To fascilitate regeneration of currently intractable large bone defects, stem cell therapy has emerged as a possible solution. Bone marrow injection, in a sense, represents a primitive form of stem cell therapy. The method had been used to treat long-bone  defects and enhance fracture repair prior to establishment of the concept of stem cells. However, because various cells are present in bone marrow aspirate, a small proportion of which are stem cells, it cannot be truly categorised as a stem cell therapy.