3. Reduction and fixation

We used a modified Stoppa approach combined with a lateral window of the ilioinguinal approach. First, we aimed to reduce the displaced anterior column to the posterior ilium. A 5.0 mm Schanz screw was inserted in the anterior inferior iliac spine, and the iliac wing was internally rotated. The elevated anterior column fragment was squeezed out using a ball spike pusher. A 5–6-hole reconstruction plate or small locking compression plate was undercontoured and placed at the junction of the fracture line along the pelvic brim. The distal part of the plate was placed on the free anterior column fragment, and cortical screws were fixed to the proximal portion of the plate—the stable portion of the posterior ilium. With the tightening of the screws, the under-bent plate pressed the anterior column fragment into alignment with the intact ilium. Cortical screws were then fixed into the distal portion of the plate while exercising caution to avoid pulling the anterior column

fragment. We also performed reduction and fixation of the iliac wing with a lag screw or reconstruction plate, if required.

Subsequently, the posterior column was reduced. Notably, as this column was already almost reduced by ligamentotaxis via traction through the limb positioner in most cases, only fine adjustment or augmentation was required. The pelvic arm of the collinear reduction clamp was placed in the lesser sciatic notch from the lateral window of the ilioinguinal approach. Further, the collinear reduction clamp was assembled with the pelvic arm and gently squeezed while observing the reduction status via the Stoppa window. After confirming that the quadrilateral surface was adequately reduced to the anterior column via direct visualization, a 3.5 mm long lag screw was placed in the direction of the ischial spine. We made it a rule to place at least two screws for the posterior column fixation.

Finally, a curved 12-hole pelvic reconstruction plate was contoured and applied along the pelvic brim, from the innominate bone adjacent to the sacroiliac joint to the pubic tubercle. Remarkably, the plate was introduced from the lateral window of the ilioinguinal approach in the direction of the distal Stoppa incision. The cranial- and caudal-most screws were placed to buttress and stabilize the reduced anterior column fragment. An additional posterior column screw was placed through the plate hole or separately next to the plate hole if required.

The fixation status was confirmed using an intraoperative image intensifier in the anteroposterior, iliac wing, and obturator oblique views. If a large posterior wall fragment was present or the posterior column reduction was unsatisfactory, they were corrected and stabilized using a separate posterior approach. After completion of all fixations, the traction was released and a final radiographic assessment was performed before wound closure.
