Subscapularis re-tears associated with preoperative advanced fatty infiltration and greater subscapularis involvement, leading to inferior functional outcomes and decreased acromiohumeral distance.

ABSTRACT

PURPOSE: This study aimed to investigate the influence of repaired subscapularis integrity on midterm results for anterosuperior massive rotator cuff tears (MRCTs) treated with partial rotator cuff repair. METHODS: This study included 57 patients who underwent arthroscopic partial repair for an anterosuperior MRCT. They were assigned to the healed subscapularis group (Group H 37 patients) or subscapularis re-tear group (Group R 20 patients). Preoperative and postoperative functional scores and active ranges of motion (ROMs) were assessed. Preoperative and 6-month follow-up magnetic resonance arthrography (MRA)/computed tomography arthrography (CTA) images were compared between groups. RESULTS: At the final follow-up, mean functional shoulder scores including ROMs improved significantly in both groups compared to preoperative values (p < 0.001), except for forward flexion and internal rotation in Group R. All final functional values and ROMs (excluding external rotation) were better in Group H than in Group R (p < 0.001). Preoperative stage of fatty infiltration in the subscapularis muscle was significantly worse in Group R (p < 0.001). On follow-up MRA/CTA, the immediate residual defect after partial repair increased in 81% (30/37; mean, 17.8 mm) of patients in Group H and 100% (mean 24.6 mm) in Group R (p < 0.001). At final follow-up, mean acromiohumeral distance significantly decreased from 8.2 to 6.0 mm in Group H (p < 0.001) and from 8.3 to 4.9 mm in Group R (p < 0.001). There was a significant difference in final acromiohumeral distance between groups (p < 0.001). CONCLUSION: After a minimum 5-year follow-up after arthroscopic partial repair of anterosuperior MRCT, subscapularis re-tear was identified in 35% of patients (20/57) on early postoperative follow-up MRA/CTA. The subscapularis re-tear group exhibited more preoperative advanced fatty infiltration and greater extents of subscapularis involvement, which led to statistically inferior functional outcomes and decreased acromiohumeral distance at final follow-up. Nonetheless, in terms of a minimal clinically important difference, substantial clinical benefit, and patient-acceptable symptomatic state for clinical significance, there were no significant differences between the groups. LEVEL OF EVIDENCE III.