Comparison of Steroid, PRP,and PRP Plus Hyaluronic Acid Injection for Rotator Cuff Lesions.

Inclusion Criteria: * A. Shoulder pain for at least 1 months * B.partial-thickness tear diagnosed by MRI or Echo * C.age between 20 and 85 years old Exclusion Criteria: * A. inflammatory disease, such as rheumatoid arthritis, SLE, etc. * B. pregnancy * C. known malignancy * D. hematologic disease (or hemoglobin \<10 g/dl, platelet \<150.000 ul) * E. history of shoulder infection * F. history of shoulder surgery * G. prior steroid injection for 3 times or more * H. full-thickness tear * I. other shoulder problems, such as osteoarthritis, fracture malunion, etc. * J. subjects who cannot comply with the protocol of study * K. The shoulder pain area has been treated with PRP for less than 3 months