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Indications for MARS-MRI in Patients Treated With Metal-on-Metal Hip Resurfacing Arthroplasty

James W Connelly1, Vincent P Galea1, Sean J Matuszak1

  • 1Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, MA.

The Journal of Arthroplasty
|April 3, 2018
PubMed
Abstract

Insights

High blood cobalt and chromium levels predict adverse local tissue reactions in metal-on-metal hip resurfacing arthroplasty patients. A new algorithm using these markers offers improved sensitivity for detecting these reactions.

Area of Science:

  • Orthopedic Surgery
  • Biomaterials Science
  • Radiology

Background:

  • Metal-on-metal (MoM) hip resurfacing arthroplasty (HRA) lacks standardized guidelines for Metal Artifact Reduction Sequence MRI (MARS-MRI) imaging.
  • Adverse Local Tissue Reaction (ALTR) is a significant concern in MoM HRA patients.

Purpose of the Study:

  • To identify patient and clinical factors predicting ALTR in Articular Surface Replacement (ASR) HRA.
  • To develop an algorithm for indicating MARS-MRI in ASR HRA patients.
  • To compare the developed algorithm against existing MARS-MRI guidelines.

Main Methods:

  • A prospective, multicenter study of 182 patients with unilateral ASR HRA.
  • MARS-MRI was performed at a mean of 7.8 years post-surgery.
  • Statistical analysis identified predictors of ALTR and established cutoffs for an algorithm.

Main Results:

  • Elevated blood cobalt (Co) and chromium (Cr) levels were significant predictors of ALTR.
  • The developed algorithm, using Co cutoff of 1.15 ppb and Cr cutoff of 1.09 ppb, achieved 96.6% sensitivity for ALTR prediction.
  • This algorithm demonstrated superior sensitivity compared to existing guidelines.

Conclusions:

  • Blood Co and Cr levels are key indicators of ALTR in ASR HRA.
  • The novel algorithm effectively predicts ALTR in ASR HRA patients with high sensitivity.
  • This tool can aid in optimizing MARS-MRI indications for MoM HRA patients.
Keywords:
Articular Surface ReplacementMARS-MRIadverse local tissue reactionhip resurfacing arthroplastymetal-on-metal

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