Strength after surgical repair of the rotator cuff.

Abstract

Forty-two consecutive patients (20 men and 22 women, age range 39 to 78 years) with full-thickness rotator cuff tears underwent a comprehensive isokinetic strength assessment before and at 3-month intervals for 1 year after surgery. All patients underwent acromioplasty and rotator cuff repair and were treated with a standardized postoperative rehabilitation program. Isokinetic strength testing was performed in flexion/extension, abduction/adduction, and external/internal rotation at 60 degrees/sec. The unaffected contralateral shoulder was tested for comparison. Clinical outcomes were assessed with the University of California Los Angeles Shoulder Rating Scale (maximum = 35 points). The average University of California Los Angeles score was 31.2 by 1 year after operation. Patients with small and medium tears had an average rating of 33.5, whereas those with large and massive tears had an average score of 28.3. Strength increased gradually during the first postoperative year. The preoperative mean peak torque was 54%, 45%, and 64% of the uninvolved shoulder in flexion, abduction, and external rotation, respectively; after operation it increased to 78%, 80%, and 79% by 6 months and 84%, 90%, and 91% by 12 months. The greatest improvement in strength consistently occurred during the first 6 months after surgery. Patients also showed marked increases in both work and power. By 12 months after operation mean work had increased to 70% in flexion and abduction and 90% in external rotation of the uninvolved shoulder. Similarly, mean power had increased to 68%, 79%, and 90% of the uninvolved shoulder in flexion, abduction, and external rotation, respectively, by 12 months after operation. Recovery of strength correlated primarily with the size of the tear: for small and medium tears recovery of strength was almost complete during the first year, and for large and massive tears it was much slower and less consistent. By using isokinetic strength evaluation we found that recovery of strength after rotator cuff repair requires at least 1 year of rehabilitation.