Long-term effects of intra-articular oxygen-ozone therapy versus hyaluronic acid in older people affected by knee osteoarthritis: A randomized single-blind extension study

BACKGROUND: There is little evidence on intra-articular (IA) treatment in knee osteoarthritis (KOA) and there is a lack of long-term follow-up studies. OBJECTIVE: To assess the long-term effectiveness and safety of IA oxygen-ozone (O2O3) and hyaluronic acid (HA) in terms of functioning in KOA patients over a 31-week period. METHODS: Patients aged > 60 years with KOA were randomly allocated to receive 4 IA knee injections (1/week) of O2O3 or HA (T0-T3) and a follow-up visit 4 weeks after the fourth injection (T4). In this extension study we assessed VAS and safety in patients with Visual Analogue Scale (VAS) > 4 at the at 6-month follow-up visit (T5), undergoing a second treatment cycle (T5-T8) and 1-month follow-up visit (T9). RESULTS: Forty-two patients (aged 70.5 +/- 5.8 years) were randomly allocated to O2O3 ( n = 22) or HA group ( n = 20). Twenty-three underwent another IA cycle: 12 (54.6%) in the O2O3 group and 11 (55.0%) in the HA group. Both groups showed significant reduction in VAS (p < 0.013) compared to baseline during both cycles. At follow-up visits (T4 and T9), VAS was significantly lower in the HA group (p < 0.013). There were no differences in adverse events occurrence between groups. CONCLUSIONS: IA O2O3 might be comparable to HA in terms of effectiveness and safety in reducing pain in KOA patients, although at both follow-up visits (T4 and T9) VAS was significantly lower in the HA group.