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.