Biomedical Engineering Reference
In-Depth Information
(a)
(b)
Figure 6.12
Images (
µ
CT) of human bones: (a) healthy ver-
tebra; (b) osteoporotic vertebra, (
by SCANCO Medical
AG, Br uttisellen Switzerland).
Total hip joint replacement involves surgical removal of the diseased head
(''ball'') of a thigh bone, the femur, and a ''cup-shaped'' bone of the pelvis called the
acetabulum
(''socket'') and replacing them with an artificial ball and stem inserted
into the femur bone and an artificial plastic cup socket. Knowing the mechanical
properties of trabecular bone allows the design and optimization of artificial hips
with properties close to the natural complement, which is supposed to prevent the
loosening of the implanted prosthesis.
Osteoarthritis
14)
is a type of arthritis (damage of the body joints) that is caused by
the breakdown and eventual loss of the cartilage of one or more joints. Cartilage is
a proteinaceous substance that serves as a ''lubricant'' or ''cushion'' between the
bones of the joints. The load transmission between the bones and a joint is related
to the mechanical properties of all constituents, and thus, changing properties of
the trabecular may cause damage to the tribological system.
6.4.1
Structural Analogies: Cellular Plastics and Metals
For a long time, the development of artificial cellular materials has been aimed
at utilizing the outstanding properties of biological materials in technical applica-
tions. As an example, the geometry of honeycombs was identically converted into
aluminum structures, which have been used since the 1960s as cores of lightweight
sandwich elements in the aviation and space industries [34, 35]. Nowadays, in
particular, foams made of polymeric materials are widely used in all fields of
technology. For example, Styrofoam
and hard polyurethane foams are widely
used as packaging materials. Other typical application areas are the fields of heat
14)
Also known as degenerative
arthritis,
degenerative joint disease.
