To evaluate the results and safety of ultrasound-guided MDs shoulder injection in the treatment of supraspinatus tendonitis at Thai Binh Medical University Hospital. Method: Descriptive, longitudinal, non-controlled study. Each patient received 2 ml of MDs Shoulder collagen (1 vial per session) injected into the subacromial bursa under ultrasound guidance, for a total of 5 consecutive injections, one week apart.