80 patients with MRI-diagnosed full-thickness rotator cuff tears were randomized to undergo either single-row (SR) or transosseous-equivalent double-row (TEDR) arthroscopic rotator cuff repair, to compare these two treatment approaches with respect to clinical and functional outcomes at 18 months post-operation. Results indicated that, in tears that were less than 3 cm in length, Oxford Shoulder Scores (OSS), University of CA Los Angeles scores (UCLA), and Constant-Murley Outcome Scores (CMS) did not differ between groups. When tears were greater than 3 cm, transosseous-equivalent double-row repair resulted in significantly better OSS, UCLA and CMS scores compared to single-row repair.