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Bone Grafting When a section of the bone has died, as is the case in ON, for some reason it doesn’t seem to heal. One of the ways that can cause the bone to heal is to surgically remove the dead bone and fill the empty space with bone graft that is either taken from the patient or from the bone bank. The success of this approach depends upon the quantity of bone that has died. Another problem is that during the healing process, which can be very long (6-12 months) the patient must be on weight-bearing restriction.
Vascularized Bone Grafting Regular bone graft, whether from the bone bank or from the patient is itself dead bone. It serves as a scaffold for the body to build new bone around but the body also has to grow a new blood supply. For this procedure, a bone with its blood vessels is taken from the patient and hooked up to blood vessels near the hip. The dead bone is removed from the femoral head and replaced with the grafted bone that carries with it its own blood supply. The advantage of this approach is that the body doesn't have to rebuild a new blood supply and the bone graft retains its physical and mechanical properties.
Healing and complete filling of the defect still has to take place, during which time crutches or a walker has to be used. The disadvantage also is that a substantial piece of bone has to be taken from the lower leg (the fibula, the smaller bone of the lower leg below the knee). Some patients will develop symptoms in the area from which the bone graft is taken. The operation also takes several hours and requires a team experienced in these techniques.
Osteotomy Usually it is the main weight-bearing area of the bone that is involved with ON. In some cases the bone can be cut below the area of involvement and rotated or turned so that another portion tion of the bone that is not involved in the ON can become the new weight-bearing area (fig. ). These operations are not very common anymore, but may apply to special cases.
Femoral Head Resurfacing Initially only the femoral head is involved, not the socket of the hip joint. FHR involves implanting a metal hemisphere over the femoral head, which exactly matches the size of the original femoral head. This is similar to capping a tooth when the root is still good, as opposed to pulling the tooth and putting in a false tooth. It is known that over a period of many years, the metal head will gradually replacement. This procedure is designed to "buy time" for the younger individual whose extent of disease or degree of progression is such that one of the preservative procedures listed above cannot be performed. Most patients with ON are under 50. It is generally believed that total hip replacement today will not last the 30+ most of these patients will require. Therefore, if 2 procedures are likely to be necessary, it is important that the first procedure does not make the second procedure more difficult or less likely to succeed. A THR following a failed femoral head resurfacing is more likely to be successful than revision THR that follows a failed primary THR.