Fig. 1

Adipocyte volume, and the number of crown-like structures (CLS) and stromal vascular fraction (SVF) cells in the infrapatellar fat pad (IFP) did not correlate with body mass index (BMI). Adipocytes were isolated from the IFP from patients with osteoarthritis (OA), who were undergoing total knee-replacement surgery, adipocyte volume was determined and the correlation with BMI was assessed (N = 56) (a). Adipocyte size was determined upon haematoxylin and eosin (H&E) staining and the correlation with BMI was assessed (N = 18) (b). IFP tissue was stained for CD68 and the number of CLS was quantified. A representative picture of the staining at × 20 (left) and × 40 (right) magnification (c) and the summary of all results is shown (N = 11) (d). The number of SVF cells per gram adipose tissue was determined and the correlation with BMI was assessed (N = 39) (e). Correlation was tested using Spearman’s rank correlation (a, b) or Pearson correlation coefficient (e). Each dot represents one patient. HPF high power field