RESEARCH ARTICLE Unipolar versus bipolar he

Full list of author information is available at the end of the articleIntroduction Femoral neck fracture is a common fracture in senior pa-tients, which can decrease mobility and increase mortality [1]. There are many options for these fractures including internal fixation, hemiarthroplasty, and total hip arthro-plasty [2]. Among these procedures, hemiarthroplasty has become the most preferred treatment option for surgeons according to the surveys [1-3]. There are two types of options, including unipolar hemiarthroplasty (UH) and bipolar hemiarthroplasty (BH), when using a hemiarthro-plasty. In comparison to UH, BH has an additional inner bearing between the stem and the endoprosthetic head component. In theory, this design would decrease acetab-ular erosion, decrease protrusion, and decrease disloca-tion, as well as maintain joint stability and improve hip function [4,5]. However, whether UH or BH is preferable for the patient population remains uncertain [6-13]. Although several randomized controlled trials (RCTs) on this topic have been published, these studies showed in-conclusive and controversial results [14-23]. The previous systematic reviews demonstrated that further well-designed * Correspondence