The role of stem cells in fracture healing and nonunion

Abstract

Nonunion and large bone defects present a therapeutic challenge to the surgeon and are often associated with significant morbidity. These defects are expensive to both the health care system and society. However, several surgical procedures have been developed to maximise patient satisfaction and minimise health-care-associated and socioeconomic costs. Integrating recent evidence into the diamond concept leads to one simple conclusion that not only provides us with answers to the "open questions" but also simplifies our entire understanding of bone healing. It has been shown that a combination of neo-osteogenesis and neovascularisation will restore tissue deficits, and that the optimal approach includes a biomaterial scaffold, cell biology techniques, a growth factor and optimisation of the mechanical environment. Further prospective, controlled, randomised clinical studies will determine the effectiveness and economic benefits of treatment with mesenchymal stem cells, not in comparison to other conventional surgical approaches but in direct conjunction with them.

Fig. 1

A 5-cm tibial defect following debridement in an infected nonunion

Fig. 2

a Anteroposterior radiograph of a right subtrochanteric femoral nonunion with a broken nail in situ 6 months following fixation. b Using the reamer/irrigator/aspirator (RIA) reamers, autologous graft was harvested from the left femoral canal. c Bone marrow aspirate was harvested from the left iliac crest. d Bone morphogenetic protein−7 (BMP-7) was prepared for implantation following dilution with 2 ml of sterile normal saline. e RIA graft was mixed with the concentrated bone marrow aspirate. f Nonunion was stabilised with a blade. The RIA graft mixed with the bone marrow aspirate and the BMP-7 was implanted at the site of the nonunion (white arrow). g Nonunion site (white arrow) was filled with the graft material. h, i Anteroposterior and lateral radiographs of the right femur 4 months after the operation illustrating healing of the previous nonunion