Subacromial Injection of Allogeneic Platelet Rich Plasma (PRP) for Shoulder Impingement Syndrome

Inclusion Criteria: * Male or female 18 years of age and older * Patients who have unilateral shoulder pain. * Patients who have had pain at least for 3 months * To be included in the study- participants are required to have a \& b.(mentioned below) 1. Pain with one of the two tests * Neer's sign: passive overpressure at full shoulder flexion with the scapula fixed * Hawkins test: passive internal rotation at 90 degree of shoulder flexion in the scapular plane and in progressive degree of horizontal adduction 2. Pain with one of the two tests * Painful arc: active shoulder abduction * Jobe's test: The examiner passively elevates the patient's shoulder to 90 degrees of abduction with internal rotation. The examiner then applies a downward pressure against the arm Exclusion Criteria: * Patients who received any drug by subacromial injection for treatment within 3 months prior to this enrollment. * Patients who have a history of shoulder trauma including dislocation- subluxation- and fracture- breast cancer- or surgery around shoulder- neck and upper back * Patients who have a isolated acromioclavicular joint pathology * Patients who have a full-thickness rotator cuff tear (evidenced by MR or ultrasonography) * Patients with symptomatic cervical spine disorders * Patients who have a History of allergic adverse reactions to corticosteroid * Patients are unable to give informed consent to participate in the study * Patients are unable to come into the clinic for regular follow-up * Patients with adhesive capsulitis- acromioclavicular arthropathy- polyarthritis- infectious arthritis- rheumatoid arthritis or diagnosed fibromyalgia * Patients with concurrent bilateral shoulder pain * Patients with neurological deficit * Patients who have severely abnormal radiological findings including malignancy, severe osteoarthritis of the glenohumeral joint, severe skeletal abnormalities decreasing the subacromial space and etc. * Presence of shoulder pain with limitation of both active and passive movements of the glenohumeral joint of 25% in at least 2 directions (abduction, flexion, external rotation, internal rotation), as compared with the contralateral shoulder or with normal values * Patients with Diabetes mellitus * Patients taking anticoagulants * Pregnant women or lactating mothers * Patients who are difficulty participating in data collection due to communication problem and serious mental illness * Patients with serious condition which can affect this study such as severe cardiovascular diseases- renal diseases- liver diseases- endocrine diseases- and cancers