Table 3.

Results of the included studies

Author, year of publication	Results
Raeissadat et al. 2018 (4)	VAS HA → T0:7.1±3.2; T1: 3.0±2.4. VAS Ozone → T0:7.6±2.8; T1: 2.6±2.0. WOMAC total HA → T0: 40.8±9.0; T1: 17.1±4.2. WOMAC total Ozone → T0: 38.5±8.0; T1: 20.4±5.0. WOMAC pain HA → T0: 8.8±4.0 ; T1: 2.9±1.6. WOMAC pain Ozone → T0: 3.2±1.6; T1: 3.2±1.6. WOMAC Stiffness HA → T0: 2.1±1.6; T1: 1.1±0.8. WOMAC Stiffness Ozone → T0: 2.3±2.4; T1: 1.1±1.6. WOMAC function HA → T0: 27.6±6.6; T1: 13.1±3.2. WOMAC function Ozone → T0: 29.2±7.0; T1: 16.1±4.2.
Duymus et al. 2016 (19)	VAS HA → T0: 8.3 ± 0.4; T1: 2.6 ± 1.2; T2: 3.1 ± 0.9; T3: 4.3 ± 1.3; T4: 6.8 ± 0.1. VAS Ozone → T0: 7.2 ± 1.1; T1: 3.5 ± 1.5; T2: 5.7 ± 1.2; T3: 7.3 ± 1.03; T4: 7.6 ± 1.1. WOMAC total HA → T0: 77.0 ± 2.5; T1: 33.2 ± 12.2; T2: 35.3 ± 10.5; T3: 44.5 ± 6.6; T4: 69.3 ± 4.3. WOMAC total Ozone → T0: 76.0 ± 11.9; T1: 31.1 ± 12.9; T2: 53.1 ± 15.9; T3: 76.6 ± 10.7; T4: 77.0 ± 10.1. WOMAC pain HA →T0: 16.6 ± 1.1; T1: 6.1 ± 2.4; T2: 7.00 ± 1.74; T3: 9.7 ± 1.6; T4: 14.2 ± 1.1. WOMAC pain Ozone → T0: 16.0 ± 2.7; T1: 6.6 ± 3.5; T2: 11.1 ± 3.4; T3: 16.0 ± 2.9; T4: 16.2 ± 2.8. WOMAC Stiffness HA → T0: 6.0 ± 0.8; T1: 2.7 ± 1.1; T2: 3.2 ± 1.0; T3: 3.8 ± 1.1; T4: 5.4 ± 0.7. WOMAC Stiffness Ozone →T0: 6.4 ± 1.0; T1: 2.7 ± 1.6; T2: 4.2 ± 1.3; T3: 6.4 ± 1.0; T4: 6.5 ± 0.1. WOMAC function HA →T0: 54.3 ± 1.8 ; T1: 24.3 ± 9.5; T2: 25.1 ± 8.9; T3: 30.1 ± 5.7; T4: 49.6 ± 3.3. WOMAC function Ozone →T0: 53.5 ± 8.7; T1: 21.7 ± 8.6; T2: 387 ± 12.2; T3: 54.1 ± 7.3; T4: 54.2 ± 7.9.
Giombini et al. 2016 (17)	VAS HA →T0: 6.93±0.68; T1: 4.58±0.44; T2: 2.40±0.48. VAS O2O3 →T0: 6.71±0.87; T1: 3.98±1.10; T2: 2.40±1.41.
Invernizzi et al. 2017 (9)	VAS HA →T0: 6.3839±0.8472; T1: 4.2857±0.89285; T2: 3.0357±0.69195. VAS O2O3 →T0: 7.0089±0.55805; T1: 4.553±0.57779; T2: 4.1332±0.3778.
Auerbach et al. 2002 (18)	VAS HA → T0: 29.03±30.46; T1: 18.33±24.80; T2: 21.33±29.18; T3: 20.38±30.80; T4: 14.52±24.11. VAS O2 → T0: 28.89±28.73; T1: 16.92±24.42; T2: 14.43±23.95; T3: 17.44±27.90; T4: 14.43±24.47. WOMAC pain HA → T0: 8.2±4.2; T1: 5.3±3.7; T2: 5.7±4.2; T3: 4.6±4.8; T4: 4.5±4.2. WOMAC pain O2 → T0: 6.8±4.7; T1: 4.0±4.0; T2: 4.3±3.8 ; T3: 4.0±3.9; T4: 3.7±3.9. WOMAC Stiffness HA → T0: 2.7±1.9; T1: 2.2±1.8; T2: 2.3±1.8; T3: 2.6±2.0; T4: 2.2±1.9. WOMAC Stiffness O2 → T0: 2.7±2.3; T1: 2.0±2.1; T2: 1.8±1.8 ; T3: 1.7±1.8; T4: 1.7±2.1. WOMAC function HA →T0: 22.5±15.0; T1: 17.7±13.5; T2: 16.6±13.2; T3: 16.7±16.3; T4: 15.1±15.8. WOMAC function O2 →T0: 20.6±15.5 ; T1: 14.4±13.8 ; T2: 13.8±13.9; T3: 12.6±13.5; T4: 11.1±14.2.
Momenzadeh et al. 2014 (23)	VAS HA → T0: 8.07±0.74; T1: 5.00±1.31; T2: 2.97±1.24. VAS Ozone → T0: 8.30±0.79; T1: 5.43±1.43; T2: 2.63±1.12. WOMAC total HA → T0: 60.33±10; T1: 42.13±10.92; T2: 26.60±9.78. WOMAC total Ozone → T0: 67.62±8.26; T1: 42.20±9.84; T2: 24.80±8.54.