One hundred one patients with semirigid, large, posterosuperior rotator cuff tears were randomized to receive either early motion rehabilitation (n=53) or delayed motion rehabilitation (n=48) after arthroscopic rotator cuff repair with biceps rerouting. The primary outcome of interest was the active range of motion (ROM), measured at 3, 6, and 12 months postoperatively. Secondary outcomes included the visual analog scale (VAS) for pain, University of California-Los Angeles (UCLA) shoulder scores, and retear rates assessed via MRI at 12 months. Results showed no clinically significant differences in ROM, functional scores, or retear rates between the two groups, except for faster ROM recovery in the early motion group by 3 months. This study suggests early motion rehabilitation as a safe and effective option for postoperative recovery.