The polymer Polyactive\+sp\TM\-sp\ as a bone-filling substance: an experimental study in rabbits

Reports on experiments in which a 4 mm borehole in one femur of a rabbit was filled with a cylinder of porous Polyactive (PA) while the other was left untreated. Analyses were performed after 4, 8, 26 and 52 weeks and comprised dual energy X-ray absorptiometry (DXA) and image analysis of histological sections. DXA revealed an increased bone mineral density in the filled defects compared to the controls. Histology showed that gap-bridging had occurred within 8 weeks. PA70/30 seemed to be more suitable compared to PA60/40, in that the highest amount of bone marrow was formed within the shortest period of time. Incubation of PA with allogenic bone marrow resulted in inflammatory reactions, which delayed bone growth, but did not prevent it. (Original abstract - amended)