Ultrastructural characterisation of the hydroxyapatite–coated pedicle screw and human bone interface
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