2023, Vol. 27 ›› Issue (4): 612-618

Optimal angle for prosthesis implantation in total knee arthroplasty

Xu Xiangjun1, Wang Chao2, Song Qunshan1, Li Bingyan3, Zhang Jichao4, Wang Guodong1, Dong Yuefu1   

Abstract: BACKGROUND: The motion of the knee joint is a three-dimensional motion with three translational degrees of freedom and three rotational degrees of freedom. When the prosthesis is implanted in total knee arthroplasty, the varus angle of the coronal plane, the anteroposterior angle of the sagittal plane and the rotation angle of the axial plane should be fully considered.  
OBJECTIVE: To summarize the clinical advantages and disadvantages of femoral and tibial prosthesis implantation angle in total knee arthroplasty, so as to provide reference for effective prosthesis implantation in total knee arthroplasty.
METHODS:   The first author searched the literature on prosthesis implantation in PubMed database and CNKI database by computer. The English key words were “total knee arthroplasty, total knee replacement, femoral, tibial, coronal, sagittal, axial, prosthesis, component, alignment, osteotomy”. The Chinese key words were “total knee arthroplasty, femur, tibia, prosthesis, osteotomy, coronal, sagittal, axial, alignment”. The articles that meet the search terms are preliminarily screened, and the relevant articles related to the review content and the clinical advantages and disadvantages of prosthesis implantation are retained for further detailed analysis, induction and summary.  
RESULTS AND CONCLUSION: (1) On the coronal plane of the femur, the angle between the mechanical axis of the lower limb and the anatomical axis of the femur is measured through the full-length film of the weight-bearing position of the lower limb as a reference for femoral osteotomy. The 4-6° valgus osteotomy is often taken, and the prosthesis is implanted perpendicular to the mechanical axis. (2) In the sagittal plane of the femur, to obtain good knee flexion function, the 0-3°anteversion osteotomy is often taken and the prosthesis is implanted slightly anteversion. (3) In the axial plane of the femur, although surgical transepicondylar axis is regarded as the rotation center of the distal femur, it is more convenient to refer to posterior condylar axis when using surgical instruments, and the prosthesis is rotated 2-5° outward relative to posterior condylar axis. (4) In the coronal plane of the tibia, to obtain the rectangular space and horizontal joint line in the extended position, the prosthesis should be implanted perpendicular to the mechanical axis of the tibia. (5) In the sagittal plane of the tibia, the polyethylene gasket has a certain retroversion angle, and the prosthesis is often implanted with a retroversion of 0-7°. (6) In the axial plane of the tibia, because the Akagi line is approximately parallel to the anterior and posterior axis of the tibia, the anterior and posterior axis of the prosthesis is often implanted parallel to the Akagi line.
Key words: total knee arthroplasty, prosthesis implantation, precise osteotomy, coronal plane, sagittal plane, axial plane