Knee osteoarthritis (OA) is a major cause of disability and a risk factor for falls in older people. The purpose of this study was to assess the falls risk of people with knee OA before surgery and at 4 months following surgery and to compare this to a control group.Thirty-five patients with knee OA prior to undergoing knee replacement surgery and 27 asymptomatic age-matched controls participated in the study. The surgical group were tested prior to their surgery and at 4 months post-surgery. The short form of the Physiological Profile Assessment was used to assess falls risk and included tests of vision, lower limb proprioception, knee extension strength, reaction time and postural sway. Physical activity, quality of life, fear of falls and disability before and after surgery were also documented.At least one fall in the previous 12 months was reported for 48% of the surgical group compared with 30% of the control group. Following the surgery, there was a reduction in fear of falling and pain, and improvements in function for the surgical group. However, compared to the control group, the surgical group exhibited a greater fear of falling and reduced lower limb proprioception and knee extension strength both pre- and post-surgery.People who undergo knee replacement surgery may be at increased risk of falls both prior to and 4 months following their surgery, primarily due to deficits in knee extension strength and lower limb proprioception. Therefore, interventions to reduce the risk of falls should be implemented early after the surgery.