Treatment of Type IV Fragility Fractures of Pelvis With Robotic-Assisted Minimally Invasive Triangular Fixation

Objective: Type IV fragility fractures of pelvis (FFP IV) are serious and complicated and the treatment is challengeable. Robotic-assisted minimally invasive triangular fixation (RoboTFX) is a new and advanced technique to treat this injury. The objective of this report is to evaluate the clinical outcomes of FFP IV treated with RoboTFX.

Methods: From March 2017 to December 2022, 22 consecutive patients with FFP IV were included in the study. Patients were divided into two groups according to the surgical method employed (RoboTFX or robotic-assisted minimally invasive iliosacral screws, RoboISS). Between two groups, we compared clinical data on operation time, intraoperative bleeding, intraoperative fluoroscopy time, favorable fracture healing rate, implant loosening rate, and Majeed pelvic outcome score.

Results: All operations were undertaken from 3 to 15 days (average 5.7 ± 1.7 days) following primary injuries. All patients were followed up continuously 15 months. The average surgical time was 125.3 ± 15.5 (55-190) min in group RoboTFX, 137.1 ± 17.2 min in group RoboISS (p > 0.05). The average amount of intraoperative bleeding was 320.4 ± 25.2 (50-550) mL in group RoboTFX, 302.4 ± 21.5 (50-500) mL in Group 2 (p > 0.05). The average intraoperative fluoroscopy time of the two groups was 23.3 ± 4.5 (15-35) s in group RoboTFX and 40.3 ± 3.8 (10-75) s in group RoboISS (p < 0.05). No patients experienced loss of reduction, 5 of 40 screws had implant loosening in group RoboTFX, meanwhile 13 of 48 screws had implant loosening in Group 2. Four of 20 vertical sacral fractures were healed undesirable including 2 nonunion and the favorable healing rate of 80% in group RoboTFX, meanwhile 8 of 24 fractures were undesirable including 4 nonunion and the favorable healing rate was 66.7% in group RoboISS. Implant loosening rate in the RoboTFX group were all significantly better than those of the RoboISS group (p < 0.05). There were no occurrences of wound infection in both groups, and Majeed scores for the last follow-up were 76.2 ± 3.4 in group RoboTFX and 74.2 ± 2.7 in group RoboISS (p > 0.05).

Conclusion: RoboTFX has the advantages of less intraoperative fluoroscopy and implant loosening rate compared to RoboISS which is better than other methods. We thus recommend RoboTFX as an effective option for treating FFP IV. However, the indications of its operation should be strictly evaluated.