Abstract
Objectives
High energy long bone fractures with critical bone loss are at risk for nonunion without
strategic intervention. We hypothesize that a synthetic membrane implanted at a single
stage improves bone healing in a preclinical nonunion model.
Methods
Using standard laboratory techniques, microspheres encapsulating bone morphogenic
protein-2 (BMP2) or platelet derived growth factor (PDGF) were designed and coupled
to a type 1 collagen sheet. Critical femoral defects were created in rats and stabilized
by locked retrograde intramedullary nailing. The negative control group had an empty
defect. The induced membrane group (positive control) had a polymethylmethacrylate
spacer inserted into the defect for four weeks and replaced with a bare polycaprolactone/beta-tricalcium
phosphate (PCL/β-TCP) scaffold at a second stage. For the experimental groups, a bioactive
synthetic membrane embedded with BMP2, PDGF or both enveloped a PCL/β-TCP scaffold
was implanted in a single stage. Serial radiographs were taken at 1, 4, 8, and 12
weeks postoperatively from the definitive procedure and evaluated by two blinded observers
using a previously described scoring system to judge union as primary outcome.
Results
All experimental groups demonstrated better union than the negative control (p = 0.01). The groups with BMP2 incorporated into the membrane demonstrated higher
average union scores than the other groups (p = 0.01). The induced membrane group performed similarly to the PDGF group. Complete
union was only demonstrated in groups with BMP2-eluting membranes.
Conclusions
A synthetic membrane comprised of type 1 collagen embedded with controlled release
BMP2 improved union of critical bone defects in a preclinical nonunion model.
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Article info
Publication history
Published online: January 14, 2022
Accepted:
January 4,
2022
Footnotes
☆Investigation Performed at Stanford University Department of Orthopaedic Surgery, Stanford CA
Identification
Copyright
© 2022 Elsevier Ltd. All rights reserved.
