Diagnostic value of magnetic resonance imaging for patients with periprosthetic joint infection: a systematic review

Purpose The purpose of this study was to provide a critical systematic review of the role of magnetic resonance imaging (MRI) as a noninvasive method to assess periprosthetic joint infections (PJIs). Methods The electronic databases PubMed and EMBASE were searched, since their inception up to March 27, 2022. The included studies evaluated the reproducibility and accuracy of MRI features to diagnose PJIs. The article quality assessment was conducted by the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) and Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). Results Among 1909 studies identified in the initial search, 8 studies were eligible for final systematic review. The included studies evaluated the reproducibility and accuracy of MRI features to diagnose PJIs. Seven of 8 studies showed good to excellent reliability, but only one article among them in which accuracy was evaluated had a low risk of bias. The intraclass correlation coefficient (ICC) and Cohen coefficient (κ) varied between 0.44 and 1.00. The accuracy varied between 63.9% and 94.4%. Potential MRI features, such as lamellated hyperintense synovitis, edema, fluid collection, or lymphadenopathy, might be valuable for diagnosing PJIs. Conclusion The quality of the evidence regarding the role of MRI for PJIs diagnosis was low. There is preliminary evidence that MRI has a noteworthy value of distinguishing suspected periprosthetic joint infection in patients with total knee arthroplasty or total hip arthroplasty, but the definition of specific MRI features related to PJIs diagnosis lacks consensus and standardization. Large-scale studies with robust quality were required to help make better clinical decisions in the future. Supplementary Information The online version contains supplementary material available at 10.1186/s12891-023-06926-5.


Introduction
Total joint arthroplasty (TJA) has become the most common standard treatment for severe end-stage hip or knee disease, allowing joint pain relief, improvement of physical activity, and an increase in quality of life [1][2][3][4].Although the postsurgical outcomes are usually excellent [5][6][7][8], the incidence of various complications will continue to increase over time, in large part due to the rise in the number of TJA over recent years and the increased life expectancy [9,10].Among these, periprosthetic joint infections (PJIs) is devastating because of prolonged hospitalization, repeated surgical interventions, or severe psychological and economic burden to patients [11,12].
Determining the presence of PJIs remains a challenge of modern orthopedics as there is no gold standard diagnostic tool [13,14].In the last decade, the commonly used diagnostic criteria for PJIs were released by the European Bone and Joint Infection Society (EBJIS), Musculo-Skeletal Infection Society (MSIS) or two International Consensus Meetings on PJIs in 2013 (ICM 2013) and 2018 (ICM 2018) [15][16][17].In general, the diagnostic approach in patients with suspected PJIs involves clinical findings, laboratory evaluation, radiology, biopsies with microbiological analysis, nuclear imaging, or intraoperative findings [18,19].There is no clear consensus about the choice of the most accurate imaging technique to detect suspected PJIs [20], especially in the case of a challenging diagnosis of an early or low-virulence infection.
Since the development of advanced metal artifact reducing techniques, magnetic resonance imaging (MRI) has been increasingly recognized as a noninvasive and valuable method in the evaluation of patients with septic arthritis [21] or hip and knee pain after arthroplasty [22][23][24][25].However, there are two issues with the MRI diagnostic value of PJIs: (1) To date, there is no consensus on the diagnostic value of MRI for PJIs in total hip arthroplasty (THA) or total knee arthroplasty (TKA) patients [26][27][28][29][30][31][32][33]; and (2) There are no consistent criteria for the identification or definition of specific MRI features related to PJIs diagnosis.Consequently, it is necessary to systematically evaluate the diagnostic value of MRI features for PJIs.
This systematic review aimed to analyze the main value of MRI for PJIs diagnosis and summarize various helpful MRI appearances in identifying infected prostheses for THA or TKA patients.

Materials and methods
This systematic review strictly adheres to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines [34].Ethics committee approval was not needed to conduct a systematic review of the published literature.

