Research Title: Long Term Functional Outcome of a Single Hyaluronic Acid Injection in Improving Symptoms and Function in Patients With Knee Osteoarthritis - A Single-Arm Open-Label Study (DIART ONE).

Single-arm, open-label studies play a crucial role in the clinical research ecosystem. These studies are often conducted to:

• Assess the performance of a novel HA formulation (e.g., different molecular weights, cross-linking technologies).
• Gather "real-world" evidence in broader, less restrictive patient populations.
• Provide preliminary data to support the design of larger, more expensive RCTs.
• Investigate outcomes in specific patient subpopulations (e.g., severe OA, different age groups).

• To compare mean differences VAS Score 0,1,3,6,12 months. 2. To study comparison WOMACS mean differences. 3. To document the safety and tolerability of a single HA injection in a real-world clinical setting.

Inclusion criteria

i. Adults aged 40-75 years with a clinical and radiographic diagnosis of knee OA (Kellgren-Lawrence grade II-III).

ii. Persistent knee pain (≥4 on a 10-point Visual Analogue Scale [VAS]) for at least 3 months.

iii. Failure to achieve adequate pain relief with conservative treatments (e.g., NSAIDs, physical therapy).

iv. Willingness to provide informed consent and comply with study procedures.

Exclusion criteria

i. Severe OA (Kellgren-Lawrence grade IV). ii. History of knee surgery or HA injection within the past 6 months. iii. Inflammatory arthritis (e.g., rheumatoid arthritis, gout). iv. Contraindications to HA injections (e.g., infection, allergy to HA products).

v. Significant comorbidities that may interfere with study participation (e.g., uncontrolled diabetes, morbid obesity, severe cardiovascular disease).