Fig. 1　Imaging progression.

Plain radiographs of the left hip (anteroposterior view) : (a) At the time of the femoral neck fracture; (b) Immediately after hemiarthroplasty; (c) At 1.5 years postoperatively, osteolysis at the lateral acetabular rim led to superior-lateral displacement of the outer cup. Radiolucent lines were noted around the proximal femur, and the hip was malaligned. (d) Corresponding CT image demonstrated bone loss of the posterior acetabular wall with posterior subluxation.