Studies of the healing of bone grafts, and the incorporation of titanium implants in grafted bone: an experimental animal model

An insufficient quality and amount of bone often necessitate the clinical use of implants together with bone transplants. The present study describes an experimental animal model for the study of implants in bone grafts. Circular defects were made bilaterally in the tibia of 36 rabbits. The defects received either autologous cortical bone (control), demineralized bone matrix (DBM), plasma-augmented DBM or were left empty (without bone graft). In all defects a titanium implant was centrally placed and anchored in the opposite cortex. Evaluation with light microscopic morphometry showed that the insertion of a threaded titanium implant centrally in a cortical defect was followed by a spontaneous healing of the defect after 6 mon. After 6 wk, all implants in cortical grafts were well integrated with a significantly higher bone-to-implant contact than in the DBM and plasma-augmented groups. After 6 mon, all experimental groups had a mean bone area within the threads ranging between 69% and 80% and a mean bone-to-implant contact between 31% and 42%. The results from the present study indicate that the model allows comparative studies on the early formation, resorption and remodelling of bone around implants after modification of implant, graft and host properties.