Comparison 1. Hyaluronic acid versus Placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 AOS total (combined pain and function score) at 6months	2	45	Mean Difference (IV, Fixed, 95% CI)	‐12.53 [‐23.84, ‐1.22]
2 AOS total (combined pain and function score) at 3months	2	92	Mean Difference (IV, Fixed, 95% CI)	‐2.26 [‐11.23, 6.72]
3 Pain (AOS pain) at 3months	2	92	Mean Difference (IV, Fixed, 95% CI)	‐1.83 [‐11.33, 7.68]
4 Physical Function ( AOS disability) at 3months	2	92	Mean Difference (IV, Fixed, 95% CI)	‐0.13 [‐9.26, 9.01]
5 Serious adverse events	3	109	Risk Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
6 Any adverse events	3	109	Peto Odds Ratio (Peto, Fixed, 95% CI)	2.34 [0.45, 12.11]
7 Patients who withdraw because of an adverse event	3	109	Risk Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]