Biomimetic Hydroxyapatite Coated Titanium Screws Demonstrate Rapid Implant Stabilization and Safe Removal In-Vivo

• The early fixation of bone screws after surgical implantation still remains a challenge in the fieldof traumatology. Whilst hydroxyapatite (HA) coatings are known to enhance the fixation of implants;their removal at a later time-point may be problematic. An HA coating has been developedto demonstrate that both implant fixation and safe removal are feasible in the same design. Accordinglythe aim of this study was to compare the in-vivo performance of thin biomimetic HA coatedtitanium screws to uncoated counterparts used as control after bilateral implantation in the femoralcondyle of 36 New Zealand White Rabbits. The screws were analysed macroscopically, byhistology, micro-CT and biomechanically at both two and six weeks post-implantation. The HAcoated screws demonstrated excellent biocompatibility. At two weeks the HA coated screws demonstrateda significant increase in removal torque values as well as a strong trend towards higherpull-out forces. In addition histology confirmed a higher degree of osseointegration and directbone to implant contact. At six weeks no difference in pull-out force and removal torque could bedetected. SEM images confirmed the absence of any residual HA coating indicating a fast coatingdegradation in-vivo. The low level of removal torque after full osseointegration at 6 weeks supportsthe feasibility of safe and easy removal of the implant. The HA coating under study appearsto offer a unique characteristic of enhanced fixation with a minimal increase in removal torqueafter full osseointegration. This may be of value in clinical applications where it is necessary toassure both screw fixation and later removal.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Nanoteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Nano-technology (hsv//eng)

Keyword

Teknisk fysik med inriktning mot nanoteknologi och funktionella material

Engineering Science with specialization in Nanotechnology and Functional Materials

Teknisk fysik med inriktning mot materialvetenskap

Engineering Science with specialization in Materials Science

Publication and Content Type

ref (subject category)

art (subject category)