Not actually tested – The 510(k) Ancestry of a Metal-on-Metal Hip Implant

In recent years, metal on metal hip replacements have been causing problems, depositing worn-off metal around the body and having to be taken out.

A NEJM paper shows the ancestral tree of hip replacements.


The authors describe how new devices’ safety was assured by their similarity to old ones.  This is an indirect non-inferiority test and does not truly assure safety and effectiveness.  It is arguably a watered-down form of the traceability that the quality cartel uses to assure the validity of measurements by showing an unbroken chain to their SI reference source.  This is rather like the old chain of being, but for clever scientists, regulators and healthcare lobbyists.

The approach hasn’t worked.  Like accreditation itself, the hip prostheses were not actually tested.

Tracing the evolution of the implants gave clearer insight into why they were unsuitable.  Recalling the evolution of accreditation from unskilled factory work might reveal why it is not suitable for its current application.

Ref:  Brent M. Ardaugh, M.P.H., Stephen E. Graves, M.B., B.S., and Rita F. Redberg, M.D.  The 510(k) Ancestry of a Metal-on-Metal Hip Implant.  N Engl J Med 2013; 368:97-100.  January 10, 2013.  DOI: 10.1056/NEJMp1211581.

This entry was posted in Laboratory medicine, Medicine, Practical problems, Science and tagged , , , , , , , , . Bookmark the permalink.

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