Concentrated autologous bone marrow aspirate is not “stem cell” therapy in the repair of nonunions and bone defects

Autogenous bone grafting is the gold standard for replacing large bone defects. Due to limitations in the quantity and quality of harvested bone from the iliac crest, and the potential associated morbidity, the technique of cell grafting has been developed. Autogenous bone marrow aspirate is concentrated (so called BMAC) and delivered locally to the intended site with minimally invasive techniques. However, there are only about 1 in 30,000 Colony Forming Unit-Fibroblast (CFU-F) progenitor cells in unconcentrated iliac crest aspirate. Current techniques for cell concentration only increase these numbers by about 5-fold. Thus, BMAC is not equivalent to “stem cell therapy”.