Role of free vascularized bone grafts in the experimentally-induced ischemic necrosis of the femoral head.

In 15 mongrel adult dogs, an ischemic necrosis of the femoral head was produced, following the technique described by Gartsman and colleagues. Five weeks later, a 6- to 8-cm long rib graft was harvested with its vascular bundle and transferred into the previously induced ischemic femoral head. Microsurgical anastomoses were performed for revascularizing the rib graft. Dogs were studied using scintigraphy, blood flow measurements, roentgenograms, angiograms, and histology at four, eight and 12 weeks after grafting. New bone and vascular formation was exhibited throughout the study, as demonstrated by a highly positive scintigraphic activity and the formation of numerous arterial terminal branches arising from the rib graft circulation which entered the femoral head and reached the subchondral plate. The formerly necrotic femoral head bone exhibited osteoblastic activity, viable osteocytes, and well-populated bone marrow. The rib graft was also incorporated into the femoral head. These results suggest that a vascularized bone graft is able to repair a femoral head necrosis, and may be considered a rational approach for clinical purposes.