Lessons from retrievals: retrievals help understand the reason for revision of coated hip arthroplasties

Danielle de Villiers, Harry Hothi, Harman Khatkar, Jayantilal Meswania, Gordon Blunn, John Skinner, Alister Hart

Research output: Contribution to journalArticlepeer-review


Coatings have been applied to all surfaces of hip implants with the majority performing well in the laboratory, but there are few reports of their performance in humans. The rationale for coating the metal-on-metal bearing surfaces includes a reduction in metal ion release and risk of adverse reaction to metal debris; yet there are no reports of retrieved coated metal-on-metal hip implants despite the concern that they may delaminate. The aim of this study was to better understand the performance of coated hip implants in humans through findings of three coated metal-on-metal hip resurfacings, retrieved after failure for unexplained pain. Analysis of these implants included quantification of the amount and mechanism of coating loss which was correlated with clinical, imaging and blood data. In all cases, there were large areas of complete coating loss in which the metal substrate was exposed and found to be rougher than the coated areas. The coating loss gave rise to third body abrasive wear of the coating and the exposed metal, the latter of which led to high blood levels of cobalt and chromium. Coating of the bearing surfaces of metal-on-metal hip resurfacings, therefore, do not prevent metal ion release when implanted into humans. This is an example of a need for increased retrieval analysis of newly introduced implants and expansion of laboratory testing regulations to better reflect the clinical environment.

Original languageEnglish
Pages (from-to)804-811
Number of pages8
JournalProceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine
Issue number11
Early online date25 Oct 2015
Publication statusPublished - Nov 2015


  • Arthroplasty, Replacement, Hip
  • Biomechanical Phenomena
  • Coated Materials, Biocompatible
  • Equipment Failure Analysis
  • Friction
  • Hip Prosthesis
  • Humans
  • Niobium
  • Prosthesis Failure
  • Reoperation
  • Titanium


Dive into the research topics of 'Lessons from retrievals: retrievals help understand the reason for revision of coated hip arthroplasties'. Together they form a unique fingerprint.

Cite this