2. Time to return work (days).

Study	Comparison	Experimental group	Control group	SS E	SS_C	P value	Results format
al‐Hassan 1990	Open vs closed (midline)	28 (nr)	14 (nr)	50	46	nr	Mean (SD)
Al‐Salamah 2007	Open vs closed (midline)	42.2 (5.3)	15.6 (3.4)	192	188	<0.001	Mean (SD)
Füzün 1994	Open vs closed (midline)	17.6 (12‐21)	10.7 (9‐21)	55	55	<0.05	Mean (range)
Kareem 2006	Open vs closed (midline)	35.51 (5.06)	10.35 (2.72)	37	40	<0.0001	Mean (SD)
Søndenaa 1992	Open vs closed (midline)	27.39 (36.82)	15.4 (9.17)	58	55	<0.002	Mean (SD)
Khawaja 1992	Open vs closed (midline)	42 (nr)	19.5 (nr)	23	23	‐22 (‐26, ‐17)	Median difference (95% CI)
Gencosmanoglu 2005	Open vs closed (midline)	3 (2, 8)	21 (14, 63)	73	69	<0.001	Median (range)
Karakayali 2009	Open healing vs closed (off‐midline)	11.2 (5.8)	17.9 (9.3)	70	70	<0.001	Mean (SD)
Sheikh 2007	Open healing vs closed (off‐midline)	8.15 (1.46)	3.53 (1.33)	13	13	nr	Mean (SD)
Testini 2001	Open vs closed (off‐midline)	25.7 (11‐77)	10.4 (5‐32)	50	50	<0.0001	Mean (range)
Fazeli 2006	Open vs closed (off‐midline)	17.5 (nr)	11.9 (nr)	72	72	<0.001	Mean
Akca 2005	Closed (midline) vs closed (off‐midline)	19 (15, 20)	9.5 (8, 12)	100	100	<0.001	Median (IQR)
Ersoy 2009	Closed (off‐midline) vs closed (off‐midline)	15 (5‐45)	14 (5‐46)	50	50	0.346	Median (range)
Nordon 2009	Closed (off‐midline) vs closed (off‐midline)	14 (7‐42)	14 (3.5‐28)	29	26	nr	Median (range)
Abu Galala 1999	Closed (midline) vs closed (off‐midline)	14 (nr)	23 (nr)	22	24	0.0001	Mean
Sakr 2006	Closed (midline) vs closed (off‐midline)	21‐28	21‐28	82	79	nr	Range
Ertan 2005	Closed (midline) vs closed (off‐midline)	28.5 (14‐60)	15.8 (7‐25)	50	50	0.001	Mean (range)
Cihan 2006	Closed (off‐midline) vs closed (off‐midline)	11.7 (0.45)	9.3 (0.34)	35	33	0.001	Mean (SD)

nr= not reported