Efficacy and Safety of Intra-Articular Therapy with Cross-Linked Hyaluronic Acid in Patients with Knee Osteoarthritis

<b>Background/Objectives</b>: Knee osteoarthritis (OA) is a degenerative chronic disease characterized by a reduction in articular cartilage, as well as pain and functional limitations. We evaluated both the efficacy and safety of cross-linked high-molecular-weight hyaluronic acid in patients with knee OA. <b>Methods:</b> In this observational prospective single-arm study, a cross-linked high-molecular-weight hyaluronic acid (DIART ONE 90 mg in 3 mL) was administered in single injections to 50 patients aged 18-65 years, with a follow-up at 3, 6, and 12 months. Several scores were evaluated, including the Knee Injury and Osteoarthritis Outcome Score as the primary outcome measure and the Visual Analogue Scale, Timed Up and Go Test, Six-Minute Walking Test, General Health Assessment with 36-Item Short Form Health Survey, Zung's Self-Rating Anxiety Scale, and Zung's Self-Rating Depression Scale as secondary outcome measures. Both physicians and patients knew the kind of treatment they received. <b>Results</b>: During the follow-ups, we observed a statistically significant improvement in clinical scores at 3 and 6 months, with a decrease in clinical benefit at 12 months. Functional and psychological benefits were significant at 3, 6, and 12 months. No side effects were described except pain associated with the site of injection. <b>Conclusions:</b> In conclusion, we documented that cross-linked high-molecular-weight hyaluronic acid (DIART ONE 90 mg in 3 mL) represents an effective option in the management of mild-moderate osteoarthritis.