Search strategy
In March 27, 2022, a systematic literature search of the PubMed (Medline) and EMBASE (Elsevier) databases was conducted to identify the original studies that reported the imaging features of MRI for the diagnosis of PJIs.The detailed search terms were as follows: (Periprosthetic Infection OR Infected OR painful OR symptomatic) AND (THA OR TKA OR TJA OR TKR OR THR OR Knee Arthroplasty OR Hip Arthroplasty) AND (MRI OR MR OR MR Imaging OR magnetic resonance imaging) AND (Hip OR knee).The bibliographies of the included studies were also hand-screened to expand the search extent and to avoid missing relevant articles.Moreover, there were no search date limits in this study.

Inclusion and exclusion criteria
After inspection for duplicates, studies were included based on the following inclusion criteria: (1)

Study selection and data extraction
The eligible articles were independently selected by two reviewers according to title and abstract assessment.The final decision regarding inclusion was based on the fulltext articles.If consensus was not reached in case of disagreement, a third reviewer was included.

Methodologic quality appraisal and analysis
The included articles evaluated the reproducibility and accuracy of MRI features to diagnose PJIs.To assess the quality of these articles, the COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN) tool and Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool were used.
The QUADAS-2 tool is recommended for use in rating bias and applicability of a majority of diagnostic accuracy studies [40].The QUADAS-2 contains 4 domains: patient selection, index test, reference standard, and flow and timing.Each question can be assessed with "low risk of bias", "high risk of bias", or "unclear risk" [41].Moreover, sensitivity, specificity, PPV, NPV and accuracy were also calculated for each MRI feature.

Search results
A flowchart of study selection is shown in Fig. 1.The systematic search strategy identified 1909 articles from PubMed and EMBASE.After removing 236 duplicate articles, 1673 articles remained.Of these, 1664 were excluded after analyzing the information in the title and abstract, while the remaining 9 full-text articles were downloaded for a further assessment.One article was excluded because it included only one patient with PJIs [42].No other potentially relevant studies were extracted from the bibliographies of these articles.Finally, 8 eligible articles, which included a total of 645 patients, were summarized and analyzed in this study [26][27][28][29][30][31][32][33].

Characteristics of included studies
The detailed study characteristics are summarized in Table 1.The included studies were published in 2013

Study quality appraisal and analysis
For reproducibility assessment (Table 2), seven studies were scored adequate to very good by the COSMIN reliability box [26-30, 32, 33], and only one study was scored inadequate [31].Nevertheless, approximately 12.5% of the included articles did not analyze interrater reliability, and 50% of the included studies did not provide intrarater reliability assessment.For accuracy assessment (Figs. 2 and 3), the methodological quality of seven studies had a high risk of bias [27][28][29][30][31][32][33], and only one study had a low risk of bias [26].Because only one retrospective study scored a low risk of bias [26], the accuracy of the included articles showed more concerns regarding patient selection.Generally, the retrospective study design property will increase susceptibility to selection bias.In addition, the majority of included studies provide necessary information in regard to index test, reference standard, or flow and timing [26-29, 32, 33].

MRI findings and PJIs
As shown in Tables 2 and 3, MRI features demonstrated high diagnostic performance in evaluating suspected PJIs, but the individual MRI signs of PJIs around the prosthesis varied or were inconsistent among all included studies.The important MRI findings of PJIs are summarized as follows: Synovitis is common in patients with hip or knee prostheses, and the lamellated hyperintense synovitis (LHS) is the most suggestive MRI sign of PJIs in THA [26,28,31] or TKA [32,33] patients.Reasonable reliability results were found regarding LHS, with an interrater reliability of (K, 0.76-0.907)and interrater reliability of (K, 0.44-0.89)[26,28,32,33].The sensitivity and specificity for diagnosing PJIs by LHS on MRI varied between 26.3% and 86% for sensitivity and between 84% and 98.8% for specificity.The diagnostic accuracy of LHS ranged from 74.8 to 94.4% [26,28,32,33].
Details of other MRI signs of PJIs are shown in Tables 2  and 3.

