Objectives
:
Microindentation has
the potential to measure
the
elasticity
(stiffness)
of individual
patients’
bone
. Bone elasticity plays a crucial role in the press
-
fit st
ability of orthopaedic
implants.
Arming surgeons with accu
rate
bone elasticity
information
ma
y reduce surgical
compli
cations
including peri
-
prosthetic fractures.
Th
e question we address with this systematic
review
is whether microindentation can accurately measure cortical bone
stiffness
.
Methods:
A systematic review of all English
l
anguage
articles using a keyword searc
h was
undertaken in Medline, Embase, PubMed, Scopus and Cochrane databases. Studies
that
only
used nanoindentation
, cancellous bone
or
animal tissue were
excluded
.
Results:
10
94
abstracts were retrieved and
3
2
papers were include
d in the analysis, 20 of
which used reference point indentation and 1
2
of
which used traditional depth sensing
indentation.
There are a number of factors
that
must be taken into account when using
microindentation such as tip size, depth and method of anal
ysis.
O
nly
two studies
validated
microindentatio
n
against
traditional mechanical testing techniques. Both
studies used reference
point indentatio
n
(RPI)
with one showing that
RPI parameters correlate well with mechanical
testing, but
another suggest
ed
that
they do not.
Conclusion:
Microindentation
has been used in various studies to assess bone elasticity but
only two studies with conflicting results compared microindentation to traditional mechanical
testing techniques
.
Further research
,
including
more st
udies compar
ing
microindentation
to
other mechanical testing
methods
are needed
,
before microindentation can be reliably used to
calculate cortical bone
stiffness
.