Prospective Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Aug 18, 2021; 12(8): 565-574
Published online Aug 18, 2021. doi: 10.5312/wjo.v12.i8.565
Performance of alpha-defensin lateral flow test after synovial fluid centrifugation for diagnosis of periprosthetic knee infection
Rodrigo Calil Teles Abdo, Riccardo Gomes Gobbi, Chilan Bou Ghosson Leite, Sandra Gofinet Pasoto, Elaine Pires Leon, Ana Lucia Lei Munhoz Lima, Eloisa Bonfa, José Ricardo Pécora, Marco Kawamura Demange
Rodrigo Calil Teles Abdo, Riccardo Gomes Gobbi, Chilan Bou Ghosson Leite, Ana Lucia Lei Munhoz Lima, José Ricardo Pécora, Marco Kawamura Demange, Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Sao Paulo 05403-010, Brazil
Sandra Gofinet Pasoto, Elaine Pires Leon, Eloisa Bonfa, Division of Rheumatology, Faculdade de Medicina da Universidade de São Paulo, Sao Paulo 01246-903, Brazil
Author contributions: Abdo RCT wrote the draft of the article, collected the samples and contributed to the data analysis, intellectual concept and design of the study; Gobbi RG reviewed the article and contributed to the intellectual concept and design of the study; Leite CBG wrote the article and contributed to the data analysis; Pasoto SG performed the laboratory tests and contributed to the strategy for alpha-defensin analysis according to its dilution; Leon EP conducted the laboratory tests; Lima ALLM contributed to data analysis, design and intellectual concept of the work; Bonfa E contributed to data analysis and intellectual concept of the work; Pécora JR and Demange MK contributed to the design and intellectual.
Supported by Fundação de Amparo à Pesquisa do Estado de São Paulo.
Institutional review board statement: The study was approved by the local Institutional Review Board (2179456).
Informed consent statement: All study participants, or their legal guardian, provided written consent prior to study enrollment.
Conflict-of-interest statement: The authors declare that there are no any conflicts of interest.
Data sharing statement: There is no additional data available.
CONSORT 2010 statement: The authors have read the CONSORT 2010 Statement, and the manuscript was prepared and revised according to the CONSORT 2010 Statement.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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: Chilan Bou Ghosson Leite, MD, Attending Doctor, Research Fellow, Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Ovídio Pires de Campos St, 333, 2nd Floor, Cerqueira César, Sao Paulo 05403-010, Brazil. chilan@usp.br
Received: April 24, 2021
Peer-review started: April 24, 2021
First decision: June 7, 2021
Revised: June 14, 2021
Accepted: July 9, 2021
Article in press: July 9, 2021
Published online: August 18, 2021
Processing time: 108 Days and 22.4 Hours
ARTICLE HIGHLIGHTS
Research background

Periprosthetic joint infection (PJI) is a serious postoperative complication that leads to severe morbidity as well as substantial financial burden to the healthcare system. Currently, two synovial alpha-defensin tests [the quantitative enzyme-linked immunosorbent assay (ELISA) and the qualitative lateral flow test] are available and provide important information during PJI investigation, with the ELISA presenting slightly superior performance. However, the lateral flow test offers benefits in terms of the ease of use, time-efficiency and cost.

Research motivation

While the synovial fluid sample has to be centrifuged preceding ELISA, prior centrifugation is not routinely performed to the lateral flow test. The maintenance of synovial fluid debris could potentially interfere in the lateral flow results.

Research objectives

This study aimed to evaluate the performance of the alpha-defensin lateral flow test with prior synovial fluid centrifugation and compare the results with the synovial alpha-defensin ELISA.

Research methods

In this prospective study, 53 cases of total knee arthroplasty were evaluated: 22 classified as PJI and 31 classified as aseptic knees. Synovial fluid samples were collected and submitted to centrifugation, and the supernatant was evaluated by lateral flow test and ELISA. Sensitivity, specificity, and accuracy of each method as well as the agreement between those two methods were calculated.

Research results

Alpha-defensin ELISA and lateral flow tests showed negative results for infection in all 31 aseptic patient samples. In regard to the 22 infected cases, the lateral flow test showed positive results in 19 cases (86.4%) whereas the ELISA was positive in 21 cases (95.5%). Sensibility, specificity, and accuracy were 86.4% (95%CI: 65.1%-97.1%), 100% (95%CI: 88.8%-100%) and 93.2% (95%CI: 82.8%-98.3%), respectively, for the lateral flow test and 95.5% (95%CI: 77.2%-99.9%), 100% (95%CI: 88.8%-100%) and 98.1% (95%CI: 89.9%-100%) for ELISA. Agreement of 96.2% between these two methods were found, without statistical difference between them (P = 0.48).

Research conclusions

Alpha-defensin lateral flow test with prior synovial fluid centrifugation showed high sensitivity, specificity, and accuracy, achieving comparable results to ELISA. Given the lower complexity of the lateral flow test, a prior centrifugation might be a valuable strategy to enhance its performance.

Research perspectives

Prior synovial fluid centrifugation may be a novel and interesting strategy to improve the lateral flow performance during the PJI diagnosis. Further investigation is required to clarify its actual benefit.