Optimizing free fibular grafting in femoral head osteonecrosis: the Ioannina aiming device

The extracapsular placement of a vascularized fibular graft in the subchondral region of the femoral head now is a widely accepted method for treating patients with osteonecrosis of the femoral head. The effectiveness of the fibular graft seems to be dependent on precise placement in a biologically and anatomically relevant site within the femoral head. The current authors present the Ioannina technique for application of a new computer-aided design and computer-aided manufacturing process in the treatment of osteonecrosis of the femoral head using free vascularized fibular transplantation. The objective was to develop a computer-assisted design and manufacturing system for an accurate and easier approach to the necrotic area in the femoral head. The Ioannina technique uses serial computed tomography scans of the proximal femur to identify the configuration of the proximal femur, and the size, location, and configuration of the lesion using a computer-aided design and computer-aided manufacturing process. Optimal graft placement is determined and a guide wire canal is drilled into an patient-specific aiming device. In this process, identification of the optimal graft location is related to achieving that location surgically. The more arbitrary placement of the graft during conventional fibular graft surgery leads to accurate graft placement in only 55% of the patients, whereas the use of the patient-specific Ioannina aiming device resulted in optimal graft placement in 89% of the patients.