Abstract : Osteoarthritis (OA) is a shared progressive disorder in old-aged adults that is marked by joint pains and dysfunctions. Hyaluronic acid (HA) is an integral constituent of synovial fluids that play as joints lubricants throughout shear-stress and shocks absorption Intraarticular injecting by exogenous HA is proposed to substitute this OA-persuaded deficit and for production stimulation of endogenous HA, which can alleviate signs of knee OA by means of various path-ways. Determine the impact of intra-articular HA injections on knee Osteoarthritis cases. A clinical trial to assess the impact of intraarticular HA on gait functions and clinical outcomes detected in radiographic imaging moderate-severe knee OA cases. A sample of 100 patients from 40 to 80-yrs old, provided knowledgeable agreement at the pretreatment visits 1-wk previous to the 1st injection, and all contributors have detected knee OA built on the criteria set forth via the American College of Rheumatology. A highly significant change was found among different periods regarding WOMAC score. We concluded that the findings of this work showed that a regime of intraarticular injections of hyaluronic acid has a significantly high influence on functional outcomes and a decrease in osteoarthritic knee pains for at least six months.