title: Osseous integration of hydroxyapatite grafts in metaphyseal bone defects of the proximal tibia (CT-study).
abstract: OBJECTIVE
  The purpose of the study was the examination of the osseous integration of hydroxyapatite grafts used for the filling of metaphyseal bone defects in tibia head fractures.
  
  
  METHODS
  Four patients with lateral tibia plateau fractures AO-type B3 (12) were included in the study. Patients were treated by arthroscopically assisted reduction and percutaneous screw fixation. The metaphyseal bone defects were filled with prepared solid hydroxyapatite graft blocks (Endobon Fa. Merk Darmstadt, Germany). In all of the patients a CT study for the osseous integration of hydroxyapatite grafts used for the filling of metaphyseal bone defects in tibial head fractures was performed. Measurements of density were performed of the implant region, the periimplant region, the distant periimplant region and the fibula bone. Follow-up CT examinations of these specific regions were performed 6 and 12 months postoperative.
  
  
  RESULTS
  In all cases an increase of density of the hydroxyapatite graft after 6 months and 12 months follow-up was detected. The periimplant region showed in all cases a decrease of density. A progressive decrease of the periimplant and the distant cancellous tibial bone region was also detectable after 6 and 12 months post-op. A similar decrease of density was visible in the region of the cancellous bone of the fibula. In the interface region a direct bone formation between the hydroxyapatite graft and the adjected cancellous bone was visible in all cases during follow-up.
  
  
  CONCLUSIONS
  The increase of density of the hydroxyapatite grafts and the direct bone formation in the interface region between the hydroxyapatite graft and the adjacent cancellous bone are clear radiomorphological signs for an osteointegration of hydroxyapatite grafts in the metaphyseal region.
authors.affiliation: Abteilung für Unfall- und Wiederherstellungschirurgie Medizinische Fakultät der Humbolt Universität zu Berlin, Charite, Augustenburger Platz 1, 13353 Berlin, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Khodadadyan-Klostermann
authors.forename: T
authors.initials: T
authors.lastname: Liebig
authors.forename: I
authors.initials: I
authors.lastname: Melcher
authors.forename: M
authors.initials: M
authors.lastname: Raschke
authors.forename: N P
authors.initials: NP
authors.lastname: Haas
mesh_terms: D000328:Adult; D001182:Arthroscopy; D018786:Bone Substitutes; D017886:Durapatite; D005260:Female; D005593:Fracture Fixation, Internal; D006801:Humans; D008297:Male; D008875:Middle Aged; D016348:Osseointegration; D013978:Tibial Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed
chemical_list: D018786:Bone Substitutes; C104266:endobon; D017886:Durapatite