The goal of this randomized, double blind, placebo-controlled clinical trial is to learn about, the effect of metformin compared with placebo-controlled group on disease activity and interleukin-6 level in patients with knee osteoarthritis.The main question it aims to answer is:Is Metformin as add-on therapy more effective in reducing disease activity in Ibuprofen-treated patients with grade II-III knee osteoarthritis? Half of Participants will receive metformin with standard of care(ibuprofen and rabeprazole) while other half placebo and standard of care (ibuprofen and rabeprazole).