Synovial fluid calprotectin performs better than synovial fluid polymerase chain reaction and interleukin-6 in the diagnosis of periprosthetic joint infection

Abstract

Aims The preoperative diagnosis of periprosthetic joint infection (PJI) remains a challenge due to a lack of biomarkers that are both sensitive and specific. We investigated the performance characteristics of polymerase chain reaction (PCR), interleukin-6 (IL6), and calprotectin of synovial fluid in the diagnosis of PJI. Methods We performed systematic search of PubMed, Embase, The Cochrane Library, Web of Science, and Science Direct from the date of inception of each database through to 31 May 2021. Studies which described the diagnostic accuracy of synovial fluid PCR, IL6, and calprotectin using the Musculoskeletal Infection Society criteria as the reference standard were identified. Results Overall, 31 studies were identified: 20 described PCR, six described IL6, and five calprotectin. The sensitivity and specificity were 0.78 (95% confidence interval (CI) 0.67 to 0.86) and 0.97 (95% CI 0.94 to 0.99), respectively, for synovial PCR;, 0.86 (95% CI 0.74 to 0.92), and 0.94 (95% CI 0.90 to 0.96), respectively, for synovial IL6; and 0.94 (95% CI 0.82 to 0.98) and 0.93 (95% CI 0.85 to 0.97), respectively, for synovial calprotectin. Likelihood ratio scattergram analyses recommended clinical utility of synovial fluid PCR and IL6 as a confirmatory test only. Synovial calprotectin had utility in the exclusion and confirmation of PJI. Conclusion Synovial fluid PCR and IL6 had low sensitivity and high specificity in the diagnosis of PJI, and is recommended to be used as confirmatory test. In contrast, synovial fluid calprotectin had both high sensitivity and specificity with utility in both the exclusion and confirmation of PJI. We recommend use of synovial fluid calprotectin studies in the preoperative workup of PJI. Cite this article: Bone Joint J 2022;104-B(3):311–320.

Diagnosis of periprosthetic joint infections in patients who have rheumatoid arthritis

“…This investigation had several limitations: 1) it was a single-centre retrospective study with a limited sample size and selection bias, and the conclusions need to be further verified by multicentre and large samples; 2) we observed that patients in the RA group were more often female (although this constitutes a potentially sex-confounding bias, the prevalence of RA in women is known to be higher in general, not only in our study population); 3) not all patients performed the synovial fluid tests, resulting in a small sample size of synovial fluid in our study; 4) patients who took antibiotics selfprophylactically before admission were not excluded, which may have lowered the predictive power of the detection indexes; 5) since it was a retrospective study, the bloody synovial fluid samples in this study were not calculated using the adjusted synovial WBC formula; and 6) the observation index is limited, so it is necessary to further explore the value of other markers, such as interleukin 6 (IL-6), synovial fluid alpha-defensin, and synovial fluid calprotectin, [44][45][46] for diagnosing RA-PJI in the future.…”

Diagnosis of Periprosthetic Joint Infection: The Utility of Biomarkers in 2023

“…While further research on calprotectin is necessary, according to recent diagnostic meta-analyses [ 117 , 118 ] synovial calprotectin has the potential to be a promising biomarker for diagnosing PJI due to its benefits, including its high diagnostic accuracy and convenience. However, it is important to note that current data are insufficient in order to be able to consider synovial calprotectin as a suitable stand-alone diagnostic marker for PJI.…”

Role of Biomarkers in Periprosthetic Joint Infections

“…Additionally, the synovial IL-6 level does not provide any additional benefit in the diagnosis of PJI [ 59 ]. Again, in a meta-analysis published in 2022 supporting these findings, it was stated that the synovial fluid IL-6 level may be more useful as a confirmatory biomarker rather than as a diagnostic biomarker [ 60 ].…”