The accurate position and angle of the acetabular prosthesis is one of the keys to the success of THA. An inaccurate acetabulum placement may lead to adverse consequences such as high dislocation rate of hip joint, impact, and artificial joint repair [
13‐
15]. During THA operation, the anatomic hallmarks that can be used for positioning of the acetabulum prosthesis include transverse ligament of the acetabulum, location points of pelvic anatomical hallmarks such as the groove between the posterior margin of acetabulum and the sciatic tuber, and the intersection of the lower edge of eminentia iliopectinea, as well as the lateral part of the rami superior ossis pubis, the highest point of the acetabular rim, and the acetabular notch angle [
16‐
20]. However, the accuracy of the manual positioning of the acetabular prosthesis by these anatomical landmarks is low [
21]. Intraoperative computer navigation is helpful in the accurate implantation of the acetabulum prosthesis [
22]. However, this device is not widely used. We first considered the possible effect of the surgical approach on the acetabular angle in determining the position of the acetabulum prosthesis [
23,
24]. For example, if the anterior approach is adopted, the acetabular anteversion can easily become large, which should be corrected during surgery. The boundary where the acetabulum and femoral head infused was first accurately determined, and osteotomy was conducted. The acetabular height was determined based on the abovementioned osseous markers of the pelvis, as well as the upper margin of the obturator foramen and the posterior margin of ischium. Next, the center of the acetabulum was determined according to the femoral head center, which was exposed after femoral neck osteoctomy. The Kirschner wire was driven perpendicular into the surface of the osteotomy, and the center line of the acetabulum was determined by X-ray during the surgery. The anteversion and abduction angles were determined by observing the position of the patient and the angle of the Kirschner wire. Through these methods, the acetabulum can be accurately located. It was found that bony fusion mostly occurred in the weight-bearing area above the hip joint, and soft tissue septa may appear in the bottom part of the acetabulum [
25]. Therefore, when reaming the acetabulum, observation is necessary, and the reaming depths were determined by the remaining soft tissues in the bottom of the acetabulum, the acetabular fossa, and the acetabular transverse ligament.