Major bone defect treatment with an osteoconductive bone substitute.

A bone defect can be provoked by several pathological conditions (e.g. bone tumours, infections, major trauma with bone stock loss) or by surgical procedures, required for the appropriate treatment. Surgical techniques currently used for treating bone defects may count on different alternatives, including autologous vascularized bone grafts, homologous bone graft provided by musculoskeletal tissue bank, heterologous bone graft (xenograft), or prostheses, each one of them dealing with both specific advantages and complications and drawbacks. The main concerns related to these techniques respectively are: donor site morbidity and limited available amount; possible immune response and viral transmission; possible animal-derived pathogen transmission and risk of immunogenic rejection; high invasiveness and surgery-related systemic risks, long post-operative. physical recovery and prostheses revision need. Nowadays, an ideal alternative is the use of osteoconductive synthetic bone substitutes. Many synthetic substitutes are available, used either alone or in combination with other bone graft. Synthetic bone graft materials available as alternatives to autogeneous bone include calcium sulphates, special glass ceramics (bioactive glasses) and calcium phosphates (calcium hydroxyapatite, HA; tricalcium phosphate, TCP; and biphasic calcium phosphate, BCP). These materials differ in composition and physical properties fro each other and from bone (De Groot in Bioceramics of calcium phosphate, pp 100-114, 1983; Hench in J Am Ceram Soc 74:1487-1510, 1994; Jarcho in Clin Orthop 157:259-278, 1981; Daculsi et al. in Int Rev Cytol 172:129-191, 1996). Both stoichiometric and non-stoichiometric HA-based substitutes represent the current first choice in orthopedic surgery, in that they provide an osteoconductive scaffold to which chemotactic, circulating proteins and cells (e.g. mesenchymal stem cells, osteoinductive growth factors) can migrate and adhere, and within which progenitor cells can differentiate into functioning osteoblasts (Szpalski and Gunzburg in Orthopedics 25S:601-609, 2002). Indeed, HA may be extemporarily combined either with whole autologous bone marrow or PRP (platelet rich plasma) gel inside surgical theatre in order to favour and accelerate bone regeneration. A case of bifocal ulnar bone defect treated with stoichiometric HA-based bone substitute combined with PRP is reported in here, with a 12-month-radiographic follow-up.