Rotator cuff lesions are common causes of shoulder pain. Although patients with symptoms caused by chronic rotator cuff tendinopathy can be treated using conservative treatments, some of them may still experience refractory symptoms. Hypertonic dextrose prolotherapy (DPT) may be another treatment choice for these refractory symptoms. However, conventional prolotherapy injection is complicated with multiple injection sites. Thus, we considered it necessary to design a rigorous trial to specifically evaluate the effectiveness of DPT injection for the supraspinatus tendon, which is mostly involved in rotator cuff tendinopathy.

This double-blind, randomized, controlled study will recruit patients with chronic shoulder pain diagnosed as chronic supraspinatus tendinopathy. We recruit 20 participants, with a total of 10 participants in each treatment arm. The hypertonic DPT group will receive 5mL of 20% glucose water prolotherapy injection, and the control group will receive normal saline by using the same injection protocol as that used for the study group. Demographic data will be recorded at baseline. Visual analog scale, Shoulder Pain and Disability Index, range of motion, ultrasound will be recorded at baseline, after intervention (week 2, and week 6). Descriptive statistics will be calculated for feasibility outcomes, and measures of clinical effectiveness will be explored using repeated measures analysis of variance.

Prolotherapy injection group presented improved of VAS, SPADI, and range of motion after 2 weeks of injection with comparing baseline. However, the effect was not maintained to 6 weeks after injection. There was no difference of histogram changes before and after prolotherapy injection. With comparing control group, improved VAS and SPADI was better among study group at 2 weeks after injection but no difference at 6 weeks after injection.

Our pilot study demonstrated that hypertonic dextrose prolotherapy injection can improve pain and function of chronic rotator cuff tendinosis patients in short-term period.