title: Osseointegration of porous titanium implants with and without electrochemically deposited DCPD coating in an ovine model.
abstract: BACKGROUND
  Uncemented fixation of components in joint arthroplasty is achieved primarily through de novo bone formation at the bone-implant interface and establishment of a biological and mechanical interlock. In order to enhance bone-implant integration osteoconductive coatings and the methods of application thereof are continuously being developed and applied to highly porous and roughened implant substrates. In this study the effects of an electrochemically-deposited dicalcium phosphate dihydrate (DCPD) coating of a porous substrate on implant osseointegration was assessed using a standard uncemented implant fixation model in sheep.
  
  
  METHODS
  Plasma sprayed titanium implants with and without a DCPD coating were inserted into defects drilled into the cancellous and cortical sites of the femur and tibia. Cancellous implants were inserted in a press-fit scenario whilst cortical implants were inserted in a line-to-line fit. Specimens were retrieved at 1, 2, 4, 8 and 12 weeks postoperatively. Interfacial shear-strength of the cortical sites was assessed using a push-out test, whilst bone ingrowth, ongrowth and remodelling were investigated using histologic and histomorphometric endpoints.
  
  
  RESULTS
  DCPD coating significantly improved cancellous bone ingrowth at 4 weeks but had no significant effect on mechanical stability in cortical bone up to 12 weeks postoperatively. Whilst a significant reduction in cancellous bone ongrowth was observed from 4 to 12 weeks for the DCPD coating, no other statistically significant differences in ongrowth or ingrowth in either the cancellous or cortical sites were observed between TiPS and DCPD groups.
  
  
  CONCLUSIONS
  The application of a DCPD coating to porous titanium substrates may improve the extent of cancellous bone ingrowth in the early postoperative phase following uncemented arthroplasty.
authors: Surgical & Orthopaedic Research Laboratories, Prince of Wales Hospital, University of New South Wales, Sydney, Australia.
authors: Dong
authors: D
authors: Chen
authors: Nicky
authors: N
authors: Bertollo
authors: Abe
authors: A
authors: Lau
authors: Naoya
authors: N
authors: Taki
authors: Tomofumi
authors: T
authors: Nishino
authors: Hajime
authors: H
authors: Mishima
authors: Haruo
authors: H
authors: Kawamura
authors: William R
authors: WR
authors: Walsh
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000494:pharmacology*; D020099:Coated Materials, Biocompatible / Q000494:pharmacology; D055664:Electrochemical Techniques; D005269:Femur / Q000187:drug effects* / Q000601:surgery; D006614:Hindlimb / Q000187:drug effects / Q000601:surgery; D016348:Osseointegration / Q000187:drug effects*; D016062:Porosity; D019736:Prostheses and Implants; D033081:Shear Strength / Q000187:drug effects*; D012756:Sheep; D013977:Tibia / Q000187:drug effects* / Q000601:surgery; D014025:Titanium / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D014025:Titanium; C494366:calcium phosphate, dibasic, dihydrate