Biomedical Engineering Reference
In-Depth Information
8
Polymers for bone repair
M. A. MAteos-tiMonedA, institute for Bioengineering
of catalonia (iBec), ciBer-BBn, spain
Abstract
: the use of polymeric materials for bone repair applications has
attracted a great deal of attention for many years, particularly for total hip
replacement prostheses and bone defect fillers. In this chapter, the most used
polymers in the field of bone replacement, both biodegradable and non-
degradable, are reviewed. special attention is paid to properties/application
relationship for each of the materials described.
Key words
: acrylic polymers, biodegradable polymers, bone cement, bone
repair, polymers, prostheses, UHMWPe.
8.1 Introduction
the substitution of tissues owing to tumours, pathologies or traumatic accidents
is well known and different branches of surgery perform this kind of surgery
on a daily basis with relative ease. the substitution of bone tissue is especially
relevant as it contributes to the structural stability of the body.
Bone tissue is composed of an organic matrix, a mineral component
and water in approximately similar volumes. the combination of these
elements forms a composite material with different hierarchical levels in its
microstructure. it is still not possible to reproduce this highly hierarchical
structure.
Historically, articular prostheses have been made of metallic materials
owing to the high mechanical tensions that they will suffer once implanted,
as well as their good fatigue resistance and tenacity. Lately, the use of
polymeric materials has attracted a great deal of attention, although they have
not yet arrived to the market. on the other hand, the choice of a material for
filling bone defects or bone cavities is greater, ranging from biodegradable
polymers to calcium phosphate cements and ceramics.
the role of polymers in bone substitution is relevant but limited to a few
applications, such as articulating bearing surfaces of joint replacements, both
hip and knee, and as interpositional cementing material between the implant
surface and bone. In the first application, the ultimate choice is ultra-high
molecular weight polyethylene (UHMWPe) and in the second one the most
used polymer is poly(methyl methacrylate) (PMMA). recently, the use of
biodegradable polymers has grown significantly in applications dealing
with the support structures needed for the normal movement of articulating
joints.
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