Reverse modelling of human long bones using T-splines-case of tibia

Abstract

Creating a sufficiently accurate digital model of human bone geometry for a specific patient is the starting point for personalized orthopaedic surgical treatment. Such geometrical model of a particular human bone serves as a template for designing personalized bone implant, which can be an endoprostheses, fixator plate or even scaffold. Due to that role, the geometry of a human bone model has to be reusable and modifiable. Otherwise, design of the corresponding personalized implant for a particular human bone is a very difficult task. Modern reverse modelling techniques have greatly accelerated the creation of a bone geometric model. The prevailing modern approach is based on the use of non-uniform rational B-splines. However, recent research shows that the very complex topology of bio-shapes, such as human bones, can be reconstructed more easily using T-Splines. The presented approach of using T-splines in a modelling process allows creation of a bone model with important advantages regarding quality, flexibility and geometric accuracy. The process of reverse modelling starts from the cloud of points gained through computer-tomography images and uses selected referential geometric, i.e. anatomic entities as guiding elements in digital reconstruction of the particular bone geometry.