Table 5.

Criteria used to assess the quality of sub-analyses in the meta-analyses summarized in Table S2 of studies in which treatment of primary knee osteoarthritis with different types of stem cells was investigated.

No.		Na	Nr [%]
1	At least 2 different clinical studies were included.	141	89.8
2	Only clinical studies on pkOA were included.	141	89.8
3	Only clinical studies in which stem cells were applied were included.	155	98.7
4	Only randomized controlled trials were included.	133	84.7
5	Only clinical studies were included in which application of stem cells was compared with placebo treatment or in which application of stem cells plus concomitant therapy (including arthroscopic debridement, high tibial osteotomy, injection of hyaluronic acid, etc.) was compared with the concomitant therapy alone, respectively.	55	35.0
6	Only clinical studies using, respectively, autologous or allogeneic stem cells were included.	64	40.8
7	Only clinical studies in which, respectively, cultured or uncultured cells were applied were included.	133	84.7
8	Clinical studies in which more than 1 dose of stem cells was applied were only considered once in the corresponding meta-analysis.	100	63.7

Abbreviations: N_a and N_r, absolute (NA) and relative (NR) number of sub-analyses that fulfilled the corresponding criterion; No., number of criteria; and pkOA, primary knee osteoarthritis.