Low Molecular-weight Hyaluronic Acid Versus Physiotherapy for the Treatment of Supraspinatus Tendinopathy: A Randomized Comparative Clinical Trial.

INTRODUCTION The tendons of the rotator cuff are major sources of shoulder pain. This study aimed to compare the effects of low molecular-weight hyaluronic acid with physiotherapy (PT) in patients with supraspinatus tendinopathy (ST). METHODS We carried out a parallel two-group randomized comparative clinical trial in an outpatient clinic of physical medicine and rehabilitation at a teaching hospital. In total, 51 patients (31 women) aged 20 to 55 years with ST were randomly allocated to subacromial hyaluronate injection (n = 28) and PT (n = 23) groups. For the hyaluronate group, we administered a single injection of 2 mL (20 mg) hyaluronate 1% (500 to 700 kDa). For PT, we prescribed three sessions of treatment per week for 12 weeks, totaling 36 sessions including rotator cuff activation exercises. The primary outcome was shoulder pain in the visual analog scale. The secondary outcomes included the range of movement and the disability score of the shoulder, and a World Health Organization questionnaire on quality of life. We did the measurements at the baseline and at one, four, and 12 weeks after intervention. RESULTS The results showed that both interventions were beneficial in the management of ST. However, hyaluronate was more effective in reducing shoulder pain at rest and during activities (both P < 0.001, effect size = 0.52 and 0.68, respectively). The two interventions similarly decreased patients' disability (P = 0.196). Hyaluronate improved shoulder motion and the quality of life better than PT. CONCLUSION In the treatment of ST, low molecular-weight hyaluronate is more effective than PT, at least for three months. Particularly, hyaluronate is more successful in alleviating pain.