One hundred forty-two patients with full-thickness small to large rotator cuff tears were randomized to receive either abduction brace immobilization (n=65) or sling immobilization (n=66) for 6 weeks following arthroscopic rotator cuff repair. The primary outcome was the Pittsburgh Sleep Quality Index (PSQI) at 6 weeks postoperatively. Secondary outcomes included anxiety (Self-rating Anxiety Scale), pain levels, patient satisfaction, functional scores (ASES), and tendon healing assessed via ultrasonography at 6 weeks and 1 year. Overall, the results of the study revealed that at 6 weeks, the sling group had significantly better sleep quality, less anxiety, less pain, and higher satisfaction compared to the brace group. However, no differences were found in any outcomes at 1 year, including tendon healing. These findings suggest that sling immobilization offers early psychological and comfort advantages without compromising long-term clinical outcomes.