Background:Medicare insures the largest population of patients at risk for rotator cuff tears in the United States.Purpose:To evaluate the trends in incidence, concomitant procedures, and complications with open and arthroscopic rotator cuff repairs in Medicare patients.Study Design:Cohort study; Level of evidence, 3.Methods:All Medicare patients who had undergone open or arthroscopic rotator cuff repair from 2005 through 2011 were identified with a claims database. Annual incidence, concomitant procedures, and postoperative complications were compared between these 2 groups.Results:In total, 372,109 rotator cuff repairs were analyzed. The incidence of open repairs decreased (from 6.0 to 4.3 per 10,000 patients, P < .001) while the incidence of arthroscopic repairs increased (from 4.5 to 7.8 per 10,000 patients, P < .001) during the study period. Patients in the arthroscopic group were more likely to have undergone concomitant subacromial decompression than those in the open group (87% vs 35%, P < .001), and the annual incidence of concomitant biceps tenodesis increased for both groups (from 3.8% to 11% for open and 2.2% to 16% for arthroscopic, P < .001). While postoperative complications were infrequent, patients in the open group were more likely to be diagnosed with infection within 6 months (0.86% vs 0.37%, P < .001) but no more likely to undergo operative debridement (0.43% vs 0.26%, P = .08). Additionally, patients in the open group were more likely to undergo intervention for shoulder stiffness within 1 year (1.4% vs 1.1%, P = .01).Conclusion:In the Medicare population, arthroscopic rotator cuff repairs have increased in incidence and now represent the majority of rotator cuff repair surgery. Among concomitant procedures, subacromial decompression was most commonly performed despite evidence suggesting a lack of efficacy. Infections and stiffness were rare complications that were slightly but significantly more frequent in open rotator cuff repairs.