The surgical procedure. (A) the 4 cm long rib together with periosteum defect was created. (B) the preparation of DBMs/BMSCs and PDO cage. (C) The DBMs/BMSCs were put into the PDO cage. (D) The 6cm-long PDO cage containing two 2cm-long BMSCs/DBMs was then fit into the defect with the ends of the cage overlapping the cortex at both ends of the rib by 10 mm.