title: The use of bone-graft substitutes in large bone defects: any specific needs?
abstract: BACKGROUND
  The gold standard for restoring bone defects is still considered to be autologous bone grafting. However, clinical benefits are not guaranteed and donor-site complications and morbidity is not infrequent. Research is on-going for the development of alternative bone substitutes of both biological and synthetic origin. The purpose of this study was to evaluate the type of materials used and their efficacy for the treatment of large bone defects in traumatology and orthopaedic surgery.
  
  
  METHODS
  A literature review was carried out of Embase and PubMed databases. Inclusion criteria were articles in English language focusing on the use of bone substitutes in trauma and orthopaedic surgery for the treatment of bone defects and included details on the structural, biological or biomechanical properties of the pure product. Furthermore, based on two clinical challenges, fracture non-union and impaction grafting we elaborated on the use of polytherapy for large bone defects as guided by the diamond concept.
  
  
  RESULTS
  All the products indicated in this manuscript possess osteoconductive activities but have different resorption times and biomechanical properties. Bone graft substitute materials are used for a wide range of clinical applications even when the level of clinical evidence is low. The size and location of the defect and the local biological and mechanical environment as well as the biomechanical characteristics of the material determine the type of device that can be implanted in a bone defect.
  
  
  CONCLUSIONS
  Proper assessment of the biological and mechanical environment and accurate patient selection are necessary to judge the extent of therapy the injury warrants. A sound understanding of various aspects of biomaterial properties and their relation and influence towards bone healing is of utmost importance. We suggest the application of polytherapy for the treatment of large bone defects and advocate the use of the diamond concept as a guideline.
authors.affiliation: COR, Orthopaedic Institute, G Pini, University of Milan, Italy. gmc@studiocalori.it
authors.forename: G M
authors.initials: GM
authors.lastname: Calori
authors.forename: E
authors.initials: E
authors.lastname: Mazza
authors.forename: M
authors.initials: M
authors.lastname: Colombo
authors.forename: C
authors.initials: C
authors.lastname: Ripamonti
mesh_terms: D000042:Absorption; D000328:Adult; D001843:Bone Cements / Q000627:therapeutic use; D001857:Bone Matrix / Q000502:physiology; D019485:Bone Morphogenetic Proteins / Q000627:therapeutic use; D001861:Bone Regeneration / Q000502:physiology*; D018786:Bone Substitutes / Q000737:chemistry / Q000627:therapeutic use*; D016025:Bone Transplantation / Q000379:methods*; D002130:Calcium Phosphates / Q000737:chemistry / Q000627:therapeutic use; D002133:Calcium Sulfate / Q000627:therapeutic use; D002516:Ceramics / Q000627:therapeutic use; D019245:Compressive Strength; D017102:Fracture Healing / Q000502:physiology; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D008297:Male; D016062:Porosity; D054457:Tissue Scaffolds; D014182:Transplantation, Autologous; D014184:Transplantation, Homologous / Q000295:instrumentation; D016896:Treatment Outcome
chemical_list: D001843:Bone Cements; D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D002130:Calcium Phosphates; D002133:Calcium Sulfate