title: Early weight bearing of porous HA/TCP (60/40) ceramics in vivo: a longitudinal study in a segmental bone defect model of rabbit.
abstract: Porous interconnected hydroxyapatite (HA) and HA/tricalcium phosphate (TCP) (60/40) ceramics are promising materials for hard tissue repair. However, the mechanical properties of these materials have not been accurately determined under weight-bearing conditions. In this study, newly developed HA and HA/TCP (60/40) ceramics were used with intramedullary fixation in segmental bone defects of rabbits. Early radiological, histological, densitometric and biomechanical changes were evaluated. The mean radiological grade of healing and bonding to bone was higher in HA/TCP (60/40) ceramics than that of pure HA ceramics but the difference was not statistically significant. The densities of both implanted ceramics improved with time, supported by the histological evaluation of bone matrix ingrowth into ceramic pores, whereas the densities at the bone-ceramic interface decreased gradually. Flexural resonant frequencies and three-point bending strength increased, revealing an increase in mechanical stability during this early critical time interval where implant and/or bone-implant interface failures occur frequently. It can be concluded that both HA and HA/TCP (60/40) ceramics have a limited application in the treatment of load-bearing segmental bone defects but did not fail at the early stages of implantation.
authors.affiliation: Department of Mechanical Engineering, Başkent University, Bağlica, 06530 Ankara, Turkey.
authors.forename: Cenk
authors.initials: C
authors.lastname: Balçik
authors.forename: Turgut
authors.initials: T
authors.lastname: Tokdemir
authors.forename: Alpaslan
authors.initials: A
authors.lastname: Senköylü
authors.forename: Nurşen
authors.initials: N
authors.lastname: Koç
authors.forename: Muharrem
authors.initials: M
authors.lastname: Timuçin
authors.forename: Serhat
authors.initials: S
authors.lastname: Akin
authors.forename: Petek
authors.initials: P
authors.lastname: Korkusuz
authors.forename: Feza
authors.initials: F
authors.lastname: Korkusuz
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D015519:Bone Density; D001847:Bone Diseases / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D002130:Calcium Phosphates / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D004195:Disease Models, Animal; D017886:Durapatite / Q000737:chemistry; D008137:Longitudinal Studies; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D016062:Porosity; D011817:Rabbits; D011859:Radiography; D013997:Time Factors; D015898:Tomography Scanners, X-Ray Computed; D016474:Weight-Bearing; D014945:Wound Healing; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D002130:Calcium Phosphates; D017886:Durapatite; C018392:tricalcium phosphate