unhelpful. Important information is hidden in periprosthetic tissues that may much better reflect the current status of implant pathology. We therefore investigated the utility of the gene expression patterns of 12 candidate genes (TLR1, -2, -4, -6, and 10, DEFA1, LTF, IL1B, BPI, CRP, IFNG, and DEFB4A) previously associated with infection for detection of PJI in periprosthetic tissues of patients with total joint arthroplasty (TJA) (n = 76) reoperated for PJI (n = 38) or aseptic failure (n = 38), using the ultrafast quantitative reverse transcription-PCR (RT-PCR) Xxpress system (BJS Biotechnologies Ltd.). Advanced data-mining algorithms were applied for data analysis. For PJI, we detected elevated mRNA expression levels of DEFA1 (P < 0.0001), IL1B (P < 0.0001), LTF (P < 0.0001), TLR1 (P = 0.02), and BPI (P = 0.01) in comparison to those in tissues from aseptic cases. A feature selection algorithm revealed that the DEFA1-IL1B-LTF pattern was the most appropriate for detection/exclusion of PJI, achieving 94.5% sensitivity and 95.7% specificity, with likelihood ratios (LRs) for positive and negative results of 16.3 and 0.06, respectively. Taken together, the results show that DEFA1-IL1B-LTF gene expression detection by use of ultrafast qRT-PCR linked to an electronic calculator allows detection of patients with a high probability of PJI within 45 min after sampling. Further testing on a larger cohort of patients is needed.

Detection of Prosthetic Joint Infection Based on Magnetically Assisted Surface Enhanced Raman Spectroscopy.

Accurate and rapid diagnosis of prosthetic joint infection (PJI) is vital for rational and effective therapeutic management of this condition. Several diagnostic strategies have been developed for discriminating between infected and noninfected cases. However, none of them can reliably diagnose the whole spectrum of clinical presentations of PJI. Here, we report a new method for PJI detection based on magnetically assisted surface enhanced Raman spectroscopy (MA-SERS) using streptavidin-modified magnetic nanoparticles (MNP@Strep) whose surface is functionalized with suitable biotinylated antibodies and then coated with silver nanoparticles by self-assembly. The high efficiency of this approach is demonstrated by the diagnosis of infections caused by two bacterial species commonly associated with PJI, namely, Staphylococcus aureus and Streptococcus pyogenes. The method's performance was verified with model samples of bacterial lysates and with four real-matrix samples of knee joint fluid spiked with live pathogenic bacterial cells. This procedure is operationally simple, versatile, inexpensive, and quick to perform, making it a potentially attractive alternative to established diagnostic techniques based on Koch's culturing or colony counting methods.

124I]FIAU: Human dosimetry and infection imaging in patients with suspected prosthetic joint infection

IntroductionFialuridine (FIAU) is a nucleoside analog that is a substrate for bacterial thymidine kinase (TK). Once phosphorylated by TK, [124I]FIAU becomes trapped within bacteria and can be detected with positron emission tomography/computed tomography (PET/CT). [124I]FIAU PET/CT has been shown to detect bacteria in patients with musculoskeletal bacterial infections. Accurate diagnosis of prosthetic joint infections (PJIs) has proven challenging because of the lack of a well-validated reference. In the current study, we assessed biodistribution and dosimetry of [124I]FIAU, and investigated whether [124I]FIAU PET/CT can diagnose PJIs with acceptable accuracy. MethodsTo assess biodistribution and dosimetry, six subjects with suspected hip or knee PJI and six healthy subjects underwent serial PET/CT after being dosed with 74MBq (2mCi) [124I]FIAU intravenously (IV). Estimated radiation doses were calculated with the OLINDA/EXM software. To determine accuracy of [124I]FIAU, 22 subjects with suspected hip or knee PJI were scanned at 2–6 and 24–30h post IV injection of 185MBq (5mCi) [124I]FIAU. Images were interpreted by a single reader blinded to clinical information. Representative cases were reviewed by 3 additional readers. The utility of [124I]FIAU to detect PJIs was assessed based on the correlation of the patient's infection status with imaging results as determined by an independent adjudication board (IAB). ResultsThe kidney, liver, spleen, and urinary bladder received the highest radiation doses of [124I]FIAU. The effective dose was 0.16 to 0.20mSv/MBq and doses to most organs ranged from 0.11 to 0.76mGy/MBq. PET image quality obtained from PJI patients was confounded by metal artifacts from the prostheses and pronounced FIAU uptake in muscle. Consequently, a correlation with infection status and imaging results could not be established. Conclusions[124I]FIAU was well-tolerated in healthy volunteers and subjects with suspected PJI, and had acceptable dosimetry. However, the utility of [124I]FIAU for the clinical detection of PJIs is limited by poor image quality and low specificity.

