Non-union and avascular necrosis of the femoral head are the main complications of fractures of the femoral neck. Treatment in young adults is very difficult as arthroplasty is not indicated. A technique is described using a free vascularized fibular graft to promote healing and to prevent osteonecrosis, combined with valgus subtrochanteric osteotomy to convert shearing forces into compression and to correct leg-length discrepancy. Material-Methods: Seven patients with non-united femoral neck fracture were treated by valgus osteotomy and free vascularized fibular graft. There were four males and three females, with a mean age of 27.2 years (16 to 39). Six of them sustained a femoral neck fracture in a motor vehicle accident and initially underwent fixation with Steinmann pins or cannulated screws. One sustained a pathologic fracture due to an aneurysmal bone cyst of the femoral head and neck. The mean delay between injury and reoperation was 8 months (range 2 – 16 months). All patients presented some degree of absorption of the femoral neck and avascular necrosis of the femoral head at various stages. To secure the osteotomy in its altered position, a 120 - 150 degrees blade-plate was used. The amount of valgus angulation varied from 20 degrees to 30 degrees. A derotation screw was placed proximal to the vascularized graft. Results: There were no intraoperative complications. One patient underwent a second operation (removal of the implants) 26 months after the osteotomy. Osseous union was achieved and there was clinical and radiological improvement of the avascular necrosis in all patients. Discussion: We recommend this procedure for the treatment of young adults with difficult intracapsular fractures of the femoral neck complicated with non-union, avascular necrosis, resorption of the neck and leg shortening.