title: The bovine bone protein lyophilisate Colloss improves fixation of allografted implants--an experimental study in dogs.
abstract: BACKGROUND
  Impacted morselized bone allograft is a well-established way of giving joint arthroplasties additional support in situations where there is insufficient bone stock. For long-term survival of the implant, early implant fixation is important. We hypothesized that Col-loss, a bone protein lyophilisate, might improve early implant fixation of allografted implants.
  
  
  METHODS
  We inserted 4 porous-coated Ti implants in the distal femurs of 16 dogs. All implants were surrounded by a 2.5-mm gap, which was impacted with morselized allograft with or without Colloss. In each dog, the implants were treated with no Collos or low-, middle- or high-dose (0, 10, 20 and 40 mg) Colloss per cm3 allograft. The observation time was 4 weeks.
  
  
  RESULTS
  Mechanical implant fixation was improved for all 3 groups with Colloss-treated implants (p < 0.05). The best anchorage was seen in the middle-dose group, where fixation was improved by 100%. We saw a dramatic reduction in fibrous tissue on the surface of the Colloss-treated implants (p < 0.001). The Colloss groups showed increased ongrowth of new bone (p < 0.01) and accelerated gap remodeling (p < 0.05).
  
  
  CONCLUSIONS
  Colloss can improve early osseointegration and fixation of allografted implants.
authors.affiliation: Orthopedic Research Laboratory, Department of Orthopedics, Aarhus University Hospital, Denmark. baas@ki.au.dk
authors.forename: Jorgen
authors.initials: J
authors.lastname: Baas
authors.forename: Anders
authors.initials: A
authors.lastname: Lamberg
authors.forename: Thomas Bo
authors.initials: TB
authors.lastname: Jensen
authors.forename: Brian
authors.initials: B
authors.lastname: Elmengaard
authors.forename: Kjeld
authors.initials: K
authors.lastname: Søballe
mesh_terms: D000818:Animals; D019643:Arthroplasty, Replacement / Q000379:methods*; D001696:Biomechanical Phenomena; D018786:Bone Substitutes / Q000008:administration & dosage*; D002417:Cattle; D020099:Coated Materials, Biocompatible / Q000008:administration & dosage*; D004285:Dogs; D005269:Femur / Q000502:physiology; D020007:Implants, Experimental; D016348:Osseointegration / Q000502:physiology*; D014184:Transplantation, Homologous
chemical_list: D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible; C487179:Colloss