High- Versus Low-Molecular-Weight Hyaluronic Acid for the Treatment of Rotator Cuff Tendinopathy: A Triple-Blind Randomized Comparative Trial

Background Shoulder pain most commonly originates from the tendon structures of the rotator cuff. Objective We compared the clinical effects of high- versus low-molecular-weight (LMW) hyaluronic acid for the management of rotator cuff tendinopathy. Methods We carried out a parallel, triple-blind, randomized comparative trial at a teaching hospital. In total, 56 patients aged 16 to 70 years with rotator cuff tendinopathy were randomly allocated to 2 groups. We administered a single shoulder injection of either 1 mL of 1% high- (>2000 kDa) or 1 mL of 1% LMW hyaluronate (500-700 kDa) to the corresponding groups. The primary outcome was the intensity of shoulder pain. The secondary outcomes were range of motion and disability of the shoulder, and quality of life. We performed the measurements at baseline and at 1, 4, and 12 weeks postintervention. The pain measurements were repeated at the sixth month postintervention. Results Comparisons of baseline versus 3 months showed that both interventions were beneficial in the management of the tendinopathy (all P values <0.05). However, between-group analyses did not indicate any clinically significant difference between the 2 medications. The pain, induration (P = 0.007), and inflammation at the site of the injection were less prominent for LMW hyaluronate. Conclusion and Relevance Both medications are effective for the treatment of tendinopathy. The benefits last at least for 3 months, and pain alleviation lasts partially for 6 months. The shoulder injection of LMW hyaluronate is more tolerable to the patient. Therefore, we recommend LMW hyaluronate as the first choice for the management of rotator cuff tendinopathy.