Pain Relief Improves Key Motor Functions in Refractory Advanced Knee Osteoarthritis

BACKGROUND: Advanced knee osteoarthritis (KOA) severely impacts function and quality of life. While pain reduction is thought to improve motor function, the direct relationship remains unclear, especially in refractory cases. This study investigated the impact of pain relief following intra-articular diclofenac-etalhyaluronate (DF-HA) on motor function in advanced KOA patients unresponsive to conventional treatments. METHODS: This retrospective study included 100 knees (82 patients, Kellgren-Lawrence (KL) grade III/ IV) who received DF-HA. Patients were categorized into an Improved Group (IM-G, n= 88 knees) and a Non-Improved Group (Non-IM-G, n= 12 knees) based on visual analog scale (VAS) pain score changes 3-7 days post-injection. Japanese Orthopaedic Association Score for Osteoarthritis of the Knee (JOAS), range of motion (ROM), quadriceps femoris strength (QF), and single-legged stance (SLS) were assessed pre- and post-injection. Non-parametric tests compared changes within and between groups. RESULTS: In the IM-G, significant improvements were observed in JOAS (p< 0.001), ROM (p< 0.001), QF (p< 0.001), and SLS (p = 0.003). Conversely, the Non-IM-G showed no significant changes in JOAS, ROM, or QF, but a significant improvement in SLS (p = 0.024). CONCLUSION: Aggressive pain management with DF-HA significantly improved key motor functions in advanced KOA patients experiencing pain relief. However, balance improvement may involve mechanisms beyond pain reduction. These findings highlight the importance of pain control in improving motor function in refractory KOA.