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Revision of total knee replacement (TKR) secondary to raised cobalt levels: should this be considered in the painful TKR patient?
  1. Fred Kenny1,
  2. John P Gibbons2,
  3. Peter Keogh2 and
  4. John O'Byrne2
  1. 1School of Medicine, University of Limerick, Castletroy, Limerick, Ireland
  2. 2Orthopaedic Department, Cappagh National Orthopaedic Hospital, Dublin, Ireland
  1. Correspondence to Mr Fred Kenny; 18211216{at}


A 63-year-old woman was referred to the specialised knee revision clinic with ongoing knee pain after total knee replacement. She incidentally had cobalt and chromium levels measured. These were seen to be elevated. Comprehensive assessment and investigation did not identify any other source of cobalt or chromium. Aseptic loosening of the knee was diagnosed, and the knee was revised. At the time of surgery, the tissue was seen to be darkened consistent with metallosis. Multiple samples excluded infection on extended cultures. Aspirated fluid showed that periprosthetic fluid had elevated cobalt levels. The knee was successfully revised with good symptomatic outcome and significantly, over the course of several months post-revision, the cobalt and chromium levels returned to normal.

  • cobalt toxicity
  • prosthesis failure
  • orthopaedics
  • orthopaedic and trauma surgery

Statistics from


  • Contributors FK—primary author. JPG—second author. PK—supervisor. JO’B—principal investigator/supervisor. FK and JPG collected the data. FK wrote the case report with support from JPG and JO’B. JO’B, PK and JPG carried out the revision of total knee surgery and collected the samples. JO’B, JPG, PK and FK reviewed the patient in follow-up clinics. FK, JO’B, JPG and PK reviewed and finalised the case report.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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