Occult bilateral acetabular fractures associated with high-energy trauma and osteoporosis.

Acetabular fractures that are radiographically occult are associated with osteoporosis, low-energy trauma, and advanced age. We present a case of bilateral occult acetabular fractures in a 65-year-old woman who presented with an open tibia-fibula fracture and compartment syndrome and thoracolumbar spine fractures sustained in a motor vehicle accident. Initial radiographs of the pelvis and a pelvic CT scan did not show any bony injuries when the films were reviewed prospectively. At 6 weeks after injury, a CT scan and plain radiographs showed bilateral healing transverse acetabular fractures with acetabular protrusio on the left. At most recent follow-up, the patient had posttraumatic hip arthritis with moderate protrusio on the left and was ambulating with a cane. Total hip arthroplasty is anticipated in the future.