In vivo osteointegration of three-dimensional crosslinked gelatin-coated hydroxyapatite foams

The main requirement of bone regenerative scaffolds is to enhance the chemical reactions leading to the formation of new bone while providing a proper surface for tissue in-growth as well as a suitable degradation rate. Calcium phosphate ceramics are conformed by different shaping methods. One requirement is to design implants and scaffolds with suitable shapes and sizes, but also with interconnected porosity to ensure bone oxygenation and angiogenesis. In this work we present the in vivo performance of hierarchically arranged glutaraldehyde crosslinked, gelatin-coated nanocrystalline hydroxyapatite (HABP) scaffolds (1-400 mu m), with high potential as bone regenerators and excellent osteointegration performance, as well as an appropriate bioresorption rate. 6 x 10 mm bone defects were made in the lateral aspect of both distal femoral epiphysis of 15 mature (9 months old) male New Zealand rabbits. The bone defect in the left femur was then filled by using HABP foam cylinders, allowing the surgeon to carve the appropriate shape for a particular bone defect with high stability intra-operatively. The foam becomes swollen with body fluid and fills the cavity, ensuring good fixation without the need for a cement. Histological and radiographical studies after 4 months implantation showed healing of all treated bone defects, with bone integration of the HABP foam cylinders and bone conduction over the surface. This in vivo behaviour offers promising results as a scaffold for clinical applications, mainly in orthopaedics and dentistry. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.