Umbilical Cord-derived Mesenchymal Stem Cell Injectables for the Regeneration of Partial-thickness Rotator Cuff Tears

Inclusion Criteria: * Adults aged 19 years or older * Shoulder pain lasting for at least 3 months * A pain visual analogue scale (VAS) score of 4 or greater * Inadequate response to sufficient conservative treatment for at least 3 months, such as medication, injection therapy, physical therapy, or exercise therapy * Partial-thickness rotator cuff tear confirmed by ultrasonography or magnetic resonance imaging (MRI) * No restrictions on participation in clinical trial procedures, including hospitalization Exclusion Criteria: * Receipt of subacromial injection therapy in the affected shoulder within the past 3 months * History of rotator cuff surgery on the affected shoulder within the past 6 months * Previous treatment with a stem cell therapy for the shoulder * Presence of any of the following shoulder conditions: full-thickness rotator cuff tear, obvious isolated acromioclavicular joint arthropathy, or a clear history of trauma to the shoulder joint within the past 3 months * Radiologic findings suggestive of or consistent with any of the following: malignancy, severe glenohumeral osteoarthritis, bony abnormalities causing narrowing of the subacromial space, or clear evidence of acute traumatic rotator cuff injury * Presence of symptomatic cervical spine disease * Patients with polyarthritis, infectious arthritis, rheumatoid arthritis, or fibromyalgia * Clinical trial subjects with neurological deficits * Pregnant or breastfeeding women * Unwillingness to use an effective method of contraception during participation in the clinical trial * Presence of any serious disease that may affect participation in this clinical trial, including cardiovascular, renal, hepatic, endocrine, or neoplastic disease * Inability to understand the questions used to assess the subject's condition, including the visual analogue scale (VAS), or communication difficulties due to psychiatric illness * Unwillingness to participate in the clinical trial or difficulty in complying with follow-up visits according to the study schedule * Participation in another clinical trial within 3 months prior to enrollment in this clinical trial * Any other condition that, in the opinion of the investigator, makes the subject unsuitable for participation in this clinical trial