Coral grafting supplemented with bone marrow

Limited success in regenerating large bone defects has been achieved by bri dging them with osteoconductive materials. These substitutes lack the osteo genic and osteoinductive properties of bone autograft, A direct approach wo uld be to stimulate osteogenesis in these biomaterials by the addition of f resh bone-marrow cells (BMC). We therefore created osteoperiosteal gaps 2 cm wide in the ulna of adult ra bbits and either bridged them with coral alone (CC), coral supplemented wit h BMC, or left them empty, Coral was chosen as a scaffold because of its go od biocompatibility and resorbability, In osteoperiosteal gaps bridged with coral only, the coral was invaded chiefly by fibrous tissue. It was insuff icient to produce union after two months. In defects filled with coral and BMC an increase in osteogenesis was observed and the bone surface area was significantly higher compared with defects filled with coral alone. Bony un ion occurred in six out of six defects filled with coral and BMC after two months. An increase in the resorption of coral was also observed, suggestin g that resorbing cells or their progenitors were present in bone marrow and survived the grafting procedure. Our findings have shown that supplementat ion of coral with BMC increased both the resorption of material and osteoge nesis in defects of a clinical significance.