Histopathological and imageological studies on clinical outcomes of mineralized collagen reconstruction rod for femoral head necrosis with one case report

: In this article, the biodegradation process and bone formation of a mineralized collagen reconstruction rod embedding in necrosis of human femoral head were investigated by imageological and histological methods. Computed radiography (CR) computerized tomography (CT), common pathological section and hard tissue section analysis were used to evaluated the dynamics of imageological and histopathological changes of femoral head, interface between the host bone and implant and the bone reconstruction process. The results showed that the density of rods increased closed to that of host bones after 1 year implanting, and the interface between them turns to blurring. Hard tissue grinding sections analysis showed osteocytes appearing in sparse bone trabecular and bone pit region, as well as a few vessels in the degraded dye powder matrix were noticed, indicating the new bone forming between the implants and host bones. Regular decalcified sections analysis showed scattered osteoclasts, multinucleated giant cells and fibrosis components existing in the degraded rod and the host bone trabecular. Degraded debris was endocytosed by giant cells, and vascular network formed around the boundaries of the implanted rod. The good osteointegration has been expressed by the interface between the implanted rod and the host bone becoming blurred. Histological results indicated that the implanted rod degradation process and new bones regeneration simultaneously occurred around the boundaries of embedding rod. New bone and host bone were hinged and co-existed.