Table 1 Descriptive and main findings of the studies included

Amuzadeh, 2014, Iran [29]

Knee OA

(1–2 grade)

Prospective Observational

60

Celecoxib 200 mg/day and GS 500 mg three times/daily

Celecoxib 200 mg/day

8 weeks

Concomitant use of GS with celecoxib is more effective than celecoxib alone in reducing morning stiffness (p = 0.000) and reducing pain & improving function (WOMAC Index 95% CI, Z = -4.891, p = 0.000)

in women with early knee OA

Lu, 2019, China [30]

OA

RCT

88

Meloxicam 7.5 mg/day and GS 500 mg three times/daily

Meloxicam 7.6 mg/day

8 weeks

Concomitant use of GS and meloxicam is more effective than meloxicam alone in reducing the clinical symptoms (VAS, 2.35 ± 1.08; LI, 4.78 ± 3.34; p < 0.05) and serum biomarkers (p < 0.05) of bone resorption and bone degradation in patients with OA

Deng, 2015, China [31]

Knee OA

RCT

120

Celecoxib 200 mg/day + GS 500 mg 3 times/day

Celecoxib 200 mg/day

8 weeks

The combination of celecoxib with GS effectively reduces immune inflammatory response, oxidative stress damage, and joint pain (VAS, 2.36 ± 0.52; WOMAC, 40.35 ± 2.36; and LKSS, 87.29 ± 10.38; p < 0.05] associated with KOA

Sun, 2020,China [32]

Knee OA

RCT

80

GS 500 mg three times/daily + etoricoxib 60 mg/day

Etoricoxib

60 mg/day

6 weeks

GS combined with etoricoxib

may reduce the expression of JNK and Wnt5a to

inhibit the secretion of MMP, and then slow down the degradation of cartilage matrix, leading to an improvement in clinical scores (92.42%, p = 0.000)

Selvan, 2012, India [33]

Knee OA

RCT

100

GS 500 mg three times/daily

GS 500 mg three times/daily + NSAID

12 weeks

GS and NSAIDs group had significant improvement in pain (VAS, 1.12 [0.84–1.41], p < 0.01) (WOMAC, 5.37 [4.97–5.78], p < 0.01), physical function (8.20 [7.51–8.89], p < 0.01) and stiffness (2.23 [2.21–2.44], p < 0.01) compared to GS alone