Table 2.

Quality assessment of included studies

Authors	Year	Quality assessment
		Concealed allocation	Randomization	Blinding	Withdrawals and dropouts	Jadad score
Aradi et al.[16]	2011	2	2	2	1	7
Ari et al.[17]	2012	1	2	0	1	4
Bonello et al.[18]	2008	1	1	2	1	5
Bonello et al.[9]	2009	1	1	2	1	5
Cuisset et al.[11]	2008	1	2	0	1	4
Guan et al.[12]	2012	1	2	0	1	4
Price et al.[7]	2011	2	2	2	1	7
Gremmel et al.[19]	2012	0	1	2	1	4
Tang et al.[20]	2012	1	2	0	1	4
Trenk et al.[8]	2012	1	2	2	1	6
Wang et al.[21]	2010	1	1	2	1	5
Paarup Dridi et al.[10]	2014	1	2	2	0	5
Samardzic et al.[22]	2014	2	2	0	1	5

For the numbers, 2 indicates that the method of randomization or concealed allocation or blinding was described in the paper, and it was appropriate; 1 indicates that the method of randomization or concealed allocation or blinding or withdrawals and dropouts were described but were inappropriate; 0 indicates that randomization, concealed allocation, blinding or withdrawals, and dropouts were not mentioned in the paper.