Abstract: BACKGROUND: Intraoperative blood loss in hip hemiarthroplasty is reduced with the supercapsular percutaneously assisted total hip approach compared with the posterolateral approach, but the difference in hidden blood loss between the two approaches and the effect of tranexamic acid on it has not been fully investigated.
OBJECTIVE: To investigate whether the supercapsular percutaneously assisted total hip approach reduces perioperative hidden blood loss in hip hemiarthroplasty for unstable femoral neck fractures in advanced age compared with the posterolateral approach and to analyze the effect of combined local and intravenous tranexamic acid on it. 
METHODS: This study retrospectively analyzed a total of 200 elderly unstable femoral neck fracture patients who underwent hip hemiarthroplasty in the Department of Orthopedics, First Affiliated Hospital, Soochow University from January 1, 2020 to December 31, 2024. They were divided them into four groups (n=50 per group) according to the surgical approach and whether tranexamic acid was used in the perioperative period: (1) posterolateral approach group; (2) posterolateral approach + tranexamic acid group (combined local and intravenous administration of tranexamic acid); (3) supercapsular percutaneously assisted total hip approach group; and (4) supercapsular percutaneously assisted total hip approach + tranexamic acid group (combined local and intravenous administration of tranexamic acid). General data such as age, gender, height, weight, operation side, and basic preoperative data such as preoperative hemoglobin, hematocrit, prothrombin time, activated partial thromboplastin time and fibrinogen were collected from the patients. The hemoglobin and hematocrit were tested on the third postoperative day, and the total blood loss and hidden blood loss were calculated in each group.
RESULTS AND CONCLUSION: (1) There was no statistically significant difference between the preoperative general data of the four groups. (2) Total blood loss and hidden blood loss on postoperative day 3 were reduced in the supercapsular percutaneously assisted total hip group compared with the posterolateral approach group, with significant differences (P < 0.05). (3) The posterolateral approach combined with tranexamic acid group had significantly less total blood loss and hidden blood loss than the posterolateral approach group without tranexamic acid, with significant differences (P < 0.05). (4) The supercapsular percutaneously assisted total hip approach combined with tranexamic acid group had significantly less total blood loss and hidden blood loss than the supercapsular percutaneously assisted total hip group without tranexamic acid, with significant differences (P < 0.05). (5) The incidence of lower extremity venous thrombosis was low in all study patients and there was no statistical difference among the groups. (6) It is concluded that hip hemiarthroplasty using supercapsular percutaneously assisted total hip approach in elderly patients with unstable femoral neck fractures reduces perioperative total and hidden blood loss compared with the posterolateral approach. The combination of local and intravenous tranexamic acid reduced perioperative blood loss in both the conventional and supercapsular percutaneously assisted total hip approaches to hip hemiarthroplasty without increasing the risk of thrombosis. 

Key words: ">supercapsular percutaneously assisted total hip approach, tranexamic acid, hip hemiarthroplasty, femoral neck fracture, hidden blood loss