Retrospective Cohort Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Jan 18, 2020; 11(1): 36-46
Published online Jan 18, 2020. doi: 10.5312/wjo.v11.i1.36
Good accuracy of the alpha-defensin lateral flow test for hip periprosthetic joint infection: A pilot study in a retrospective cohort of 52 patients
Jesse WP Kuiper, Pieter Pander, Stan J Vos
Jesse WP Kuiper, Stan J Vos, Department of Orthopedic Surgery, Noordwest Ziekenhuisgroep, Alkmaar 1815 JD, Netherlands
Pieter Pander, Centre for Orthopedic Research Alkmaar, Noordwest Ziekenhuisgroep, Alkmaar 1815 JD, Netherlands
Author contributions: Kuiper JWP, Pander P, Vos SJ designed research; Kuiper JWP, Pander P, Vos SJ performed research; Kuiper JWP, Pander P analyzed data; Kuiper JWP, Pander P, Vos SJ wrote the paper.
Institutional review board statement: This study was reviewed and approved by the Ethics Committee of the Noordwest Ziekenhuisgroep.
Informed consent statement: Patients were not required to give informed consent to the study because the analysis used anonymous clinical data that were obtained after each patient agreed to treatment by written consent.
Conflict-of-interest statement: All authors declare no conflicts of interest related to this article.
Data sharing statement: No additional data are available.
STROBE statement: The manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Jesse WP Kuiper, MD, MSc, Department of Orthopedic Surgery, Noordwest Ziekenhuisgroep, Wilhelminalaan 12, Alkmaar 1815 JD, Netherlands. jwp.kuiper@gmail.com
Received: March 25, 2019
Peer-review started: March 26, 2019
First decision: June 11, 2019
Revised: October 18, 2019
Accepted: November 7, 2019
Article in press: November 7, 2019
Published online: January 18, 2020
Abstract
BACKGROUND

The alpha-defensin lateral flow (ADLF) test is a new diagnostic tool for periprosthetic joint infection (PJI). Test accuracy for combined cohorts of hip and knee PJI has been reported to be good.

AIM

To assess the accuracy of the ADLF test for hip PJI, and to compare three different diagnostic criteria for PJI.

METHODS

A cohort of 52 patients was identified, with a painful or poorly functioning total hip- or hemi-arthroplasty, that underwent aspiration and a subsequent ADLF test. PJI was diagnosed with Musculoskeletal Infection Society (MSIS) criteria, and sensitivity, specificity, overall accuracy, positive predictive value and negative predictive value were calculated. Furthermore, test specifics were compared with the European Bone and Joint Infection Society (EBJIS) and 2018 International Consensus Meeting (ICM) criteria for PJI.

RESULTS

Using MSIS criteria, sensitivity was 100% (CI: 54%-100%) and specificity was 89% (CI: 76%-96%). Six true positives and 5 false positives were found, including one case of metallosis. Using EBJIS criteria, more PJIs were found (11 vs 6), sensitivity was lower (71%, CI: 42%-92%) and specificity was higher (97%, CI: 86%-100%), with 4 false negatives and one false positive result. Using 2018 ICM criteria, sensitivity was 91% (62%-100%) and specificity 100% (91%-100%). The results in this cohort are comparable to previous studies.

CONCLUSION

Overall test accuracy of the ADLF test was good in this cohort, with a sensitivity of 100% and specificity of 89%. Using different PJI definition criteria, sensitivity and specificity changed slightly but overall accuracy remained around 90%. Using the ADLF test in metallosis cases can result in false positive results and should be performed with caution.

Keywords: Periprosthetic, Arthroplasty, Replacement, Hip, Infection, Periprosthetic joint infection, Alpha-defensin, Synovasure

Core tip: The alpha-defensin lateral flow (ADLF) test is a new diagnostic tool for periprosthetic joint infection (PJI). We evaluated a cohort of 52 patients that underwent aspiration of hip arthroplasty to assess test accuracy. Using Musculoskeletal Infection Society criteria, sensitivity was 100% (CI: 54%-100%) and specificity was 89% (CI: 76%-96%). Using European Bone and Joint Infection Society criteria, sensitivity was lower (71%, CI: 42%-92%) and specificity was higher (97%, CI: 86%-100%), Using 2018 International Consensus Meeting criteria, sensitivity was 91% (62%-100%) and specificity 100% (91%-100%). The results in this cohort are comparable to previous studies.