Friday, 30 June 2017

Bone Grafting In Posttraumatic Bone Deffects: Case Report and Review of Literature


The management of segmental bone loss remains as an unsolved controversy. Bone defects after traumatic injuries are related to poor functional outcomes and prolonged periods or recuperation. In the management of large bone defects the selection of the adequate bone graft requires a deep acknowledgment of the advantages and disadvantages of each bone substitute available. Autologous bone grafts remain the gold standard to measure all of the available bone substitutes; the ideal bone substitute must provide properties such as osteoconduction, osteoinduction and the osteogenic property, it must also be readily available, provide mechanical support, manageable, biocompatible, provide a sufficient amount of substitute according to the situation and it has to be bioresorbable. We present the case of a patient with a large (>5 cm) diaphiseal defect of the tibia managed with a single, large bone block harvested from the iliac crest and its evolution after a one year follow up.

Bone formation can be defined as the process that results from the coordinated interaction between an appropriate substrate, growth factors and osteogenic cells. Despite the first two cited elements are already available in artificial preparations, the same affirmation cannot be applied to the source of osteogenic cells that can only be found in bone autografts. When assessing the selection between the different available options for bone grafting, autologous bone graft remains the gold standard to compare all others bone substitutes. Autografts usually suffer from less resorption derived from their histocompatibility properties, the presence of viable cells and their osteoconductive and osteoinductive properties. The autografts lack the risk of transmitting infectious diseases and are available at no cost. 

The ideal graft must provide specific properties in the best combination to achieve bone growth, including: osteocon duction which refers to the ability of a graft to provide an adequate environment for bone formation and capillary ingrowth, osteoinduction: the capacity to recruit pluripotent mesenchymal stem cells that differentiate into osteoblasts and chondroblasts, osteogenic property which implies that the graft contains viable osteocytes or precursors. The ideal graft must also be readily available, manageable, provide mechanical support, biocompatible and bioreasorbable. In some situations bone autografts are not available or do not provide a sufficient quantity to fill a large bone voids. Bone substitutes such as demineralized bone matrix, morselized and cancellous allografts ceramics and ceramics composites have osteoconductive properties and in some cases (morselized and cancellous allografts, osteochondral and cortical allografts) can provide mechanical support. They lack the osteogenic property of iliac crest autografts.

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