title: Biomechanical researches on tissue engineering bone constructed by deproteinated bone.
abstract: OBJECTIVE
  To study biomechanical changes of newly formed bones 24 weeks after repairing large defects of long bones of goats using heterogeneous deproteinated bone (DPB) prepared by modified methods as an engineering scaffold.
  
  
  METHODS
  According to a fully randomized design, 18 goats were evenly divided into three groups: normal bone control group (Group A), autologous bone group (Group B) and experimental group (Group C). Each goat in Groups B and C were subjected to the periosteum and bone defect at middle-lower part of the right tibia (20% of the whole tibia in length), followed by autologous bone or DPB plus autologous MSCs + rhBMP2 implantation, respectively and semi-ring slot fixation; while goats in Group A did not perform osteotomy. At 24 weeks after surgery, biomechanical tests were carried out on the tibias.
  
  
  RESULTS
  At 24 weeks after surgery, the results of anti-compression test on tibias in three groups were recorded by a functional recorder presented as linear pressure-deformation curve. The shapes of the curves and their change tendency were similar among three groups. The ultimate pressure values were 10.74 MPa+/-1.23 MPa, 10.11 MPa+/-1.35 MPa and 10.22 MPa+/-1.32 MPa and fracture compression rates were 26.82%+/-0.87%, 27.17%+/-0.75% and 28.22%+/-1.12% in Groups A, B and C, respectively. Comparisons of anti-compression ultimate pressures and fracture compression rates among three groups demonstrated no significant difference (P(AB) equal to 0.415, P(BC) equal to 0.494). Three-point anti-bend test on tibias was recorded as load-deformation curves, and the shapes of the curves and their change tendency were similar among three groups. The ultimate pressure values of the anti-bend test were 481.52 N+/-12.45 N, 478.34 N+/-14.68 N and 475.62 N+/-13.41 N and the fracture bend rates were 2.62 mm+/-0.12 mm, 2.61 mm+/-0.15 mm and 2.81 mm+/-0.13 mm in Groups A, B and C, respectively. There was no significant difference between groups (P(AB) equal to 0.7, P(BC) equal to 0.448). The ultimate anti-torsion torque values were 6.55 Nm+/-0.25 Nm, 6.34 Nm+/-0.18 Nm and 6.42 Nm+/-0.21 Nm and fracture torsion rates were 29.51 degree+/-1.64degree, 28.88 degree+/-1.46 degree and 28.81 degree+/-1.33 degree in Groups A, B and C, respectively. There was no significant difference between groups (P(AB) equal to 0.123, P(BC) equal to 0.346).
  
  
  CONCLUSIONS
  The biomechanical characteristics of newly formed bones from heterogeneous DPB for repairing large segmental long bone defect are comparable to those of normal bones and autologous bones. DPB has the potential for clinical usage as bone graft material.
authors.affiliation: Department of Orthopaedics, Guizhou Provincial People's Hospital, Guiyang, China. jianyuekui@sina.com
authors.forename: Yue-kui
authors.initials: YK
authors.lastname: Jian
authors.forename: Xiao-bin
authors.initials: XB
authors.lastname: Tian
authors.forename: Qi-hong
authors.initials: QH
authors.lastname: Li
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.forename: Zhi
authors.initials: Z
authors.lastname: Peng
authors.forename: Wei-feng
authors.initials: WF
authors.lastname: Zhao
authors.forename: Yuan-zheng
authors.initials: YZ
authors.lastname: Wang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D005260:Female; D006041:Goats; D008297:Male; D011506:Proteins; D013977:Tibia / Q000502:physiology / Q000601:surgery*; D023822:Tissue Engineering; D054159:Torsion, Mechanical
chemical_list: D011506:Proteins