Table 4.

Assessment of methodological quality of included studies with the Methodological Index for Nonrandomized Studies (MINORS) score (0 not reported, 1 reported but inadequate, 2 reported and adequate).

Item	Rolle [10]	Franzke [11]	Liu [12]	Meyer [13]	Hassan [14]	Schmid [15]	Nagayasu [16]	Porrello [17]	Stefani [18]	Loughlin [19]	Moneke [20]
A clearly stated aim	1	2	2	2	2	2	2	2	2	2	2
Inclusion of consecutive patients	2	2	2	0	0	2	2	2	2	2	2
Prospective collection of data	1	1	0	0	2	2	0	1	1	0	1
Endpoints appropriate to the aim of the study	2	2	2	2	2	2	2	1	2	2	2
Unbiased assessment of study endpoint	0	0	0	0	0	0	0	0	0	1	1
Follow-up period appropriate to the aim of the study	0	0	2	2	2	0	2	2	1	0	2
Loss to follow-up less than 5%	0	0	1	2	1	0	2	2	0	0	0
Prospective calculation of the study size	0	0	0	0	0	0	0	0	0	0	0
Additional items in the case of comparative study
An adequate control group		2	2			2	2		2		2
Contemporary groups		2	2			2	2		1		2
Baseline equivalence of groups		1	1			1	1		1		1
Adequate statistical analyses		1	2			1	1		2		2