Soluble Mediators in Posttraumatic Wrist and Primary Knee Osteoarthritis

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Background:  New discoveries about the pathophysiology changed the concept that all forms of osteoarthritis are alike; this lead to the delineation of different phenotypes such as age, trauma or obese related forms. We aim to compare soluble mediator profiles in primary knee and posttraumatic wrist osteoarthritis. Based on the general faster progression rate of wrist osteoarthritis, we hypothesize a more inflammatory profile. Methods: We collected synovial fluid from 20 primary osteoarthritic knee and 20 posttraumatic osteoarthritic wrist joints. 17 mediators were measured by multiplex enzyme-linked immunosorbent assay: chemokine ligand 5, interferon-γ, leukemia inhibitory factor, oncostatin-M, osteoprotegerin, tumor necrosis factor-α, vascular endothelial growth factor, interleukin (IL)-1α, IL-1β, IL-1 receptor antagonist, IL-4, IL-6, IL-7, IL-8, IL-10, IL-13 and IL-17. Results:  Ten mediators were higher in posttraumatic osteoarthritic synovial fluid: tumor necrosis factor-α (TNFα), IL-1α, IL-1RA, IL-6, IL-10, IL-17, oncostatin-M, interferon-γ, chemokine ligand 5 and leukemia inhibitory factor(P<0.001). IL-1ß, IL-4, IL-7 were not detected, TNFα was not detected in knee osteoarthritic synovial fluid. IL-8, IL-13, osteoprotegerin and vascular endothelial growth factor levels did not differ between the synovial fluid types.  Conclusions:  In general wrist osteoarthritis seems characterized by a stronger inflammatory response than primary knee osteoarthritis. More pronounced inflammatory mediators might offer a paradigm for the faster progression of posttraumatic osteoarthritis. Increase of specific mediators could form a possible target for future mediator modulating therapy in wrist osteoarthritis.