Malformation of the acetabular fossa as a cause of intrapelvic injury in total hip arthroplasty

We report 2 cases of bone defects of the acetabulum. The first case was a patient who underwent a total hip arthroplasty. An intraoperative bleeding occurred because of an injury of an intrapelvic artery. Preoperative radiographs did not show this bone defect. A similar abnormality of the acetabulum was found in a series of 30 pelves that were dissected for a cadaver study. In this case, the bone defect was located in the center of the right acetabulum.