Detection of Prosthetic Joint Infection by Use of PCR-Electrospray Ionization Mass Spectrometry Applied to Synovial Fluid

PCR coupled with electrospray ionization mass spectrometry applied to synovial fluid specimens had an 81% sensitivity and a 95% specificity for the diagnosis of prosthetic joint infection.

PCR-Based Diagnosis of Prosthetic Joint Infection

We performed a meta-analysis to evaluate use of PCR assays for diagnosis of prosthetic joint infection (PJI). The pooled sensitivity and specificity were 0.86 (95% confidence interval [CI], 0.77 to 0.92) and 0.91 (CI, 0.81 to 0.96), respectively. Subgroup analyses showed that use of tissue samples may improve sensitivity, and quantitative PCR and sonication of prostheses fluid may improve specificity. The results showed that PCR is reliable and accurate for detection of PJI.

Diagnosis of periprosthetic infection following total hip arthroplasty – evaluation of the diagnostic values of pre- and intraoperative parameters and the associated strategy to preoperatively select patients with a high probability of joint infection

BackgroundThe correct diagnosis of a prosthetic joint infection (PJI) is crucial for adequate surgical treatment. The detection may be a challenge since presentation and preoperative tests are not always obvious and precise. This prospective study was performed to evaluate a variety of pre- and intraoperative investigations. Furthermore a detailed evaluation of concordance of each preoperative diagnosis was performed, together with a final diagnosis to assess the accuracy of the pre-operative assumption of PJI.MethodsBetween 01/2005 and 02/2007, a prospective analysis was performed in 50 patients, who had a two stage revision because of assumed PJI. Based on clinical presentation, radiography, haematological screening, or early failure, infection was assumed and a joint aspiration was performed. Depending upon these findings, a two stage revision was performed, with intra-operative samples for culture and histological evaluation obtained. Final diagnosis of infection was based upon the interpretation of the clinical presentation and the pre- and intraoperative findings.ResultsIn 37 patients a positive diagnosis of PJI could be made definitely. The histopathology yielded the highest accuracy (0.94) in identification of PJI and identified 35 of 37 infections (sensitivity 0.94, specificity 0.94, positive-/negative predictive value 0.97/0.86). Intra-operative cultures revealed sensitivities, specificities, positive-/negative predictive values and accuracy of 0.78, 0.92, 0.96, 0.63 and 0.82. These values for blood screening tests were 0.95, 0.62, 0.88, 0.80, and 0.86 respectively for the level of C-reactive protein, and 0.14, 0.92, 0.83, 0.29 and, 0.34 respectively for the white blood-cell count. The results of aspiration were 0.57, 0.5, 0.78, 0.29, and 0.54.ConclusionThe detection of PJI is still a challenge in clinical practice. The histopathological evaluation emerges as a highly practical diagnostic tool in detection of PJI. Furthermore, we found a discrepancy between the pre-operative suspicion of PJI and the final post-operative diagnosis, resulting in a slight uncertainty in whether loosening is due to bacterial infection or not. The variation in accuracy of the single tests may influence the detection of PJI. Level of Evidence: Diagnostic Level I.