[Short-term effectiveness of Mako robot-assisted total hip arthroplasty via posterolateral approach]

To explore the short-term effectiveness of Mako robot-assisted total hip arthroplasty (THA) via posterolateral approach.

The clinical data of 64 patients (74 hips) treated with Mako robot-assisted THA via posterolateral approach (robot group) between May 2020 and March 2021 were retrospectively analyzed and compared with the clinical data of 52 patients (55 hips) treated with traditional THA via posterolateral approach (control group) in the same period. There was no significant difference in general data such as gender, age, side, body mass index, disease type, and preoperative Harris score between the two groups ( P>0.05). The operation time, intraoperative blood loss, and complications were recorded and compared between the two groups. Acetabular inclination angle, acetabular anteversion angle, and lower limbs discrepancy were measured after operation. At last follow-up, the improvement of hip pain and function was evaluated by visual analogue scale (VAS) score, Harris score, and forgetting joint score (FJS-12).

In the robot group, 3 patients (including 1 patient with acetabular fracture during operation) were converted to routine THA because the pelvic data array placed at the anterior superior iliac spine was loose, resulting in data error and unable to register the acetabulum; the other patients in the two groups completed the operation successfully. The operation time and intraoperative blood loss in the robot group were significantly higher than those in the control group ( P<0.05). All patients were followed up 1-10 months, with an average of 4.6 months. In the robot group, 1 patient with ankylosing spondylitis had acetabular prosthesis loosening at 2 days after operation, underwent surgical revision, and 10 patients had lower limb intermuscular vein thrombosis; in the control group, 1 patient had left hip dislocation and 5 patients had lower extremity intermuscular vein thrombosis; there was no complication such as sciatic nerve injury, incision exudation, and periprosthetic infection in both groups. There was no significant difference in the incidence of complications between the robot group and the control group (17.2% vs.11.5%) ( χ ²=0.732, P=0.392). At last follow-up, the acetabular anteversion angle and FJS-12 score in the robot group were was significantly greater than those in the control group, and the lower limbs discrepancy was significantly less than that in the control group ( P<0.05); there was no significant difference in acetabular inclination angle and VAS score between the two groups ( P>0.05). The Harris scores of the two groups were significantly improved when compared with those before operation ( P<0.05), but there was no significant difference in the difference of pre- and post-operative score between the two groups ( t=1.632, P=0.119).

Compared with traditional surgery, Mako robot-assisted THA can optimize the accuracy and safety of acetabular cup implantation, reduce the length difference of the lower limbs, and has a certain learning curve. Its long-term effectiveness needs further research to confirm.