A parametric approach to construct femur models and their fixation plates

Although anatomic plates reflect an important breakthrough in the treatment of distal femur fractures, there are still some patients experiencing healing complications. For individual differences in bone morphology and fractures, the development of patient specific plates is very complex and needs a long cycle. In this study, a parametric approach was proposed to conveniently construct femur models and design their fixation plates. First, the typical femur anatomy was described with the average femur model. Second, five surface features were defined to represent the femur surface model by setting up parameterization and parameter constraints. Third, according to the fracture information of a specific patient, customized plate surface with a suitable contour was created from the reconstructed femur model. Finally, the femur plate was represented by feature parameterization, and the hierarchical constraints between femur parameters and plate parameters were built to construct a plate model. The experimental results showed that the proposed method could effectively represent femur surface shape features and intuitively construct and edit individualized plates with high-level parameters. The method is competitive in time saving and design convenience and may provide a basic tool for digital restoration of incomplete femurs and the design of patient specific femur plates.