title: Biomechanical evaluation of the rabbit tibia after implantation of porous hydroxyapatite/collagen in a rabbit model.
abstract: OBJECTIVE
  Porous hydroxyapatite/collagen composite (HAp/Col) is an artificial bone substitute with excellent osteoconduction and sponge-like elasticity. However, the porosity of porous HAp/Col is as high as 95% and its mechanical strength is very poor. The aim of this study was to biomechanically analyze sites implanted with porous HAp/Col.
  
  
  METHODS
  Rectangular cortical bone defects (3 × 8 mm) were made in the tibia of rabbits and filled with porous HAp/Col or porous β-tricalcium phosphate or left vacant. The tibia was harvested at 4 or 12 weeks after surgery. The harvested specimens were analyzed using a micro-CT system, and the mechanical strength of the specimens was examined by torsion testing.
  
  
  RESULTS
  Quantitative micro-CT analysis of the regenerated bone revealed that both bone substitutes equally facilitated bone regeneration. Biomechanical testing demonstrated that the torsional strength of HAp/Col-implanted sites was higher than that of the control (vs control: p = 0.030 and vs β-TCP: p = 0.056).
  
  
  CONCLUSIONS
  The results indicate that porous HAp/Col implantation is an effective strategy for recovery of the mechanical strength of bone defects.
authors.affiliation: Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, Japan; Department of Rehabilitation Medicine, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Masaoka
authors.affiliation: Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yamada
authors.affiliation: Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Yuasa
authors.affiliation: Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, Japan.
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Yoshii
authors.affiliation: Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Okawa
authors.affiliation: Department of Rehabilitation Medicine, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, Japan.
authors.forename: Sadao
authors.initials: S
authors.lastname: Morita
authors.affiliation: HOYA Technosurgical Corporation, 4-28-4 Yotsuya Shinjuku-ku, Tokyo, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kozaka
authors.affiliation: HOYA Technosurgical Corporation, 4-28-4 Yotsuya Shinjuku-ku, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hirano
authors.affiliation: Department of Orthopaedic Research and Development, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, 113-8519, Japan. Electronic address: sotome.orth@tmd.ac.jp.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sotome
mesh_terms: D000818:Animals; D001861:Bone Regeneration; D018786:Bone Substitutes; D003094:Collagen / Q000494:pharmacology*; D004195:Disease Models, Animal; D017886:Durapatite; D016062:Porosity; D019736:Prostheses and Implants; D011817:Rabbits; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D023822:Tissue Engineering / Q000379:methods*; D055114:X-Ray Microtomography
chemical_list: D018786:Bone Substitutes; D003094:Collagen; D017886:Durapatite