NEOCHONDROGENESIS FOR ARTICULAR BONE-CARTILAGE DEFECT: The use of free periosteal graft, porous metal mould and continuous passive motion in a rabbit model

Abstract

Full thickness articular bone-cartilage defects were created in the acetabulae of 35 adult rabbits. A double-layered titanium mesh was used in each hip so as to substitute for the bone defect. Free periosteal grafting was then sutured over the mesh, and the hip was subjected to continuous passive motion for 1 week in each rabbit. Under light microscopy, islands of chondroid tissues were shown to be present from 2 weeks onwards, and the dominant reparative tissue was hyaline-like cartilage after 6 months. The normal degree of metachromasia of the matrix by Safranin-0 staining was achieved in most but not all the specimens that were hyaline-like under the microscope. Analysis of the collagen types synthesised by the grafts revealed a combination of both type II and type I collagens. Immunohistochemical staining showed intense positive staining around the chondrocyte lacunae when stained with anti-type II collagen antibodies with the one-year group of rabbits. Although metachromasia of the matrix and collagen typing suggested that fibrocartilage was formed in addition to the hyaline cartilage, the gross appearance and nature of reparative tissues formed were quite promising. Periosteal grafting over a metallic, non-biological surface that provided the shape of the osseous defect in a massive articular defect was therefore a possible alternative.