Patient-Specific Customization of a Generic Femur Model Using Orthogonal 2D Radiographs

Visualization of the patient-specific fractured bone in three dimensions (3D) plays an important role in image guided orthopedic surgery. Existing research often focuses on intra-operative registration of the patientspsila anatomy with pre-operatively obtained 3D volumetric data (e.g. CT scans) utilizing fiduciary markers. This expensive and invasive approach is not routinely available for diagnostics, and a majority of fracture reduction procedures currently solely relies on two dimensional (2D) x-ray/fluoroscopic images. This paper presents a new concept for the construction of a 3D model of a fractured human femur that eliminates the need to have the preoperative CT scan of the patientpsilas injured anatomy. It is based on two conventional orthogonal (in anterior and lateral views) 2D radiographic images and a supporting database of 3D intact (healthy) femurs. A search over the database initially finds the closest match to the patientpsilas femur. This best match is then customized through a non-rigid registration to the shape of the patientpsilas femur. Once the customization is complete a novel 2D-3D registration process separates the bone into the proximal and distal segments and identifies the pose (position and orientation) of each fragment.