title: The polymer Polyactive as a bone-filling substance: an experimental study in rabbits.
abstract: The biocompatible, osteoconductive and resorbable polymer Polyactive (PA) was investigated for its performance as a bone-graft substitute. The model consisted of a 4 mm borehole, 1.5 cm distal of the major trochanter in both femurs of a rabbit, of which one was filled with a cylinder of porous PA. The other was left untreated. PA70/30 and PA60/40 were investigated, both before and after being incubated with allogenic bone marrow. 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, both at the defect and immediately proximal and distal of the defect. Histology showed that gap-bridging had occurred within 8 weeks, with 80%-90% of the pores of PA70/30 and PA60/40 occupied by new bone, and an intimate bone-PA contact. PA70/30 seemed to be more suitable compared to PA60/40, in that the highest amount of bone was formed within the shortest period of time. Incubation of PA with allogenic bone marrow resulted in inflammatory reactions at the sites of implantation, which delayed bone growth, but did not prevent it. It was concluded that PA70/30 and PA60/40 are suitable bone-graft substitutes.
authors.affiliation: Department of Orthopaedic Surgery, Maastricht Centre for Biomaterials Research, University Hospital Maastricht, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands. r.kuijer@orthop.unimaas.nl
authors.forename: R
authors.initials: R
authors.lastname: Kuijer
authors.forename: S J
authors.initials: SJ
authors.lastname: Bouwmeester
authors.forename: M M
authors.initials: MM
authors.lastname: Drees
authors.forename: D A
authors.initials: DA
authors.lastname: Surtel
authors.forename: E A
authors.initials: EA
authors.lastname: Terwindt-Rouwenhorst
authors.forename: A J
authors.initials: AJ
authors.lastname: Van Der Linden
authors.forename: C A
authors.initials: CA
authors.lastname: Van Blitterswijk
authors.forename: S K
authors.initials: SK
authors.lastname: Bulstra