Total hip arthroplasty revision in case of intra-pelvic cup migration: designing a surgical strategy.

Intrapelvic acetabular cup migration is a rare but serious complication, which can occur after cup loosening following total hip arthroplasty. To make safe intrapelvic implant removal, several principles must be respected: identification of potential risks with a thorough preoperative workup, preoperative planing of a surgical strategy for removing protruding hardware without injuring noble anatomical structures, preserving muscle and bone stock, pelvic anatomy reconstruction (including, as needed, osteosynthesis of the pelvis), and prosthetic components selection correcting any length discrepancy. Preoperative assessment is based on a complete radiological workup, angio-CT, as well as studies searching for signs of inflammation (blood workup and joint aspiration). All cases of intrapelvic migration of an acetabular component do not systematically command a subperitoneal approach. The presence of some residual bone shell, an intrapelvic foreign body, or a path deviation from normal in a vascular bundle or an ureter must be analyzed before deciding on the approach. The potential problems managing this mode of loosening event are a reminder for the need of periodical total hip arthroplasty follow-up. This regular monitoring helps preventing complications sometimes life threatening.