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Boller LA, McGough MA, Shiels SM, Duvall CL, Wenke JC, Guelcher SA. Settable Polymeric Autograft Extenders in a Rabbit Radius Model of Bone Formation. MATERIALS 2021; 14:ma14143960. [PMID: 34300888 PMCID: PMC8305944 DOI: 10.3390/ma14143960] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/01/2021] [Accepted: 07/08/2021] [Indexed: 11/16/2022]
Abstract
Autograft (AG) is the gold standard for bone grafts, but limited quantities and patient morbidity are associated with its use. AG extenders have been proposed to minimize the volume of AG while maintaining the osteoinductive properties of the implant. In this study, poly(ester urethane) (PEUR) and poly(thioketal urethane) (PTKUR) AG extenders were implanted in a 20-mm rabbit radius defect model to evaluate new bone formation and graft remodeling. Outcomes including µCT and histomorphometry were measured at 12 weeks and compared to an AG (no polymer) control. AG control examples exhibited new bone formation, but inconsistent healing was observed. The implanted AG control was resorbed by 12 weeks, while AG extenders maintained implanted AG throughout the study. Bone growth from the defect interfaces was observed in both AG extenders, but residual polymer inhibited cellular infiltration and subsequent bone formation within the center of the implant. PEUR-AG extenders degraded more rapidly than PTKUR-AG extenders. These observations demonstrated that AG extenders supported new bone formation and that polymer composition did not have an effect on overall bone formation. Furthermore, the results indicated that early cellular infiltration is necessary for harnessing the osteoinductive capabilities of AG.
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Affiliation(s)
- Lauren A. Boller
- Department of Biomedical Engineering, Vanderbilt University, 2201 West End Ave, Nashville, TN 37235, USA; (L.A.B.); (M.A.P.M.); (C.L.D.)
| | - Madison A.P. McGough
- Department of Biomedical Engineering, Vanderbilt University, 2201 West End Ave, Nashville, TN 37235, USA; (L.A.B.); (M.A.P.M.); (C.L.D.)
| | - Stefanie M. Shiels
- U.S. Army Institute of Surgical Research, 3698 Chambers Rd, San Antonio, TX 78234, USA; (S.M.S.); (J.C.W.)
| | - Craig L. Duvall
- Department of Biomedical Engineering, Vanderbilt University, 2201 West End Ave, Nashville, TN 37235, USA; (L.A.B.); (M.A.P.M.); (C.L.D.)
| | - Joseph C. Wenke
- U.S. Army Institute of Surgical Research, 3698 Chambers Rd, San Antonio, TX 78234, USA; (S.M.S.); (J.C.W.)
| | - Scott A. Guelcher
- Department of Biomedical Engineering, Vanderbilt University, 2201 West End Ave, Nashville, TN 37235, USA; (L.A.B.); (M.A.P.M.); (C.L.D.)
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, 2201 West End Ave, Nashville, TN 37235, USA
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, 1211 Medical Center Dr., Nashville, TN 37212, USA
- Correspondence:
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Kulkova J, Moritz N, Huhtinen H, Mattila R, Donati I, Marsich E, Paoletti S, Vallittu PK. Bioactive glass surface for fiber reinforced composite implants via surface etching by Excimer laser. Med Eng Phys 2016; 38:664-670. [PMID: 27134152 DOI: 10.1016/j.medengphy.2016.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 02/22/2016] [Accepted: 04/03/2016] [Indexed: 11/26/2022]
Abstract
Biostable fiber-reinforced composites (FRC) prepared from bisphenol-A-glycidyldimethacrylate (BisGMA)-based thermosets reinforced with E-glass fibers are promising alternatives to metallic implants due to the excellent fatigue resistance and the mechanical properties matching those of bone. Bioactive glass (BG) granules can be incorporated within the polymer matrix to improve the osteointegration of the FRC implants. However, the creation of a viable surface layer using BG granules is technically challenging. In this study, we investigated the potential of Excimer laser ablation to achieve the selective removal of the matrix to expose the surface of BG granules. A UV-vis spectroscopic study was carried out to investigate the differences in the penetration of light in the thermoset matrix and BG. Thereafter, optimal Excimer laser ablation parameters were established. The formation of a calcium phosphate (CaP) layer on the surface of the laser-ablated specimens was verified in simulated body fluid (SBF). In addition, the proliferation of MG63 cells on the surfaces of the laser-ablated specimens was investigated. For the laser-ablated specimens, the pattern of proliferation of MG63 cells was comparable to that in the positive control group (Ti6Al4V). We concluded that Excimer laser ablation has potential for the creation of a bioactive surface on FRC-implants.
