Aim: The objective of this study was to describe the outcome of reverse shoulder arthroplasty (RSA) combined with modified L'Episcopo procedure at long-term follow-up (5 to 12 years). Methods: A retrospective review of 17 RSAs (mean age 67.2 years) with the modified L'Episcopo procedure conducted between 2006 and 2016 was performed. All patients had a combined loss of active elevation and external rotation with an irreparable posterosuperior rotator cuff tear. Clinical assessment was performed with a minimum follow-up of five years (mean 97.3 months). Outcome measures included range of motion, subjective shoulder value (SSV), visual analogue scale (VAS), and Constant-Murley scores. Results: All patients (16) demonstrated a significant improvement in all clinical and functional parameters. VAS pain scores improved from 6 ± 2.6 to 1 ± 1; SSV improved from 35 ± 14 to 72 ± 10; active forward elevation increased from 66° ± 34 to 125° ± 29; and active external rotation arm at the body increased from −11° ± 22 to 21° ±11 and in 90° of abduction from −10° ± 17 to 37° ± 24. The mean Constant score improved from 25 ± 11 to 59 ± 8. Active internal rotation did not significantly change (p = 0.332). Conclusion: At long-term follow-up, RSA combined with modified L'Episcopo procedure resulted in significant improvements in pain, range of motion, and functional scores for patients with shoulder pseudoparalysis and a lack of active external rotation caused by a massive posterosuperior cuff tear with a teres minor deficiency. [ABSTRACT FROM AUTHOR]