Synovial Tissue as a Biomarker in the Early Management of Osteoarthritis

Osteoarthritis is a common disease whose prevalence continues to increase. To date, there is no medical treatment that has proven effective, and only symptomatic treatments exist, mainly to reduce pain. Arthroplasty, a costly and invasive surgical procedure, is often unavoidable in advanced stages of the disease. More than just a degenerative disease of the cartilage, osteoarthritis is now recognised as a heterogeneous disease causing multi-tissue damage of varying intensity. Synovitis plays a particularly important role in the onset and progression of osteoarthritis and has been closely correlated with radiographic severity, pain and loss of joint function. The investigators have identified several synovial histological pathotypes based on the type of synovial cell infiltrate and its distribution in samples from advanced osteoarthritis (surgical waste from prosthesis implantation). The investiogators' studies show that the presence of these pathotypes appears to be related to the clinical phenotype of patients. Analysis of synovial tissue at earlier stages of the disease is now essential to advance the understanding of the role of synovitis in osteoarthritis and its link to the clinical phenotype of patients. The objective of this protocol is to describe the different synovial histological pathotypes present in the early stages of osteoarthritis; To this end, the investigators will establish a cohort of osteoarthritis patients with a collection of synovial tissue samples obtained by ultrasound-guided needle biopsy in an outpatient setting, a well-tolerated procedure with simple follow-up, as well as blood sampling.