Engineering Bone: Challenges and Obstacles in 2017

Repair of large bone defects is a challenge for the orthopaedic surgeon. In these complex clinical conditions, the autologous bone grafts are the benchmarks as they are osteoconductive (they provide a scaffold on which bone cells can proliferate), osteoinductive (they induce proliferation of undifferentiated cells and their differentiation into osteoblasts), and osteogenic (they provide a reservoir of skeletal stem and progenitor cells that can form new bone). However, autologous bone grafting adds significant morbidity to the surgical procedure. These disadvantages have prompted an ongoing search for alternative methods including the use of banked bone, synthetic or natural bone substitutes, bone morphogenetic proteins and osteocompetent cells. In this review, we delineate, from an engineering perspective, the progress that has been made to date and the challenges remaining in using or in successfully translating these approaches to the clinics.