Treating large segmental acetabular defects that comprise more than 50% of the acetabulum is one of the most difficult challenges in revision arthroplasty of the hip. One of the surgical options is a structural acetabular allograft. Unless these allografts are protected by a cage that extends from ilium to ischium, there is an unacceptable incidence of graft failure. The cage allows reconstruction at the correct anatomic level. It provides a scaffold for bone grafting (structural and morsellized). The use of cement to stabilize the cup allows the surgeon to adjust the cup position independent of the cage. The current generation of cages does not provide biologic fixation and with time may loosen or fracture. Recent experience with a combination of a trabecular metal shell protected by a cage may offer a more favorable environment for bone grafting with permanent biologic fixation of the cup cage construct.