N. Verdonschot et al., Time-dependent mechanical properties of HA/TCP particles in relation to morsellized bone grafts for use in impaction grafting, J BIOMED MR, 58(5), 2001, pp. 599-604
In reconstructive surgery human bone defects are sometimes filled with the
use of the impaction bone grafting technique. Currently different types of
biomaterial particles are being developed as bone-substitute materials. Bef
ore these biomaterials can be applied their mechanical and biological behav
ior should be characterized. In this study the time-dependent mechanical be
havior of biomaterial particles with different tri-calcium-phosphate/hydrox
y-apatite (TCP:HA) ratios, particle sizes, and porosities is determined and
compared to the behavior of human bone grafts, the latter being the standa
rd material currently used to augment bone defects. The mechanical properti
es were assessed with the use of dynamic confined compression creep tests w
ith a loading and unloading phase. Different graft material groups were tes
ted, consisting of 100% human bone grafts, 100% biomaterial particles, and
50:50 weight mixtures of human grafts and biomaterial particles. No damage
to the particles was observed by the impaction in the test chamber or by th
e dynamic load. Relative to the human graft material, the biomaterial parti
cles hardly deformed under loading, were much stiffer, and showed almost no
viscoelastic behavior. The mixtures showed intermediate results. Particle
size and porosity influenced the behavior of the biomaterial particles. TCP
:HA ratio did not have a great effect. The conclusion is that the applicati
on of these particles should be done with great care, as their mechanical b
ehavior is drastically different than that of the human graft material. Mix
ing it with human bone grafts gave the material some biphasic, viscoelastic
behavior that may be important for its biological response. (C) 2001 John
Wiley & Sons, Inc.