ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

improvement of the shoulder prostheses and its implantation technique in order to
achieve the best possible outcome from the shoulder arthroplasty. Bearing in mind that
before studying the bone adaptation to the implant of the shoulder arthroplasty it is
important to understand the behavior of bone in healthy conditions, the aim of this work
was to validate the bone remodeling model of an accurate finite element model of a
three-dimensional model of an intact scapula.
(a)
(b)
Fig. 2. Quantitative comparison between the predicted and the actual bone density
distribution - (a) average error defined using the normalized rms of the absolute and
relative differences (b) Pearson’s correlation coefficient.
The results compare well with the work of Sharma et al. [4] and are, in some extent,
better, which heightens even more the success of the bone remodeling model used in
reproducing the actual bone density of the scapula given the greater complexity of the
three-dimensional model used here versus the two-dimensional model used by Sharma
et al.. Moreover, when comparing to Sharma et al., an additional criterion based on the
relative difference is also used, which is expected to improve the evaluation of the bone
remodeling simulations. It is important to note that if only the absolute difference
criterion was used, the best solution would point to the highest parameter m, which is
not advisable since its continuous increase leads the solution to a more homogenized
density distribution. Regarding the solution defined as best, a moderate correlation of
0.453 is found, the rms of the absolute difference is 0.38 g/cc and the absolute
difference of 40%, 70% and 89% of the nodes is under 0.2, 0.4 and 0.6 g/cc,
respectively. Considering the maximum absolute difference to be 1.8 g/cc, it is a rather
positive result to have 89% of the nodes with an absolute error below 33%.
Even though the model successfully reproduced the actual bone density of the analyzed
scapula, in the current work only one geometry of the scapula is considered.