Objective:To explore the radiology and short-term clinical outcomes of MAKO robotic-assisted total hip arthroplasty (THA).Methods:The present study retrospectively reviewed the medical records of 23 patients (32 hips) who diagnosed as osteonecrosis of the femoral head and underwent MAKO THA from August 1st to December 31st, 2018 as MAKO THA group. A total of 23 patients (32 hips) with the same diagnosis underwent manual THA at the same time as conventional THA group. There was no statistical difference between the two groups in terms of gender, affected side, age, height, weight, Body Mass Index (BMI), stage of the Association Research Circulation Osseous (ARCO), preoperative Harris hip score, WOMAC Osteoarthritis Index and limb length discrepancy. The patients in both groups were operated by the same doctors. The MAKO THA group underwent the acetabular preparation and the acetabular shell impaction with the assistance of the robotic arm. The leg length and offset were adjusted under the feedback of the MAKO system. Other intraoperative procedures and postoperative interventions of MAKO THA group were similar as conventional THA group. The operation duration, incidence of complications, the radiograph parameters (version, leg length discrepancy and offset), consistency of acetabular prosthesis position in MAKO operation plan, position in postoperative X-ray, the consistency of acetabular prosthesis inclination, version in MAKO operation plan, angles in postoperative CT and functional scores (Harris hip score, WOMAC Osteoarthritis Index and forgotten joint score) at 6 months and 12 months after operation were compared between the two groups.Results:The operation duration of the MAKO THA group was longer than that of the conventional THA group (101.2±19.9 min, 65.5±5.6 min, t=7.659, P<0.001). In terms of radiograph parameters, the different of version (22.63°±5.58°, 15.98°±7.13°, t=4.156, P<0.001) and limb length discrepancy (0.35±0.30 cm, 0.87±0.43 cm, t=4.775, P<0.001) and offset (0.27±0.19 cm, 0.49±0.16 cm, t=4.155, P<0.001) between the two groups were statistically significant. The MAKO operative plan and postoperative radiographs were measured. The difference of inclination/version were 1.18°±2.52°/2.06°±2.79° ( r=0.846, P<0.001; r=0.810, P<0.001), respectively. The horizontal/vertical directions of the joint rotation center were 2.25±1.08 mm and 2.20±1.28 mm ( r=0.975, P<0.001; r=0.974, P<0.001), respectively. In terms of functional results at 6 months and 12 months after operation, Harris hip score in MAKO THA group and in conventional THA group was 90.2±5.40/89.9±5.23 ( t=0.188, P=0.851) and 93.9±2.31/94.0±2.61 ( t=0.254, P=0.801), respectively. The WOMAC index was 27.3±10.36/29.1±12.03 ( t=0.623, P=0.535) and 16.4±8.39/15.2±8.35 ( t=0.597, P=0.552). The forgotten joint score was 76.3±6.11/73.7±6.84 ( t=1.560, P=0.124) and 81.7±4.52/80.7±5.11 ( t=0.816, P=0.418), respectively. Transient bleeding in the anterior superior iliac spine pin holes were reported in 4 hips after discharge in MAKO THA group, which were healed after dressing change. No other intraoperative or postoperative complication was reported. Conclusion:Robotic-assisted THA were more accurate and stable than conventional THA. The version of robot-assisted THA was closer to the target of 20° with similar discrepancy in leg length and hip offset. The short-term functional outcomes were similar in the two groups. However, the operation duration of robot-assisted THA was prolonged.