Biomedical Engineering Reference
In-Depth Information
affect bone remodeling more moderately than does transverse pressure.
The changes in the remodeling rate under the electrical field are smoother
and less marked.
5.5.2.4 Effect of Multifield Loadings on Bone Remodeling Process
The results in this section show bone remodeling behavior under multifield
loadings. This case simulates a bone structure that is subjected to axial and
transverse pressure and a pulsed magnetic field. Several magnetic loadings
of different intensity are examined. The results can be seen in Figures 5.16
and 5.17. The applied loadings are
P
= 1.5 kN,
p
t
= 0.2 MPa, ψ = −0.2, -0.1, 0,
0.1, 0.2A,
f
e
= 2 Hz; here, φ = φ
b
− φ
a
.
Figures 5.16 and 5.17 show that a positive magnetic field can stimulate
the bone remodeling process, whereas a negative magnetic field can do the
opposite. When the bone structure is loaded by a positive magnetic field,
both the density and cross-sectional area increase, and stronger and thicker
bone is generated. The more intense the magnetic field is, the stronger and
thicker the bone will be. However, a negative magnetic field can weaken bone
remodeling, making bone thinner and more porous. A positive magnetic
field can play the same role as an increase in transverse loading, whereas a
negative magnetic field can replicate the effect of a decrease in such loading.
The effect of magnetic loading is smooth and gentle. Used as a method to
control remodeling, it is therefore an appropriate way of dealing with bone
conditions.
0.082
0.080
0.078
0.076
0.074
0.072
-0.2 A
-0.1 A
0 A
0.1 A
0.2 A
0.070
0.068
0.066
0
100
200
300
400
500
t
(day)
FIGURE 5.16
Variations of porosity
p
for several different multifield loadings.
