[Effect of posture on total hip arthroplasty through direct anterior approach]

To investigate the effect of different postures on direct anterior approach(DAA) total hip arthroplasty.

Total of 94 patients who underwent DAA total hip arthroplasty from July 2016 to June 2020 were retrospectively analyzed. They were divided into two groups according to different positions during the operation, including 45 cases in lateral position and 49 cases in supine position (with the aid of stent). The general data such as gender, affected limb, body mass index(BMI), incision length, operation time, intraoperative bleeding volume, drainage volume 24 hours after operation, hemoglobin difference before and after operation, first landing time after operation, postoperative hospitalization time, postoperative complications, visual analogue scale(VAS) at 1 day, 1, 2 weeks, 1, 3 and 6 months after operation, Harris score at 1, 2 weeks, 1, 3 and 6 months after operation were observed and compared between the two groups.

Patients in both groups were followed up for 6 to 12 months with an average of (8.31±2.22) months. There was no significant difference between two groups in gender, affected limb, age, height, weight, body mass index(BMI), preoperative VAS score and preoperative Harris score(P>0.05). The incision length, operation time, intraoperative bleeding volume, 24-hour drainage volume, hemoglobin difference before and after operation, first time to the ground and postoperative hospitalization time of patients in supine position (assisted by stent) group were all better than those in lateral position group(P<0.05);There was no significant difference in the number of blood transfusions during and after operation(P=0.550). There was no significant difference in anteversion angle and abduction angle in the supine position(with the aid of stent) group during and after operation (P=0.825, P=0.066);There was significant difference in anteversion angle and abduction angle in the lateral position group during and after operation(P<0.05). VAS of patients in supine position (assisted by stent) group were lower than those in lateral position group at 1 day, 1, 2 weeks and 1 month after operation(P<0.05), and there was no statistical difference between two groups at 3 and 6 months after operation(P>0.05). Harris scores of patients in supine position(assisted by stent) group were higher than those in lateral position group at 1 week, 1 month and 3 months after operation(P<0.05), and there was no significant difference between two groups at 6 months after operation(P>0.05).

Compared with the lateral position, the supine position DAA total hip arthroplasty has the advantages of small incision, short operation time, less bleeding, early landing time, short hospitalization time, and small intraoperative acetabular cup position judgment error. It has the advantage of fast postoperative recovery, but the recovery of hip joint function is the same after 6 months.