“Serious” Hip Implant Corrosion Issues Reviewed in New Study

A recently published study from Maine Medical Center and Tufts University suggests "potentially very serious” issues related to mechanically associated crevice corrosion. The study, “High Incidence of Mechanically Assisted Crevice Corrosion at 10 Years in Non-Cemented, Non-Recalled, Contemporary Total Hip Replacements,” appears in the November 22, 2021 edition of The Journal of Arthroplasty.

Modular hip components are currently among the most commonly used components in total hip arthroplasty (THA). There is also growing recognition of tribocorrosion at the head-neck interface of the femoral component. At this site, mechanical abrasion and chemical corrosion can lead to breakdown of the metal components and release of metal ion and particulate debris in a process known as mechanically assisted crevice corrosion.

Sole investigator Brian McGrory, M.D., M.S., with the Tufts University School of Medicine, Maine Medical Center, explained the rationale behind the study to OTW, “There is general agreement that mechanically associated crevice corrosion occurs more frequently than previously thought in contemporary total hip replacements, but it is unknown just how frequently. This study addresses that question and is one of the first attempts to do so.”

Including primary and conversion THAs performed between January 1, 2009, and December 31, 2009, Dr. McGrory looked at cobalt and chromium levels, as well as radiographs at routine 10-year follow-up of THAs (one manufacturer) with a titanium stem, cobalt alloy femoral head, and cross-linked polyethylene countersurface.

Dr. McGrory told OTW, “We found that with this type of taper, at our institution, the incidence of mechanically associated crevice corrosion was at least 22% at 10 years follow-up. Of the patients with mechanically associated crevice corrosion, demonstrated by a serum cobalt of > 1 ppb, approximately one half had symptoms, one-half had an abnormal MRI (adverse local tissue reaction), and about 60% had undergone revision for mechanically associated crevice corrosion.”

“Clinicians need to be vigilant for this diagnosis (i.e., mechanically associated crevice corrosion), because it is more likely than previously recognized and potentially very serious. Further work needs to be done to confirm that our results are generalizable. If so (and this is likely based on similar findings in the Australian Joint Replacement Registry), then careful follow-up of patients with this taper and a metal on highly crosslinked polyethylene is advisable.”