Background: This article reviews the clinical and radiographic outcomes in a noninferiority trial use of a transosseous knotless anchor to perform arthroscopic rotator cuff repairs in a patient cohort that have an increased incidence of osteoporosis. Methods: Patients aged over 60 with a documented rotator cuff tear and who failed a rehab program underwent repair using an arthroscopic transosseous knotless (ATOK) anchor. Patients were prospectively reviewed using shoulder functional assessments (age-adjusted Constant score, Oxford Shoulder Score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES], visual analog scale [VAS] pain scores), and underwent preoperative as well as 1-, 3-, and 12-month postoperative magnetic resonance imaging. Results: 15 patients had undergone rotator cuff repair using the ATOK and were followed for a minimum of 24 months (range 24-30 months). From preoperative to 24 months post repair, median scores improved for ASES (61-89), Oxford (26-44), Constant (62-91), and VAS Pain (5-0.5). Four patients developed a partial retear of their repair, but only 1 patient sustained a complete retear: Sugaya type I, 10; type II, 1; type III, 2; type IV, 1; and type V, 1. No anchors were displaced, and there were no osteolysis, neurologic, or technique-related complications. Conclusions: Arthroscopic rotator cuff repairs using a transosseous knotless technique has achieved a satisfactory outcome in this group of patients, who typically have poor bone quality, increasing the risk of antegrade anchor pullout. This approach would appear to combine the potential biomechanical and biological advantages of a transosseous repair technique, with the benefits of the lower morbidity arthroscopic surgical approach. Level of evidence: Level IV; Case Series; Treatment Study Ó 2019 The Authors. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).