Posterior iliac crescent fracture-dislocation: what morphological variations are amenable to iliosacral screw...

Posterior iliac crescent fracture with associated sacroiliac joint disruption (PICFSID) is a type of traumatic posterior pelvic injury associated with instability. Posterior iliac fracture location and obliquity along with other details determine the treatment. Open reduction and internal fixation has been previously recommended for the majority of crescent fractures. Our objectives were to determine whether all crescents can be categorised according to the previously described Day crescent classification scheme, and to see which crescent types are amenable to percutaneous fixation.

We identified 129 crescents in 128 patients during a 7-year time period. Of these, 100 patients met the inclusion criteria of at least 3 months of clinical and radiographic follow-up. There were 57 males and 43 females, with a mean age of 42 years and a mean injury severity score of 25.5. Treatment selection was based on fracture type and overall patient factors and consisted of non-operative management, pelvic external fixation, open reduction and internal fixation, and closed reduction and percutaneous iliosacral screw fixation.

There were 16 Type I, 47 Type II and 37 Type III crescent fractures. Twelve injuries could not be classified according to the Day scheme. Percutaneous iliosacral screw fixation was utilised in 60% of all crescents after either closed or open reduction of the PICFSID.

The majority of PICFSIDs are amenable to closed reduction and percutaneous iliosacral screw fixation. The Day classification for PCIFSID should be expanded to include variant injury patterns.