Through the investigators previous study of the effect of transient increased cellular permeability after ESWT, combined ESWT and PRP may have better effect on the treatment of rotator cuff lesions. The investigators intend to conduct a prospective double blind randomized control study on the treatment effect of combined ESWT and PRP therapy for rotator cuff lesions without complete tearing. Constant Score, VAS and data from peripheral blood will be measured for the effectiveness evaluation. Shoulder MRI will be followed-up one year after ESWT. The investigators hypothesize that combined ESWT and PRP will be more effective for rotator cuff lesions.

Overall Design [Prospective randomized double-blind study for the clinical effect of combined ESWT and platelet-rich plasma (PRP) or PRP or ESWT alone or sham treatment on patients with shoulder rotator cuff lesions and without complete tear.]

The participants will be separated into 4 groups according to computer statistical randomization.

The investigators shall use STORZ MEDICAL Extracorporeal Shock Wave Therapy 3000 impulse 24KV (0.32mJ/mm2) Focus at two points (3000 impulse each point) near the insertion of supraspinatus and rotation interval of the involved shoulder.

PRP： The PRP form Regen Kit BCT 1 Platelet Rich Plasma PRP will be used and will be injected into the Subacromial bursa (Hyajoint injection as a control)

HYAJOINT Synovial Fluid Supplement, active ingredient: Sodium Hyaluronate 25 mg, package: 2.5 mL per syringe

The randomized, double-blind, placebo-controlled clinical study will involve 30-50 patients who have rotator cuff lesions without complete tear. The inclusion criteria are (1) patients who have pain around the shoulder, a positive impingement sign, and a positive imaging diagnosis of rotator cuff pathology without complete tear; (2) patients who do not respond to conservative therapy or rehabilitation for at least 3 months; and (3) patients age between 35 and 80 years, who sign the informed consent form. The investigators will exclude patients who have rheumatic diseases, glenohumeral osteoarthritis, full-thickness cuff tears, fractures, infections, or tumors; those who have received a subacromial injection within 3 weeks; and those who are pregnant or want to become pregnant; and those who have arrhythmia, pacemaker, coagulopathy, or malignancy.

The intent-to-treat population is a fully randomized group of patients who have a baseline value (Constant score and VAS before treatment). The imaging diagnosis of a rotator cuff lesion is made by a musculoskeletal radiologist who has considerable experience in interpreting magnetic resonance imaging (MRI) results for shoulders. On MRI, rotator cuff tendinosis is characterized by increased in tratendinous signal intensity onT2-weighted images without tendon disruption. The tendinosis of the MRI imaging was further diverted into three grades. Grade 1 indicates less than 1/3 of the supraspinatus tendon is involved, Grade 2 indicates 1/3 to 2/3 and Grade 3 indicates more than 2/3 of the supraspinatus tendon is involved. Partial-thickness tearing is characterized by the presence of focal hyperintense fluid or a fluid-like signal intensity that extended into the tendon on the T2-weighted images. A full thickness tear is diagnosed by the extension of hyperintense fluid or fluid-like signal intensity through the entire thickness of the interrupted rotator cuff tendon on T2-weighted images.

Every participant will have Subacromial injection of 2.5 ml PRP or HA (control) one week before ESWT or sham therapy. In Group I, patients receive 3000 impulses of shockwaves at 24kV (energy flux density, 0.32mJ/mm2) to the affected shoulder as a 1-time treatment. Treatments are performed on an outpatient basis. The area of treatment (2 points near the supraspinatus insertion and rotator interval) is focused with a control guide on the machine, and surgical lubricant is placed on the skin in contact with the shockwave tube with the patient in a supine position. The sham treatment entail use of the device in which the silicone pad was removed from the stand-off device, but the participants can still hear the sound of the shock wave and have tingling sensation over the skin but without energy transduced. The participants' vital signs and local discomfort are monitored throughout the course of treatment. The treated area is inspected for local swelling, ecchymosis, or hematoma immediately after the treatment.

The participants will have a pain medication-free interval 3 days prior to each evaluation. After treatment and during follow-up, participants will be restricted to the use of a 750mg of acetaminophen per day for pain, in order to facilitate usage and comparison of the medications among the patients. Follow-up examinations are performed independently by one of the coauthors, who is blinded to patient treatment status at 1week, 2week, 1month, 3 months, 6 months, and 12 months after treatment. Peripheral blood (10cc) will be collected one week and 1 month after treatment and shoulder MRI will be checked 12 months after treatment. The participants who have persistent shoulder discomfort may be advised to undergo surgical intervention.

Inclusion Criteria:

1. pain around the shoulder, a positive impingement sign, imaging diagnosis of rotator cuff pathology without complete tear
2. do not respond to conservative therapy or rehabilitation for at least 3 months
3. age between 35 and 80 years, who sign the informed consent form.

Exclusion Criteria:

1. rheumatic diseases, SLE, diabetic neuropathy, glenohumeral osteoarthritis, full-thickness cuff tears, fractures, infections, or tumors
2. received a subacromial injection within 3 weeks
3. pregnant or want to become pregnant.
4. arrhythmia, pacemaker, coagulopathy, or malignancy