AB0671 NO EVIDENCE OF SARS-COV-2 IN THE KNEE JOINT: A CADAVER STUDY
Authors: M. Grassi, V. Giorgi, M. Nebuloni, P. Zerbi, M. R. Gismondo, F. Salaffi, P. Sarzi-Puttini, S. G. Rimoldi, A. Manzotti
Journal: Annals of the Rheumatic Diseases (2021)

Background: Despite the considerable research efforts being made to learn more about COVID-19, little is known about the presence of SARS-CoV-2 genetic material in biological fluids other than respiratory droplets, blood, and feces 1,2 . In particular, little is known about the presence of SARS-CoV-2 in the joints either post mortem 3 or in vivo 4 . To the best of our knowledge, only Lopéz-Gonzalez et al. 5 have published a description of acute arthritides occurring during hospitalisation due to COVID-19, and they did not find any SARS-CoV-2 genetic material in the patients’ synovial fluid samples. Objectives: The aim of this post mortem study was to assess the presence of SARS-CoV-2 RNA in the knee synovial fluid, synovial tissue, and bone tissue of COVID-19 patients in order to discover whether the joint is a possible route of transmission during orthopaedic surgical procedures, and clarify the possible role of SARS-CoV-2 as a directly arthritogenic virus. Methods: Post mortem synovial fluid, synovial tissue and bone tissue samples were collected from the knees of five patients who died of COVID-19 in our hospital between September and October 2020, and analysed for the presence of SARS-CoV-2 using a commercial real-time polymerase chain reaction (RT-PCR) panel. Quantitative RT-PCR was used to test post mortem nasopharyngeal swabs of all of the patients. Results: No SARS-CoV-2 RNA was detected in any of the knee samples, despite the positivity of the throat swab. Conclusion: Our findings indicate that SARS-CoV-2 was not detected in knee synovial fluid, synovial membrane or bone. Therefore, our results suggest that all healthcare professionals performing surgical procedures on the joints of COVID-19 patients are exposed to a risk of contagion due to exposure to respiratory droplets, blood and body fluids, but not to direct exposure to joint- or bone-related tissues. Furthermore, given that some case reports of arthritis in COVID-19 patients 5-8 show that it is possible that COVID-19 patients display viral-mediated arthralgias and arthritis, the absence of the virus in the knee highlighted by our study suggests that it is unlikely that SARS-CoV-2 has a direct inflammatory action on the joint, but it could induce an inflammation-related reaction, manifesting as a reactive arthritis 9 . References: [1]Cheng ZJ, Shan J. 2019 Novel coronavirus: where we are and what we know. Infection . 2020;(0123456789):1-9. doi:10.1007/s15010-020-01401-y [2]Chen Y, Chen L, Deng Q, et al. The Presence of SARS-CoV-2 RNA in Feces of COVID-19 Patients. J Med Virol . April 2020. doi:10.1002/jmv.25825 [3]Maiese A, Manetti AC, La Russa R, et al. Autopsy findings in COVID-19-related deaths: a literature review. Forensic Sci Med Pathol . 2020. doi:10.1007/s12024-020-00310-8 [4]Baldanti F, Novazzi F, Cassaniti I, Piralla A, Di A, Bruno R. Detection of the SARS-CoV-2 in different biologic specimens from positive patients with COVID-19, in Northern Italy. Authorea . 2020. doi:10.22541/au.159724509.93056098 [5]López-González M-C, Peral-Garrido ML, Calabuig I, et al. Case series of acute arthritis during COVID-19 admission. Ann Rheum Dis . 2020;0(0):annrheumdis-2020-217914. doi:10.1136/annrheumdis-2020-217914 [6]Parisi S, Borrelli R, Bianchi S, Fusaro E. Viral arthritis and COVID-19. Lancet Rheumatol . 2020;2(11):e655-e657. doi:10.1016/S2665-9913(20)30348-9 [7]Alivernini S, Cingolani A, Gessi M, et al. Comparative analysis of synovial inflammation after SARS-CoV-2 infection. Ann Rheum Dis . 2020;0(0):2-3. doi:10.1136/annrheumdis-2020-218315 [8]Talarico R, Stagnaro C, Ferro F, Carli L, Mosca M. Symmetric peripheral polyarthritis developed during SARS-CoV-2 infection. Lancet Rheumatol . 2020;2(9):e518-e519. doi:10.1016/S2665-9913(20)30216-2 [9]Di Carlo M, Tardella M, Salaffi F. Can SARS-CoV-2 induce reactive arthritis? Clin Exp Rheumatol . 2020;In press. Acknowledgements: We would like to thank the clinical staff of the Pathology Unit for their collaboration in performing the autopsies. Disclosure of Interests: None declared