Objective:To compare the early therapeutic effects of internal fixation with percutaneous minimally invasive hollow nail assisted by electromagnetic navigation robot and guided by C-arm in the treatment of Tile type C pelvic fracture.Methods:A retrospective cohort study was conducted to analyze the clinical data of 32 patients with Tile type C pelvic fracture admitted to Weihai Central Hospital from January 2020 to March 2022, including 18 males and 14 females; aged 36-60 years [(44.1±3.9)years]. Among them, 17 patients were treated with internal fixation with percutaneous minimally invasive hollow nail assisted by electromagnetic navigation robot (electromagnetic navigation group), and 15 with internal fixation with percutaneous minimally invasive hollow nail guided by C-arm (C-arm guidance group). Operative time, intraoperative blood loss, sacroiliac screw placement time, pubic branch screw placement time, ambulation time and fracture healing time were compared between the two groups. Visual analog scale (VAS), Majeed function score and complication rate at 1 day, 6 months, 12 months after surgery and at the last follow-up were compared between the two groups.Results:All the patients were followed up for 12-24 months [(15.4±0.5)months]. The operative time and intraoperative blood loss in the electromagnetic navigation group were (42.0±2.5)minutes and (10.9±2.6)ml, shorter or less than (50.0±3.5)minutes and (14.9±3.1)ml in the C-arm guidance group (all P<0.01). The placement time of sacroiliac screw and pubic branch screw in the electromagnetic navigation group was (12.4±0.2)minutes and (10.1±0.3)minutes, shorter than (15.3±0.3)minutes and (13.2±0.3)minutes in the C-arm guidance group (all P<0.01). The ambulation time was (3.2±0.4)weeks in the electromagnetic navigation group, earlier than (3.5±0.4)weeks in the C-arm guidance group ( P<0.05). There was no significant difference in fracture healing time between the two groups ( P>0.05). VAS scores of the electromagnetic navigation group were (4.4±0.3)points and (1.1±0.1)points at 1 day and 6 months after surgery respectively, lower than those of the C-arm guidance group [(4.8±0.4)points and (1.2±0.3)points] ( P<0.05 or 0.01). Majeed function scores of the electromagnetic navigation group were (37.3±1.1)points and (88.5±1.4)points at 1 day and 6 months after surgery respectively, higher than those of the C-arm guidance group [(30.7±4.2)points and (82.6±1.8)points] (all P<0.01). There were no significant differences in VAS and Majeed scores at 12 months after surgery and at the last follow-up between the two groups (all P>0.05). There was no significant difference in the incidence of postoperative complications between the two groups ( P>0.05). Conclusion:Compared with C-arm guidance, electromagnetic navigation robot-assisted internal fixation with percutaneous minimally invasive hollow nail for Tile type C pelvic fracture can reduce operative time and intraoperative blood loss, shorten screw placement time and ambulation time, relieve pain and improve functional recovery at early stage.