Comparison 1. Different forms of surgical intervention: retrograde lateral wires versus retrograde crossed wires.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1.1 Treatment failure requiring a re‐intervention	1		Risk Ratio (M‐H, Fixed, 95% CI)	Totals not selected
1.2 Nerve injury	28	1653	Risk Ratio (M‐H, Fixed, 95% CI)	0.65 [0.46, 0.90]
1.3 Major complications (pin site infections)	18	1022	Risk Ratio (M‐H, Fixed, 95% CI)	1.08 [0.65, 1.79]
1.4 Cosmetic deformity: loss of carrying angle > 10 degrees or elbow deformity	8		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
1.4.1 Medium‐term cubitus varus	1	67	Risk Ratio (M‐H, Fixed, 95% CI)	2.91 [0.12, 69.08]
1.4.2 Medium‐term loss of carrying angle > 10°	1	21	Risk Ratio (M‐H, Fixed, 95% CI)	1.10 [0.08, 15.36]
1.4.3 Long‐term cubitus varus	2	95	Risk Ratio (M‐H, Fixed, 95% CI)	3.13 [0.55, 17.98]
1.4.4 Long‐term loss of carrying angle > 10°	6	288	Risk Ratio (M‐H, Fixed, 95% CI)	1.27 [0.39, 4.20]
1.5 Cosmetic deformity: loss of carrying angle (degrees of loss)	15		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
1.5.1 Medium‐term loss of carrying angle	5	320	Mean Difference (IV, Fixed, 95% CI)	‐0.10 [‐0.44, 0.23]
1.5.2 Long‐term loss of carrying angle	10	502	Mean Difference (IV, Fixed, 95% CI)	0.14 [‐0.26, 0.54]
1.6 Cosmetic deformity: degrees of loss of carrying angle at long‐term follow‐up	8		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
1.6.1 Medium‐term loss of flexion	3	148	Risk Ratio (M‐H, Fixed, 95% CI)	1.24 [0.37, 4.16]
1.6.2 Medium‐term loss of extension	1	21	Risk Ratio (M‐H, Fixed, 95% CI)	0.73 [0.15, 3.53]
1.6.3 Long‐term loss of flexion	2	105	Risk Ratio (M‐H, Fixed, 95% CI)	1.41 [0.84, 2.35]
1.6.4 Long‐term loss of extension	2	105	Risk Ratio (M‐H, Fixed, 95% CI)	0.85 [0.40, 1.80]
1.6.5 Long‐term loss of total range of movement	3	148	Risk Ratio (M‐H, Fixed, 95% CI)	1.26 [0.56, 2.82]
1.7 Range of motion: loss of movement	3		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
1.7.1 Long‐term loss of elbow flexion	1	55	Mean Difference (IV, Fixed, 95% CI)	2.58 [‐2.48, 7.64]
1.7.2 Long‐term loss of elbow extension	1	55	Mean Difference (IV, Fixed, 95% CI)	‐0.03 [‐5.35, 5.29]
1.7.3 Long‐term loss of total range of motion	2	92	Mean Difference (IV, Fixed, 95% CI)	0.71 [‐0.52, 1.95]
1.8 Unable to return to sport and normal activities	5	246	Risk Ratio (M‐H, Fixed, 95% CI)	0.91 [0.31, 2.69]
1.8.1 Medium term	3	151	Risk Ratio (M‐H, Fixed, 95% CI)	1.23 [0.31, 4.83]
1.8.2 Long term	2	95	Risk Ratio (M‐H, Fixed, 95% CI)	0.54 [0.08, 3.53]
1.9 Return to sport and normal activities: time to return to normal activities	1		Mean Difference (IV, Fixed, 95% CI)	Totals not selected
1.10 Radiographic deformity: loss of reduction	10	761	Risk Ratio (M‐H, Fixed, 95% CI)	1.67 [1.23, 2.26]
1.10.1 Early	1	200	Risk Ratio (M‐H, Fixed, 95% CI)	1.37 [0.93, 2.00]
1.10.2 Medium term	7	469	Risk Ratio (M‐H, Fixed, 95% CI)	2.00 [1.21, 3.30]
1.10.3 Long term	2	92	Risk Ratio (M‐H, Fixed, 95% CI)	4.00 [0.46, 34.45]
1.11 Radiographic deformity: loss of radiographic angle	14		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
1.11.1 Medium‐term loss of Baumann's angle	7	447	Mean Difference (IV, Fixed, 95% CI)	0.06 [‐0.22, 0.33]
1.11.2 Long‐term loss of Baumann's angle	7	283	Mean Difference (IV, Fixed, 95% CI)	0.05 [‐0.00, 0.11]
1.11.3 Medium‐term loss of lateral humeral‐capitellar angle	1	60	Mean Difference (IV, Fixed, 95% CI)	‐0.20 [‐2.86, 2.46]
1.11.4 Long‐term loss of lateral humeral‐capitellar angle	1	31	Mean Difference (IV, Fixed, 95% CI)	0.01 [‐0.06, 0.08]
1.11.5 Long‐term loss of humeral diaphyseal‐metaphyseal angle	2	112	Mean Difference (IV, Fixed, 95% CI)	0.10 [‐0.18, 0.39]
1.11.6 Long‐term loss of humeral medial epicondylar epiphyseal angle	1	55	Mean Difference (IV, Fixed, 95% CI)	0.86 [‐2.27, 3.99]
1.12 Resource use	3		Mean Difference (IV, Random, 95% CI)	Totals not selected
1.12.1 Operative time (minutes)	2		Mean Difference (IV, Random, 95% CI)	Totals not selected
1.12.2 Length of stay (days)	1		Mean Difference (IV, Random, 95% CI)	Totals not selected
1.13 Nerve injury: subgrouped according to technique for insertion of medial wire	21	1208	Risk Ratio (M‐H, Fixed, 95% CI)	0.71 [0.49, 1.02]
1.13.1 Percutaneous crossed wires technique	10	552	Risk Ratio (M‐H, Fixed, 95% CI)	0.41 [0.20, 0.81]
1.13.2 Open crossed wires technique	11	656	Risk Ratio (M‐H, Fixed, 95% CI)	0.91 [0.59, 1.40]