One hundred knee osteoarthritis patients were randomized to receive 3 intra-articular injections of highly-purified polynucleotides plus hyaluronic acid (n=50) or hyaluronic acid alone (n=50). This study was a 2 year follow up to a previously published 1 year follow up interim analysis. The primary outcome of interest was Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain sub-score. Secondary outcomes of interest included WOMAC stiffness, function, "walking on flat surface", and total scores, and Knee Society Score (KSS) total and pain scores scores. Results revealed no significant difference in WOMAC pain, stiffness, "walking on a flat surface", or function scores at 24 months. WOMAC total scores were significantly in favour of the combination group at 24 months. No significant difference in KSS pain or total scores were observed between groups at 24 months.