Therapeutic effect of autologous bone grafting with adjuvant bone morphogenetic protein on long bone nonunion: a systematic review and meta-analysis

Table 2 Methodological quality of the cohort studies according to the NOS

Study	Selection of cohorts	Comparability of cohorts	Assessment of outcome	Total score
Takemoto [10]	☆☆☆	☆	☆☆☆	7
Von Ruden(a) [11]	☆☆☆☆	☆☆	☆☆☆	9
VonRuden(b) [12]	☆☆☆☆	☆☆	☆☆☆	9
Hackl [13]	☆☆☆☆	☆☆	☆☆☆	9
Liu [14]	☆☆☆	☆	☆☆	6

ISSN: 1749-799X