Influence of teres minor trophicity on clinical outcomes after arthroscopically assisted posterior latissimus dorsi transfer for irreparable posterosuperior rotator cuff tears.

Abstract

The teres minor (Tm) plays an important role in external rotation and shoulder stability in patients with posterosuperior rotator cuff tears (PSRCTs). This study evaluated whether preoperative Tm trophicity affects clinical and radiologic outcomes following arthroscopically assisted posterior latissimus dorsi LD transfer in patients with irreparable PSRCTs. Patients who underwent arthroscopically assisted posterior LD transfer for irreparable PSRCTs between April 2012 and June 2020 were retrospectively reviewed. Patients were classified into hypertrophic, normal, and hypotrophic groups based on the ratio of the Tm muscle area to the total external rotator muscle area. Clinical outcomes including the visual analog scale (VAS), Constant score, and American Shoulder and Elbow Surgeons (ASES) score were evaluated preoperatively and at final follow-up. Range of motion, shoulder strength, and radiologic outcomes including acromiohumeral distance (AHD) and Hamada grade were also assessed. The minimal clinically important difference (MCID) for the VAS, ASES, and Constant scores was calculated to determine the proportion of patients achieving clinically meaningful improvement at final follow-up, and patients with incomplete follow-up or missing data were excluded. After excluding 14 patients, 83 patients were included in the final analysis: 12 in the hypertrophic group, 56 in the normal group, and 15 in the hypotrophic group. All groups demonstrated significant improvements in clinical outcomes at final follow-up. The hypertrophic group showed greater improvement in external rotation at the side and at 90° of abduction. The hypotrophic group demonstrated a smaller AHD and a higher Hamada stage at final follow-up. However, the proportion of patients achieving the MCID and complication rates did not differ significantly among groups. Arthroscopically assisted posterior LD transfer provides significant pain relief and functional improvement in patients with irreparable PSRCTs regardless of preoperative Tm trophicity. Although hypertrophic Tm was associated with greater postoperative external rotation, overall clinical improvement and MCID achievement were similar among groups. Despite smaller postoperative AHD and higher Hamada grades in the hypotrophic group, clinical outcomes were comparable. IV, retrospective case series.