20 patients scheduled for arthroscopic rotator cuff repair were randomized to surgery with or without augmentation with plasma rich in growth factors (PRGF). Histological analysis of biopsies taken at 3 months postoperatively was compared between groups, and functional outcome was assessed at 3, 6, 12, and 24 months postoperatively. While significant differences in histological parameters of synovial thickening, vascular proliferation, and chondroid metaplasia development were found in favour of the PRGF group at 3 months, no significant differences between groups were noted in functional outcomes over the 24-month follow-up.