Comparing different methods for 3D modelling/reconstruction/reconfiguration of anatomical structures in orthopaedic surgery

Nowadays many Computer Assisted Surgery (CAS) systems help orthopaedic surgeons both for intervention planning and during the surgical activities. For these systems is crucial to have at disposal the 3D models of the anatomical structures, together with the ones representing the surgical tools and the prostheses, if present. This paper classifies the methods for the generation of the 3D models in three different sets: modelling methods, reconstruction methods, and reconfiguration methods. Modelling methods generate a 3D model starting from scratch without the use of specific patient’s data; the result is a parametric model and the parameter table constitutes the interface to customize it easily for each patient; reconstruction methods use a specific patient’s data and the result is a static, non-customizable model. Finally, reconfiguration methods customize an existing 3D model using the patient’s data. Three methods appeared the most interesting from the point of view of this specific research: Parametric Solid Modelling/Reconfiguration (PSMR), Global Shape Modelling (GSM), and Free-Form Deformation (FFD). The paper describes six tests and compares them using some indicators like the quality of the results, the critical aspects of the process, and the usability. This comparison indicates that the FFD method is the best one, both in the implementation tested during this research and for what concerns possible future work.