title: Intramedullary fixation of femoral cortical osteotomies with interlocked biodegradable self-reinforced poly-96L/4D-lactide (SR-PLA96) nails.
abstract: Femoral diaphyseal osteotomies of adult sheep were fixed with intramedullary (i.m.) biodegradable self-reinforced poly-96L/4D-lactide (SR-PLA96) nails (Phi 10.66-10.78 mmx195-199 mm) that were interlocked with four Phi 1.5 mm metallic Kirschner (K) wires. Hollow i.m. nails used in the pilot study resulted in implant failure and only two of these sheep were followed long term (18 months and 3 years). In the main study, solid nails were used and this resulted in consolidation in 5/6 cases and in one non-union due to failure of both proximal K wires at 3 weeks. Sheep in the main study were followed for 6 and 12 months. Femurs were studied radiographically, microradiographically, histologically and by oxytetracycline labelling. Good bone healing was achieved and histology showed only a mild tissue reaction to the implant at 6-18 months. At 3 years, the implant had almost degraded and numerous foamy macrophages were ingesting the disintegrated material. No accumulations of lymphocytes implying an immunological inflammatory reaction were seen. This investigation demonstrated that absorbable SR-PLA96 i.m. nails can be used together with interlocking metallic K wires in fixation of simple cortical osteotomies in large animals weighing up to 63 kg. The long-term biocompatibility should be studied in a larger population.
authors.affiliation: Faculty of Veterinary Medicine, PO Box 57, University of Helsinki, FIN-00014, Finland. anu.saikku-backstrom@fimnet.fi
authors.forename: A
authors.initials: A
authors.lastname: Saikku-Bäckström
authors.forename: R-M
authors.initials: RM
authors.lastname: Tulamo
authors.forename: J E
authors.initials: JE
authors.lastname: Räihä
authors.forename: T
authors.initials: T
authors.lastname: Pohjonen
authors.forename: T
authors.initials: T
authors.lastname: Toivonen
authors.forename: P
authors.initials: P
authors.lastname: Törmälä
authors.forename: P
authors.initials: P
authors.lastname: Rokkanen
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D001673:Biodegradation, Environmental; D005269:Femur; D005593:Fracture Fixation, Internal; D010865:Pilot Projects; D011091:Polyesters; D012756:Sheep
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; C033616:poly(lactide)