Effect of Hand Grip Exercise on Rotator Cuff Strength and Shoulder Function Recovery after Arthroscopic Rotator Cuff Repair: A Prospective Randomized Controlled Trial

Background: This study aimed to evaluate the effect of hand grip exercise on rotator cuff strength and shoulder function after arthroscopic rotator cuff repair. Methods: Ninety patients who underwent arthroscopic rotator cuff repair were randomly allocated into the grip exercise group (n = 45) and control group (n = 45). The hand grip strengthening exercise (3 sets of 15 repetitions, twice daily) was applied only to the grip exercise group immediately after surgery up to 3 months. From 3 months postoperatively, the same rotator cuff and periscapu-lar muscle strengthening exercises were applied to both groups. The isometric strength of the shoulder joint (abductor, external rotator, and internal rotator) and periscapular muscles, tone and stiffness of the upper trapezius muscle, range of motion (ROM), pain visual analog scale (VAS) score, American Shoulder and Elbow Surgeons score, Constant score, and University of California, Los Angeles score were measured preoperatively and at 3, 6, and 12 months postoperatively. Changes in the supraspinatus muscle atrophy and repair integrity were assessed via magnetic resonance imaging at 6 months postoperatively. Results: At 3 months, abductor, external rotator, and internal rotator muscle strengths were not significantly different between groups, but at 6 months, the grip exercise group showed significantly higher external rotator and internal rotator strengths (all p < 0.05). Similarly, the periscapular muscle strengths were not different at 3 months, but the serratus anterior muscle strength was higher in the grip exercise group at 6 months (p = 0.034). At 12 months postoperatively, the differences in the external rotator and internal rotator muscle strengths, and serratus anterior muscle strength disappeared. There were no significant differences in the tone and stiffness of the upper trapezius muscle, ROM, pain VAS, and functional scores. In addition, changes in the supraspinatus muscle atrophy and the repair integrity were not different between groups. Conclusions: Hand grip exercise affected the rotator cuff and periscapular muscle strengths at 6 months after rotator cuff repair. The grip exercises can effectively and safely promote a faster recovery of shoulder muscle strength and function, without compro-mising rotator cuff healing. © 2026 by The Korean Orthopaedic Association.