Avulsion fracture of the pelvis: separation of the secondary ossification center in the superior margin of the acetabulum.

A 13-year-old female sustained a rare avulsion fracture of the secondary ossification center in the superior margin of the acetabulum as the result of contraction of the reflected head of the rectus femoris muscle. Diagnosis was made from plain films and CT scans with 3D image reconstruction. The patient was treated non-operatively by bed rest with semiflexion of the hip and knee, and appropriate analgesia. Copyright 2003 Wiley-Liss, Inc.