Effect of Human-Derived Collagen Injection on Clinical and Structural Outcomes after Arthroscopic Rotator Cuff Repair: A Prospective Randomized Controlled Trial

Background: Arthroscopic rotator cuff repair is widely performed; yet tendon healing failure still occurs in some cases and remains a challenge. To address this issue, several studies have investigated intraoperative injection or patch augmentation using porcine-derived collagen; however, no randomized controlled trials have evaluated the efficacy of human-derived collagen. Methods: This prospective, single-center, single-blind, randomized controlled trial included 60 adult patients with full-thickness rotator cuff tears who underwent arthroscopic repair between November 2022 and October 2023. Patients were randomly assigned to either the collagen group (n = 30) or the control group (n = 30). In the collagen group, following tendon repair, human-derived collagen was injected between the tendon and the footprint, as well as into the tendon matrix. Clinical outcomes were assessed using functional scores including the Constant score, University of California, Los Angeles score, American Shoulder and Elbow Surgeons score, and Simple Shoulder Test, as well as range of motion and the visual analog scale (VAS). Structural outcomes were evaluated using magnetic resonance imaging (MRI)-based Sugaya classification and shear wave elastography. Results: = 0.001). Conclusions: Human-derived collagen injections during rotator cuff repair did not result in superior clinical outcomes. However, postoperative MRI showed significantly lower Sugaya grades, and shear wave elastography demonstrated significantly greater tendon elasticity.