Three-dimensional CT reconstruction. (a) The massive osseous lesion in the posterolateral aspect of the acetabulum, partially connected with the posterior column, and surrounding the whole posterior hip joint from the roof of the acetabulum to the intertrochanteric line. (b,c) Bone defects and joint incongruence were revealed in the posterior wall (red dotted line and arrow in b). (d) Old impaction and degeneration exist at the posteroinferior portion of femoral head (white arrow in d). However, the weight-bearing portion of the femoral head had a normal appearance.