BACKGROUND: Although periprosthetic fractures of the femur are a recognized complication of total hip arthroplasty, periprosthetic fractures of the acetabulum are rare. Simultaneous periprosthetic fractures of both the acetabulum and the femur have not been reported, to our knowledge.

CASE REPORT: We report a simultaneous fracture of the acetabulum and the femur in a 68-year-old female patient who had previously sustained a subcapital fracture of the femur, treated with a bipolar uncemented prosthesis. We discuss the possible mechanism of this combination of fractures.

CONCLUSIONS: Simultaneous periprosthetic fractures of the femur and the acetabulum can occur if, in the presence of osteoporotic bone, the metallic femoral head has migrated medially in the acetabulum while the femoral stem is not loose.

Keywords: Acetabulum, Femur, Internal Fixators, Periprosthetic Fractures