Objective To investigate effectiveness of the modified anterior subcutaneous internal fixation (M-INFIX) in treating pubic symphysis diastasis by comparing with open reduction and plate fixation. Methods A retrospective analysis was conducted on the clinical data of 33 patients with AO/Orthopaedic Trauma Association (OTA) type C1 pelvic fractures, who were admitted between January 2020 and January 2025 and met the selection criteria. Among them, 17 patients underwent open reduction and plate fixation of the pubic symphysis (control group), and 16 patients underwent M-INFIX (modified group). There was no significant difference in baseline data, such as age, gender, and time from injury to operation, between the two groups (P>0.05). The operation time, intraoperative blood loss, and incision length of pubic symphysis were recorded and compared between groups. The quality of pelvic fracture reduction was evaluated using the Matta scoring criteria based on postoperative X-ray films, and fracture healing was observed. During follow-up, pelvic functional recovery was evaluated using the Majeed scoring criteria. Results Compared with the control group, the modified group showed shorter operation time and incision, and less intraoperative bleeding, with all differences being significant (P<0.05). All patients were followed up, with follow-up durations of (16.81±3.45) months in modified group and (19.00±3.06) months in control group, showing no significant difference (t=1.929, P=0.063). Radiographic review revealed no significant difference in the quality of pelvic fracture reduction between groups (P>0.05). Fractures healed in both groups. All posterior pedicle screws were removed in both groups. The anterior subcutaneous internal fixators were removed at 6 months after operation in 7 cases of modified group. At last follow-up, there was no significant difference in pelvic function assessed by Majeed scores and ratings between groups (P>0.05). No complication occurred in modified group, while 2 cases of screw loosening and 2 cases of incision infection occurred in control group. The difference in incidence of complications between groups was significant (P<0.05). ConclusionCompared with open reduction and plate fixation, the M-INFIX for treatment of pubic symphysis diastasis offers the advantages of fewer complications, a smaller incision, less bleeding, and shorter operation time, making it a safe and effective surgical approach.
