This is a randomized parallel controlled double-blind phase 2 clinical study.All subjects are recruited from the patients of rotator cuff tear, lateral epicondylitis or chronic achilles tendonitis. Patients will be randomly divided into three groups. Autologous pure platlet-rich plasma (P-PRP) and platlet-rich plasma (PRP) are purified from the peripheral blood .Patients of case groups will receive P-PRP or PRP injection once a week for three times while the control group received the same dose compound betamethasone injection. Follow up visit will occur at 1 month,3 months, 6 months,12 months after the last injection. Clinical quantitative assessment will measure by the visual analogue scale(VAS). The secondary outcomes are the constant-murley score(CMS) and the rating scale of the American shoulder and elbow surgeons(ASES) and the disability of arm shoulder and hand(DASH). The objective evaluation methods is that the examination of MRI or ultrasound were accomplished before the first injection and at 6 and 12 months afterwards.

All injection will be done under ultrasound guidance.

Inclusion Criteria:

1. clinically diagnosed as rotator cuff tear, lateral epicondylitis or chronic achilles tendonitis;
2. symptom duration is over 3 months, non-steroidal drug treatment , rehabilitation treatment and other conservative treatment is invalid;
3. patient that can understand the clinical trials and signed the informed consent.

Exclusion Criteria:

1. patient that underwent other injection treatment within 6 weeks
2. some associated diseases (such as arthritis, synovitis, entrapment of related nerve, radiculopathy to the target lesion, generalized pain syndrome, rheumatoid arthritis, pregnancy, impaired sensibility, paralysis, history of allergic or hypersensitive reaction to bovine-derived proteins or fibrin glue)
3. patient that enrolled other clinical trials within 3 months
4. history of drug/alcohol addiction, habitual smoker