Biomedical Engineering Reference
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are commonly used in predicting joint motion and quantifying plantar pressure distributions. However,
the load transfer mechanism and the states of internal stress within the soft tissues and the bony struc-
tures remain unaddressed due to the difficulties and limitations of the experimental approach. The
functional role of different anatomical components on load distribution and stabilizing ability depends
merely on gross pressure distribution, as recorded from experimental measurements. Experimental
measurements are time-consuming and would need to be conducted on a significant number of patients
or specimens with different characteristics to yield generalized and promising results.
Computational models based on FE methods have been used increasingly in many biomechanical
investigations with great success due to the capability of modeling structures with irregular geom-
etry and complex material properties, and varying boundary and loading conditions. Computational
modeling can be easily used to vary factors, including geometrical features such as the shapes of
articular surfaces and the arrangement of ligaments, mechanical properties of the bones and soft
tissues, muscle forces, external loads, and different supporting conditions.
A number of FE models were developed to investigate foot biomechanics and a few studies
provided biomechanical information for footwear design (Lemmon et al. 1997; Chen, Ju, and
Tang 2003; Verdejo and Mills 2004; Cheung and Zhang 2008). The simplified models available for
stress-strain analyses were either two-dimensional (Nakamura, Crowninshield, and Cooper 1981;
Lewis 2003; Lemmon et al. 1997; Erdemir, Saucerman, and Lemmon 2005; Verdejo and Mills
2004; Goske et al. 2006; Spears et al. 2007) or partial three-dimensional foot skeleton or connected
bony structure (Chu, Reddy, and Padovan 1995; Chen, Ju, and Tang 2003). More geometrically
accurate three-dimensional FE models were developed later (Gefen et al. 2000; Cheung and Zhang
2005). Successful FE analyses (Chu, Reddy, and Padovan 1995; Chen, Ju, and Tang 2003; Cheung
et al. 2005) have been carried out on insoles and ankle-foot orthoses. A comprehensive review of the
development of foot FE models was undertaken in 2009 (Cheung et al. 2009). In the last five years,
the number of FE studies on the foot and its support has increased remarkably, as summarized in
Table 1.1. FE modeling, if conducted properly, could potentially make significant contributions to
the understanding of foot biomechanics and improvements in footwear design.
table 1.1
Finite element models and applications in the literature since 2009
reference
geometrical Properties
Parameters of Interest
Garcia-Aznar et al. (2009)
Three-dimensional (3D),
computerized tomography (CT)
images (foot bones)
Load transfer mechanism of different metatarsal
geometries
Garcia-Gonzalez et al. (2009)
The effect of tendon transfer on dorsal
displacement to claw toe deformity
Bayod et al. (2010)
Comparison of proximal interphalangeal joint
fusion and flexor tendon transfer
Bayod et al. (2012)
Effect of bone graft harvesting on calcaneus
Halloran, Erdemir, and
van den Bogert (2009)
Two-dimensional (2D; bone,
encapsulated soft tissue)
Demonstration of surrogate modeling system in
comparison of finite element analysis
Halloran et al. (2010)
Alteration of movement to soft tissue loading
Chen et al. (2010)
3D, CT images (foot bones,
encapsulated soft tissue)
Effect of internal stress concentration to plantar
soft tissue
Chen et al. (2012)
Effect of muscle forces on forefoot pressure,
metatarsophalangeal, and ankle joint motion
Gu et al. (2010a)
3D, CT, and magnet resonance (MR)
images (hindfoot bones,
encapsulated soft tissue, fat
pad, skin)
Different skin stiffness at heel-strike
Gu et al. (2010b)
Different inversion landing angles on forefoot
pressure and metatarsal stress
Gu et al. (2011)
Different foot support to metatarsal loading
Continued
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