BIOLOX - Nanocomposite for Arthoplasty

BIOLOX ® delta Minimizes Stripe Wear
A manageable problem
Occasionally in hip arthroplasty, the acetabular
cup cannot be implanted in the ideal
position. Such cases are particularly prone
to subsequent micro-separation whereby
the ball head retracts slightly from the cup
when it is not loaded. With the next step
of the patient, the ball head is pressed back
into its original position and exposed to
considerable edge loading. In hard-on-hard
bearings, this can lead to stripe wear in
particular zones of the femoral head and
on the rim of the cup.
Specific Testing
The materials BIOLOX ® forte and BIOLOX ®
delta (as well as combinations of these
materials) show significant performance
differences in tests designed to simulate
micro-separation in the motion cycle. The
stripe wear was highest in the forte-forte
combination and lowest in the delta-delta
combination. This difference can be seen
in the run-in phase of the first million
cycles and in the following steady state.
While stripe wear has been observed in all
hard-on-hard bearings, it does not represent
a risk in ceramic bearings. “Of all
hard-on-hard wear couples, bearings made
of BIOLOX ® delta are best at resisting the
phenomenon of stripe wear, both on the
13
Stripe wear after wear
test under severe microseparation
(2mm). The
zones showing increased
wear are color-coded.
femoral and acetabular side.” 1
1
Prof. Dr. Ian Clarke, Orthopedic Research Center,
Loma Linda University, USA
Average rate of wear in
the run-in phase (0 to
1 million cycles) and in
the steady state (1 to 5
million cycles)
Wear volume (in mm 3 per million cycles)
5
0 to 1 million cycles
1 to 5 million cycles
4
3
2
1
0
Prof. Dr. Ian Clarke, Loma Linda University, USA
Source: Image courtesy of Dr. Todd D Stewart, Institute of Medical and
Biological Engineering, The University of Leeds
BIOLOX ® forte /
BIOLOX ® forte
BIOLOX ® forte /
BIOLOX ® delta
BIOLOX ® delta /
BIOLOX ® forte
BIOLOX ® delta /
BIOLOX ® delta