Aim: Both intra-articular ozone and hyaluronic acid injections are commonly used for treatment of knee osteoarthritis (KOA). It was aimed to evaluate and compare the effectiveness of intra-articular ozone and hyaluronic acid (HA) injections on pain and functional limitations of participants with KOA.

Methods: One hundred and eight consecutive patients (eighty-four women, twenty-four men) aged 40-75 years visited to outpatient clinic with knee pain for longer than 3 months. HA injections were performed as a single dose, and ozone injections were administered once a week as three doses in total. The Visual Analog Scale (VAS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) were performed before treatment, one and three months after treatment.

Results: Seventy-six participants were included in the study. The randomization was done as Hyaluronic Acid (n=39) and Ozone (n=37) groups. No significant difference was found in terms of WOMAC-total, WOMAC-pain, and VAS (p>0.05) at all stages among groups. WOMAC-stiffness score was found significantly different between first month and third month follow-ups (p=0.011). Also, there was a significant change in WOMAC-function scores between before treatment and first month follow-ups (p=0.008), and before treatment and third month follow-ups (p=0.002) in inter-group analysis.

Conclusion: Both ozone and HA injections were effective treatment methods for KOA. However, intraarticular HA injection had a longer-lasting effect on pain and function than ozone injection.

Keywords: Hyaluronic acid, injection, intraarticular, osteoarthritis, ozone therapy