Table 4. Question: knee infiltration with hyaluronic acid versus saline solution - GRADE.

Certainty assessment							Patients number		Effect		Certainty	Importance
Studies number	Study design	Bias risk	Inconsistency	Indirect evidence	Imprecision	Other considerations	Hyaluronic acid	Saline solution	Relative (95%CI)	Absolute (95%CI)
WOMAC global - pain - 18-26 weeks
3	Randomized clinical trials	Seriousa,b	Seriousc	Not serious	Seriousd	None	375	360	-	MD 0.16 lower (0.23 lower to 0.1 lower)	⨁ ◯◯◯ Very low
VAS - pain reduction (rest) - 52 weeks
2	Randomized clinical trials	Seriousa, b	Seriousc	Not serious	Seriousd	None	186	140	-	MD 0.27 lower (6.34 lower to 5.79 higher)	⨁ ◯◯◯ Very low
Lequesne’s Functional Index - 26 and 52 weeks
5	Randomized clinical trials	Seriousa,b	Seriousc	Not serious	Seriousd	None	671	601	-	MD 0.24 lower (1.24 lower to 0.76 higher)	⨁ ◯◯◯ Very low
WOMAC - Functional - Reduction from Base Line - 26 weeks
4	Randomized clinical trials	Seriousa,b	Seriousc	Not serious	Seriousd	None	785	761	-	MD 0.18 lower (1.61 lower to 1.26 higher)	⨁ ◯◯◯ Very low
WOMAC - Pain - Reduction from Base Line - 26 weeks
5	Randomized clinical trials	Seriousa,b	Seriousc	Not serious	Seriousd	None	830	748	-	MD 3.16 higher (1.12 lower to 7.44 higher)	⨁ ◯◯◯ Very low
VAS 0-100 Pain (walking) - 26-52 weeks
7	Randomized clinical trials	Seriousa, b	Seriousc	Not serious	Seriousd	None	1,164	1,137	-	MD 2.95 lower (6.07 lower to 0.18 higher)	⨁ ◯◯◯ Very low
Adverse events
14	Randomized clinical trials	Seriousa,b	Seriousc	Not serious	Seriousd	None	1,161/2,067 (56.2%)	1,058/1,902 (55.6%)	L	0 less by 1,000 (40 less to 40 more)	⨁ ◯◯◯ Very low