title: Effect of glycerol-L-lactide coating polymer on bone ingrowth of bFGF-coated hydroxyapatite implants.
abstract: Basic fibroblast growth factor (bFGF)-coated hydroxyapatite (HA) cylinders showed good bony incorporation in a previously conducted animal study. However, some cylinders exhibited focal inhomogeneous bone ingrowth. The purpose of the current study was to test whether glycerol-L-lactide polymer coating could improve release properties and bone incorporation of bFGF-coated HA implants. bFGF-coated HA cylinders with or without coating polymer were investigated for in vitro release of bFGF by an immuno-ligand-assay and also for bone ingrowth in miniature pigs after 42 and 84 days. Release from bFGF polymer composites was lower for the first 3 days compared to the other group but was more homogenous and detectable amounts were still found after 20 days. There was significant delay in bone ingrowth of the polymer implants in which even after 84 days bone ingrowth was not completed, whereas in the other group incorporation after 42 days occurred. Detailed histology revealed filling of the HA pores with the polymer, making ingrowth of the surrounding host bone impossible. Only after 84 days starting resorption of the polymer accompanied by bone ingrowth was found. The current study showed that glycerol-L-lactide is not suitable for coating of HA implants due to polymer induced "locking" of HA pores.
authors.affiliation: Department of Trauma Surgery, Justus-Liebig-University Giessen, Rudolf-Buchheim-Str. 7, 35385 Giessen, Germany. Volker.Alt@chiru.med.uni-giessen.de
authors.forename: Volker
authors.initials: V
authors.lastname: Alt
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Pfefferle
authors.forename: Jörg
authors.initials: J
authors.lastname: Kreuter
authors.forename: Jens-Peter
authors.initials: JP
authors.lastname: Stahl
authors.forename: Theodoros
authors.initials: T
authors.lastname: Pavlidis
authors.forename: Christof
authors.initials: C
authors.lastname: Meyer
authors.forename: Jürgen
authors.initials: J
authors.lastname: Mockwitz
authors.forename: Sabine
authors.initials: S
authors.lastname: Wenisch
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schnettler
mesh_terms: D000818:Animals; D018786:Bone Substitutes / Q000737:chemistry; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000493:pharmacokinetics; D017886:Durapatite / Q000737:chemistry*; D005269:Femur / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D020007:Implants, Experimental; D016348:Osseointegration / Q000187:drug effects*; D011091:Polyesters / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D013552:Swine; D013556:Swine, Miniature
chemical_list: D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible; D011091:Polyesters; D011108:Polymers; C496968:glycerol lactide polymer; D016222:Fibroblast Growth Factor 2; D017886:Durapatite