Operative stabilization of fracture dislocations of the sacroiliac joint.

Posterior fracture dislocations of the sacroiliac joint (crescent fracture) represent a subset of lateral compression pelvic fractures. The crescent fracture consists of a posterior iliac wing fracture with extension into the sacroiliac joint and a dislocation of the inferior 1/2 of the sacroiliac joint. The posterior superior iliac spine remains firmly attached to the sacrum by the strong posterior ligaments. As a result of this combination of bony and soft tissue injury, the hemipelvis is rotationally unstable, but because the sacrospinous and sacrotuberous ligaments remain intact the involved hemipelvis is stable to vertically applied forces. Operative stabilization is necessary to restore articular congruity of the sacroiliac joint, pelvic stability, and to allow early mobilization of the patient. Stabilization of the pelvis may be achieved through either an anterior or a posterior approach with or without transarticular fixation. A posterolateral approach to the crescent fracture and a method of stabilization using extraarticular fixation, intertable lag screws and outer table antiglide plates are described. The results of using this technique in 22 patients are reviewed.