Modified pedicle screw-rod versus anterior subcutaneous internal pelvic fixation for unstable pelvic anterior ring fracture: A retrospective study and finite element analysis

Abstract

Objectives: This study compared the stability and clinical outcomes of modified pedicle screw-rod fixation (MPSRF) and anterior subcutaneous internal pelvic fixation (INFIX) for the treatment of anterior pelvic ring fractures. Methods: In a retrospective review of a consecutive patient series conducted in a level 1 trauma university hospital, 63 patients with Orthopaedic Trauma Association (OTA)/Arbeitsgemeinschaft für Osteosynthesefragen (AO) type B or C pelvic ring fractures were treated by MPRSF (n=30) or INFIX (n=33). The mean follow-up was 20 months. The main outcome measure was the incidence of complications and adverse outcomes, and fixation stability was evaluated by finite element analysis (FEA). Results: The 2 groups did not differ in terms of injury severity score, OTA classification, cause of injury, and time to pelvic surgery (P>0.05). However, the MPSRF group had a higher satisfactory rate according to the Tornetta and Matta grading system than the INFIX group (73.33% vs 63.63%) as well as a higher Majeed score (81.5±10.4 vs 76.3±11.2), which was statistically significant at 6 months’ post-surgery (P<0.001). FEA showed that MPRSF was stiffer and more stable than INFIX and had a lower risk of implant failure. Conclusions: Both MPSRF and INFIX have acceptable biomechanical stability for the treatment of unstable pelvic anterior ring fractures. However, MPRSF has better fixation stability and lower risk of implant failure, which can lead to better clinical outcomes.