Comparative outcomes of supraspinatus tendon reconstruction and superior capsule reconstruction for massive irreparable posterosuperior rotator cuff tears.

Superior capsule reconstruction (SCR) is established for irreparable massive rotator cuff tears (IMRCTs). Supraspinatus tendon reconstruction (STR), a novel technique restoring muscle anatomy, lacks comparative studies with SCR. To compare STR and SCR efficacy in shoulder function, ROM, and radiological outcomes for posterosuperior IMRCTs. This retrospective cohort study analyzed 59 patients (SCR: n = 16; STR: n = 43) treated between December 2019 and November 2023. Outcomes included isokinetic muscle strength, active ROM (forward flexion [FF], abduction [ABD], external rotation [ER], internal rotation [IR]), patient-reported scores (VAS, ASES, Constant, UCLA), and radiological measures (acromiohumeral distance [AHD], Sugaya score, Goutallier classification). Both groups demonstrated significant improvements in ROM, shoulder scores, and AHD postoperatively (P < 0.05). STR required shorter operative times (197.86 ± 32.88 vs. 291.25 ± 72.69 min, P < 0.01) and showed superior reductions in supraspinatus fat infiltration (Goutallier classification: P < 0.01) and greater gains in abduction (ΔABD: P = 0.021) and forward flexion strength (ΔFF: P < 0.01) compared to SCR. No differences were observed in VAS, ASES, or UCLA scores between groups (P > 0.05). Both techniques similarly improve shoulder function. STR demonstrates advantages in operative efficiency, muscle recovery, and mitigating fat infiltration, suggesting potential preference for posterosuperior IMRCTs.