Comparison 1. Other type of HTO (aHTO) versus closing wedge high tibial osteotomy (CW‐HTO).

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Pain	4	216	Std. Mean Difference (IV, Random, 95% CI)	‐0.13 [‐0.55, 0.29]
2 Stiffness	1		Mean Difference (IV, Random, 95% CI)	Subtotals only
2.1 WOMAC stiffness	1	32	Mean Difference (IV, Random, 95% CI)	‐1.20 [‐2.63, 0.23]
3 Function	4	216	Std. Mean Difference (IV, Random, 95% CI)	‐0.10 [‐0.57, 0.36]
3.1 WOMAC function	1	32	Std. Mean Difference (IV, Random, 95% CI)	‐0.93 [‐1.67, ‐0.20]
3.2 Knee Society Score	1	50	Std. Mean Difference (IV, Random, 95% CI)	‐0.16 [‐0.71, 0.40]
3.3 Hospital for Special Surgery	1	92	Std. Mean Difference (IV, Random, 95% CI)	0.12 [‐0.29, 0.53]
3.4 Lysholm	1	42	Std. Mean Difference (IV, Random, 95% CI)	0.37 [‐0.24, 0.98]
4 Walking distance (km)	1	92	Mean Difference (IV, Random, 95% CI)	0.70 [‐0.95, 2.35]
5 Valgus angle	4		Std. Mean Difference (IV, Random, 95% CI)	Subtotals only
5.1 HKA angle	3	184	Std. Mean Difference (IV, Random, 95% CI)	0.04 [‐0.77, 0.85]
5.2 FTA	1	32	Std. Mean Difference (IV, Random, 95% CI)	‐0.60 [‐1.32, 0.11]
6 Participant satisfaction	1		Mean Difference (IV, Random, 95% CI)	Subtotals only
6.1 VAS satisfaction	1	50	Mean Difference (IV, Random, 95% CI)	‐0.90 [‐1.79, ‐0.01]
7 Willingness to undergo surgery again	1	32	Risk Ratio (M‐H, Random, 95% CI)	1.94 [0.87, 4.31]
8 Serious adverse events	4	265	Risk Difference (M‐H, Random, 95% CI)	0.03 [‐0.03, 0.09]
9 Reoperation rate	4	224	Risk Difference (M‐H, Random, 95% CI)	0.19 [‐0.08, 0.47]
10 Patellar height (Insall‐Salvati ratio)	3	191	Mean Difference (IV, Random, 95% CI)	‐0.08 [‐0.24, 0.09]
11 Inclination of the tibial plateau (degrees)	2	141	Mean Difference (IV, Random, 95% CI)	4.45 [2.21, 6.69]
12 Medial laxity	1	50	Mean Difference (IV, Random, 95% CI)	0.10 [‐1.11, 1.31]
13 Lateral laxity	1	50	Mean Difference (IV, Random, 95% CI)	‐0.20 [‐0.78, 0.38]