DEVELOPMENT OF A PATIENT-SPECIFIC FINITE ELEMENT MODEL OF A PATHOLOGICAL TRAPEZIOMETACARPAL JOINT
Transcript of DEVELOPMENT OF A PATIENT-SPECIFIC FINITE ELEMENT MODEL OF A PATHOLOGICAL TRAPEZIOMETACARPAL JOINT
DEVELOPMENT OF A PATIENT-SPECIFIC FINITE ELEMENT MODEL OF A PATHOLOGICAL TRAPEZIOMETACARPAL JOINT
Ana Matos (1), António Completo (1), Abel Nascimento (2), Carlos Relvas (1), Antonio Ramos (1), Jose Simoes (1)
1. Department of Mechanical Engineering, University of Aveiro, Portugal
Introduction
One of the reasons that allows man to distinguish
himself from the other animals lies in the fact that
he possesses a hand gifted with a thumb that,
throughout evolution, has grown different from the
other fingers. Surprisingly, this particularization
lead to the development of a pathology
denominated Rhizarthrosis, which generates
instability and subsequent immobilization of the
first finger. This fact is, therefore, sufficient to
develop a study area exclusively dedicated to the
thumb and, particularly, to the
trapeziometacarpiana articulation (TMC). TMC is
an unstable articulation, from the selar type, which
involves the trapezium and the first metacarpus,
thus needing a steady ligament support and
justifying the 16 ligaments that it consists of. Its
complexity leads to the development of several
pathologies, amongst which Rhizarthrosis will be
the study core of this project [Bettinger].
Rhizarthrosis is a severe disease that aggravates
throughout the ageing process and that occurs
primarily in female patients, with ages between 45
and 65 years. It is also largely diagnosed in men
whose daily work involves the rotation movement
of the wrist. This work leads with the need to
provide a better answer to the solution of this
problem. The main goal of this study was develop
finite element models to study comparatively the
biomechanical behaviour of a health and a
pathological trapeziometacarpal joint in order to
understand the main structural differences.
Methods
With the purpose of achieving the proposed
objectives, two different CT scans of the joint were
used – one relative to a pathological joint, and the
other of an health joint. In a first step were
developed both 3D image models of the
trapeziometacarpal joint in the health and
pathological cases through a processing and
segmentation software - ScanIP. In a second step
the 3D image data were converted in volumetric
models (Figure-1) that were used to generate
volume mesh models. The mesh models generated
had automatically assigned the material properties
from grey level data of the CT scans. These ready
meshes were directly imported into a commercial
non linear FE package MSC.MARC. After that
were performed the non-linear structural analysis at
the joint, where were determined the stress-strain
fields at the joint region and the contact forces for
different load-cases. The result were compared
between the health and pathological models.
Figure 1: 3D model of the case at study.
Results
The results at the joint demonstrated different
stress-strain behaviour between the health and the
pathological models., as well as different contact
forces at the joint surfaces for the same load-cases.
The load-cases applied changes considerably the
stress-strain distributions at the joint.
Discussion
The obtained results will be utilized to guide the
development of a new concept of resurfacing
implant to this joint.
Acknowledgement
Program COMPETE through the projects
PTDC/EME-PME/103578/2008,PTDC/EME- PME
/111305/2009 and PTDC/EME TME/113039/2009.
References
Bettinger PC, Linscheid RL, Berger RA, Cooney
WP, 3rd, An KN. An anatomic study of the
stabilizing ligaments of the trapezium and
trapeziometacarpal joint. J Hand Surg [Am] 786-
798 (1999)
Presentation 1006 − Topic 27. Joint arthroplasty S355
ESB2012: 18th Congress of the European Society of Biomechanics Journal of Biomechanics 45(S1)