Intra-articular Injection of a Cross-Linked Hyaluronic Acid Combined with Triamcinolone Hexacetonide Improves Pain at 6 Months in Patients with Mild to Moderate Hip Osteoarthritis: A Prospective Observational Study.

Objectives: Joint-preserving interventions, such as intra-articular viscosupplementation injections, are evolving, requiring efficacy and safety evaluation through an evidence-based approach. The objective of this study was to assess the use of a hyaluronic acid and corticosteroid-based injection (Cingal™; Anika Therapeutics, Bedford, MA, USA) in improving pain and functional outcomes for patients aged 40 to 65 with mild to moderate hip osteoarthritis (OA) six months post-injection.

Methods: This prospective observational study included 100 patients receiving a single ultrasound-guided intra-articular injection of Cingal™. Eligible patients seen in participating orthopaedic, physiatry and sports medicine clinics, were evaluated at baseline, one-month, and six-month follow-up. The primary outcome was patient-reported hip pain (Visual Analogue Scale, VAS) at six months post-injection. Secondary outcomes included hip function (Hip Disability and Osteoarthritis Outcome Score, HOOS), quality of life (Short-Form 12, SF-12), pain medication use, range of motion (ROM), physical activity (activity tracker), and adverse events.

Results: 96 patients received the injection; 91 had complete data for primary outcome analysis. Statistically significant improvements were observed in VAS (p<0.001), HOOS (p<0.001), and SF-12 scores (Physical Component Summary, p=0.005; Mental Component Summary, p=0.022) from baseline to six months post-injection. Pain medication use decreased from 50.0% to 34.0% (p=0.035). No statistically significant change was observed in ROM or activity level. Adverse events were reported in 9.5% of patients: five (5.3%) experienced hip pain for less than seven days, one for greater than seven days but less than one month, and three (3.2%) underwent hip arthroplasty.

Conclusion: Patients receiving an ultrasound-guided Cingal™ injection for hip OA reported statistically significantly reduced hip pain, improved function and quality of life, and reduced pain medication use at six months. The most common adverse event was transient hip pain.

Level of evidence: Prospective observational study, Level III.