Finite Element Analysis of the Wrist Joint Affected by Rheumatoid Arthritis - Computational Biomechanics of the Wrist Joint - page 41

Chapter 5
Finite Element Analysis of the Wrist Joint
Affected by Rheumatoid Arthritis
Abstract This chapter presents the information on the biomechanical analysis of
the rheumatic wrist using the finite element method. This study was designed to
better understand the biomechanical behaviour of the diseased wrist, thus assuring
better future treatments. The three-dimensional model of the wrist affected by
rheumatoid arthritis was constructed from CT images of the healthy volunteer, by
considering ten characteristics involving three main symptoms and seven patho-
physiology criteria of the disease. Comparison was made between the simulated
healthy wrist which functions as control and the rheumatic wrist model. Both
models were assigned with the same loading simulating static hand grip action. It
was revealed from the finite element analyses that the RA model produced ten
times higher contact pressure at the articulations in comparison with the healthy
model. Additionally, normal physiological load transfer changed from primarily
through the radial side to an increased load transfer of 5 % towards the ulnar.
These significant findings recommend that future treatments should be able to
avoid any unphysiological impacts as addressed in this study.
Keywords Finite element analysis Rheumatoid arthritis Computational
modelling High contact pressure Unphysiological load direction
5.1 Finite Element Model Construction of the Rheumatic
Wrist
Based on past literatures (see Chap. 3 ) , symptoms and the pathophysiology of
rheumatoid arthritis (RA) were well-identified. Type IIIa (disintegration type with
more ligamentous instability according to Simmen and Hubber classification) of
RA was simulated, wherein 10 criteria were included: