46.
A small peptide bone substitute (P-15) significantly improved
microarchitecture of concentric gap mass and enhanced implant fixation
in sheep
Ming Ding, Christina Andreasen, Mads Dencker, Anders Jensen, Søren
Overgaard
Department of Orthopaedics and Traumatology Odense University Hospital,
Institute of Clinical Research, University of Southern Denmark; Department of
Orthopaedics and Traumatology, Odense University Hospital, Institute of
Clinical Research, University of Southern Denmark; Department of
Orthopaedics and Traumatology, Odense University Hospital, Institute of
Clinical Research, University of Southern Denmark
Background:
Today 2.2 million bone-graft surgeries are performed annually
on world basis. A variety of biomaterials have been tried out for tissue
engineering of bone healing and repair.
Purpose / Aim of Study:
The aim of this study was to evaluate the effects of a
small peptide (P-15-BGS), a synthetic 15-amino acid residue, on implant
fixation in sheep model. We further assessed whether P-15-BGS combined
with hydroxyapatite+
β
tricalciumphosphate+Poly- Lactic-Acid (HA/
β
TCP-
PDLLA) could enhance implant fixation.
Materials and Methods:
Eight female adult sheep were used. Cylindrical
critical size defects were created at distal femoral condyles bilaterally.
Titanium implants with 2 mm concentric gaps were inserted and the gaps were
filled with one of the four materials: allograft as gold standard (control), P-15-
BGS, P-15-BGS with HA/
β
TCP-PDLLA, or HA/
β
TCP-PDLLA. After nine
weeks, the sheep were sacrificed. Bone-implant blocks were harvested and
sectioned into two parts: one for micro- CT scanning and push-out test, and
one for histomorphometry. The data were evaluated statistically.
Findings / Results:
Interestingly, the microarchitecture of the P-15-BGS
group was significantly different from the control group. Significantly greater
tissue volume fraction and thicker trabeculae were seen in the P-15-BGS group
compared with the allograft group. Despite these differences, the bone
formation and bone ingrowth to porous titanium implant assessed were not
significantly different among the four groups. The P-15-BGS group had
similar shear mechanical properties on implant fixation as the allograft group.
Adding HA/
β
TCP-PDLLA to P-15-BGS did not significantly change these
parameters.
Conclusions:
The P-15-BGS significantly improved microarchitecture of
concentric gap mass, and its enhancements of bone formation and implant
fixation were at least as good as allograft.
