title: Effects of gold coating on experimental implant fixation.
abstract: Insertions of orthopedic implants are traumatic procedures that trigger an inflammatory response. Macrophages have been shown to liberate gold ions from metallic gold. Gold ions are known to act in an antiinflammatory manner by inhibiting cellular NF-kappaB-DNA binding and suppressing I-kappa B-kinase activation. The present study investigated whether gilding implant surfaces augmented early implant osseointegration and implant fixation by its modulatory effect on the local inflammatory response. Ion release was traced by autometallographic silver enhancement. Gold-coated cylindrical porous coated Ti6Al4V implants were inserted press-fit in the proximal part of tibiae in nine canines and control implants without gold inserted contralateral. Observation time was 4 weeks. Biomechanical push-out tests showed that implants with gold coating had approximately 50% decrease in mechanical strength and stiffness. Histomorphometrical analyses showed gold-coated implants had a decrease in overall total bone-to-implant contact of 35%. Autometallographic analysis revealed few cells loaded with gold close to the gilded implant surface. The findings demonstrate that gilding of implants negatively affects mechanical strength and osseointegration because of a significant effect of the released gold ions on the local inflammatory process around the implant. The possibility that a partial metallic gold coating could prolong the period of satisfactory mechanical strength, however, cannot be excluded.
authors.affiliation: Orthopaedic Research Center, Department of Orthopaedics, Aarhus University Hospital, Noerrebrogade 44, Building 1A, DK-8000 Aarhus C, Denmark. kza@studmed.au.dk
authors.forename: Kasra
authors.initials: K
authors.lastname: Zainali
authors.forename: Gorm
authors.initials: G
authors.lastname: Danscher
authors.forename: Thomas
authors.initials: T
authors.lastname: Jakobsen
authors.forename: Stig S
authors.initials: SS
authors.lastname: Jakobsen
authors.forename: Jørgen
authors.initials: J
authors.lastname: Baas
authors.forename: Per
authors.initials: P
authors.lastname: Møller
authors.forename: Joan E
authors.initials: JE
authors.lastname: Bechtold
authors.forename: Kjeld
authors.initials: K
authors.lastname: Soballe
mesh_terms: D000497:Alloys; D000818:Animals; D002477:Cells / Q000187:drug effects; D020099:Coated Materials, Biocompatible / Q000009:adverse effects / Q000627:therapeutic use; D004285:Dogs; D006046:Gold / Q000494:pharmacology* / Q000627:therapeutic use; D020007:Implants, Experimental; D007249:Inflammation / Q000188:drug therapy; D055595:Mechanical Phenomena; D016348:Osseointegration / Q000187:drug effects; D013977:Tibia; D014025:Titanium / Q000627:therapeutic use
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; C031462:titanium alloy (TiAl6V4); D006046:Gold; D014025:Titanium