title: In vivo comparison of the osseointegration of vacuum plasma sprayed titanium- and hydroxyapatite-coated implants.
abstract: For the last 15 years, orthopedic implants have been coated with hydroxyapatite (HA) to improve implant fixation. The osteoconductive effect of HA coatings has been demonstrated in experimental and clinical studies. However, there are ongoing developments to improve the quality of HA coatings. The objective of this study was to investigate whether a rough and highly crystalline HA coating applied by vacuum plasma spraying (VPS) had a positive effect on the osseointegration of special, high-grade titanium (Ti) implants with the same surface roughness. Ti alloy implants were coated (VPS) with special, high-grade Ti or HA. The osseointegration of the implants was evaluated by either light microscopy or pullout tests after 1, 2, and 4 weeks of unloaded implantation in the cancellous bone of 18 sheep. The interface shear strength increased significantly over all time intervals. By 4 weeks, values had reached approximately 10N/mm(2). However, the difference between the coatings was not significant at any time interval. Direct bone-implant contact was significantly different between the coatings after 2 and 4 weeks, and reached 46% for Ti and 68% for HA implants by 4 weeks. This study indicates that the use of a rough and highly crystalline HA coating, applied by VPS, enhances early osseointegration. Accelerated establishment of secondary implant fixation decreases the risk of early loosening.
authors.affiliation: Department of Orthopaedic Surgery, University of Otago, Dunedin, New Zealand. Nikolaus_Aebli@health.qld.gov.au
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Aebli
authors.forename: Jörg
authors.initials: J
authors.lastname: Krebs
authors.forename: Hermann
authors.initials: H
authors.lastname: Stich
authors.forename: Peter
authors.initials: P
authors.lastname: Schawalder
authors.forename: Mark
authors.initials: M
authors.lastname: Walton
authors.forename: Daryl
authors.initials: D
authors.lastname: Schwenke
authors.forename: Heiko
authors.initials: H
authors.lastname: Gruner
authors.forename: Beat
authors.initials: B
authors.lastname: Gasser
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Theis
mesh_terms: D000818:Animals; D018786:Bone Substitutes; D001842:Bone and Bones / Q000378:metabolism*; D020099:Coated Materials, Biocompatible; D017886:Durapatite; D005260:Female; D017102:Fracture Healing / Q000502:physiology; D023421:Models, Animal; D034561:Sheep, Domestic; D014025:Titanium
chemical_list: D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible; D017886:Durapatite; D014025:Titanium