IDENTIFICATION OF BIOMARKERS ASSOCIATED WITH THE SEVERITY AND RADIO-CLINICAL PROGRESSION OF KNEE OSTEOARTHRITIS

Knee osteoarthritis (OA) is an heterogeneous disease, both symptomatically and structurally, with very different evolving profiles. Although several serum, urinary or synovial biomarkers have been developed in knee OA, their interest as potential predictive factors of clinical and structural progression remains poorly known. Similarly, to date, no biological predictive markers of response to OA treatments have been validated, particularly for intra-articular treatments \[corticosteroids (CTC), hyaluronic acid (HA), platelet-rich plasma (PRP)\]. Finally, although cohorts of OA patients have already been established in the past, none of them has made it possible to establish a biobank of serum and synovial fluid obtained from the same patient at inclusion but also during the follow-up of the OA disease, up to the joint replacement. The investigators hypothesize that some biomarkers in serum, PRP and synovial fluid in knee OA: * are be correlated with the clinical symptoms and radiological lesions, thus allowing to define distinct clusters of patients whose clinical and radiological evolving profile could be different * are correlated with the clinical evolution (pain and functional limitation) * can predict the radiographic progression but also in the long term the necessity of joint replacement * could constitute predictive factors of response to intra-articular treatments (CTC, HA and PRP). To validate theses hypothesis, investigators will conduct a longitudinal cohort study with long term follow-up until joint replacement in patients with knee OA. In parallel to this longitudinal study, a cross-sectional ancillary study will be conducted to compare the levels of different serum and synovial biomarkers between subjects with knee OA and subjects with chronic inflammatory rheumatism (rheumatoid arthritis, spondylarthritis) A/ Main objectives: \- Longitudinal study To study the correlations between changes in clinical symptoms (pain, function, quality of life, eff