Table 4.

Type of analysis performed in the meta-analyses summarized in Table S2 in which treatment of primary knee osteoarthritis with stem cells was investigated.

C	N	Description
1	12	Meta-analysis of studies in which treatment of pkOA with stem cells was compared with placebo treatment (or studies in which treatment of pkOA with stem cells plus concomitant therapy was compared with the concomitant therapy alone, respectively).
2	4	Meta-analysis in which only endpoints of the same patients before and after treatment were compared.
3	3	Network meta-analysis that included only a small number of studies on the treatment of pkOA with stem cells and a much higher number of studies on the treatment of pkOA without stem cells.
Sum	19

Abbreviations: C, category; N, number of meta-analyses; i.a., intra-articular; pkOA, primary knee osteoarthritis; PRP, platelet rich plasma; CS, corticosteroid; and HA, hyaluronic acid.