High levels of synovial fluid osteoprotegerin (OPG) and increased serum ratio of receptor activator of nuclear factor-κB ligand (RANKL) to OPG correlate with disease severity in patients with primary knee osteoarthritis

ObjectiveEvaluation of serum and synovial fluid OPG and sRANKL in 37 patients with primary knee osteoarthritis.Design and methodOPG and sRANKL were measured using ELISA.ResultsOPG, sRANKL and sRANKL/OPG were increased in osteoarthritis patients' serum. Synovial OPG was higher than serum OPG, while sRANKL/OPG was higher in the serum; both correlated with disease severity.DiscussionRANKL/OPG pathway is implicated in the pathogenesis of knee osteoarthritis being a suitable target for therapeutic intervention.