Functionalization of Screw Implants with Superelastic Structured Nitinol Anchoring Elements

Abstract Demographic change is leading to a increase in the number of osteoporotic patients, so that a rethink is required in implantology in order to be able to guarantee adequate anchoring stability in the bone. The functional modification of conventional standard screw implants by the use of superelastic, structured Ti6Al4V anchoring elements promises great potential for increasing anchoring stability. For this purpose, conventional screw implants were mechanically machined and extended so that structured-superelastic-positionable-Ti6Al4V anchoring elements could be used. The set-up of the anchoring elements was investigated in CT studies in an artificial bone. In a subsequent handling test, the handling of the function samples was evaluated under surgical conditions. The anchorage stability to standard screw implants was investigated in a final pull-out test according to "ASTM F543".The functionalization of conventional screw implants with structured superelastic Ti6Al4V anchoring elements is technically realizable. It has been demonstrated that the anchoring elements can be set up in the artificial bone without any problems. The anchorage mechanism is easy to handle under operating conditions and the anchoring elements have no negative impact on the surgical procedure. It was shown that, compared to conventional standard screws, more mechanical work is required to remove the functional patterns completely from the bone.In summary, it was shown that conventional standard screw implants can be functionalized with Ti6Al4V structured NiTi anchoring elements and are suitable for orthopedic and neurosurgical use. A first biomechanical test showed that the anchoring stability can be increased by the anchoring elements.