“…Ectopic bone formation was investigated in six studies using subcutaneous implantation in the back of animals or by muscular implantation (e.g., leg muscles) ( Table 2 ) ( Maire et al, 2005a ; Degat et al, 2009 ; Hayashi et al, 2009 ; Fricain et al, 2013 ; Chen et al, 2019 ; Yu et al, 2020 ). Orthotopic implantations were mainly performed on maxillofacial defects and long bone defects ( Tables 3 , 4 , 5 ) ( Lafont et al, 2004 ; Chen et al, 2005 ; Chen et al, 2006 ; Chen et al, 2007 ; Hayashi et al, 2009 ; Abbah et al, 2012 ; Fujioka-Kobayashi et al, 2012 ; Miyahara et al, 2012 ; Fricain et al, 2013 ; Bölgen et al, 2014 ; Schlaubitz et al, 2014 ; Takahata et al, 2015 ; Togami et al, 2015 ; Frasca et al, 2017 ; Ribot et al, 2017 ; Charoenlarp et al, 2018 ; Fricain et al, 2018 ; Ritz et al, 2018 ; Ding et al, 2019 ; Fang et al, 2019 ; Popescu et al, 2020 ; Shoji et al, 2020 ; Maurel et al, 2021 ; Wang et al, 2021 ). Nine studies investigated calvarial defects, six studies focused on mandibular or maxillary defects (e.g., periodontal, sinus bone augmentation), whereas 10 studies were performed on femoral defects (e.g., condyle, epiphysis, metaphysis), one study on ulnar defect and one study on tibial defect.…”