Abstract
We will report the case of an acetabular displacement after a rotational acetabular osteotomy (RAO). The patient was 49 years old female. Before the operation, an x-ray of the hip joint showed acetabular dysplasia and a narrowing of the joint space (in an advanced stage). RAO was performed and, simultaneously, an anterior rotation of the acetabulum was performed aggressively due to the stage of osteoarthritis. Immediately after the operation, x-ray showed good congruity and coverage of the femoral head. However two weeks after surgery, joint congruity was lost, and reoperation was performed. An electron microscope examination revealed that the screws had crack lines. So, the displacement of the acetabulum was thought to be caused by a break following the crack lines of the PLLA screw.
