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mviceconti63
06-07-2004, 07:34 PM
I serve as a reviewer for a few biomechanics or orthopaedics
journals, some of which have a clear clinical perspective. In
particular I frequently revise papers where finite element models are
used as the main research tool.

These models are becoming more and more effective and powerful, and
it is not rare to find papers where the authors, on the basis on the
results obtained with the model, draw conclusions that may have a
clinical relevance, i.e. affect clinical decisions.

The problem I have is methodological: are we allowed to draw
clinically relevant conclusions from the predictions obtained by a
numerical model? Or, more appropriately, what are the conditions a
numerical model must fulfill in order to considered so reliable that
we can reasonably use it to draw clinically relevant conclusions?

In order to foster the discussion let me bring in my two cents.

In my understanding a numerical model is a particular instance of a
theoretical model. Once we are sure that the theoretical model has
been solved with sufficient numerical accuracy (and this is in
general possible with post-hoc indicators) what remains to be proved
is the adequacy of the theoretical model.

A theoretical model (a theory) in principle can be assumed to be true
(in the sense of a scientific truth, i.e. as far as we, as a
community we know, and within the limits of validity of the theory),
if with this model we can predict the outcomes of independent
experiments (independent in the sense that they are not those
measurements that were used to identify the model) and/or if starting
from the model we can deduct derivative conditions that are proved to
be true.

How do we translate these general rules in the specific of our
research domain, biomechanics? Can we say that once a model predicts
with sufficient accuracy the results of an in vitro experiment, we
can consider it valid and use it to draw clinically relevant
conclusions? Or is it sufficient to prove that the model is
numerically accurate and all the model assumptions and parameters are
well supported by experimental observations?

As usual I am ready to post a summery of the comments I shall receive.

Regards


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MARCO VICECONTI, PhD (viceconti@tecno.ior.it)
Laboratorio di Tecnologia Medica tel. 39-051-6366865
Istituti Ortopedici Rizzoli fax. 39-051-6366863
via di barbiano 1/10, 40136 - Bologna, Italy

Tiger! Tiger! Burning bright in the forest of the night,
what immortal hand or eye could frame thy fearful symmetry?
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Opinions expressed here do not necessarily reflect those of my employer

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