Technical Note on Placement of Low-Profile Triangular Osteosynthesis for Unstable Posterior Pelvic Ring Injuries

Triangular osteosynthesis is a technique used to stabilize posterior pelvic ring injuries. Conventional triangular fixation can be problematic for several reasons, including the need for advanced skill sets to place instrumentation, difficulty with pelvic reduction and placing the connecting construct, and prominent instrumentation. The purpose of this study is 2-fold: (1) to describe in detail a technique for lumbopelvic fixation using implants that are easy to connect, allow distraction for complex lumbosacral displacements, and are placed in a location minimizing soft tissue prominence and (2) to present our initial case series using this technique. We present a retrospective review of 18 consecutively treated patients with this technique. Inclusion criteria were patients with complete disruption through the sacrum or sacroiliac joint from blunt trauma (OTA/AO type C injuries). Outcomes included pelvic reduction/malreduction, wound healing, and complications. Fourteen patients underwent unilateral fixation (81%), and 4 patients underwent bilateral fixation (19%). All patients (18 of the 18) had a well-reduced pelvis after fixation. No patient (0%) required a return trip to the operating room for loss of reduction/malreduction, wound breakdown, or implant failure. This study presents an updated technique for a low-profile triangular osteosynthesis construct with straightforward application for unstable posterior pelvic ring injuries. This technique does not require rod bending, results in a consistently more recessed iliac screw and connecting rod, and can be used in a wide variety of unstable posterior pelvic ring injuries, including comminuted sacral fractures, L5/S1 facet fractures, and vertical shear injuries.