Immune System and Bone Regeneration.

Kenneth A. Johnson bone, resulting in delayed or non-union is a vexing clinical problem in all species of animals. Recently, the focus of attention in orthopaedics has been on the treatment of fractures by bone grafts, mesenchymal stem cells, growth factors, biomaterials and improved mechanical environment, either alone or in some combination. These therapies have produced clearly demonstrable benefits in treating delayed and non-union. However there is still much to learn about the complex processes of fracture healing, and why it fails in some patients despite the management by ‘state of the art’ surgery employing, for example, minimally invasive osteosynthesis, locking implants, exogenous growth factor application, and 3D printed biomaterials and stem cells for the reconstruction of critical sized defects. Even so, in a proportion of fracture patients, endogenous factors predispose to impaired fracture healing. The pivotal role of immunity in fracture healing and bone regeneration was one such endogenous factor under discussion at the symposium. The immune system has direct involvement in guiding all stages of fracture healing starting with inflamImmune System and Bone Regeneration