Effects of Allogenic Umbilical Cord-Derived Mesenchymal Stem Cells on Patients With Rotator Cuff Disease

Inclusion Criteria: * Male or female 19 years of age and older. * Patients with unilateral shoulder pain lasting for at least 3months * Patients who do not respond to conservative treatment. * Patients who have not responded to sufficient non-surgical treatments, including medication, injection therapy, physical therapy, or exercise therapy, for more than 3 months * Patients who have a partial-thickness rotator cuff tear confirmed with magnetic resonance imaging (MRI) or ultrasonography (US). * Patients without any restrictions on clinical trial procedures, including hospitalization. Exclusion Criteria: * Patients who have received subacromial injection therapy on the affected shoulder within the past 3 months. * Patients who have undergone rotator cuff surgery on the affected shoulder within the past 6 months * Patients with a history of receiving stem cell therapy for the shoulder. * Patients with the following shoulder conditions: complete rotator cuff tear, adhesive capsulitis, or isolated acromioclavicular joint arthropathy. * Patients showing or suspected of having the following radiological findings: malignancy, severe osteoarthritis of the glenohumeral joint, or skeletal abnormalities decreasing the subacromial space. * Patients presenting with symptomatic cervical spine disorders. * Patients with concurrent bilateral shoulder pain * Patients with polyarthritis, infectious arthritis, rheumatoid arthritis, or fibromyalgia. * Patients with neurological deficit * Pregnant women or lactating mothers. * Patients unwilling to use effective contraception during the clinical trial period. * Patients with current HBV, HCV, or HIV infections, or those with a positive RPR test. * Patients with severe diseases that may affect the clinical trial, including cardiovascular disease, renal disease, liver disease, endocrine disorders, or malignancies. * Patients who are unable to understand the questionnaires used for assessing their clinical status, including the Visual Analogue Scale (VAS), or those with psychiatric disorders impairing communication. * Patients who do not wish to participate in the clinical trial or are unable to comply with follow-up schedules. * Patients who have participated in another clinical trial within the last 3 months. * Patients deemed unsuitable for participation in this clinical trial at the investigator's discretion