Jo CH, et al. - Via involving 19 patients with a partial-thickness rotator cuff tear, researchers tested the mid-term safety and effectiveness of an intratendinous injection of autologous adipose tissue derived MSCs (AD MSCs) for rotator cuff disease at 2-year follow-up. In the mid- and high-dose groups, intratendinous injection of AD MSCs decreased shoulder pain by nearly 90% at 1 and 2 years. In the high dose group, the strengths of the supraspinatus, infraspinatus, and teres minor significantly increased greater than 50% at 2 years. The structural outcomes assessed with MRI exhibited volume of the bursal-side defect in the high-dose group almost disappeared from 1 year, and did not return up to 2 years. This research showed continued safety and effectiveness of intratendinous injection of AD MSCs over 2 years for the treatment of a partial-thickness rotator cuff tear by tendon defect regeneration. There were no adverse events associated with treatment at a minimum of 2 years of follow-up.