Rotator cuff strength following open subscapularis tendon repair

The purpose of this study was to evaluate supraspinatus and subscapularis strength following repair of either isolated or anterosuperior subscapularis tears associated with a supraspinatus tear. Open subscapularis repairs were done in 24 patients, 12 isolated and 12 anterosuperior. At an average follow-up of 40 months, UCLA, ASES, and Constant scores were recorded. Subscapularis and supraspinatus strengths were tested using a spring gauge. Ultrasound scanning was performed in 20 patients. Average scores were 27 UCLA, 77 ASES and 90 relative Constant. Subscapularis strength was 92% of the non-operated shoulder. Supraspinatus strength was 90%. Statistical analysis showed a significant decrease in supraspinatus strength in the anterosuperior group. No other significant differences were noted. Ultrasound scanning showed an intact subscapularis tendon in all. Full thickness supraspinatus tears were found in 5 and partial thickness in 1. Not the subscapularis, but the supraspinatus determines the outcome of anterosuperior repairs, with more re-tears and decreased strength.