Objective To investigate the effectiveness of modified internal fixator (INFIX) to fix the anterior pelvic ring for Tile C1.3 pelvic fracture by comparing with the traditional INFIX. MethodsThe patients with Tile C1.3 pelvic fractures admitted between April 2018 and June 2021 were taken as the study objects. Of them, 55 cases were included in the study according to the selection criteria. During operation, the anterior pelvic ring was fixed with the modified INFIX in 30 cases (modified group) and with the traditional INFIX in 25 cases (control group). The posterior pelvic ring in 55 cases was fixed with sacroiliac screws. There was no significant difference between the two groups in gender, age, cause of injury, time from injury to operation, and combined injury (P>0.05). The operation time, intraoperative blood loss, and complications were recorded and compared between the two groups. The X-ray film was taken to evaluate the reduction of the anterior pelvic ring after operation, grade the reduction according to the Matta scoring standards, and observe the fracture healing and healing time. The function was evaluated according to Majeed scoring standards during follow-up. Results The operation time of the modified group was significantly longer than that of the control group (Z=–3.837, P<0.001), but there was no significant difference in the intraoperative blood loss between the two groups (t=–1.831, P=0.076). All patients were followed up 12-18 months (mean, 14 months). X-ray film reexamination showed that the excellent and good rate of Matta scoring for anterior pelvic ring reduction in the modified group was 88.00%, which was significantly better than that in the control group (63.33%) (χ2=4.373, P=0.037). All fractures healed, and the fracture healing time of the modified group and the control group was (12.04±3.59) and (14.83±4.83) weeks respectively, with a significant difference (t=2.401, P=0.020). At last follow-up, the excellent and good rates of Majeed scoring were 80.00% in the modified group and 76.67% in the control group, with no significant difference (χ2=0.089, P=0.766). In the modified group, 2 cases (8%) had complications, all of which were incision infection above pubic symphysis. In the control group, 9 cases (30%) had complications, including 5 cases of lateral femoral cutaneous nerve injury, 2 cases of femoral nerve paralysis, and 2 cases of delayed fracture healing. The incidence of complications was significantly lower in the modified group than in the control group (χ2=4.125, P=0.042). ConclusionCompared with the traditional INFIX, the modified INFIX to fix the anterior pelvic ring for Tile C1.3 pelvic fracture has fewer complications, better stability, shorter fracture healing time, and lower risk of nerve injury.