Jorge Ochoa, Ph.D.
Exponent, Inc.
E-mail: jochoa@exponent.com


TITLE:

"Biomechanics of Metal on Metal Hip Replacement - Fact, Fiction and What You Don't See On TV"


ABSTRACT:

Some national joint registries have shown a high early failure rate of
some types of metal-on-metal hip replacements. It is unknown whether the
principal mechanism of failure is mechanical, physiological or a
combination thereof. It is also uncertain whether the main limitation in
their use is a) surgeon / component position related or b) design /
manufacturer related. Assessing and analyzing clinical category of
failure (infection, loosening, and dislocation, and malalignment,
fracture, unexplained) will help stratify and identify the relationship
between potential failure modes and potential root causes. Additionally,
clinical factors such as pre-revision blood metal ion levels (using
ICP-Mass Spectrometry), component position analysis (CT scan and plane
radiographs) and soft tissue analysis (MRI and tissue histology) can be
utilized to study the physiologic nature of failure modes in the
patient.  The role of the regulatory process in identifying and
mitigating any potential risks to the patient inherent in these and
similar devices will also be explored.