Histologic and mechanical evaluation of impacted morcellized cancellous allografts in rabbits - Comparison with hydroxyapatite granules

The bioactivity and mechanical properties of morcellized allografts and hyd roxyapatite (HA) granules were evaluated in a rabbit model. Allografts were replaced by viable trabecular structures within 8 weeks. The yield strengt h and stiffness of allografts were within normal cancellous bone revels by 3 weeks and were maintained afterward. The amount of newly formed bone arou nd HA granules was comparable to that around allografts. The yield strength and stiffness of HA granules were significantly higher than those of allog rafts at 3 and 12 weeks. Allografts offer the advantage of being replaced b y host-bone without significant deterioration in mechanical properties over the course of remodeling. HA granules can also be used for a bone substitu te given their bioactivity in bone conduction and superiority in mechanical properties to allografts.