We conducted a prospective cohort study of 286 patients with severe hip osteoarthritis who underwent THA and examined fall history during the first year postoperatively. Baseline characteristics including age, body mass index, number of prescribed medications, comorbidities, and history of falling in the past year were evaluated as covariates and determined using a self-administered questionnaire and interview preoperatively. We assessed functional outcomes, including passive range of motion of the hip joint (flexion, extension, abduction, and adduction), muscle strength (hip abduction and knee extension), gait velocity, and gait abnormality, at 3 weeks postoperatively. Cox proportional hazard regression models were used to analyze the relationship between the presence of gait abnormality and falls.