Abstract:

Knee osteoarthritis （KOA） has become an important factor affecting the quality of life of the elderly. Studies have shown that early KOA is mainly confined to the single compartment. For unicompartmental KOA， unicompartmental knee arthroplasty （UKA） has become an important treatment. Compared with total knee arthroplasty （TKA）， UKA has significant advantages， but the long-term survival of the prosthesis is lower. Among the factors affecting the survival rate of UKA prosthesis， the position of the prosthesis is one of the important factors， so it is crucial to choose the appropriate position of the prosthesis during the surgical procedure. In this study， by searching the keywords "unicompartmental knee arthroplasty"， "fixedbearing"， "prosthesis"， "appropriate position" in Pubmed， Medline， Clinical Key， China National Knowledge Infrastructure（CNKI）， Wanfang， and China Science and Technology Journal Databases（VIP）. Relevant literature in recent years was collected and organized. In summary， the femoral prosthesis should be placed in the coronal plane at the center of the femoral condyle， in the sagittal plane between flexion of five degrees and extension of 10°， and in the transverse plane between internal and external rotations of three degrees. The tibial prosthesis can be placed in the coronal plane in a neutral position or in a mildly inverted position， and in the sagittal plane between zero and eight degrees， but the anatomical posterior slope angle of the patient has to be taken into account. In the transverse plane， internal and external rotations of three degrees should be chosen. The difference in height between the preoperative and postoperative joint lines should be limited to less than two minimeters.The above summarization is expected to provide clinicians with a reference to improve the accuracy of prosthesis placement in unicompartmental knee arthroplasty and to improve the long-term survival of the prosthesis.

Key words: Arthroplasty, replacement, knee, Prostheses and implants