Fig. 4

Representative macroscopic and histological findings. Representative (a) macroscopic findings and serial sagittal sections stained with (b) hematoxylin and eosin (H&E), (c) Azan, and (d) Alcian blue of normal patellar tendon (left column), PRP group (middle column; 2, 4, 6, 8, and 10 weeks post-operation), and control group (right column; 2, 4, 6, 8, and 10 weeks post-operation). Black arrowhead: infiltrating inflammatory cell. Red arrowhead: blood capillary