Seventy patients with rotator cuff tears were randomized to receive either hyaluronic acid injection (n=35) or placebo (n=35) after arthroscopic rotator cuff repair. The primary outcome of interest was tendon integrity assessed by MRI using the Sugaya classification. Secondary outcomes included VAS pain scores, ASES, CONSTANT scores, range of motion, and strength. Outcomes were assessed at 2 weeks, 3 months, 6 months, and 12 months. Overall, the results of the study revealed that hyaluronic acid did not improve pain or functional scores compared with placebo but was associated with greater recovery of abduction, internal rotation, and external rotation at 6 and 12 months, and a lower re-tear rate on MRI (14.4% vs 26.7%). The findings suggest that hyaluronic acid may aid tendon healing and accelerate recovery of range of motion after cuff repair.