Settable polymer/ceramic composite bone grafts stabilize weight-bearing tibial
plateau slot defects and integrate with host bone in an ovine model.
Authors Lu S, McGough MAP, Shiels SM, Zienkiewicz KJ, Merkel AR, Vanderburgh JP, Nyman
JS, Sterling JA, Tennent DJ, Wenke JC, Guelcher SA
Submitted By Submitted Externally on 7/31/2018
Status Published
Journal Biomaterials
Year 2018
Date Published 10/1/2018
Volume : Pages 179 : 29 - 45
PubMed Reference 29960822
Abstract Bone fractures at weight-bearing sites are challenging to treat due to the
difficulty in maintaining articular congruency. An ideal biomaterial for
fracture repair near articulating joints sets rapidly after implantation,
stabilizes the fracture with minimal rigid implants, stimulates new bone
formation, and remodels at a rate that maintains osseous integrity.
Consequently, the design of biomaterials that mechanically stabilize fractures
while remodeling to form new bone is an unmet challenge in bone tissue
engineering. In this study, we investigated remodeling of resorbable bone
cements in a stringent model of mechanically loaded tibial plateau defects in
sheep. Nanocrystalline hydroxyapatite-poly(ester urethane) (nHA-PEUR) hybrid
polymers were augmented with either ceramic granules (85% ß-tricalcium
phosphate/15% hydroxyapatite, CG) or a blend of CG and bioactive glass (BG)
particles to form a settable bone cement. The initial compressive strength and
fatigue properties of the cements were comparable to those of non-resorbable
poly(methyl methacrylate) bone cement. In animals that tolerated the initial few
weeks of early weight-bearing, CG/nHA-PEUR cements mechanically stabilized the
tibial plateau defects and remodeled to form new bone at 16 weeks. In contrast,
cements incorporating BG particles resorbed with fibrous tissue filling the
defect. Furthermore, CG/nHA-PEUR cements remodeled significantly faster at the
full weight-bearing tibial plateau site compared to the mechanically protected
femoral condyle site in the same animal. These findings are the first to report
a settable bone cement that remodels to form new bone while providing mechanical
stability in a stringent large animal model of weight-bearing bone defects near
an articulating joint.