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Affiliation(s)
- Julia Kulkova
- Turku Clinical Biomaterials Centre (TCBC), Department of Biomaterials Science, Institute of Dentistry, University of Turku and Biocity Turku Biomaterials Research Program and City of Turku Welfare Division, Itäinen pitkäkatu 4B (PharmaCity), FI-20520 Turku, Finland
| | - Niko Moritz
- Turku Clinical Biomaterials Centre (TCBC), Department of Biomaterials Science, Institute of Dentistry, University of Turku and Biocity Turku Biomaterials Research Program and City of Turku Welfare Division, Itäinen pitkäkatu 4B (PharmaCity), FI-20520 Turku, Finland.
| | - Hannu Huhtinen
- Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, FI-20014, Finland
| | - Riina Mattila
- Turku Clinical Biomaterials Centre (TCBC), Department of Biomaterials Science, Institute of Dentistry, University of Turku and Biocity Turku Biomaterials Research Program and City of Turku Welfare Division, Itäinen pitkäkatu 4B (PharmaCity), FI-20520 Turku, Finland
| | - Ivan Donati
- Department of Life Sciences, University of Trieste, Via Licio Giorgieri 5, I-34127 Trieste, Italy
| | - Eleonora Marsich
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Piazza dell'Ospitale 1, 34129 Trieste, Italy
| | - Sergio Paoletti
- Department of Life Sciences, University of Trieste, Via Licio Giorgieri 5, I-34127 Trieste, Italy
| | - Pekka K Vallittu
- Turku Clinical Biomaterials Centre (TCBC), Department of Biomaterials Science, Institute of Dentistry, University of Turku and Biocity Turku Biomaterials Research Program and City of Turku Welfare Division, Itäinen pitkäkatu 4B (PharmaCity), FI-20520 Turku, Finland
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Keränen P, Koort J, Itälä A, Ylänen H, Dalstra M, Hupa M, Kommonen B, Aro HT. Bioceramic inlays do not improve mechanical incorporation of grit-blasted titanium stems in the proximal sheep femur. J Biomed Mater Res A 2010; 92:1578-86. [PMID: 19437438 DOI: 10.1002/jbm.a.32494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The aim of the present study was to determine, if bioactive glass (BG) surface inlays improve osseointegration of titanium implants in the proximal femur of adult sheep. In simulation of uncemented primary stems (nine animals), only the proximal part of the implants was grit-blasted and three surface slots of the grit-blasted region were filled with sintered BG microspheres. Primary stems were implanted using press-fit technique. In revision stem simulation (eight animals), grit-blasting was extended over the whole implant and seven perforating holes of the stem were filled by sintered BG granules. Revision stems were implanted with a mixture of autogenous bone graft and BG granules. Comparison with solid partially or fully grit-blasted control stems implanted in the contralateral femurs was performed in the primary and revision stem experiments at 12 and 25 weeks, respectively. Implant incorporation was evaluated by torsional failure testing and histomorphometry. Only one-third of the primary stems anchored mechanically to bone. The revision stems incorporated better and the BG inlays of the revision stems showed ingrowth of new bone. However, there were no significant differences in the torsional failure loads between the stems with BG inlays and the control stems. In conclusion, surface BG inlays gave no measurable advantage in mechanical incorporation of grit-blasted titanium implants. Overall, the proximal sheep femur, characterized by minimal amount of cancellous bone and the presence of adipocytic bone marrow, seemed to present compromised bone healing conditions.
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Affiliation(s)
- Pauli Keränen
- Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
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Zhao DS, Moritz N, Laurila P, Mattila R, Lassila LVJ, Strandberg N, Mäntylä T, Vallittu PK, Aro HT. Development of a multi-component fiber-reinforced composite implant for load-sharing conditions. Med Eng Phys 2008; 31:461-9. [PMID: 19109047 DOI: 10.1016/j.medengphy.2008.11.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 05/18/2008] [Accepted: 11/11/2008] [Indexed: 11/30/2022]
Abstract
Fiber-reinforced composites (FRC) have the potential for use as load-bearing orthopaedic implants if the high strength and elastic modulus of FRC implant can be matched with local requirements. This study tested the in vivo performance of novel FRC implants made of unidirectional glass fibers (E-glass fibers in Bis-GMA and TEGDMA polymeric matrix). The implant surface was covered with bioactive glass granules. Control implants were made of surface-roughened titanium. Stress-shielding effects of the implants were predicted by finite element modelling (FEM). Surgical stabilization of bone metastasis in the subtrochanteric region of the femur was simulated in 12 rabbits. An oblong subtrochanteric defect of a standardized size (reducing the torsional strength of the bones approximately by 66%) was created and an intramedullary implant made of titanium or the FRC composite was inserted. The contralateral femur served as the intact control. At 12 weeks of healing, the femurs were harvested and analyzed by radiography, torsional testing, micro-CT imaging and hard tissue histology. The functional recovery was unremarkable in both groups, although the final analysis revealed two healed undisplaced peri-implant fractures in the group of FRC implants. FEM studies demonstrated differences in stress-shielding effects of the titanium and FRC implants, but the expected biological consequences did not become evident during the follow-up time of the animal study. Biomechanical testing of the retrieved femurs showed no significant differences between the groups. The torsional strength of the fixed bones had returned the level of contralateral intact femurs. Both implants showed ongrowth of intramedullary new bone. No adverse tissue reactions were observed. Based on these favorable results, a large-scale EU-project (NewBone, www.hb.se/ih/polymer/newbone) has been launched for development of orthopaedic FRC implants.
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Affiliation(s)
- D S Zhao
- Orthopaedic Research Unit, University of Turku, Turku, Finland
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