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Evaluation of machining methods for trabecular metal implants in a rabbit intramedullary osseointegration model
Author(s) -
Deglurkar Mukund,
Davy Dwight T.,
Stewart Matthew,
Goldberg Victor M.,
Welter Jean F.
Publication year - 2007
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.30627
Subject(s) - osseointegration , machining , materials science , implant , porosity , biomedical engineering , electrical discharge machining , intramedullary rod , composite material , metallurgy , surgery , medicine
Implant success is dependent in part on the interaction of the implant with the surrounding tissues. Porous tantalum implants (Trabecular Metal™, TM) have been shown to have excellent osseointegration. Machining this material to complex shapes with close tolerances is difficult because of its open structure and the ductile nature of metallic tantalum. Conventional machining results in occlusion of most of the surface porosity by the smearing of soft metal. This study compared TM samples finished by three processing techniques: conventional machining, electrical discharge machining, and nonmachined, “as‐prepared.” The TM samples were studied in a rabbit distal femoral intramedullary osseointegration model and in cell culture. We assessed the effects of these machining methods at 4, 8, and 12 weeks after implant placement. The finishing technique had a profound effect on the physical presentation of the implant interface: conventional machining reduced surface porosity to 30% compared to bulk porosities in the 70% range. Bone ongrowth was similar in all groups, while bone ingrowth was significantly greater in the nonmachined samples. The resulting mechanical properties of the bone implant‐interface were similar in all three groups, with only interface stiffness and interface shear modulus being significantly higher in the machined samples. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007