Change in the pennation angle of the supraspinatus muscle after rotator cuff tear repair

The pennation angle is an important architectural and functional feature of pennate muscles. The purpose of this study was to investigate the change in the pennation angle of the supraspinatus muscle after rotator cuff tear repair. The study included 68 patients who underwent arthroscopic rotator cuff repair and magnetic resonance imaging. The size of the tear was measured under arthroscopic visualization. The pennation angle of the supraspinatus both preoperatively and postoperatively and the integrity of the repaired cuff were determined by magnetic resonance imaging. The preoperative pennation angle was significantly greater with enlargement of the tear size (P