A bioactive synthetic membrane improves bone healing in a preclinical nonunion model

Published:January 14, 2022DOI:



      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.


      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.


      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.


      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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        • Schmitz J.P.
        • Hollinger J.O.
        The critical size defect as an experimental model for craniomandibulofacial nonunions.
        Clin Orthop Relat Res. 1986; : 299-308
        • Desai BM
        Am J Orthop. 2007; 36: 8-11
        • Roddy E.
        • DeBaun M.R.
        • Daoud-Gray A.
        • Yang Y.P.
        • Gardner M.J.
        Treatment of critical-sized bone defects: clinical and tissue engineering perspectives.
        Eur J Orthop Surg Traumatol. 2018; 28: 351-362
        • DeBaun M.R.
        • Stahl A.M.
        • Daoud A.I.
        • Pan C.C.
        • Bishop J.A.
        • Gardner M.J.
        • et al.
        Preclinical induced membrane model to evaluate synthetic implants for healing critical bone defects without autograft.
        J Orthop Res. 2019; 37: 60-68
        • Aho O.M.
        • Lehenkari P.
        • Ristiniemi J.
        • Lehtonen S.
        • Risteli J.
        • Leskela H.V.
        The mechanism of action of induced membranes in bone repair.
        J Bone Joint Surg Am. 2013; 95: 597-604
        • Masquelet A.C.
        • Begue T.
        The concept of induced membrane for reconstruction of long bone defects.
        Orthop Clin North Am. 2010; 41 (table of contents): 27-37
        • Ren L.
        • Kang Y.
        • Browne C.
        • Bishop J.
        • Yang Y.
        Fabrication, vascularization and osteogenic properties of a novel synthetic biomimetic induced membrane for the treatment of large bone defects.
        Bone. 2014; 64: 173-182
        • Kang Y.
        • Ren L.
        • Yang Y.
        Engineering vascularized bone grafts by integrating a biomimetic periosteum and beta-TCP scaffold.
        ACS Appl Mater Interfaces. 2014; 6: 9622-9633
        • Zeng W.
        • Rong M.
        • Hu X.
        • Xiao W.
        • Qi F.
        • Huang J.
        • et al.
        Incorporation of chitosan microspheres into collagen-chitosan scaffolds for the controlled release of nerve growth factor.
        PLoS One. 2014; 9e101300
        • Kim S.
        • Kang Y.
        • Krueger C.A.
        • Sen M.
        • Holcomb J.B.
        • Chen D.
        • et al.
        Sequential delivery of BMP-2 and IGF-1 using a chitosan gel with gelatin microspheres enhances early osteoblastic differentiation.
        Acta Biomater. 2012; 8: 1768-1777
        • Li Y.
        • Chen S.K.
        • Li L.
        • Qin L.
        • Wang X.L.
        • Lai Y.X.
        Bone defect animal models for testing efficacy of bone substitute biomaterials.
        J Orthop Transl. 2015; 3: 95-104
        • Kokubu T.
        • Hak D.J.
        • Hazelwood S.J.
        • Reddi A.H.
        Development of an atrophic nonunion model and comparison to a closed healing fracture in rat femur.
        J Orthop Res. 2003; 21: 503-510
        • Mehta M.
        • Strube P.
        • Peters A.
        • Perka C.
        • Hutmacher D.
        • Fratzl P.
        • et al.
        Influences of age and mechanical stability on volume, microstructure, and mineralization of the fracture callus during bone healing: is osteoclast activity the key to age-related impaired healing?.
        Bone. 2010; 47: 219-228
        • Pelissier P.
        • Masquelet A.C.
        • Bareille R.
        • Pelissier S.M.
        • Amedee J.
        Induced membranes secrete growth factors including vascular and osteoinductive factors and could stimulate bone regeneration.
        J Orthop Res. 2004; 22: 73-79
        • Koolen M.
        • Longoni A.
        • van der Stok J.
        • Van der Jagt O.
        • Gawlitta D.
        • Weinans H.
        Complete regeneration of large bone defects in rats with commercially available fibrin loaded with BMP-2.
        Eur Cell Mater. 2019; 38: 94-105
        • Peng K.T.
        • Hsieh M.Y.
        • Lin C.T.
        • Chen C.F.
        • Lee M.S.
        • Huang Y.Y.
        • et al.
        Treatment of critically sized femoral defects with recombinant BMP-2 delivered by a modified mPEG-PLGA biodegradable thermosensitive hydrogel.
        BMC Musculoskelet Disord. 2016; 17: 286
        • Priddy L.B.
        • Chaudhuri O.
        • Stevens H.Y.
        • Krishnan L.
        • Uhrig B.A.
        • Willett N.J.
        • et al.
        Oxidized alginate hydrogels for bone morphogenetic protein-2 delivery in long bone defects.
        Acta Biomater. 2014; 10: 4390-4399
        • Diab T.
        • Pritchard E.M.
        • Uhrig B.A.
        • Boerckel J.D.
        • Kaplan D.L.
        • Guldberg RE
        A silk hydrogel-based delivery system of bone morphogenetic protein for the treatment of large bone defects.
        J Mech Behav Biomed Mater. 2012; 11: 123-131
        • Glatt V.
        • Miller M.
        • Ivkovic A.
        • Liu F.
        • Parry N.
        • Griffin D.
        • et al.
        Improved healing of large segmental defects in the rat femur by reverse dynamization in the presence of bone morphogenetic protein-2.
        J Bone Joint Surg Am. 2012; 94: 2063-2073
        • Eckardt H.
        • Christensen K.S.
        • Lind M.
        • Hansen E.S.
        • Hall D.W.
        • Hvid I.
        Recombinant human bone morphogenetic protein 2 enhances bone healing in an experimental model of fractures at risk of non-union.
        Injury. 2005; 36: 489-494
        • Skelly J.D.
        • Lange J.
        • Filion T.M.
        • Li X.
        • Ayers D.C.
        • Song J.
        Vancomycin-bearing synthetic bone graft delivers rhBMP-2 and promotes healing of critical rat femoral segmental defects.
        Clin Orthop Relat Res. 2014; 472: 4015-4023
        • Kaipel M.
        • Schutzenberger S.
        • Schultz A.
        • Ferguson J.
        • Slezak P.
        • Morton T.J.
        • et al.
        BMP-2 but not VEGF or PDGF in fibrin matrix supports bone healing in a delayed-union rat model.
        J Orthop Res. 2012; 30: 1563-1569
        • Xu L.
        • Lv K.
        • Zhang W.
        • Zhang X.
        • Jiang X.
        • Zhang F.
        The healing of critical-size calvarial bone defects in rat with rhPDGF-BB, BMSCs, and beta-TCP scaffolds.
        J Mater Sci Mater Med. 2012; 23: 1073-1084
        • Park S.Y.
        • Kim K.H.
        • Shin S.Y.
        • Koo K.T.
        • Lee Y.M.
        • Seol Y.J.
        Dual delivery of rhPDGF-BB and bone marrow mesenchymal stromal cells expressing the BMP2 gene enhance bone formation in a critical-sized defect model.
        Tissue Eng Part A. 2013; 19: 2495-2505
        • Montijo H.E.
        • Kellam J.F.
        • Gettys F.K.
        • Starman J.S.
        • Nelson M.K.
        • Bayoumi E.M.
        • et al.
        Utilization of the AO LockingRatNail in a novel rat femur critical defect model.
        J Invest Surg. 2012; 25: 381-386