CLINICAL EVALUATION OF BONE CEMENT AND AUTOGENOUS BONE GRAFT IN DOGS

Various biological bone g rafts have been used for osteogenes i s , osteoconduction and even osteoinduction, but due to systemic influences and local factors, the outcome of successful incorporation of a bone graft has not been satisfactory. This study was therefore conducted on 15 clinically healthy adult dogs between 1 to 3 years of age weighing 20 to 30 kg to evaluate the effect of bone cement and autogenous bone grafts. A piece of 3 cm complete mid-shaft right tibial cortical bone was removed in all animals. Then they were subsequently divided into three groups of 5 animals each. In group I the bone was fixed with a suitable intramedullary pin, whereas the gap was filled with harvested autogenous rib bone graft in group II animals. Bone cement was used to fill the gap in animals of group III for the first 30 days, then it was replaced with iliac bone chips and observation was made accordingly for 60 days in all animals of the three groups. After 60 days, before collection of callus samples, there was granulation and fibrocartilage tissue in groups I and II respectively, whereas a thick fibrous capsule or pseudomembrane layer was seen around bone cement on day 30 before removal of cement and on day 60 after replacement by iliac bone graft in group III animals. There were combinations of heavily impacted fibrous a n d fibrocartilagineous tissues with thick bundles of collagen fibers among hypertrophic chondroblasts in histomorphological cross section in group I animals, whereas active sequestra were present in group II animals. Fibrotic capsule, periosteal layer, lacunae, osteoblasts, osteocytes and well formed bone marrow with RBC and adipose tissue were noted in group III animals. It appears that the local reaction induced by bone cement leading to fibrotic capsule formation was quite helpful in delaying iliac bone graft resorption and enhancing osteogenic stimulation as to fill the gap with impacted callus with normal cortical structure. The application of bone cement in gap non:::union:::, crushed bone and fragmental fractures is therefore highly recommended.