RESUMO
BACKGROUND: Anterior and lateral columns of the femoral head integrity and stability have been reported to present a positive correlation with the prognosis of the osteonecrosis of the femoral head (ONFH) and efficacy of hip preserving. China-Japan Friendship Hospital Classification stressed that the retention of the anterior and lateral columns of the femoral head was of great importance to avoid the femoral head collapse, but there is little reported on its three-dimensional (3D) digital model.OBJECTIVE: To explore the method of establishing highly-simulated 3D model of China-Japan Friendship Hospital Classification for ONFH.METHODS: 3D reconstruction of normal and necrotic femoral head was established according to the CT and MRI of individuals with normal femoral head. A healthy adult male volunteer was selected and his CT image was collected; three adult male patients with types L1, L2 and L3 ONFH were selected, whose MRI images were obtained, respectively. 3D solid models were established based on CT and MRI data on Mimics 15.0, Geomagic Studio 13, Geomagic Design X, Solidworks2014 and Abauqus6.14 software. RESULTS AND CONCLUSION: A highly-simulated 3D model of L type ONFH was established, including the corticaland cancellous bones of ilium and proximal femur, articular cartilage, necrotic articular cartilage, muscles, joint capsuleand ligaments. It clearly showed the spatial structures of L type ONFH, by which different surgical programs could be compared in a virtual environment for selecting an appropriate treatment strategy to improve the success rate of hip preserving. The highly-simulated 3D model paves ways for surgical simulation and biomechanical analysis.