[Research progress of lower extremity alignment in total knee arthroplasty]

Knee osteoarthritis has become one of the common diseases of the elderly, total knee arthroplasty （TKA） is the most effective treatment for end-stage knee osteoarthritis at present. In TKA, the effective restoration of the lower extremity alignment is one of the key factors for the success of the operation, which greatly affects the postoperative clinical effect and prosthesis survival rate of patients. Mechanical alignment is a TKA alignment method which is first proposed, recognized and widely used in TKA. In recent years, with the in-depth research on the lower limb alignment and the rapid development of computer technology, the alignment technology in TKA has realized the transformation from "unified" to "individualized", two-dimensional to three-dimensional. New alignment methods, such as adjusted mechanical alignment, anatomic alignment, kinematic alignment, inverse kinematic alignment, restricted kinematic alignment and functional alignment have been proposed to provide surgeons with more choices. However, there is no conclusion on which alignment method is the best choice. This paper summarizes the current research status, advantages and disadvantages of various alignment methods in TKA, and aims to provide some reference for the selection of alignment methods in TKA.