Seventy-two patients with full-thickness rotator cuff tears were randomized to receive either arthroscopic rotator cuff repair (ARCR) with intraoperative injection of autologous dermal fibroblasts (ADFs) (n=35) or ARCR alone (n=37). The primary outcome of interest was the retear rate assessed by MRI at 6 months postoperatively. Secondary outcomes included range of motion, ASES score, Constant score, and simple shoulder test (SST), evaluated at baseline, 6 months, and 12 months. Overall, the results of the study revealed a significantly lower retear rate in the ADF group compared to the control group (2.9% vs. 16.2%, p=0.012), although there were no significant differences in clinical outcomes between groups at follow-up. These findings suggest that ADF injection may enhance tendon healing after ARCR without compromising clinical recovery.