Complications following iliac crest bone grafting.

Avulsion of the anterior superior iliac spine occurred after procurement of bicortical bone grafts from the anterior superior iliac crest area in two patients. The defect in the anterior ilium with a weak spike of bone created a significant stress riser and led to avulsion of the anterior superior iliac spine by the action of the sartorius and tensor fascia lata. Bicortical grafts should be taken from areas as much as 5 cm posterior to the anterior superior iliac spine to avoid this complication.