Introduction: Lower limb amputations have a high prevalence in Brazil and affect a young portion of the population, increasing the risk of falls. Despite efforts to characterize gait and balance in individuals with unilateral lower limb amputation, the role of dual-task in fall frequency and joint load in prosthetic users remains unclear. 

Objectives: To study the relationship between performance in functional tests, Dual-Task Index, fear and frequency of falls; to investigate the effect of cognitive dual-task on static balance; and to examine joint load in the knees of individuals with unilateral lower limb amputation. 

Methods: This cross-sectional study evaluated 50 individuals with unilateral lower limb amputation. Results of functional tests, center of pressure oscillation on a force platform, and three-dimensional gait assessment were collected. Joint load data in individuals with transtibial amputation were analyzed and compared with a control group without amputation. 

Results: The knee of the preserved limb experiences greater load than the knee of the amputated side, even when compared to the knee of individuals without amputation, despite the lower average gait speed in individuals with unilateral transtibial amputation. The peak adductor moment, time to reach the peak, and adductor moment rate were not significantly different between the knee of the preserved limb and the knee of the control group. 

Conclusions: The knee of the preserved limb in individuals with unilateral transtibial amputation experiences greater joint load when compared to the amputated side and the knee of individuals without amputation, which may explain the high prevalence of knee osteoarthritis in this population.