Previously, to create an implantable bone tissue associated with blood vessels, we co-cultured rabbit bone marrow mesenchymal stem cells (MSCs) with MSC-derived endothelial cells (ECs) within a porous polylactic acid-based scaffold utilizing a rotating wall vessel (RWV) bioreactor. Here, this engineered tissue was orthotopically implanted into defects made in femurs of immunodeficient rats, and histological analysis were carried out to examine the repair of the damage and the formation of bone around the implant. The bone defects were better repaired in the implanted group than control group after 3 weeks. The results indicate that the engineered bone could repair bone defects. (c) 2012 Elsevier B. V. All rights reserved.