Growth factors in bone repair.

The role of growth factors (GF) in bone repair is widely recognised, particularly for bone morphogenetic proteins (BMPs), fibroblast growth factor (FGF), insulin-like growth factors (IGFs), platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-beta) and vascular endothelial growth factor (VEGF). GF are usually stored in the extracellular matrix (ECM), but after injury are actively released by ECM, cells and platelets. In this paper, the use of different recombinant GF for bone repair stimulation is summarised in experimental research and clinical applications. Drug delivery systems, including carriers, cell or gene therapy, are needed to ensure a sustained local release of the factors, but efficacy and potential side effects of such systems require additional research prior to clinical applications. Current sources for delivery of a GF mixture into the site of bone repair are platelet gel and demineralised bone matrix. Nevertheless, the levels of GF in such preparations are affected by variability among donors and differences in preparation. Autogenous GF, produced by the patient himself during the bone repair process, potentially interfere with prosthetic devices or even have a role in implant loosening due to the periprosthetic tissue reaction. In conclusion, GF are key components of functional bone regeneration: screening of basic research results and controlled clinical trials are accelerating the development of GF in orthopaedic surgery.