Abstract
This experimental study evaluated vascular impairment and revascularization in the femoral diaphysis caused by cavity reaming and insertion of a prosthesis. Forty-two rabbits (adult female Japanese white rabbits) were used for this study. Stainless steel wires were inserted into the femoral cavity of the rabbits after reaming. To compare the effects of the canal fill ratio, rabbits were divided into two groups according to the canal fill ratio : group A (n=21), the low canal fill ratio group and group B (n=24), the high canal fill ratio group. Vascular impairment and revascularization processes were examined by microangiography and histopathology. Studies were performed 1, 2, 4, 6, 8, 16, and 32 weeks after surgery. Findings were compared between groups A and B. Reaming and insertion of the wire impaired the nutrient artery. As a recovery reaction, newly formed vessels penetrated the ischemic areas around the wire. Gradually, these vessels penetrated further and formed a network around the wire at 8 weeks in group A and at 16 weeks in group B. Thus, a longer period was required to reestablish the canal blood supply in rabbits of the high canal fill ratio group than in the low canal fill ratio group. Histologically, reaming and insertion of the wire caused extensive avascular necrosis in the bone marrow and the cortex around the wire. Bone marrow repair was almost complete at 8 weeks. However, in the cortex, necrotic tissue persisted 32 weeks after the surgery in both groups. These results suggest a long period is required to revascularize and recover from bone necrosis after insertion of a prosthesis.
