THE USE OF A CORAL COMPOSITE IMPLANT CONTAINING BONE MORPHOGENETIC PROTEIN TO REPAIR A SEGMENTAL TIBIAL DEFECT IN SHEEP

A composite implant consisting of a coral cylinder, moose bone morphog enetic protein and type IV collagen tvas used to repair a segmental ti bial defect in sheep. Healing, related variance in mechanical strength and immune responses were evaluated. In comparison with a coral contr ol, a larger amount of newly formed external callus was observed in th e composite group at 6 weeks. The maximal torque capacity, maximal ang ular deformation at failure and bone stiffness of a healed osteotomise d tibia recovered 113%, 117% and 120% in the coral controls and 67%, 9 2% and 79% in the composite implants against the corresponding contral ateral tibia at 16 weeks respectively. A significantly elevated anti-B MP antibody was detectable in the composite group at 3 and 6 weeks, Au gmented bone formation at art early stage and weakened torsional perfo rmance at a later stage in the composite implants may indicate the pha se-specific osteoinduction and the immune response of xenogenic BMP wi th time.