Outcomes of lower trapezius tendon transfer in patients with superior humeral migration: Comparable results between acromiohumeral distance ≥6 mm and <6 mm

Introduction: Lower trapezius tendon (LTT) transfer has emerged as a joint-preserving surgical option for irreparable posterosuperior rotator cuff tears (PSRCTs). This study aims to compare clinical and radiographic outcomes after LTT transfer between patients with Hamada 1 (Acromiohumeral distance (AHD) ≥6 mm) and Hamada 2 (AHD <6 mm) in irreparable PSRCTs. Methods: Patients who underwent arthroscopic-assisted LTT transfer for irreparable PSRCTs between May 2017 and September 2021 were retrospectively reviewed. Inclusion criteria included irreparable tears involving the supraspinatus and infraspinatus with minimal glenohumeral arthritic changes (Hamada grade ≤2). Patients lost to follow-up or those with incomplete clinical data were excluded. Clinical outcomes included Visual Analog Scale (VAS) pain score, American Shoulder and Elbow Surgeons (ASES) score, Constant score, and range of motion. MCID achievement and complication rates, including retear and progression of cuff tear arthropathy, were also analyzed. Results: After excluding 19 patients, a total of 173 patients (Hamada 1, n = 147; Hamada 2, n = 26) were included in the final analysis. Both groups demonstrated significant improvements in VAS pain score, ASES score, Constant score, and range of motion at the final follow-up compared with preoperative values (p < .05). The Hamada 1 group maintained AHD postoperatively, whereas the Hamada 2 group demonstrated a slight increase. At the final follow-up, AHD remained significantly smaller in the Hamada 2 group compared with the Hamada 1 group. However, no significant differences were observed between the groups in postoperative clinical outcomes, MCID achievement, tendon integrity, complication rates, or progression of cuff tear arthropathy. Conclusion: Arthroscopic-assisted LTT transfer demonstrated favorable clinical and radiographic outcomes in patients with irreparable PSRCTs. Both Hamada 1 and Hamada 2 groups showed significant postoperative improvement without significant differences in clinical outcomes between the two groups. In addition, no significant complications were observed between the groups. Level of evidence: Level of evidence 3, retrospective comparative cohort study.