This study will be performed to examine the effect of ultrasound-guided subacromial sodium hyaluronate injection in patients with impingement syndrome without rotator cuff complete tear.

Rotator cuff disease in particular is a common cause of shoulder pain and weakness and comprises a significant proportion of the musculoskeletal complaints presenting to primary care doctors. Ultrasound is a readily available and cheap modality for looking more specifically at the rotator cuff and surrounding structures. More recently, ultrasound guidance has become a commonly employed method to perform diagnostic or therapeutic interventions. Despite the long history and the fact that this is a common diagnosis made in clinical practice, the exact cause and best treatment for this condition still are being explored. Although there are a few high-quality studies demonstrating the efficacy of sodium hyaluronate injection for rotator cuff disease, this study will be performed to examine the effect of ultrasound-guided subacromial sodium hyaluronate injection in patients with impingement syndrome without rotator cuff complete tear.

Inclusion Criteria:

• age >= 18 years
• subacromial impingement syndrome
• without a complete tear of rotator cuff
• willingness to participate

Exclusion Criteria:

• had any rheumatic disease, glenohumeral osteoarthritis, full-thickness rotator cuff tears, fractures, diabetes mellitus, infections, or tumors.
• had hypersensitivity to hyaluronate
• had participated in any other study within 6 months
• had received a subacromial injection within 8 weeks
• were pregnant or planned to become pregnant
• were at risk of complications of intra-articular injections such as patients who received anti-coagulant drugs.