Stem cells aim to fix torn shoulder tendons

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Aged between 18 and 70 years, regardless of gender; 2. Tear size classified as small (\< 1 cm) or medium-sized (1 cm to 3 cm) according to the DeOrio and Cofield classification system; 3. Persistent shoulder pain or functional limitations despite at least 3 months of non-surgical treatment, with indications for arthroscopic rotator cuff repair; 4. Willing to sign the informed consent form and agree to participate in this study. Exclusion Criteria: 1. Tear size classified as large (3 cm to 5 cm) or massive (\> 5 cm) according to the DeOrio and Cofield classification, or Patte grade 3 tendon retraction; 2. Subscapularis tendon tear; 3. Complicated with anterior, posterior, or multidirectional shoulder joint instability; 4. Indications for repair of anterior or posterior labral injury; 5. Intra-articular injection of hyaluronic acid or corticosteroids within 3 months prior to the planned surgery; 6. Comorbidities that contraindicate arthroscopic shoulder surgery; 7. Local (shoulder, abdomen, buttocks) or systemic infection, osteomyelitis, or sepsis; 8. Diabetes mellitus, untreated thyroid disease, chronic kidney disease, or rheumatoid arthritis; 9. Immunodeficiency; 10. Chronic diseases involving coagulation or platelet aggregation, or severe coagulopathy; 11. Severe cardiovascular disease; 12. Stroke or acute cardiovascular event within 6 months prior to the planned surgery; 13. Weight loss \> 30 kg for any reason within 12 months, or unexplained weight loss \> 10 kg within 12 months; 14. Eating disorder or body dysmorphic disorder; 15. Alcohol/drug addiction or mental illness that may affect compliance with postoperative protocols; 16. Pregnant or lactating women; 17. Refusal to sign the informed consent form; 18. Other conditions deemed inappropriate by the investigators.