Ultrasound-Guided Injection of a Tendon-Compatible Hyaluronic Acid Preparation for the Management of Partial Thickness Rotator Cuff Tear: A Case Report.

Partial-thickness rotator cuff (RC) tear constitutes the most common cause of shoulder pain and disability. Its management is challenging, and a conservative approach is suggested as a first-line treatment. Nonetheless, minimally invasive approaches have been described in clinical trials, such as ultrasound (US)-guided tendon-compatible hyaluronic acid (HA) injection preparation in the rupture site. HA is believed to fill the intradermal space and thus support the regeneration process by its integration in the damaged extracellular matrix. A reduced healing period required for a tendon tear when treated with a tendon-compatible HA preparation compared to placebo has been previously described in the literature, enabling a more rapid return to exercise. The current study aims to provide a thorough analysis of a regular CrossFit practitioner case with a partial-thickness bursal-side RC tear of the anterior Supraspinatus (SS) fibers with 7 mm on the anteroposterior axis and 5 mm on the longitudinal axis in magnetic resonance imaging (MRI), that caused pain, and limited functional status. Two US-guided injections of a specific high molecular weight (one million Daltons) tendon-compatible HA preparation (12 mg/1.2 mL) separated by six weeks were performed. A supervised rehabilitation protocol was then followed and training was progressively introduced. In the 12 weeks follow-up visits, a reduction in pain intensity was noticed as well as an improvement of the functional status. At the six months, one year, and two years follow-ups, no pain and a normal joint function were observed, despite engaging in continuous overload and overhead activities during CrossFit practice. MRI was performed one year after the intervention presenting a reduction of the injury size and only a partial intrasubstance tear of 4 mm was observed in the SS tendon. US imaging in the two years follow-up presented an additional reduction in tear size to 3.9 mm length. No adverse effects were reported. It is thus believed that US-guided injections of tendon-compatible HA on partial-thickness RC tears can be a feasible and effective treatment option in the management of this frequent pathology, and more studies, particularly randomized controlled trials, should be implemented to substantiate and validate this approach.