title: The influence of surface porosity on gap-healing around intra-articular implants in the presence of migrating particles.
abstract: The aim of the present study was to compare the effect of two different porous coatings on bone ongrowth and on the peri-implant migration of polyethylene (PE) particles. Porous-coated cylindrical implants with an either plasma-sprayed closed-pore coating (Pl) or titanium fiber metal open-pore coating (Fi) were inserted intra-articular in exact fit or with a 0.75 mm peri-implant gap. A weight-loaded implant device in the distal femur was used. We used a randomized paired design in eight dogs. PE particles were injected repeatedly intra-articular in the knee until the dogs were killed after 8 weeks. Fi implants had significantly more bone ongrowth 8 (0-21)% compared with Pl implants 0 (0-0)% in gap situations and reduced the number of peri-implant PE particles significantly. Among exact-fitted implants we found that peri-implant tissue around Pl implants consisted of significantly more fibrous tissue than around Fi implants. A sealing effect against the migration of PE particles was found for both Fi and Pl implants in exact fit.
authors.affiliation: Orthopedic Research Laboratory, Aarhus University Hospital, Nørrebrogade 44, Building 1A, DK-8000 Aarhus C, Denmark. ole_rahbek@hotmail.com
authors.forename: Ole
authors.initials: O
authors.lastname: Rahbek
authors.forename: Soren
authors.initials: S
authors.lastname: Kold
authors.forename: Berit
authors.initials: B
authors.lastname: Zippor
authors.forename: Soren
authors.initials: S
authors.lastname: Overgaard
authors.forename: Kjeld
authors.initials: K
authors.lastname: Soballe
mesh_terms: D000497:Alloys; D000818:Animals; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D004285:Dogs; D019544:Equipment Failure Analysis; D005549:Foreign-Body Reaction / Q000209:etiology / Q000473:pathology* / Q000517:prevention & control; D007593:Joint Instability / Q000209:etiology / Q000473:pathology* / Q000517:prevention & control; D007719:Knee Joint / Q000473:pathology / Q000601:surgery; D007720:Knee Prosthesis / Q000009:adverse effects*; D010316:Particle Size; D016062:Porosity; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D016896:Treatment Outcome; D014945:Wound Healing / Q000502:physiology*
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; C031462:titanium alloy (TiAl6V4); D014025:Titanium