“…In this regard, human synovium‐derived stem cells (hSSCs) have been identified as a good cell source based on their superior potential for chondrogenesis and proliferation compared with other adult stem cells in vitro (Sakaguchi, Sekiya, Yagishita, & Muneta, ). We have been developing several strategies for cartilage repair using hSSCs in vivo (Shimomura et al, ; Yasui, Ando, et al, ) and, moreover, have shown successful formation of cartilage‐like tissue from hSSCs in vitro (Chijimatsu et al, ; Koizumi et al, ; Yasui, Chijimatsu, et al, ). Although it will be potential alternatives for ACI, the cost to induce chondrogenesis using growth factors is not a negligible issue for clinical applications.…”