Long-term changes in blood metal ion levels in patients with hip resurfacing implants: implications for patient surveillance after 10 years follow-up

Aleksi Reito, Olli Lainiala, Fiona Berryman, David J. Dunlop, Antti Eskelinen, Gulraj S. Matharu

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Background: Studies investigating changes in blood metal ion levels during the second decade of the implant lifetime in MoM hip resurfacing patients are scarce. Methods: Patients implanted with either Birmingham Hip Resurfacing (BHR) or Articular Surface Replacement (ASR) hip resurfacings with >10 years follow-up and repeated blood metal ion measurements were identified at 2 large specialist European arthroplasty centres. After excluding patients with initial metal ion levels >7 ppb, the proportion of patients with an increase in blood metal ion levels above previously validated implant-specific thresholds (cobalt 2.15 ppb for unilateral implants, cobalt or chromium 5.5 ppb for bilateral) was assessed. Results: We included 2743 blood metal ion measurements from 457 BHR patients (555 hips) and 216 ASR patients (263 hips). Of patients with initial metal ion levels below implant specific thresholds, increases in cobalt or chromium level, respectively, to above these thresholds during the second decade were seen as follows: unilateral BHR (cobalt = 15.6%), unilateral ASR (cobalt = 13.8%), bilateral BHR (cobalt = 8.2%, chromium = 11.8%), bilateral ASR (cobalt = 8.5%, chromium = 4.3%). Measurement-to-measurement changes exceeding +2.15 ppb or +5.5 ppb were, however, uncommon during the second decade. Subgroup results with small diameter (<50 mm) implants were similar. Conclusions: We recommend less frequent blood metal ion measurements are needed (every 3 to 5 years) for hip resurfacing patients if initial values were below 7ppb.

Original languageEnglish
Pages (from-to)864-871
JournalHIP INTERNATIONAL
Volume33
Issue number5
Early online date2022
DOIs
Publication statusPublished - 2023
Publication typeA1 Journal article-refereed

Keywords

  • Chrome
  • cobalt
  • follow-up
  • hip resurfacing
  • metal ions
  • metal-on-metal

Publication forum classification

  • Publication forum level 1

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine

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