The best management of irreparable rotator cuff tears remains uncertain, with multiple new techniques introduced over the past 2 decades. Two options for treatment are arthroscopic debridement and biceps tenotomy, or the subacromial balloon spacer. Early trial results favored the former option, but the 2-year results have not yet been reported. Purpose: To report the 2-year follow-up outcomes of the START:REACTS trial, investigating the use of a subacromial balloon spacer for irreparable rotator cuff tears of the shoulder.