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Animal experiment: Surface wear analysis1475Analysis of the Ti6Al4V condylar component Macroscopically, the non-coated condyles exhibited a significant amount of surface damage, ranging from superficial scratches to deep pits, whereas on the coated condyles no obvious damage could be observed (Fig. 4 C and D). This was again confirmed by 3D scans of the condylar surfaces where pits and scratches could be observed in the center of the non-coated condyles while the surface of the coated condyles appeared smooth. Microscopic investigation of the surface revealed multidirectional surface scratches on both types of condyles, yet the scratches appeared remarkably deeper and more densely concentrated on the noncoated Ti6Al4V condylar surfaces than on the H-DLC-coated surfaces (Fig. 7 B and C). For both types, the surface damage was limited to the loadbearing surface of the condyle. In comparison to the pristine condyle, similar multi-directional scratches were seen on the retrieved coated condyles, indicating that these scratches are due to the polishing protocol that is applied before coating the condyle (Fig. 7 A). The amount of surface marks found on the explanted non-coated condyles was markedly higher, indicating that some abrasion had occurred during usage. For a more detailed investigation of the coated surfaces, scanning electron microscopy (SEM) analysis was performed. This analysis confirmed that in five out of six condyles, multi-directional scratches were present without significant damage to the articular surface (Fig. 8 A and B). The condylar surface of ewe #2177 presented deeper marks, for which an additional surface topography analysis using MeX (Alicona Imaging GmbH, Raaba, Austria) was performed, revealing that the surface damage penetrated through the DLC coating (Fig. 8 C and D). The surface roughness of the condylar bearing surface was analyzed using a confocal laser microscope. The 3D as well as 2D surface roughness amplitude parameters are presented in Table 1 and 4. Overall, these quantitative results indicate that the roughness for the non-coated Ti6Al4V condylar surface was higher than for the DLC-coated Ti6Al4V condylar surface and analysis showed a statistically significant difference between both the coated and non-coated average surface roughness for both Sa (p = 0.0083; Mann-Whitney U test) and Ra (p = 0.0182; MannWhitney U test).Nikolas de Meurechy NW.indd 147 05-06-2024 10:14