Robot-assisted Percutaneous Cannulated Screw Fixation of Femoral Neck Fractures: Preliminary Clinical Results

Objective: To assess the clinical efficacy of TiRobot-assisted percutaneous cannulated screw fixation in the treatment of femoral neck fractures. Methods: From September 2015 to July 2017, 26 patients with unilateral femoral neck fractures were treated with TiRobot-assisted percutaneous cannulated screw fixation. The femoral necks were fixed using three cannulated screws with robot assistance applying the following procedure: image acquisition, path planning, and needle and screw placement. The results of the treatment, including operation duration, frequency of fluoroscopy use, implant placement accuracy, intraoperative bleeding, total drilling, surgical complications, fracture healing time, fracture healing rate, and Harris scores at the last follow-up, were recorded and compared with 23 similar patients who underwent conventional manual positioning surgery. Results: A total of 147 cannulated screws were placed in all patients. The TiRobot group had shorter operation duration (62.6 8.7 min vs 72.4 +/- 10.3 min) and fracture healing time (5.1 +/- 2.4 months vs 5.9 +/- 2.8 months) than the conventional group (P > 0.05). The robot group had significantly less use of fluoroscopy (26.5 +/- 7.4 times vs 51.3 +/- 9.4 times), intraoperative bleeding (8.2 +/- 5.3 mL vs 36.4 +/- 12.5 mL), and total drilling (9.4 +/- 4.2 times vs 18.3 +/- 9.1 times) than the conventional group (all P < 0.05). The screw parallelism was significantly improved (24.0 +/- 0.6 points vs 21.5 +/- 1.2 points) and the neck-width coverage (72.0 +/- 6.7 mm(2)vs 53.8 +/- 10.4 mm(2)) was significantly enlarged compared to the conventional group (P < 0.05). Only three guiding needles were used to penetrate the femoral head during manual insertion in the TiRobot group, which was significantly lower than that in the conventional group (3/78, 3.8% vs 9/69, 13.0%; P < 0.05). Other complications such as wound infection, vascular or nerve injury, screw loosening, and secondary screw displacement, did not occur in the two groups. There was no significant difference between the two groups in fracture healing rate (88.4% vs 82.6%) and Harris scores at the last follow up (88.2 +/- 3.6 points vs 87.3 +/- 4.7 points; P > 0.05). Conclusion: TiRobot-assisted percutaneous cannulated screw fixation of femoral neck fractures is advantageous over conventional surgery with manual positioning due to easier manipulation, more accurate screw insertion, less invasion, and less radiation exposure, suggesting that it is a better method to stabilize femoral neck fractures.