Table 1.

Results of the meta-analysis by Saito and Kotake [15]

References	Patients, n	RRa of pain [95% CI]	RRa of inflammation [95% CI]	RRa of efficacy [95% CI]
Tanaka et al. [16]	175	1.19 [0.96–1.47]	1.40 [1.07–1.83]	1.29 [1.07–1.55]
Tanaka et al. [17]	203	1.83 [1.44–2.32]	1.78 [1.37–2.32]	1.76 [1.40–2.21]
Goto [18]	20	2.00 [0.68–5.85]	1.60 [0.80–3.20]	2.12 [1.06–4.26]
Matuno [19]	26	2.75 [1.18–6.42]	3.50 [0.89–13.78]	4.00 [1.46–10.93]
Komatubara et al. [20]b	286	–	–	1.10 [0.95–1.27]
Pooled RR		1.64 [1.14–2.35]	1.61 [1.34–1.92]	1.64 [1.14–2.35]

^aA value of risk ratio (RR) greater than 1 indicates that the observed results favours HA injections as compared to placebo

^bThe study by Komatubara et al. was excluded from the estimation of RR of pain and inflammation because the authors used a different outcome measure with respect to the other included studies