Prognostic level II. See instructions for authors for a complete description of levels of evidence.

We found a lack of consensus with regard to the definition of fracture-healing in the current orthopaedic literature. Without valid and reliable clinical or radiographic measures of union, the interpretation of fracture care studies remains difficult.

Sacral dysmorphism occurred in 44% of patients in this consecutive series. Many anatomic differences were consistently found between the two morphologies with clinical relevance to iliosacral screw placement. Specifically, the dysmorphic upper sacral segment safe zone is significantly smaller and more obliquely oriented but is still large enough to accommodate an iliosacral screw in nearly all patients. The second sacral segment safe zone is approximately transversely oriented in both sacral types but is more than twice as large in dysmorphic sacra. This segment may be a primary fixation opportunity in patients with sacral dysmorphism.

Background: Upper sacral segment dysplasia increases the risk of cortical perforation during iliosacral screw insertion.