Title: Ultrastructural characterisation of the hydroxyapatite-coated pedicle screw and human bone interface

Authors: Kathryn Grandfield; Fredric Ericson; Bengt Sandén; Carina B. Johansson; Sune Larsson; Peter Thomsen; Anders Palmquist; Gianluigi A. Botton; Håkan Engqvist

Addresses: The Ångström Laboratory, Department of Engineering Sciences, Uppsala University, Box 534, 751 21, Uppsala, Sweden. ' The Ångström Laboratory, Department of Engineering Sciences, Uppsala University, Box 534, 751 21, Uppsala, Sweden. ' Department of Surgical Sciences-Orthopaedics, Uppsala University Hospital, Akademiska Sjukhuset, ing 61, 6 tr, 751 85, Uppsala, Sweden. ' School of Health and Medical Sciences, Örebro University, 701 85, Örebro, Sweden. ' Department of Surgical Sciences-Orthopaedics, Uppsala University Hospital, Akademiska Sjukhuset, ing 61, 6 tr, 751 85, Uppsala, Sweden. ' Department of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Box 412, 705 30, Gothenburg, Sweden. ' Department of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Box 412, 705 30, Gothenburg, Sweden. ' Department of Materials Science and Engineering, McMaster University, 1280 Main St. W., JHE 357, L8S 4L7, Hamilton, Ontario, Canada. ' The Ångström Laboratory, Department of Engineering Sciences, Uppsala University, Box 534, 751 21, Uppsala, Sweden

Abstract: The early fixation of pedicle screws is crucial for improving spinal stabilisation. Firm and immediate fixation between pedicle screws and bone prevents aseptic loosening and implant failure. Coating with hydroxyapatite is a possible method to improve the fixation of metallic implants in bone. In this study, scanning transmission electron microscopy (STEM) has been used to investigate the ultrastructure of the plasma-sprayed hydroxyapatite coating and human bone interface in detail. Focused ion beam sample preparation also enabled the investigation of the bone-lacunae interface. An intimate contact and elemental analysis between bone and HA coatings suggests bioactive fixation. Therefore, coating with hydroxyapatite leads to enhanced biocompatibility at the ultrastructural level and may lead to improved early and long-term fixation of pedicle screws.

Keywords: hydroxyapatite coating; pedicle screws; bioactive fixation; TEM; FIB; human bone interface; spinal stabilisation; aseptic loosening; implant failure; metallic implants; bone implants; ultrastructure; biocompatibility; biomaterials.

DOI: 10.1504/IJNBM.2012.048209

International Journal of Nano and Biomaterials, 2012 Vol.4 No.1, pp.1 - 11

Available online: 29 Jul 2012 *

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