Total knee arthroplasty (TKA) is the most common surgery for treating late-stage knee osteoarthritis. Previous studies have shown that after unilateral TKA, the load-carrying on lower limbs is asymmetrical and the contralateral knee have to bear even greater loads. Therefore, the osteoarthritis side is susceptible to become even worse and under the risk of subsequent replacement. In this review, factors affecting asymmetrical loading on lower limbs, including changes in alignment, pain, muscle weakness, loss of proprioception, and psychological factors are reviewed. The overall effects of these affecting factors on human body,