Predictive factors for vascularized iliac bone graft for nontraumatic osteonecrosis of the femoral head.

We reviewed the results of 35 operations performed on 29 patients with osteonecrosis of the femoral head in which a pedicle iliac bone was utilized. The average age was 35 years (17-62). There were 28 patients of stage 2 and 7 of stage 3; there were 17 type C-1 hips and 18 type C-2 hips. The pedicle bone was inserted in the anterolateral direction of the femoral head. The average follow-up period was 8 years and 7 months. Collapse of the femoral head occurred in 19 hip joints. Although 16 of 28 stage 2 hips showed collapse, all 7 stage 3 hips resulted in collapse. Thirteen of 17 hips did not show collapse in patients with type C-1 necrosis, whereas 15 of 18 hips developed collapse in patients with type C-2 necrosis. When the bone graft was inserted in the anterolateral direction of the femoral head, incidence of collapse was reduced. These results indicate that deep circumflex iliac pedicle bone graft may be indicated for stage 2 type C-1 necrosis, and that the penetration of the graft into the anterolateral aspect of the lesion is essential for the procedure to succeed.