PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow diagram representing search and screen process of studies reporting on nonoperative and operative treatment of irreparable massive rotator cuff tears. CENTRAL, Cochrane Central Register of Controlled Trials; PT, Physical therapy; D, Débridement; PR, Partial repair; GI, Graft interposition; TT, Tendon transfer; SCR, Superior capsular reconstruction; BA, Balloon arthroplasty; RSA, Reverse shoulder arthroplasty; FU, Follow-up; MRCT, Massive rotator cuff tear; RA, Rheumatoid arthritis.