reticulated composites are formed with a thin coating of a ductile biocompatible metal such as tantalum on a brittle biocompatible substrate such as vitreous carbon . such composites exhibit physical properties that permit these monolithic composites to be morselized , or sized and shaped manually . such composites exhibit surfaces with excellent ductile metal biocompatibility properties , but with strength and fracture physical properties that are more characteristic of the brittle substrate than of the ductile metal . such composites fracture easily , and may be morselized or worked by manual sizing and shaping . such morselization and working is accomplished by breaking or fracturing the composite , rather than plastically deforming it . morselized or manually shaped reticulated composites exhibit excellent biocompatibility characteristics with micro - and nano - textured surfaces that promote rapid bone ingrowth and adhesion . when the composite is broken , the substrate is exposed . the presence of exposed substrate does not significantly impair the biocompatibility of these composites .