Table 1

Methodological quality and risk of bias were assessed using the 12-point Methodological Items for Nonrandomized Studies (MINORS) scale.^a

Study	Stated Aims	Consecutive Patients	Prospective Data Collection	End Points Appropriate to the Aims	Unbiased End Point Assessment	Appropriate Follow-up Period	<5% Loss to Follow-up	Study Size Calculation	Adequate Control Group	Contemporary Group	Baseline Equivalence Group	Statistical Analysis	Total Score
Abe 2000	1	2	0	1	0	2	2	0	0	0	0	1	9
Boriani 2000	2	2	0	2	0	2	2	0	1	1	1	0	13
Melcher 2007	1	2	0	2	0	2	2	0	0	0	0	2	11
Kawahara 2010	2	2	0	2	0	2	2	0	0	0	0	0	10
Liljenqvist 2010	1	2	0	2	2	2	2	0	0	0	0	0	11
Martin 2010	1	2	0	2	0	2	2	0	0	0	0	0	9
Disch 2011	1	2	2	0	2	0	2	2	0	0	0	0	12
Boriani 2012	2	2	0	1	0	2	2	0	0	0	0	1	9
Huang 2018	2	2	0	2	0	2	2	0	0	0	0	1	11
Xiong 2018	2	2	0	2	0	2	2	0	0	0	0	1	11
Shimuzu 2018	2	2	0	2	0	2	2	0	0	0	0	1	11
Yang 2019	2	2	0	2	0	2	2	0	0	0	0	1	11
											Average score		11
											Average score		11