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Animal experiment: Inflammatory cell response evaluation1676A distinction was made between acute and chronic inflammatory response by light microscopic evaluation with manual cell counting. Lymphocytes were identified based on cell morphology. To be counted as a lymphocyte, cells had to be mononuclear with a solitary round and dark blue nucleus (no multiple lobes as in neutrophils) and have minimal surrounding cytoplasm. Macrophages had to be round to oval in shape (10-30 µm in diameter), with an eccentrically placed, oval or indented nucleus. Although the cytoplasm is usually “foamy”, this need not be the case and was not used as an exclusion criterium. Statistical analysisPer TMJR, two stained samples were evaluated. A total of five grids were applies per sample. This resulted in a total of 60 grids for the sheep implanted with a DLC-coated condyle (n=6) and 70 grids for those with an uncoated condyle (n=7). A total of ten randomly selected grids were examined on the ewe that underwent sham surgery. For each grid, the number of macrophages and lymphocytes was counted, as well as polymorphonuclear leukocytes if present. The normality macrophage and lymphocyte counts was assessed by a Kolmogorov-Smirnov and ShapiroWilk test, which revealed non-normal distributions (P < 0.001). Thus, a Kruskal-Wallis non-parametric ANOVA test was used to test for differences in numbers of macrophages and lymphocytes between treatment groups, with a Bonferroni correction. The mean number of cells per group was calculated. All data are expressed as mean ± SD. Results No signs of acute infection, marked by the presence of neutrophiles, were found in any of the samples. There were signs of chronic inflammation and presence of macrophages in all samples. (Figs. 2 & 3) Analysis of the distribution plot for lymphocytes (Fig. 4) in the DLCcoated and uncoated samples, reveals higher outliers in the uncoated (140), compared to the coated group (91), as well as a larger mean and larger distribution in the uncoated group (34.51 ± 28.58) compared Nikolas de Meurechy NW.indd 167 05-06-2024 10:14