Biological and pharmacological factors influencing the fracture healing.

Many experimental data are available about the positive effect of some molecules on fracture repair, but data on their efficacy in the clinical use in humans are still lacking. Bone Morphogenetic Proteins are currently used in the treatment of delayed unions, but it is necessary to insert them surgically in the fracture site. The only pharmacological factor with clinical data is teriparatide, but more data are needed to confirm its effect on fracture healing in humans, even if experimental data in animals are robust. Data are also available on the effect on bone healing of other molecules used in osteoporosis treatments. Bisphosphonates favour the formation of a bigger callus, mechanically competent, but with a slow rate of remodelling. Estrogens and strontium ranelate have some experimental evidence of stimulating healing process. Robust experimental data are also available on an anti-Sost antibody. Anti-inflammatory drugs have a negative effect on bone healing, interfering with the early phases of inflammation. In conclusion more data, experimental and mainly clinical, are advocated to define whether it is possible to enhance bone healing, even if promising molecules, as teriparatide, are already available.