The efficacy of intra-articular HYADD4-G injection in the treatment of femoroacetabular impingement: results at one year follow up.

Objective: Femoroacetabular impingement (FAI) is a condition that has been increasingly recognized as a source of hip pain and a possible risk factor to early development of hip osteoarthritis (OA). To our knowledge, the use of HA in the treatment of femoroacetabular FAI has been investigated only by two studies, both using a high molecular weight HA. The aim of this study was to evaluate the efficacy of two weekly injections of an hexadecylamide derivative of HA (HYADD4-G, HYMOVIS, Fidia Farmaceutici) in FAI.

Methods: All patients received two weekly intra-articular injections of Hymovis at baseline and after 7 days. Clinical and functional assessments were performed at baseline and was repeated after 1, 3, 6 and 12 months. Functional measures included visual analogue scale (VAS) for pain, Harris Hip score (HHS), Lequesne Index (LI), Tegner activity level scale (TALS) and monthly consumption of nonsteroidal anti-inflammatory drugs (NSAIDs).

Results: Twenty-one hips (19 patients, 2 bilateral cases) were treated. The variables VAS, HHS as well as Lequesne improved significantly from T0 to T4 (at 12 months) with the best improvement between T0 and T1. At the same time, a reduction in NSAIDs monthly intake was registered. On the other hand, a significant improvement in Tegner scale was not observed. No adverse events were registered.

Conclusion: This study states that one cycle of HYADD4-G could be a safe and effective treatment in patients with FAI, showing significative results in term of pain control as well as hip functionality and quality of life up to 1 year.