Clinical outcomes according to the location of graft retear after arthroscopy-assisted lower trapezius tendon transfer in posterosuperior irreparable rotator cuff tears

Aims This study aimed to compare clinical outcomes according to the location of transferred graft retear in arthroscopy-assisted lower trapezius tendon transfer (aLTT) for posterosuperior irreparable rotator cuff tears (PSIRCTs). Methods This retrospective clinical study enrolled 100 patients who underwent aLTT for PSIRCTs between January 2017 and September 2022. Transferred graft integrity was evaluated using the Sugaya classification on MRI, with any discontinuity (Sugaya classification IV or V) considered a graft retear. Patients were divided into three groups according to the presence or absence of graft retear and the location of the retear: Group 1, intact graft; Group 2, graft tear medial to the supraspinatus footprint; and Group 3, graft tear at the supraspinatus footprint. Clinical outcomes were evaluated with visual analogue scale (VAS) for shoulder pain, Constant score, American Shoulder and Elbow Surgeons (ASES) score, activities of daily living that require active external rotation (ADLER) score, and active range of motion. The acromiohumeral distance (AHD) was evaluated as a radiological outcome. Results The overall rate of transferred graft retear was 19.0% (Groups 1, 2, and 3: n = 81, ten, and nine, respectively). Overall, the postoperative clinical outcomes were significantly better than the preoperative findings across all patient groups combined. Although transferred graft tear did not improve the ADLER and external rotation, transferred graft tears covering the supraspinatus footprint (Group 2) had equivalent VAS scores (mean 1.4 (SD 0.7) vs 1.6 (SD 0.5), p = 0.235) and functional outcomes, including Constant score (mean 67.5 (SD 10.9) vs 64.3 (SD 12.0), p = 0.384), ASES score (mean 79.7 (SD 12.3) vs 75.0 (SD 14.8), p = 0.035), and abduction (mean 148.9 (SD 28.0) vs 145.0 (SD 19.0), p = 0.051), to those of intact grafts. However, transferred graft tears at the supraspinatus footprint (Group 3) showed lower clinical improvements compared to Group 1 and Group 2. In Groups 1 and 2, there was no significant difference between preoperative and postoperative AHD (mean 8.4 (SD 2.0) vs 8.3 (SD 2.0), p = 0.214). However, there was a significant decrease in postoperative AHD (from mean 8.6 (SD 0.9) to 6.8 (SD 1.4), p = 0.015) in group 3. Conclusion These findings suggest that the location of graft retear may influence postoperative outcomes. Transferred graft tears covering the SSP footprint showed significant pain scores and functional outcomes. Transferred graft tears at the supraspinatus footprint did not result in significant functional outcomes. However, the small sample size in the retear groups may limit statistical power. Cite this article: Bone Joint J 2025;107-B(10):1085–1093.