ANALYSIS OF SUSPECTED IMPLANT RELATED COMPLICATIONS WITH RAMAN SPECTROSCOPY REVEALS POLYMER AND TITANIUM DIOXIDE MICROPARTICLES IN SYNOVIAL FLUID

Background: Due to mechanic stress, wear particles can be generated at the metal-to-metal interface of orthopedic implants [1]. These particles include polyethylene microplastics and titanium dioxide and can cause oxidative stress and cause inflammation through NLRP-3 dependent processes, comparable with monosodium urate crystals in gout [2]. Recognition and characterization of these particles can therefore be of clinical value in the treatment of implant related complications. Objectives: In this study we evaluate the microparticle content of synovial fluid from patients with suspected implant related complications using an integrated Raman spectroscope with an ordinary polarized light microscope. Methods: We retrieved 10 synovial fluid samples from patients with problematic prosthetic implants. In this study, only samples were chosen from patients who had a clinical suspicion of complications of their prosthetic joint (i.e., a painful, warm and/or swollen prosthetic joint). We analyzed the presence or absence and the nature of microparticles in the samples with iRPolM. Results: Table 1 shows the results of Raman spectroscopic analyses of the 10 included samples. Titanium dioxide particles were present in 90%, microplastics were present in 80% of the samples. Patients 1 till 7 were positive for bacteria after culture, indicating a microbial infection. All patients were positive for pro-inflammatory particles in their synovial fluid and there was no difference between patients with and without signs of bacterial infection. Conclusion: Raman spectroscopy can be of additional value to physicians in cases with problematic implants and swollen joints. Analysis demonstrates a ubiquitous presence of titanium dioxide and microplastics in the periprosthetic synovium. As these microparticles have been proven to be pro-inflammatory through NLRP-3 dependent processes, these patients might benefit from inflammasome-inhibitory therapies. Therefore, Raman spectroscopy can aid in the guidance on therapeutic options for non-microbial implant related complications. REFERENCES: [1] Yao, J.J., E.A. Lewallen, W.H. Trousdale, W. Xu, R. Thaler, C.G. Salib, et al., Local Cellular Responses to Titanium Dioxide from Orthopedic Implants. BioResearch open access, 2017. 6 (1): p. 94-103. [2] Ruiz, P.A., B. Morón, H.M. Becker, S. Lang, K. Atrott, M.R. Spalinger, et al., Titanium dioxide nanoparticles exacerbate DSS-induced colitis: role of the NLRP3 inflammasome. Gut, 2017. 66(7): p. 1216-1224. Acknowledgements: Jan Maarten van Dijk, Marjan Wouthuyzen-Bakker. Disclosure of Interests: Tom Niessink: None declared, Jorrit Schoenmakers: None declared, Matthijs Janssen Crystalytics B.V., Cees Otto Hybriscan Technologies B.V., Tim Jansen Crystalytics B.V. DOI: 10.1136/annrheumdis-2024-eular.2165 Keywords: Diagnostic test, Biomarkers Citation: , volume 83, supplement 1, year 2024, page 1282Session: Crystal related disorders (Publication Only)

Diagnostic test, Biomarkers