Free Vascularized Fibular Graft
Free vascularized fibular graft is an operation that can reestablish blood flow to the femoral head. In osteonecrosis (aka avascular necrosis or AVN) the blood flow to the femoral head is impaired. The bone dies. Sometimes blood flow is reestablished and it heals spontaneously. If blood flow remains cut off, the dead bone eventually dies and the head collapses. This is stage 3 osteonecrosis. At this point hip replacement is the only effective treatment.
The femoral head is by far the most common bone in the body to develop osteonecrosis. It is most often caused by excess alcohol consumption, prolonged high dose steroid use (prednisone type, not muscle building steroids), major hip trauma (fracture or dislocation, not a hard fall on the hip) or sickle cell disease. Exactly why these cause necrosis is not known. Clearly, there is some individual susceptibility because only a small percentage of patients exposed to alcohol and steroids get osteonecrosis. About 1/3 of cases do not have any associated risk factors and are labeled “idiopathic”.
In the earlier stages, before collapse, there are often mild symptoms. There are several operations that have been promoted to induce new blood flow to the femoral head in order to heal it before it collapses. The only one that I believe is effective is the free vascularized fibular graft. It is a complicated operation that only a few surgeons routinely perform.
The fibula is a small bone in the leg that is removed together with its blood supply. The bone is inserted through a large hole drilled through the femoral neck into the femoral head. The blood vessels are re-connected to new vessels near the hip. New blood flow is now brought directly in contact with the dead bone in the femoral head. When this operation is done prior to head collapse, the dead bone can heal and the hip joint is preserved in 95% of cases. If the head is already collapsed there is no point to this operation because the joint cartilage has already lost its support and will always fail.
The problems with this operation are complexity, long recovery, and donor site morbidity. This is a long and complicated operation that requires multiple surgeons and is very expensive. Patients are usually required to stay on crutches for months after the operation. It is relatively safe to remove a 3-4 inch section of fibula from just above the ankle, because the larger tibia can take the load. But some residual leg or ankle pain may be present permanently. Also clawing of the toes may result as a complication of removing the fibula. In stage 1 and 2 of necrosis in a young patient I think it is worthwhile to consider this option.