Direct visualization and quantification of bone growth into porous titanium implants using micro computed tomography
- 502 Downloads
The utility of porous metals for the integration of orthopaedic implants with host bone has been well established. Quantification of the tissue response to cementless implants is laborious and time consuming process requiring tissue processing, embedding, sectioning, polishing, imaging and image analysis. Micro-computed tomography (μCT) is a promising three dimensional (3D) imaging technique to quantify the tissue response to porous metals. However, the suitability and effectiveness of μCT for the quantification of bone ingrowth remains unknown. The purpose of this study was to evaluate and compare bone growth within porous titanium implants using both μCT and traditional hard-tissue histology techniques. Cylindrical implants were implanted in the distal femora and proximal tibiae of a rabbit. After 6 weeks, bone ingrowth was quantified and compared by μCT, light microscopy and backscattered electron microscopy. Quantification of bone volume and implant porosity as determined by μCT compared well with data obtained by traditional histology techniques. Analysis of the 3D dataset showed that bone was present in the pores connected with openings larger 9.4 μm. For pore openings greater than 28.2 μm, the size of the interconnection had little impact on the bone density within the porosity for the titanium foams.
KeywordsAverage Pore Size Bone Ingrowth Flat Panel Detector Backscatter Scanning Electron Microscopy Porous Network Interconnectivity
The authors would like to thanks J.P.Nadeau for the preparation of the specimens and are also grateful for Dr. L Lim’s assistance with the animal surgery. The support of the team of Object Research System (ORS) inc. was also greatly appreciated.
- 7.Heiner AD, Brown TD. Frictional coefficients of a new bone ingrowth structure. Trans Orthopaed Res Soc. 2007;32:1623.Google Scholar
- 8.Boyde A, Jones SJ. Back-scattered electron imaging of skeletal tissues. Metab Bone Dis Relat Res 1983–1984;5(3):145–50.Google Scholar
- 17.Bernhardt R, Scharnweber D, Müller B, Thurner P, Schliephake H, Wyss P, et al. Comparison of microfocus and synchrotron X-ray tomography for the analysis of osseontegration around Ti6Al4 V-implants. Euro Cell Mater. 2004;7:42–51.Google Scholar
- 18.Bobyn JD, Pilliar RM, Cameron HU, Weatherly GC. The optimum pore size, for the fixation of porous-surfaced metal implants by the ingrowth of bone. Clin Orthop Relat Res. 1980;150:263–70.Google Scholar
- 19.Baril E, Lefebvre LP, Piché N. X-ray microtomographic visualization and quantification of metallic foam structure filled with second phases—examples in biomedical applications. The proceeding of the 6th Int. Conf on Porous Metals and Metallic Foams (Metfoam 2009); 2009 Sep 1–4; Bratislava, Slovakia.Google Scholar
- 20.Otsuki B, Takemoto M, Fujibayashi S, Neo M, Kokubob T, Nakamura T. Pore throat size and connectivity determine bone and tissue ingrowth into porous implants: three-dimensional micro-CT based structural analyses of porous bioactive titanium implants. Biomaterials. 2006;27(35):5892–900.CrossRefGoogle Scholar
- 22.Lefebvre LP, Thomas Y. Method of making open cell material. US Patent No. 6,660,224 B2, 2003.Google Scholar
- 23.Wazen R, Lefebvre LP, Baril E, Nanci A. Initial evaluation of bone ingrowth into a novel porous titanium coating. J Biomed Mat Res-Part B. 2010;94(1):64–71.Google Scholar
- 24.Gauthier M, Menini R, Bureau MN, So SKV, Dion MJ, Lefebvre LP. Properties of novel titanium foams intended for biomedical applications. ASM Materials and Processes for Medical Devices Conference, 2003 Sep 8–10; Anaheim, California: 382–387.Google Scholar
- 28.Hsieh J. Computed tomography: principles, design, artifacts, and recent advances. 2nd ed. Bellingham, New York: SPIE Press and Wiley; 2009.Google Scholar
- 29.Sethian JA. Level set methods and fast marching methods : evolving interfaces in computational geometry, fluid mechanics, computer vision, and materials science. 2nd ed. Cambridge: Cambridge University Press; 1999.Google Scholar