Repeated magnetic resonance imaging in 154 hips with large-diameter metal-on-metal hip replacement

Acta Orthop. 2014 Dec;85(6):570-6. doi: 10.3109/17453674.2014.961868. Epub 2014 Sep 19.

Abstract

Background and purpose: The US Food and Drug Administration and the UK Medicines and Health Regulation Agency recommend using MRI in the evaluation of patients with large-diameter metal-on-metal (LD-MoM) hips. Such recommendations do not take into account the relevance of repeated cross-sectional imaging. We therefore investigated the natural course of pseudotumors in patients with LD-MoM hip replacements.

Patients and methods: Of 888 ASR patients (1,036 hips) 674 patients (798 hips) underwent 2 follow-up visits at our institution. Of these, we identified 124 patients (154 hips) who had undergone repeated clinical assessment including MRI and whole-blood metal ion assessment.

Results: A change in classification in imaging findings between the 2 MRIs was seen in 17 of the 154 hips (11%). In 13 hips (8%), a significant progression of the pseudotumor was evident, while in 4 (3 %) there was a retrogressive change. 10 of these 13 hips had had a normal first MRI. Patients with a progressive change in the scans did not differ significantly from those without a change in MRI classification regarding follow-up time, time interval between MRIs, or changes in whole-blood Cr and Co levels between assessments.

Interpretation: A change in classification was rare, considering that all patients had a clinical indication for repeated imaging. Progression of the findings did not appear to correlate clearly with symptoms or whole-blood metal values.

MeSH terms

  • Adult
  • Aged
  • Arthroplasty, Replacement, Hip / adverse effects*
  • Arthroplasty, Replacement, Hip / instrumentation*
  • Chromium Alloys
  • Cysts / etiology
  • Cysts / pathology
  • Exudates and Transudates
  • Female
  • Follow-Up Studies
  • Granuloma, Plasma Cell / etiology
  • Granuloma, Plasma Cell / pathology*
  • Hip Prosthesis / adverse effects*
  • Humans
  • Magnetic Resonance Imaging / methods*
  • Male
  • Metal-on-Metal Joint Prostheses / adverse effects*
  • Middle Aged
  • Postoperative Complications / etiology
  • Postoperative Complications / pathology
  • Prosthesis Design

Substances

  • Chromium Alloys