title: Combining transforming growth factor-beta(1) to a bioabsorbable self-reinforced polylactide pin for osteotomy healing: an experimental study on rats.
abstract: The effect of a bioabsorbable pin containing transforming growth factor-beta(1) on fracture healing was studied in a rat model. The growth factor was mixed into a bioabsorbable polymer paste (a blend of an l-lactic acid oligomer and a copolymer of epsilon-caprolactone and dl-lactide) that was used to fill the grooves of a self-reinforced fracture fixation pin made of a poly-ld-lactic acid copolymer. In an in vitro assay, sustained release of the growth factor from the pins over a 7-day period was demonstrated. A distal femoral osteotomy was made in 60 rats and stabilized with the fracture fixation pin in 48 of them; In the remaining 12 rats, no fixation was performed. The pin used in the study group contained either 5 microg (15 rats) or 50 microg (15 rats) of the growth factor, while in a control group of 18 rats an identical pin without the growth factor was used. After a follow-up of 1, 3, or 6 weeks, the femurs were examined radiographically, histologically, histomorphometrically, and microradiographically, and also used in tetracycline labeling studies. Faster callus formation was evident in the growth factor-treated rats but no acceleration in the healing of the osteotomy was detected.
authors.affiliation: The Department of Surgery, Helsinki University Central Hospital, Topeliuksenkatu 5, 00260 Helsinki, Finland.
authors.forename: L
authors.initials: L
authors.lastname: Tielinen
authors.forename: M
authors.initials: M
authors.lastname: Manninen
authors.forename: P
authors.initials: P
authors.lastname: Puolakkainen
authors.forename: H
authors.initials: H
authors.lastname: Pätiälä
authors.forename: T
authors.initials: T
authors.lastname: Pohjonen
authors.forename: J
authors.initials: J
authors.lastname: Rautavuori
authors.forename: P
authors.initials: P
authors.lastname: Rokkanen
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001858:Bone Nails; D002208:Caproates / Q000494:pharmacology*; D016009:Chi-Square Distribution; D020099:Coated Materials, Biocompatible; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000628:therapy*; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D017102:Fracture Healing / Q000187:drug effects*; D019344:Lactic Acid / Q000494:pharmacology*; D007783:Lactones / Q000494:pharmacology*; D008297:Male; D008852:Microradiography; D010027:Osteotomy; D011091:Polyesters / Q000494:pharmacology*; D011108:Polymers / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D002208:Caproates; D020099:Coated Materials, Biocompatible; D007783:Lactones; D011091:Polyesters; D011108:Polymers; D016212:Transforming Growth Factor beta; D019344:Lactic Acid; C033616:poly(lactide); C121056:caprolactone