Discussion
The present study aimed to systematically review the role of MRI in the assessment of infected joint prostheses for THA or TKA patients.The main findings suggest that MRI is capable of identifying suspected periprosthetic joint infection, but the definition of specific MRI features related to PJIs diagnosis lacks consensus and standardization.
All included articles were published in the last 8 years, with a rapid rise in published articles per year over time, especially in 2020-2021.The publication trend indicated that MRI assessment of PJIs is currently a research focus.MRI of metallic joint arthroplasty implants needs modified and advanced MRI pulse sequences to eliminate vast metal artifacts between the implant components and the surrounding soft tissues [23,24].High performance of 1.5 T MRI system is suited for achieving this function of substantial reductions in artifacts around metallic implants [23].Hence, MRI is increasingly recognized as a noninvasive and valuable tool in the assessment of patients with problematic arthroplasty [19,20,43].
When inconsistent laboratory tests or nonspecific clinical symptoms are found, distinguishing between aseptic and septic implant failure remains imperfect and challenging [13,14].The clinical manifestation of PJIs includes the chronic, acute, low-grade, and highgrade implant infections.To date, there is no consistent are inconsistent and multifarious [19].Due to the complicated anatomical structure of the hip joint, the extraction of typical MRI features on PJIs is difficult.(2) Some problems in the retrospective studies might result in serious bias risks.Most relevant articles that have been published are retrospective [26-30, 32, 33].Because the retrospective nature of the study, it might lead to high selection bias and the possibility that the diagnostic value was falsely calculated.For example, the control group in some studies did not manifest characteristics of PJIs, but a possible low-virulence infection could not be excluded in a timely manner.(3) A periprosthetic mechanical stress reaction in MRI cannot be distinguished well from PJIs; in other words, a single positive MRI feature cannot be exclusive for implant infections [44].(4) MRI is not extensively utilized to diagnose PJIs in clinical practice because of limitations such as high cost, long acquisition time, complex image postprocessing, and operator dependence.
Although MRI itself has the above inevitable limitations, the intrinsic multiparametric nature of MRI is conducive to achieving qualitative grading of bone destruction, synovitis, soft tissue edema, fluid collection, periosteal reaction, or lymphadenopathy, without Fig. 3 The methodologic quality of the included studies using QUADAS-2 shows each domain of studies with high, low, or unclear risk of bias and concerns regarding applicability Fig. 2 The methodologic quality of the included studies using QUADAS-2 shows the proportions of studies with high, low, or unclear risk of bias and concerns regarding applicability ionizing radiation [25].In this study, some MRI features, such as lamellated hyperintense synovitis, edema, fluid collection, or lymphadenopathy, were valuable diagnostic imaging findings.Diagnostic properties were found in terms of sensitivity, specificity, PPV and NPV (26.3 − 100%, 47 − 98%, 46 − 94.7% and 73.8 − 98%) with satisfactory accuracy (63.9 − 94.4%) and adequate reliability.Standardization is challenging, but a unique metric for the evaluation of PJIs as well as a standardized MRI protocol should be strenuously achieved, allowing MRI criteria of PJIs to be used in some suspected infections of patients who are difficult to diagnose.Some inherent limitations included the following: (1) Collecting large-scale populations with PJIs in clinical practice is difficult, and only 206 patients with PJIs were included in this study.(2) The included studies showed statistical homogeneity and a high risk of bias, so it is improbable to perform a meta-analysis and categorize In conclusion, there is preliminary evidence that MRI has a noteworthy value of distinguishing suspected PJIs in patients with TKA or THA, but the definition of specific MRI features related to PJIs diagnosis lacks consensus and standardization.Large-scale studies with robust quality were required to help make better clinical decisions in the future.

Fig. 1
Fig. 1 Flowchart of the literature systematic search

Table 3
Accuracy of MRI Measurements to Diagnose Periprosthetic Joint Infection : positive predictive value; NPV: negative predictive value; NA: not applicable; RNS: ratio of nodal size; RNN: ratio of node number; DNS; difference of nodal size; DNN: difference of node number *Data shown are for reader 1 or A in the original study standardized MRI features for PJIs; (3) Due to the design limitations of the included studies, the diagnostic value of MRI for different types of PJIs was not clear.(4) Most included articles were retrospective designs which might result in serious variation and bias risk.Some larger prospective studies should be conducted to evaluate standardized MRI features for PJIs diagnosis in the future. PPV