Clinical Orthopaedics and Related Research®

, Volume 471, Issue 9, pp 2964–2971

Do Ion Levels in Metal-on-metal Hip Resurfacing Differ From Those in Metal-on-metal THA at Long-term Followup?

  • Lucia Savarino
  • Matteo Cadossi
  • Eugenio Chiarello
  • Nicola Baldini
  • Sandro Giannini
Clinical Research

DOI: 10.1007/s11999-013-2981-z

Cite this article as:
Savarino, L., Cadossi, M., Chiarello, E. et al. Clin Orthop Relat Res (2013) 471: 2964. doi:10.1007/s11999-013-2981-z

Abstract

Background

Metal-on-metal hip resurfacing arthroplasty (MOM HR) has become an established alternative to traditional metal-on-metal total hip arthroplasty (MOM THA) for younger, more active patients. Nevertheless, concerns remain regarding wear and corrosion of the bearing surfaces and the resulting systemic metal ion distribution.

Questions/purposes

We therefore asked whether (1) serum ion concentrations in patients with MOM HR at the time of long-term followup were higher than concentrations in a control population with no hip implants; (2) the ion concentrations in patients with MOM HR were different from those in patients with MOM THA; and (3) sex would influence ion levels with regard to implant type.

Methods

The MOM HR and MOM THA groups consisted of 25 patients (evaluated at a minimum of 96 months) and 16 patients (evaluated at a minimum of 106 months), respectively. Forty-eight healthy donors were recruited for reference values. Cobalt, chromium, nickel, and molybdenum were measured by furnace graphite atomic absorption spectrophotometry.

Results

Ion concentrations of cobalt, chromium, and molybdenum in MOM HR were higher than in controls. Chromium and cobalt release were higher in MOM HR than in MOM THA. The sex-based analysis showed the difference was because women had higher concentrations in the MOM HR group than in the MOM THA group, whereas there was no difference between the men in the two groups.

Conclusions

In MOM HR, high metal ion release persists for the long term. Consequently, it is important to implement strict biomonitoring for patients who have received these implants. The sustained high levels of chromium in females within the MOM HR group are concerning and merits strong consideration when choosing implants in this patient group.

Level of Evidence

Level III, therapeutic study. See the Instructions for Authors online for a complete description of level of evidence.

Copyright information

© The Association of Bone and Joint Surgeons® 2013

Authors and Affiliations

  • Lucia Savarino
    • 1
  • Matteo Cadossi
    • 2
  • Eugenio Chiarello
    • 2
  • Nicola Baldini
    • 1
    • 3
  • Sandro Giannini
    • 2
    • 3
  1. 1.Laboratory for Orthopaedic Pathophysiology and Regenerative MedicineRizzoli Orthopaedic InstituteBolognaItaly
  2. 2.Department I of Orthopaedics and TraumatologyRizzoli Orthopaedic InstituteBolognaItaly
  3. 3.Bologna UniversityBolognaItaly