Cup-on-cup technique to manage severe protrusio acetabular defects.

Previous studies have demonstrated that revision of total hip arthroplasty consumes considerably more resources than the primary procedure. Worse, patients who need revision procedures are more likely to have radiographic evidence of acetabular and femoral bone loss than those undergone primary total hip arthroplasty. Many techniques have been introduced to manage different conditions of acetabular deficiencies. We describe a rare case of a 67-year-old man with severe acetabular bone loss, which was caused by a long-term loose acetabular component and was successfully managed by cup-on-cup technique. We also discuss the similarities and differences between cup-on-cup and cup-in-cup techniques in the management of protrusio acetabular defects, with a case-based approach.