Technical Tip: Salvage Procedure for Metal-on-Metal Acetabular Revision
We describe a salvage revision technique used in a patient with a painful metal-on-metal hip replacement, with local soft tissue swelling, lymphadenopathy, and elevated cobalt and chromium ions (Co 4.1 ppb and Cr 4.2 ppb). Cementing a polyethylene liner into an acetabular shell or cage is not new but, to date, there are no reports of cementing into a low-friction large-diameter metal bearing. Pull-out testing after roughening the highly polished cobalt chrome surface using a carbide burr increased pull-out strength from 1179 to 3500 N, equivalent to existing cement-in techniques. Following revision, metal ions returned to normal, hip function improved, and at 2 years’ follow-up there was no evidence of loosening. This is a promising technique for revision hip surgeons in select patients.