Failure of free vascularized fibular graft for osteonecrosis of the femoral head - A histopathologic study of 6 cases

The rationale for the use of free vascularized fibular graft for osteonecrosis of the hip is based on the assumption that the graft will provide support and blood supply to the osteonecrotic head. We report the histopathologic features of 6 consecutive osteonecrotic heads with failed vascularized fibular grafts. Three grafts were partially viable, and 3 were necrotic. The medullary canal was completely necrotic in 4 grafts. A thin layer of new, viable periosteal bone and bone remodeling was present at the surface of 4 grafts. New bone applied to the surface of the graft, especially in the 3 necrotic ones, suggests that the new bone originated from the host bed and not from the graft. Therefore, the risks and benefits of the vascular anastomosis, which in these cases provided no viability to the graft, should be re-evaluated. These findings were observed in failed cases and cannot be extrapolated to successful ones.