Introduction <p>Superior capsular reconstruction (SCR) and reverse shoulder arthroplasty (RSA) are viable treatment options for active patients with posterosuperior irreparable rotator cuff tears (PSIRCTs). In this study, we aimed to compare the clinical outcomes and recovery of muscle strength following RSA and SCR in PSIRCTs patients without arthritis.</p> Material and methods <p>Fifteen patients were included in the RSA and SCR groups using propensity score matching, which was performed to minimize selection bias among the surgical treatments, RSA or SCR. Clinical outcomes were evaluated based on the degree of pain and patient-reported clinical scores. Functional outcomes were assessed with active range of motion of the shoulder and muscle strength. Radiological outcomes were assessed with acromiohumeral distance and Hamada grade.</p> Results <p>Both groups showed significant improvement in postoperative clinical and functional outcomes; there was no significant difference between the groups. However, mean improvement in the Constant score, American Shoulder and Elbow Surgeons (ASES) score, University of California Los Angeles (UCLA) score, forward elevation, and abduction was significantly better in the RSA group. Moreover, the achievement of MCID for ASES score and UCLA score was significantly better in the RSA group (<i>p</i> = 0.001 and 0.009, respectively). Although the muscle strength was improved following SCR or RSA, it was not statistically significant. In the SCR group, five patients (30%) showed postoperative progression of arthritic change, and seven patients (46.7%) had graft re-tear.</p> Conclusions <p>Our findings suggest that RSA provides greater improvements in functional outcomes and a higher likelihood of achieving MCID compared to SCR in patients with PSIRCTs without arthritis. However, given the small sample size, the potential for indication bias, and the high variability in patient selection criteria, these results should be interpreted with caution.</p> Level of evidence <p>III.</p>