How Should We Follow-Up Asymptomatic Metal-on-Metal Hip Resurfacing Patients? A Prospective Longitudinal Cohort Study

J Arthroplasty. 2016 Jan;31(1):146-51. doi: 10.1016/j.arth.2015.08.007. Epub 2015 Aug 14.

Abstract

Current surveillance for metal-on-metal hip resurfacing (MoMHR) patients is not evidence based. This study established changes that occurred in 152 asymptomatic MoMHRs using repeat ultrasound and patient-reported outcomes. Factors associated with (1) ultrasound progression and (2) developing new pseudotumors were analyzed. Patients underwent repeat assessments 4.3 years later. Ultrasound progression was observed in 19% (n = 29), with 10% (n = 15) developing new pseudotumors. Key predictors of ultrasound progression included high blood cobalt (P = .00013) and chromium (P = .00065), and high initial ultrasound grade (P = .003) and volume (P = .036). No asymptomatic MoMHRs with initially normal metal ions (<2 μg/L) and normal ultrasounds (33% of cohort) developed new pseudotumors. This patient subgroup does not require repeat follow-up within 5 years.

Keywords: asymptomatic; blood metal ions; follow-up; hip resurfacing; metal-on-metal; ultrasound.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Arthroplasty, Replacement, Hip / methods*
  • Chromium / blood
  • Chromium / chemistry
  • Cobalt / blood
  • Cobalt / chemistry
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Granuloma, Plasma Cell / diagnosis
  • Granuloma, Plasma Cell / diagnostic imaging*
  • Hip Prosthesis*
  • Humans
  • Ions / blood
  • Longitudinal Studies
  • Male
  • Metals / blood
  • Middle Aged
  • Prospective Studies
  • Prosthesis Design*
  • Ultrasonography

Substances

  • Ions
  • Metals
  • Chromium
  • Cobalt