Effect of a Single Diclofenac-Ethylhyaluronate Injection on Pain and Function in Patients with Severe Knee Osteoarthritis

Purpose: This study evaluated the efficacy of diclofenac-etalhyaluronate (DF-HA), a novel conjugate drug composed of diclofenac covalently linked to sodium hyaluronate, in patients with advanced knee osteoarthritis. Methods: Seventy-two outpatients (86 knees) with Kellgren-Lawrence grade III and IV osteoarthritis who have not achieved satisfactory pain control with conventional treatment were recruited. Clinical and functional assessments were performed immediately before and after a single intra-articular injection of DF-HA. The efficacy of DFHA injections in improving pain using visual analogue scale score (VAS), range of motion (ROM), quadriceps strength (QS: N/kg), single-leg-stance time (SLS), and Japanese Orthopaedic Association Score (JOAS). Values presented as medians (interquartile range). Results: Both VAS and JOAS improved significantly (p< 0.001): VAS from 6 (5, 8) to 3 (2, 5) and JOAS from 65 (59, 75) to 70 (65, 85). ROM also improved from 110° (100°, 120°) to 115° (104°, 125°) (p< 0.001). Additionally, QS increased from 4.1 (2.7) to 4.9 (3.6, 6.1) (p< 0.001) and SLS 12 (5, 52) to 21 (8, 60) (p= 0.002). Improvement rates exceeded 50% for all items. VAS had a significantly higher rate compared to all other indicators (vs. JOAS: p= 0.003, vs. ROM: p<0 .001, vs. QS: p= 0.006, vs. SLS: p= 0.001). Conclusions: DF-HA demonstrated a rapid and significant reduction in pain, improved knee joint function, and led to significant improvements in JOAS in over half of patients with advanced osteoarthritis. However, further longitudinal studies are needed to identify appropriate patient subgroups and optimize the use of repeated injections.