Vadym Voropai (Magdeburg, DE), Maren Nieher (Mittweida, DE), Alexander Kratsch (Mittweida, DE), Wilhelm Kirchner (Berlin, DE), Bernd Giggel (Bösdorf, DE), Prof. Dr. Christoph H. Lohmann (Magdeburg, DE), Prof. Dr. Jessica Bertrand (Magdeburg, DE), Prof. Dr. Steffen Weißmantel (Mittweida, DE), Dr. Joachim Döring (Magdeburg, DE)
Abstract text (incl. figure legends and references)
Introduction
Knee joint replacement with a total knee endoprosthesis is one of the most common surgeries in Germany. Tribological wear processes cause formation of PE and metal wear particles as well as emission of metal ions. These can cause complications that require a revision surgery. The use of a hard-on-hard bearing with a low-friction and wear-resistant coating can eliminate PE wear and significantly reduce metal wear and ion emission.
Objectives
In this research, smooth and microstructured ta-C (tetrahedral amorphous carbon) coatings were tested to investigate their suitability on knee joint replacements. The hypothesis is that the ta-C coating with a laser-generated microstructure can provide good tribological properties as well as biocompatibility and barrier function against ion emission.
Materials & Methods
The ta-C coatings were deposited using a patented Pulsed Laser Deposition technology. The surface quality was analysed using the 3D confocal microscopy and SEM. Mechanical properties and adhesion were evaluated using nanoindentations and scratch test. The tribological tests were carried out in a tribology cell using calf serum as a lubricant. The barrier effect against the metal ions was investigated using a long-term test in calf serum. Biocompatibility and antibacterial potential were tested with two types of cells and bacteria.
Results
The ta-C coatings showed the roughness Ra of 5 to 35 nm, hardness up to 60 GPa and adhesion comparable to commercially available coatings. The tribological tests confirm the advantages of microstructures that provide a lower friction coefficient and wear rate. The deposited coatings demonstrated excellent biocompatibility and moderate antibacterial potential.
Conclusion
Due to the advantageous mechanical and tribological properties as well as excellent biocompatibility, the ta-C coatings show a high potential for application on knee joint replacements and this potential can be enhanced in further studies.