Knee osteoarthritis (OA) is one of the most prevalent musculoskeletal complaints worldwide, affecting 30-40% of the population by the age of 65 yr.Individuals with knee OA suffer progressive loss of function.Balance is an integral component of these and many other activities of daily living. Individuals with knee OA display impairment in postural control, mostly under dynamic testing condition. Total knee replacement (TKR) has an established place in the treatment of knee osteoarthritis and is considered to be an effective intervention.It remains unknown whether TKR impact significantly at balance state of the patients with OA and whether improving in functional abilities after TKR correlates with balance control ability in this population.The purpose of this study is to determine whether TKR have any effects on relatively new postural control measures using force platform system - Balance master, in correlation with functional balance assessment.