Efficacy of Oral Hyaluronic Acid and Collagen Supplementation Compared With Hyaluronic Acid Infiltration Treatment in Rotator Cuff Tendinopathies: A Prospective Study

Background Shoulder pain is a prevalent symptom primarily affecting the adult population, with an incidence of approximately 19 per 1000 and a prevalence ranging from 7 to 26%, particularly affecting women. The primary cause of shoulder pain is rotator cuff pathology, characterized by nocturnal pain and weakness, especially during external rotation and elevation movements of the shoulder, attributable to excessive loading on the cuff tissues. These symptoms often result in disability and functional impairment.

The etiology of rotator cuff pathology appears multifactorial, often associated with chronic age-related degeneration characterized by a reduced ability to synthesize collagen, increased levels of free radicals, and heightened catabolic activity (5). Tendinopathies exhibit widespread structural changes, including increased apoptosis of tenocytes, collagen fiber disintegration leading to a decrease in collagen type I, an increase in collagen type III resulting in a reversal of the collagen I/III ratio, and ineffective neoangiogenesis.

As tendinopathy primarily represents a degenerative condition where the inflammatory component plays a minor role, current therapeutic strategies mainly focus on regenerative approaches. While intra-articular cortisone therapy has historically been utilized to alleviate pain from rotator cuff injuries, its potential detrimental effect on tendon collagen limits its long-term efficacy, rendering cortisone therapy beneficial only in the short term.

Conversely, intra-articular treatment with hyaluronic acid (HA) for rotator cuff injuries appears promising in reducing pain and improving shoulder function. A recent review analyzed 11 studies encompassing a total of 1102 patients. Low to medium molecular weight hyaluronic acids were utilized in these studies, with infiltration performed either via anatomical landmarks or ultrasound guidance, targeting either intra-articular or subacromial sites. Moreover, rare minor side effects (such as pain at the injection site or slight vagal effects) were reported, with no instances of allergic reactions.

Hyaluronic acid (HA) is a carbohydrate, specifically a mucopolysaccharide, naturally present in all living organisms. When unbound to other molecules, it binds to water, imparting a rigid viscous 'jelly-like' quality. HA serves as an integral component of synovial fluid, crucial for joint chondroprotection, and constitutes a significant portion of the tendon extracellular matrix.