Biomechanical Properties and Behaviours of the Wrist Joint - Computational Biomechanics of the Wrist Joint - page 17

2.4 Current Trends in Biomechanical Modelling
Previous works had shown progress of modelling techniques, started with as
simple as two-dimensional modelling with only a few bones involved, then pro-
gressively become more complicated and highly efficient attributed to the existing
of high-end computational technology. However, due to the complexity of the
wrist joint as compared to other joints, reported studies on the wrist modelling
were still focused at the very early stage of its model development.
2.4.1 Rigid Body Spring Method
The patterns of load distributions, the kinematics, the effect of constraints as well
as unique cases related to pathological conditions were aspects analysed in the
previous studies [ 21 - 24 ]. Several approaches have been introduced to tackle
aforementioned matters. In comparison with other available methods, rigid body
spring method (RBSM) was commonly used to analyse multiple body contact
forces as well as to perform kinematics analysis. This technique applied rigid body
elements representing the bones, whereas the cartilages and ligaments were
modelled using spring elements [ 24 ].
This method has also been utilised to investigate load transfer. In accordance to a
two-dimensional study on 120 normal wrists, percentage of load transfer at the
radiocarpal and ulnacarpal joints has been successfully unfolded [ 24 ]. 55 % of loads
were transferred through radioscaphoid articulation, 35 % through radiolunate
articulation whereas the remaining 10 % through the ulnacarpal articulation. Total
load of 10 N simulating grasp action was applied at the five metacarpals. The car-
tilage with a stiffness of 15 MPa was simulated via compressive springs with stiffness
of 200 N/mm each whereas tensile spring elements were used to model 28 ligaments.
This study suggested that improvements should be taken into consideration in future
studies especially regarding contact area between bones. A more recent study
implemented three-dimensional RBSM wrist modelling sufficiently simulating the
wrist joint kinematics and the findings were validated experimentally [ 25 ].
2.4.2 Finite Element Method
The finite element (FE) method is a computational numerical analysis technique,
which is combined with computational modelling to obtain stress and strain pat-
terns in modelled bodies, and has been widely used as solutions to engineering
problems [ 26 ]. Variety of shapes and models can be analysed using FE method,
either from as simple as a sphere, up to more complex and complicated design,
such as an aeroplane. It can be defined as a tool used to predict behaviour of a